WorldWideScience

Sample records for lst based permafrost

  1. Assessment of urban heat Island for Craiova from satellite-based LST

    Science.gov (United States)

    Udristioiu, Mihaela Tinca; Velea, Liliana; Bojariu, Roxana; Sararu, Silviu Constantin

    2017-12-01

    The urban heat island is defined as an excess of heating in urban areas compared with surrounding rural zones which is illustrated by higher surface and air temperatures in the inner part of the cities. The aim of this study is to identify the UHI effect for Craiova - the largest city in the South-Western part of Romania - and to assess its intensity during summer. To this end, MODIS Land surface temperature (LST) for day and night for summer months (June, July, August), in the interval 2002-2017, as well as yearly Land Cover Type (LCT) data also from MODIS were employed. Furthermore, measurements of air and soil temperature from meteorological station Craiova, available from the National Meteorological Administration database, were used to investigate their relation with LST. The analysis shows that in the urban area of Craiova the long-term summer mean LST is about 4 °C (2 °C), higher than in the rural area during daytime (nighttime). During high temperatures episodes, the mean daytime LST reaches 45-47 °C in the city, while the difference from the rural surrounding area is of 2-3 °C. A high correlation (0.77-0.83) is found between LST and air temperature for all land-use types in the area considered. Both LST and 2m-air temperature time-series manifest an increasing linear tendency over the period considered, being more pronounced during the day.

  2. Development of a Global Evaporative Stress Index Based on Thermal and Microwave LST towards Improved Monitoring of Agricultural Drought

    Science.gov (United States)

    Hain, C.; Anderson, M. C.; Otkin, J.; Holmes, T. R.; Gao, F.

    2017-12-01

    This presentation will describe the development of a global agricultural monitoring tool, with a focus on providing early warning of developing vegetation stress for agricultural decision-makers and stakeholders at relatively high spatial resolution (5-km). The tool is based on remotely sensed estimates of evapotranspiration, retrieved via energy balance principals using observations of land surface temperature. The Evaporative Stress Index (ESI) represents anomalies in the ratio of actual-to-potential ET generated with the ALEXI surface energy balance model. The LST inputs to ESI have been shown to provide early warning information about the development of vegetation stress with stress-elevated canopy temperatures observed well before a decrease in greenness is detected in remotely sensed vegetation indices. As a diagnostic indicator of actual ET, the ESI requires no information regarding antecedent precipitation or soil moisture storage capacity - the current available moisture to vegetation is deduced directly from the remotely sensed LST signal. This signal also inherently accounts for both precipitation and non-precipitation related inputs/sinks to the plant-available soil moisture pool (e.g., irrigation) which can modify crop response to rainfall anomalies. Independence from precipitation data is a benefit for global agricultural monitoring applications due to sparseness in existing ground-based precipitation networks, and time delays in public reporting. Several enhancements to the current ESI framework will be addressed as requested from project stakeholders: (a) integration of "all-sky" MW Ka-band LST retrievals to augment "clear-sky" thermal-only ESI in persistently cloudy regions; (b) operational production of ESI Rapid Change Indices which provide important early warning information related to onset of actual vegetation stress; and (c) assessment of ESI as a predictor of global yield anomalies; initial studies have shown the ability of intra

  3. Retrieval of land surface temperature (LST) from landsat TM6 and TIRS data by single channel radiative transfer algorithm using satellite and ground-based inputs

    Science.gov (United States)

    Chatterjee, R. S.; Singh, Narendra; Thapa, Shailaja; Sharma, Dravneeta; Kumar, Dheeraj

    2017-06-01

    The present study proposes land surface temperature (LST) retrieval from satellite-based thermal IR data by single channel radiative transfer algorithm using atmospheric correction parameters derived from satellite-based and in-situ data and land surface emissivity (LSE) derived by a hybrid LSE model. For example, atmospheric transmittance (τ) was derived from Terra MODIS spectral radiance in atmospheric window and absorption bands, whereas the atmospheric path radiance and sky radiance were estimated using satellite- and ground-based in-situ solar radiation, geographic location and observation conditions. The hybrid LSE model which is coupled with ground-based emissivity measurements is more versatile than the previous LSE models and yields improved emissivity values by knowledge-based approach. It uses NDVI-based and NDVI Threshold method (NDVITHM) based algorithms and field-measured emissivity values. The model is applicable for dense vegetation cover, mixed vegetation cover, bare earth including coal mining related land surface classes. The study was conducted in a coalfield of India badly affected by coal fire for decades. In a coal fire affected coalfield, LST would provide precise temperature difference between thermally anomalous coal fire pixels and background pixels to facilitate coal fire detection and monitoring. The derived LST products of the present study were compared with radiant temperature images across some of the prominent coal fire locations in the study area by graphical means and by some standard mathematical dispersion coefficients such as coefficient of variation, coefficient of quartile deviation, coefficient of quartile deviation for 3rd quartile vs. maximum temperature, coefficient of mean deviation (about median) indicating significant increase in the temperature difference among the pixels. The average temperature slope between adjacent pixels, which increases the potential of coal fire pixel detection from background pixels, is

  4. Elevation-based upscaling of organic carbon stocks in High-Arctic permafrost terrain

    DEFF Research Database (Denmark)

    Weiss, Niels; Faucherre, Samuel; Lampiris, Nikos

    2017-01-01

    Accurate quantity and distribution estimates of permafrost soil organic carbon (SOC) stocks are needed to project potential feedbacks to climate, following warming. Still, upscaling from local field observations to regional estimates to circumarctic assessments remains a challenge. Here we explore...... elevation-based upscaling techniques for High-Arctic permafrost SOC stocks. We combine two detailed, high-resolution SOC inventories on Spitsbergen (Svalbard) with regional validation data. We find a clear relationship between elevation and SOC content, and use this observed exponential correlation, as well...... as discrete elevation classes, as upscaling models for Spitsbergen. We estimate the total amount of permafrost SOC currently present in soils on Spitsbergen to be 105.36 Tg (0.11 Pg), with a mean SOC content of 2.84 ± 0.74 kg C m−2 (mean ± 95% confidence interval). Excluding glaciers and permanent snowfields...

  5. Quantifying the clear-sky bias of satellite-derived infrared LST

    Science.gov (United States)

    Ermida, S. L.; Trigo, I. F.; DaCamara, C.

    2017-12-01

    Land surface temperature (LST) is one of the most relevant parameters when addressing the physical processes that take place at the surface of the Earth. Satellite data are particularly appropriate for measuring LST over the globe with high temporal resolution. Remote-sensed LST estimation from space-borne sensors has been systematically performed over the Globe for nearly 3 decades and geostationary LST climate data records are now available. The retrieval of LST from satellite observations generally relies on measurements in the thermal infrared (IR) window. Although there is a large number of IR sensors on-board geostationary satellites and polar orbiters suitable for LST retrievals with different temporal and spatial resolutions, the use of IR observations limits LST estimates to clear sky conditions. As a consequence, climate studies based on IR LST are likely to be affected by the restriction of LST data to cloudless conditions. However, such "clear sky bias" has never been quantified and, therefore, the actual impact of relying only on clear sky data is still to be determined. On the other hand, an "all-weather" global LST database may be set up based on passive microwave (MW) measurements which are much less affected by clouds. An 8-year record of all-weather MW LST is here used to quantify the clear-sky bias of IR LST at global scale based on MW observations performed by the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) onboard NASA's Aqua satellite. Selection of clear-sky and cloudy pixels is based on information derived from measurements performed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on-board the same satellite.

  6. Landsat-based trend analysis of lake dynamics across northern permafrost regions

    Science.gov (United States)

    Nitze, Ingmar; Grosse, Guido; Jones, Benjamin M.; Arp, Christopher D.; Ulrich, Mathias; Federov, Alexander; Veremeeva, Alexandra

    2017-01-01

    Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here we present, a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM,ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e. upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.

  7. Permafrost Distribution along the Qinghai-Tibet Engineering Corridor, China Using High-Resolution Statistical Mapping and Modeling Integrated with Remote Sensing and GIS

    Directory of Open Access Journals (Sweden)

    Fujun Niu

    2018-02-01

    Full Text Available Permafrost distribution in the Qinghai-Tibet Engineering Corridor (QTEC is of growing interest due to the increase in infrastructure development in this remote area. Empirical models of mountain permafrost distribution have been established based on field sampled data, as a tool for regional-scale assessments of its distribution. This kind of model approach has never been applied for a large portion of this engineering corridor. In the present study, this methodology is applied to map permafrost distribution throughout the QTEC. After spatial modelling of the mean annual air temperature distribution from MODIS-LST and DEM, using high-resolution satellite image to interpret land surface type, a permafrost probability index was obtained. The evaluation results indicate that the model has an acceptable performance. Conditions highly favorable to permafrost presence (≥70% are predicted for 60.3% of the study area, declaring a discontinuous permafrost distribution in the QTEC. This map is useful for the infrastructure development along the QTEC. In the future, local ground-truth observations will be required to confirm permafrost presence in favorable areas and to monitor permafrost evolution under the influence of climate change.

  8. Permafrost distribution map of San Juan Dry Andes (Argentina) based on rock glacier sites

    Science.gov (United States)

    Esper Angillieri, María Yanina

    2017-01-01

    Rock glaciers are frozen water reservoirs in mountainous areas. Water resources are important for the local populations and economies. The presence of rock glaciers is commonly used as a direct indicator of mountain permafrost conditions. Over 500 active rock glaciers have been identified, showing that elevations between 3500 and 4500 m asl., a south-facing or east-facing aspect, areas with relatively low solar radiation and low mean annual air temperature (-4 to 0 °C) favour the existence of rock glaciers in this region. The permafrost probability model, for Dry Andes of San Juan Province between latitudes 28º30‧S and 32°30‧S, have been analyzed by logistic regression models based on the active rock glaciers occurrence in relation to some topoclimatic variables such as altitude, aspect, mean annual temperature, mean annual precipitation and solar radiation, using optical remote sensing techniques in a GIS environment. The predictive performances of the model have been estimated by known rock glaciers locations and by the area under the receiver operating characteristic curve (AUROC). This regional permafrost map can be applied by the Argentinean Government for their recent initiatives which include creating inventories, monitoring and studying ice masses along the Argentinean Andes. Further, this generated map provides valuable input data for permafrost scenarios and contributes to a better understanding of our geosystem.

  9. Monitoring and Quantifying Subsurface Ice and Water Content in Permafrost Regions Based on Geophysical Data Sets

    Science.gov (United States)

    Hauck, C.; Bach, M.; Hilbich, C.

    2007-12-01

    Based on recent observational evidence of climate change in permafrost regions, it is now recognised that a detailed knowledge of the material composition of the subsurface in permafrost regions is required for modelling of the future evolution of the ground thermal regime and an assessment of the hazard potential due to degrading permafrost. However, due to the remote location of permafrost areas and the corresponding difficulties in obtaining high-quality data sets of the subsurface, knowledge about the material composition in permafrost areas is scarce. In frozen ground subsurface material may consist of four different phases: rock/soil matrix, unfrozen pore water, ice and air-filled pore space. Applications of geophysical techniques for determining the subsurface composition are comparatively cheap and logistically feasible alternatives to the single point information from boreholes. Due to the complexity of the subsurface a combination of complementary geophysical methods (e.g. electrical resistivity tomography (ERT) and refraction seismic tomography) is often favoured to avoid ambiguities in the interpretation of the results. The indirect nature of geophysical soundings requires a relation between the measured variable (electrical resistivity, seismic velocity) and the rock-, water-, ice- and air content. In this contribution we will present a model which determines the volumetric fractions of these four phases from tomographic electrical and seismic data sets. The so-called 4-phase model is based on two well-known geophysical mixing rules using observed resistivity and velocity data as input data on a 2-dimensional grid. Material properties such as resistivity and P- wave velocity of the host rock material and the pore water have to be known beforehand. The remaining free model parameters can be determined by a Monte-Carlo approach, the results of which are used additionally as indicator for the reliability of the model results. First results confirm the

  10. Estimating Rates of Permafrost Degradation and their Impact on Ecosystems across Alaska and Northwest Canada using the Process-based Permafrost Dynamics Model GIPL as a Component of the Integrated Ecosystem Model (IEM)

    Science.gov (United States)

    Marchenko, S. S.; Genet, H.; Euskirchen, E. S.; Breen, A. L.; McGuire, A. D.; Rupp, S. T.; Romanovsky, V. E.; Bolton, W. R.; Walsh, J. E.

    2016-12-01

    The impact of climate warming on permafrost and the potential of climate feedbacks resulting from permafrost thawing have recently received a great deal of attention. Permafrost temperature has increased in most locations in the Arctic and Sub-Arctic during the past 30-40 years. The typical increase in permafrost temperature is 1-3°C. The process-based permafrost dynamics model GIPL developed in the Geophysical Institute Permafrost Lab, and which is the permafrost module of the Integrated Ecosystem Model (IEM) has been using to quantify the nature and rate of permafrost degradation and its impact on ecosystems, infrastructure, CO2 and CH4fluxes and net C storage following permafrost thaw across Alaska and Northwest Canada. The IEM project is a multi-institutional and multi-disciplinary effort aimed at understanding potential landscape, habitat and ecosystem change across the IEM domain. The IEM project also aims to tie three scientific models together Terrestrial Ecosystem Model (TEM), the ALFRESCO (ALaska FRame-based EcoSystem Code) and GIPL so that they exchange data at run-time. The models produce forecasts of future fire, vegetation, organic matter, permafrost and hydrology regimes. The climate forcing data are based on the historical CRU3.1 data set for the retrospective analysis period (1901-2009) and the CMIP3 CCCMA-CGCM3.1 and MPI-ECHAM5/MPI-OM climate models for the future period (2009-2100). All data sets were downscaled to a 1 km resolution, using a differencing methodology (i.e., a delta method) and the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climatology. We estimated the dynamics of permafrost temperature, active layer thickness, area occupied by permafrost, and volume of thawed soils across the IEM domain. The modeling results indicate how different types of ecosystems affect the thermal state of permafrost and its stability. Although the rate of soil warming and permafrost degradation in peatland areas are slower than

  11. A ground temperature map of the North Atlantic permafrost region based on remote sensing and reanalysis data

    DEFF Research Database (Denmark)

    Westermann, S.; Østby, T. I.; Gisnås, K.

    2015-01-01

    Permafrost is a key element of the terrestrial cryosphere which makes mapping and monitoring of its state variables an imperative task. We present a modeling scheme based on remotely sensed land surface temperatures and reanalysis products from which mean annual ground temperatures (MAGT) can be ...... with gradually decreasing permafrost probabilities. The study exemplifies the unexploited potential of remotely sensed data sets in permafrost mapping if they are employed in multi-sensor multi-source data fusion approaches.......Permafrost is a key element of the terrestrial cryosphere which makes mapping and monitoring of its state variables an imperative task. We present a modeling scheme based on remotely sensed land surface temperatures and reanalysis products from which mean annual ground temperatures (MAGT) can...

  12. The Impacts of Climate Change and Anthropogenic Processes on Permafrost Soils and USAF Infrastructure within Northern Tier Bases

    Science.gov (United States)

    2017-03-24

    radiation from clouds, snow, soil , and water surfaces (the Earth’s albedo), the distribution of continents and oceans, and topography (Davis, 2001, pp...facilities will be built on the north end of the base. Two of the borehole samples were found to have traces of massive-ice permafrost soils (Inc, 2016b...J. L. (2008). Evaluation of the CRREL Permafrost Tunnel, (August). Bonan, G. B. (1989). A computer model of the solar radiation , soil moisture

  13. The Impacts of Thawing Permafrost and Climate Change on USAF Infrastructure Within Northern Tier Bases

    Science.gov (United States)

    Graboski, A. J.

    2016-12-01

    The Department of Defense (DoD) is planning over $600M in military construction on Eielson Air Force Base (AFB) within the next three fiscal years. Although many studies have been conducted on permafrost and climate change, the future of our climate as well as any impacts on arctic infrastructure, remains unclear. This research focused on future climate predictions to determine likely scenarios for the United States Air Force's Strategic Planners to consider. This research also looked at various construction methods being used by industry to glean best practices to incorporate into future construction in order to determine cost factors to consider when permafrost soils may be encountered. The most recent 2013 International Panel on Climate Change (IPCC) report predicts a 2.2ºC to 7.8ºC temperature rise in Arctic regions by the end of the 21st Century in the Representative Concentration Pathways, (RCP4.5) emissions scenario. A regression model was created using archived surface observations from 1944 to 2016. Initial analysis using regression/forecast techniques show a 1.17ºC temperature increase in the Arctic by the end of the 21st Century. Historical DoD construction data was then used to determine an appropriate cost factor. Applying statistical tests to the adjusted climate predictions supports continued usage of current DoD cost factors of 2.13 at Eielson and 2.97 at Thule AFBs as they should be sufficient when planning future construction projects in permafrost rich areas. These cost factors should allow planners the necessary funds to plan foundation mitigation techniques and prevent further degradation of permafrost soils around airbase infrastructure. This current research focused on Central Alaska while further research is recommended on the Alaskan North Slope and Greenland to determine climate change impacts on critical DoD infrastructure.

  14. Modelling the angular effects on satellite retrieved LST at global scale using a land surface classification

    Science.gov (United States)

    Ermida, Sofia; DaCamara, Carlos C.; Trigo, Isabel F.; Pires, Ana C.; Ghent, Darren

    2017-04-01

    stratified by means of a cluster analysis using information on land cover type, fraction of vegetation cover and topography. The kernel model is then adjusted to LST data corresponding to each cluster. It is shown that the quality of the cluster based kernel model is very close to the pixel based one. Furthermore, the reduced number of parameters (limited to the number of identified clusters, instead of a pixel-by-pixel model calibration) allows improving the kernel model trough the incorporation of a seasonal component. The application of the here discussed procedure towards the harmonization of LST products from multi-sensors is on the framework of the ESA DUE GlobTemperature project.

  15. GIS-based maps and area estimates of Northern Hemisphere permafrost extent during the Last Glacial Maximum

    NARCIS (Netherlands)

    Lindgren, A.; Hugelius, G.; Kuhry, P.; Christensen, T.R.; Vandenberghe, J.F.

    2016-01-01

    This study presents GIS-based estimates of permafrost extent in the northern circumpolar region during the Last Glacial Maximum (LGM), based on a review of previously published maps and compilations of field evidence in the form of ice-wedge pseudomorphs and relict sand wedges. We focus on field

  16. Correction of the angular dependence of satellite retrieved LST at global scale using parametric models

    Science.gov (United States)

    Ermida, S. L.; Trigo, I. F.; DaCamara, C.; Ghent, D.

    2017-12-01

    Land surface temperature (LST) values retrieved from satellite measurements in the thermal infrared (TIR) may be strongly affected by spatial anisotropy. This effect introduces significant discrepancies among LST estimations from different sensors, overlapping in space and time, that are not related to uncertainties in the methodologies or input data used. Furthermore, these directional effects deviate LST products from an ideally defined LST, which should represent to the ensemble of directional radiometric temperature of all surface elements within the FOV. Angular effects on LST are here conveniently estimated by means of a parametric model of the surface thermal emission, which describes the angular dependence of LST as a function of viewing and illumination geometry. Two models are consistently analyzed to evaluate their performance of and to assess their respective potential to correct directional effects on LST for a wide range of surface conditions, in terms of tree coverage, vegetation density, surface emissivity. We also propose an optimization of the correction of directional effects through a synergistic use of both models. The models are calibrated using LST data as provided by two sensors: MODIS on-board NASA's TERRA and AQUA; and SEVIRI on-board EUMETSAT's MSG. As shown in our previous feasibility studies the sampling of illumination and view angles has a high impact on the model parameters. This impact may be mitigated when the sampling size is increased by aggregating pixels with similar surface conditions. Here we propose a methodology where land surface is stratified by means of a cluster analysis using information on land cover type, fraction of vegetation cover and topography. The models are then adjusted to LST data corresponding to each cluster. It is shown that the quality of the cluster based models is very close to the pixel based ones. Furthermore, the reduced number of parameters allows improving the model trough the incorporation of a

  17. Improved Understanding of Permafrost Controls on Hydrology in Interior Alaska by Integration of Ground-Based Geophysical Permafrost Characterization and Numerical Modeling

    Science.gov (United States)

    2015-05-01

    freeze/thaw dynamics, geophysics, ground ice, groundwater modeling, hydrologic impacts , interior Alaska, lakes, permafrost, sub-arctic, taliks, Yukon...21  Figure 4.1.1 Location map of Beaver Meadow and Twelvemile study areas...modeling, hydrologic impacts , interior Alaska, lakes, permafrost, sub-arctic, taliks, Yukon Flats Acknowledgements We would like to

  18. A multi-scale permafrost investigation along the Alaska Highway Corridor based on airborne electromagnetic and auxiliary geophysical data

    Science.gov (United States)

    Minsley, B. J.; Kass, M. A.; Bloss, B.; Pastick, N.; Panda, S. K.; Smith, B. D.; Abraham, J. D.; Burns, L. E.

    2012-12-01

    More than 8000 square kilometers of airborne electromagnetic (AEM) data were acquired along the Alaska Highway Corridor in 2005-2006 by the Alaska Department of Natural Resources Division of Geological and Geophysical Surveys. Because this large AEM dataset covers diverse geologic and permafrost settings, it is an excellent testbed for studying the electrical geophysical response from a wide range of subsurface conditions. These data have been used in several recent investigations of geology, permafrost, and infrastructure along the highway corridor. In this study, we build on existing interpretations of permafrost features by re-inverting the AEM data using traditional least squares inversion techniques as well as recently developed stochastic methods aimed at quantifying uncertainty in geophysical data. Ground-based geophysical measurements, including time-domain electromagnetic soundings, surface nuclear magnetic resonance soundings, and shallow frequency-domain electromagnetic profiles, have also been acquired to help validate and extend the AEM interpretations. Here, we focus on the integration of different types of data to yield an improved characterization of permafrost, including: methods to discriminate between geologic and thermal controls on resistivity; identifying relationships between shallow resistivity and active layer thickness by incorporating auxiliary remote sensing data and ground-based measurements; quantifying apparent slope-aspect-resistivity relationships, where south-facing slopes appear less resistive than north-facing slopes within similar geologic settings; and investigating an observed decrease in resistivity beneath several areas associated with recent fires.

  19. Investigate the plant biomass response to climate warming in permafrost ecosystem using matrix-based data assimilation

    Science.gov (United States)

    Lu, X.; Du, Z.; Schuur, E.; Luo, Y.

    2017-12-01

    Permafrost is one of the most vulnerable regions on the earth with over 40% world soil C represented in this region. Future climate warming potentially has a great impact on this region. On one hand, rising temperature accelerates permafrost soil thaw and release more C from land. On the other hand, warming may also increase the plant growing season length and therefore negatively feedback to climate change by increasing annual land C uptake. However, whether permafrost vegetation biomass change in response to warming can sequester more C has not been well understood. Manipulated air warming experiments reported that air warming has very limited impacts on grass land productivity and biomass growth in permafrost region [Mauritz et al., 2017]. It is hard to reveal the mechanisms behind the limited air warming response directly from experiment data. We employ a vegetation C cycle matrix model based on Community land model 4.5 (CLM4.5) and data assimilation technique to investigate how much do phenology and physiology processes contribute to the response respectively. Our results indicate phenology contributes the most in response to warming. The shift of vegetation parameter distributions after 2012 indicate vegetation acclimation may explain the modest response in plant biomass to air warming. The results suggest future model development need to take vegetation acclimation more seriously. The novel matrix-based model allows data assimilation to be conducted more efficiently. It provides more functional understanding of the models as well as the mechanism behind experiment data.

  20. Electron acceptor-based regulation of microbial greenhouse gas production from thawing permafrost

    DEFF Research Database (Denmark)

    Bak, Ebbe Norskov; Jones, Eleanor; Yde, Jacob Clement

    layer as well in the permafrost. These investigations are accompanied by characterization of the carbon, iron and sulfate content in the soil and will be followed by characterization of the microbial community structure. The aim of this study is to get a better understanding of how the availability...... of sulfate and iron and the microbial community structure regulate the production of CO2 and CH4 in thawing permafrost, and to elucidate how the rate of the organic carbon degradation changes with depth in permafrost-affected soils. This study improves our understanding of climate feedback mechanisms...

  1. Freeze/Thaw-Induced Deformation Monitoring and Assessment of the Slope in Permafrost Based on Terrestrial Laser Scanner and GNSS

    Directory of Open Access Journals (Sweden)

    Lihui Luo

    2017-02-01

    Full Text Available Most previous studies of the Qinghai-Tibet engineering corridor (QTEC have focused on the impacts of climate change on thaw-induced slope failures, whereas few have considered freeze-induced slope failures. Terrestrial laser scanning was used in combination with global navigation satellite systems to monitor three-dimensional surface changes between 2014 and 2015 on the slope of permafrost in the QTEC, which experienced two thawing periods and a freezing period. Soil temperature and moisture sensors were also deployed at 11 depths to reveal the hydrological–thermal dynamics of the active layer. We analyzed scanned surface changes in the slope based on comparisons of multi-temporal point cloud data to determine how the hydrological–thermal process affected active layer deformation during freeze–thaw cycles, thereby comprehensively quantifying the surface deformation. During the two thawing periods, the major structure of the slope exhibited subsidence trends, whereas the major structure of the slope had an uplift trend in the freezing period. The seasonal subsidence trend was caused by thaw settlement and the seasonal uplift trend was probably due to frost heaving. This occurred mainly because the active layer and the upper permafrost underwent a phase transition due to heat transfer. The ground movements occurred approximately in the soil temperature conduction direction between the top of the soil and the permafrost table. The elevation deformation range was mainly −0.20 m to 0.20 m. Surface volume increases with heaving after freezing could have compensated for the loss of thawing twice and still led to the upward swelling of the slope. Thus, this type of slope in permafrost is dominated by frost heave. Deformation characteristics of the slope will support enhanced decision making regarding the implementation of remote sensing and hydrological–thermal measurement technologies to monitor changes in the slopes in permafrost adjacent to

  2. A new web-based course: dealing with glaciers and permafrost hazards

    Science.gov (United States)

    Oswald, S.; Kaeaeb, A.; Haeberli, W.

    2003-04-01

    The intensive human use of high mountains intersects more and more with the hazard zones of such environments. Because of the complexity of such processes and impacts, dealing with such risks requires a broad education in many sub-domains of the earth sciences and the socio-economic field. Inter- and trans-disciplinary training and education of professionals is therefore essential. Thus the goal of the Swiss Virtual Campus project "Dealing with Natural Hazards" is to provide such a course program covering the basics of dealing with natural hazards, including technical, environmental and social aspects. In the field of natural hazards and risk management, education at the Swiss universities is mostly structured in narrow sectors. Using the advantages of the internet, the Virtual Campus provides teachers and students an interdisciplinary discussion platform on the integral approach and the handling with natural hazards. The course content is organised in 5 modules: 1 basic knowledge and tools, 2 hydrological / meteorological hazards, 3 geological hazards, 4 vulnerability of property and of socio-economic systems and 5 integral natural risk management. To ensure a national and international access the courses are designed in English and published on the internet. Within the scope of this project we are developing lessons in the subject area of natural hazards related to glaciers and permafrost. These are ice avalanches, glacier floods, glacier length variations and permafrost. The content is divided into chapters, which are consistent over the entire module: (1) processes: characterisation of the different processes, (2) triggering: initiating events, (3) data acquisition, mapping and monitoring: appropriate methods, (4) estimation models: application of the adequate model, (5) combinations and interactions: interrelation and impacts of different hazards, (6) long-term effects: global change effects, (7) integral hazard recognition and assessment: integral proceedings

  3. InSAR-based detection of McKenzie River Delta Permafrost loss

    Science.gov (United States)

    Oliver-Cabrera, T.; Wdowinski, S.

    2017-12-01

    Permafrost underlies most of the McKenzie River, North America's largest delta. The in the delta is catalogued as discontinuous permafrost due to the influence of shifting river channels on near-surface ground temperatures. The area is affected by climate change, studies show that ground temperature has increased by 1.5°C since 1970, due to rising annual mean air temperature. Flooding regimes within the delta are also affected by the changing climate due to melting of near surface ground ice together with sea-level rise increasing the potential of land subsidence. Observed consequences of changes occurring in the region are vegetation growth and northward migration of the tree line. The growing vegetation can affect physical properties of the accumulated snow, including depth, density and thermal conductivity. Thogether these variations affect permafrost stability. Permafrost changes can be measured throughout the impacts on river runoffs, ground water, drainages, carbon release, land subsidence and even infrastructure damages. Degradation of permafrost can also be measured by observing ecological changes in the area. In this study, we use InSAR observations to detect permafrost changes and their transition to wetland or vegetated land cover. Our data consist of four ALOS-PALSAR frames covering the entire McKenzie River Delta with temporal coverage spanning from January 2007 to March of 2011. Each frame has 20 to 24 acquisitions, in which half of the data acquired with HH polarization and the other half with HH+HV. We process the data using ROI_PAC and PYSAR software packages. Preliminary results have detected the following spatial patterns: (1) An overall good coherence of summer interferograms with 46-92 day interferograms, (2) Low coherence of winter interferograms (November to February), probably to the increase in snow coverage, (3) Phase jumps along the border of the river reflecting morphological differences between the region near to the river and other

  4. High-resolution Mapping of Permafrost and Soil Freeze/thaw Dynamics in the Tibetan Plateau Based on Multi-sensor Satellite Observations

    Science.gov (United States)

    Zhang, W.; Yi, Y.; Yang, K.; Kimball, J. S.

    2016-12-01

    The Tibetan Plateau (TP) is underlain by the world's largest extent of alpine permafrost ( 2.5×106 km2), dominated by sporadic and discontinuous permafrost with strong sensitivity to climate warming. Detailed permafrost distributions and patterns in most of the TP region are still unknown due to extremely sparse in-situ observations in this region characterized by heterogeneous land cover and large temporal dynamics in surface soil moisture conditions. Therefore, satellite-based temperature and moisture observations are essential for high-resolution mapping of permafrost distribution and soil active layer changes in the TP region. In this study, we quantify the TP regional permafrost distribution at 1-km resolution using a detailed satellite data-driven soil thermal process model (GIPL2). The soil thermal model is calibrated and validated using in-situ soil temperature/moisture observations from the CAMP/Tibet field campaign (9 sites: 0-300 cm soil depth sampling from 1997-2007), a multi-scale soil moisture and temperature monitoring network in the central TP (CTP-SMTMN, 57 sites: 5-40 cm, 2010-2014) and across the whole plateau (China Meteorology Administration, 98 sites: 0-320 cm, 2000-2015). Our preliminary results using the CAMP/Tibet and CTP-SMTMN network observations indicate strong controls of surface thermal and soil moisture conditions on soil freeze/thaw dynamics, which vary greatly with underlying topography, soil texture and vegetation cover. For regional mapping of soil freeze/thaw and permafrost dynamics, we use the most recent soil moisture retrievals from the NASA SMAP (Soil Moisture Active Passive) sensor to account for the effects of temporal soil moisture dynamics on soil thermal heat transfer, with surface thermal conditions defined by MODIS (Moderate Resolution Imaging Spectroradiometer) land surface temperature records. Our study provides the first 1-km map of spatial patterns and recent changes of permafrost conditions in the TP.

  5. Highly specific and rapid immuno-fluorescent visualization and detection of E. coli O104:H4 with protein-A coated magnetic beads based LST-MUG assay.

    Science.gov (United States)

    Barizuddin, Syed; Balakrishnan, Baskar; Stringer, R Cody; Dweik, Majed

    2015-08-01

    A method combining immunomagnetic separation and fluorescent sensing was developed to detect Escherichia coli (E. coli) O104:H4. The antibody specific to E. coli O104:H4 was immobilized on protein A-coated magnetic beads. This protein-A-anti E. coli O104:H4 complex was used to bind Fluorescein IsoThioCyanate (FITC) labeled E. coli O104:H4 antigen (whole cell) on it. The goal was to achieve a fluorescently detectable protein-A-anti E. coli O104:H4-E. coli O104:H4 complex on the magnetic beads. Fluorescent microscopy was used to image the magnetic beads. The resulting fluorescence on the beads was due to the FITC labeled antigen binding on the protein-A-anti E. coli O104:H4 immobilized magnetic beads. This visually proves the antigen-antibody binding. The fluorescent imaging results were obtained in 2 h if the minimum available bacteria in the sample were at least 10(5) CFU/ml. If no fluorescence was observed on the magnetic beads during fluorescent imaging, it indicates the bacterial concentration in the sample to be too low for it to have bound to the magnetic beads and hence no detection was possible. To detect bacterial concentration less than 10(5) CFU/ml in the sample, an additional step was required for detection. The magnetic bead complex was added to the LST-MUG (lauryl sulfate tryptose-4-methylumbelliferyl-β-D-glucuronide), a signaling reporter. The E. coli O104:H4 grows in LST-MUG and releases β-glucuronidase enzyme. This enzyme cleaves the MUG substrate that produces 4-methylumbelliferone, a highly fluorescent species. This fluorescence was detected using a spectrofluorometer. The emission peak in the fluorescent spectrum was found to be at 450 nm. The lower and upper detection range for this LST-MUG assay was found to be 2.05×10(5)-4.09×10(8) CFU/ml. The results for the LST-MUG assay for concentrations below 10(5) CFU/ml were ascertained in 8h. The advantages of this technique include the specific detection of bacteria without an enrichment step and

  6. Rat Monoclonal Antibodies Specific for LST1 Proteins

    OpenAIRE

    Schiller, Christian; Nitschké, Maximilian J. E.; Seidl, Alexander; Kremmer, Elisabeth; Weiss, Elisabeth H.

    2009-01-01

    The LST1 gene is located in the human MHC class III region and encodes transmembrane and soluble isoforms that have been suggested to play a role in the regulation of the immune response and are associated with inflammatory diseases such as rheumatoid arthritis. Here we describe the generation and characterization of the first monoclonal antibodies against LST1. Two hybridoma lines secreting monoclonal antibodies designated 7E2 and 8D12 were established. The 7E2 antibody detects recombinant a...

  7. A comprehensive data set of lake surface water temperature over the Tibetan Plateau derived from MODIS LST products 2001-2015.

    Science.gov (United States)

    Wan, Wei; Li, Huan; Xie, Hongjie; Hong, Yang; Long, Di; Zhao, Limin; Han, Zhongying; Cui, Yaokui; Liu, Baojian; Wang, Cunguang; Yang, Wenting

    2017-07-25

    Lake surface water temperature (LSWT) is sensitive to long-term changes in thermal structure of lakes and regional air temperature. In the context of global climate change, recent studies showed a significant warming trend of LSWT based on investigating 291 lakes (71% are large lakes, ≥50 km 2 each) globally. However, further efforts are needed to examine variation in LSWT at finer regional spatial and temporal scales. The Tibetan Plateau (TP), known as 'the Roof of the World' and 'Asia's water towers', exerts large influences on and is sensitive to regional and even global climates. Aiming to examine detailed changing patterns and potential driven mechanisms for temperature variations of lakes across the TP region, this paper presents the first comprehensive data set of 15-year (2001-2015) nighttime and daytime LSWT for 374 lakes (≥10 km 2 each), using MODIS (Moderate Resolution Imaging Spectroradiometer) Land Surface Temperature (LST) products as well as four lake boundary shapefiles (i.e., 2002, 2005, 2009, and 2014) derived from Landsat/CBERS/GaoFen-1 satellite images. The data set itself reveals significant information on LSWT and its changes over the TP and is an indispensable variable for numerous applications related to climate change, water budget analysis (particularly lake evaporation), water storage changes, glacier melting and permafrost degradation, etc.

  8. Impact of the assimilation of satellite soil moisture and LST on the hydrological cycle

    Science.gov (United States)

    Laiolo, Paola; Gabellani, Simone; Delogu, Fabio; Silvestro, Francesco; Rudari, Roberto; Campo, Lorenzo; Boni, Giorgio

    2014-05-01

    The reliable estimation of hydrological variables (e.g. soil moisture, evapotranspiration, surface temperature) in space and time is of fundamental importance in operational hydrology to improve the forecast of the rainfall-runoff response of catchments and, consequently, flood predictions. Nowadays remote sensing can offer a chance to provide good space-time estimates of several hydrological variables and then improve hydrological model performances especially in environments with scarce ground based data. The aim of this work is to investigate the impacts on the performances of a distributed hydrological model (Continuum) of the assimilation of satellite-derived soil moisture products and Land Surface (LST). In this work three different soil moisture (SM) products, derived by ASCAT sensor, are used. These data are provided by the EUMETSAT's H-SAF (Satellite Application Facility on Support to Operational Hydrology and Water Management) program. The considered soil moisture products are: large scale surface soil moisture (SM OBS 1 - H07), small scale surface soil moisture (SM OBS 2 - H08) and profile index in the roots region (SM DAS 2 - H14). These data are compared with soil moisture estimated by Continuum model on the Orba catchment (800 km2), in the northern part of Italy, for the period July 2012-June 2013. Different assimilation experiments have been performed. The first experiment consists in the assimilation of the SM products by using a simple Nudging technique; the second one is the assimilation of only LST data, derived from MSG satellite, and the third is the assimilation of both SM products and LST. The benefits on the model predictions of discharge, LST and soil moisture dynamics were tested.

  9. Thermal erosion of a permafrost coastline: Improving process-based models using time-lapse photography

    Science.gov (United States)

    Wobus, C.; Anderson, R.; Overeem, I.; Matell, N.; Clow, G.; Urban, F.

    2011-01-01

    Coastal erosion rates locally exceeding 30 m y-1 have been documented along Alaska's Beaufort Sea coastline, and a number of studies suggest that these erosion rates have accelerated as a result of climate change. However, a lack of direct observational evidence has limited our progress in quantifying the specific processes that connect climate change to coastal erosion rates in the Arctic. In particular, while longer ice-free periods are likely to lead to both warmer surface waters and longer fetch, the relative roles of thermal and mechanical (wave) erosion in driving coastal retreat have not been comprehensively quantified. We focus on a permafrost coastline in the northern National Petroleum Reserve-Alaska (NPR-A), where coastal erosion rates have averaged 10-15 m y-1 over two years of direct monitoring. We take advantage of these extraordinary rates of coastal erosion to observe and quantify coastal erosion directly via time-lapse photography in combination with meteorological observations. Our observations indicate that the erosion of these bluffs is largely thermally driven, but that surface winds play a crucial role in exposing the frozen bluffs to the radiatively warmed seawater that drives melting of interstitial ice. To first order, erosion in this setting can be modeled using formulations developed to describe iceberg deterioration in the open ocean. These simple models provide a conceptual framework for evaluating how climate-induced changes in thermal and wave energy might influence future erosion rates in this setting.

  10. The effect of permafrost thaw on short- and long-term carbon accumulation in permafrost mires

    Science.gov (United States)

    Olid, Carolina; Klaminder, Jonatan; Monteux, Sylvain; Johansson, Margareta; Dorrepaal, Ellen

    2017-04-01

    Permafrost stores twice as much carbon (C) as is currently present in the atmosphere. During recent years, warmer temperatures in the Arctic has caused rapid thawing of permafrost, which have dramatically altered permafrost C storage by increasing both microbial decomposition and plant productivity. Although current research focuses on the effects of climate change on these two processes, there are still no scientific consensus about the magnitude or even the direction of future C feedbacks from permafrost ecosystems. Field manipulation experiments have been widely used during the last decade to improve our knowledge about the net effects of permafrost thaw in the permafrost C storage. However, due to the slow response (decades) of permafrost ecosystems to environmental changes and the short-time nature of these experiments (usually shorter than 5-9 years), there are still concerns when attempting to extrapolate the results to predict long term effects. In addition, measurements are mostly taken exclusively during the summer season, without taking into account inter-annual variability in C fluxes and underestimating microbial activity throughout the cold season. The need to develop a comprehensive understanding of C fluxes over the entire year and at long temporal scales sets the basis of this study. This study aims to quantify the effects of permafrost thawing in permafrost C fluxes using a 12 years permafrost thaw experiment in northern Sweden. Our aims were to quantify the effect of permafrost thaw in both decomposition and primary production in active layer and newly thawed permafrost, and its implications for the C balance. Based on previous observations, we hypothesized that 1) soil decomposition rates were higher in manipulated thaw plots. However, 2) the observed increase in nutrients availability and the higher presence of vascular plants after thawing stimulate primary production, which compensates to some extent the increased C losses by respiration. To

  11. Trends in LST over the peninsular Spain as derived from the AVHRR imagery data

    DEFF Research Database (Denmark)

    Khorchani, Makki; Vicente-Serrano, Sergio M.; Azorin-Molina, Cesar

    2018-01-01

    between LST and NDVI changes. The areas that experienced an increase in the LST were spatially consistent with those areas with no changes or even a dominant decrease in vegetation coverage. In addition, the strong increase of LST is coherent with observations of the recent radiative forcing affecting...

  12. Effects of permafrost degradation on alpine grassland in a semi-arid basin on the Qinghai–Tibetan Plateau

    International Nuclear Information System (INIS)

    Yi Shuhua; Zhou Zhaoye; Ren Shilong; Xu Ming; Qin Yu; Chen Shengyun; Ye Baisheng

    2011-01-01

    Permafrost on the Qinghai–Tibetan Plateau (QTP) has degraded over the last few decades. Its ecological effects have attracted great concern. Previous studies focused mostly at plot scale, and hypothesized that degradation of permafrost would cause lowering of the water table and drying of shallow soil and then degradation of alpine grassland. However, none has been done to test the hypothesis at basin scale. In this study, for the first time, we investigated the relationships between land surface temperature (LST) and fractional vegetation cover (FVC) in different types of permafrost zone to infer the limiting condition (water or energy) of grassland growth on the source region of Shule River Basin, which is located in the north-eastern edge of the QTP. LST was obtained from MODIS Aqua products at 1 km resolution, while FVC was upscaled from quadrat (50 cm) to the same resolution as LST, using 30 m resolution NDVI data of the Chinese HJ satellite. FVC at quadrat scale was estimated by analyzing pictures taken with a multi-spectral camera. Results showed that (1) retrieval of FVC at quadrat scale using a multi-spectral camera was both more accurate and more efficient than conventional methods and (2) the limiting factor of vegetation growth transitioned from energy in the extreme stable permafrost zone to water in the seasonal frost zone. Our study suggested that alpine grassland would respond differently to permafrost degradation in different types of permafrost zone. Future studies should consider overall effects of permafrost degradation, and avoid the shortcomings of existing studies, which focus too much on the adverse effects.

  13. Hydrological modelling over different scales on the edge of the permafrost zone: approaching model realism based on experimentalists' knowledge

    Science.gov (United States)

    Nesterova, Natalia; Makarieva, Olga; Lebedeva, Lyudmila

    2017-04-01

    Quantitative and qualitative experimentalists' data helps to advance both understanding of the runoff generation and modelling strategies. There is significant lack of such information for the dynamic and vulnerable cold regions. The aim of the study is to make use of historically collected experimental hydrological data for modelling poorly-gauged river basins on larger scales near the southern margin of the permafrost zone in Eastern Siberia. Experimental study site "Mogot" includes the Nelka river (30.8 km2) and its three tributaries with watersheds area from 2 to 5.8 km2. It is located in the upper elevated (500 - 1500 m a.s.l.) part of the Amur River basin. Mean annual temperature and precipitation are -7.5°C and 555 mm respectively. Top of the mountains with weak vegetation has well drained soil that prevents any water accumulation. Larch forest on the northern slopes has thick organic layer. It causes shallow active layer and relatively small subsurface water storage. Soil in the southern slopes has thinner organic layer and thaws up to 1.6 m depth. Flood plains are the wettest landscape with highest water storage capacity. Measured monthly evaporation varies from 9 to 100 mm through the year. Experimental data shows importance of air temperature and precipitation changes with the elevation. Their gradient was taken into account for hydrological simulations. Model parameterization was developed according to available quantitative and qualitative data in the Mogot station. The process-based hydrological Hydrograph model was used in the study. It explicitly describes hydrological processes in different permafrost environments. Flexibility of the Hydrograph model allows take advantage from the experimental data for model set-up. The model uses basic meteorological data as input. The level of model complexity is suitable for a remote, sparsely gauged region such as Southern Siberia as it allows for a priori assessment of the model parameters. Model simulation

  14. Permafrost slowly exhales methane

    Science.gov (United States)

    Herndon, Elizabeth M.

    2018-04-01

    Permafrost soils store vast quantities of organic matter that are vulnerable to decomposition under a warming climate. Recent research finds that methane release from thawing permafrost may outpace carbon dioxide as a major contributor to global warming over the next century.

  15. Semiautomatic mapping of permafrost in the Yukon Flats, Alaska

    Science.gov (United States)

    Gulbrandsen, Mats Lundh; Minsley, Burke J.; Ball, Lyndsay B.; Hansen, Thomas Mejer

    2016-01-01

    Thawing of permafrost due to global warming can have major impacts on hydrogeological processes, climate feedback, arctic ecology, and local environments. To understand these effects and processes, it is crucial to know the distribution of permafrost. In this study we exploit the fact that airborne electromagnetic (AEM) data are sensitive to the distribution of permafrost and demonstrate how the distribution of permafrost in the Yukon Flats, Alaska, is mapped in an efficient (semiautomatic) way, using a combination of supervised and unsupervised (machine) learning algorithms, i.e., Smart Interpretation and K-means clustering. Clustering is used to sort unfrozen and frozen regions, and Smart Interpretation is used to predict the depth of permafrost based on expert interpretations. This workflow allows, for the first time, a quantitative and objective approach to efficiently map permafrost based on large amounts of AEM data.

  16. Non-IgE-related diagnostic methods (LST, patch test).

    Science.gov (United States)

    Matsumoto, Kenji

    2015-01-01

    Although most food allergy patients have immediate-type reactions, some have delayed-type reactions. Unlike for the detection of food-specific IgE antibody in immediate-type (IgE-mediated) food allergies, only a few tests are currently available to aid in the diagnosis of delayed-type (non-IgE-mediated) food allergies. This chapter summarizes our current understanding of one in vitro test and one in vivo test for non-IgE-mediated food allergies: the lymphocyte stimulation test (LST) and the atopy patch test (APT). Although the LST is not yet standardized, a food protein-specific LST might be a useful tool for diagnosing delayed-type food allergies, and especially those manifesting with gastrointestinal symptoms but not skin symptoms. Various remaining issues - including basophil contamination of the peripheral blood mononuclear cell fraction and lipopolysaccharide contamination of food antigen preparations - are also discussed. The APT uses an epicutaneous patch technique to occlusively apply food antigens to the skin to induce inflammatory reactions at the patch application site. Because the APT shows modest sensitivity and specificity, the clinical benefit of the APT in the diagnosis of food allergies in patients with atopic dermatitis is limited. A position paper on the APT issued by the European Academy of Allergy and Clinical Immunology/Global Allergy and Asthma European Network in 2006 is briefly summarized, and several recent APT-related topics, including APT use for the diagnosis of food protein-induced enterocolitis syndrome, are discussed. © 2015 S. Karger AG, Basel.

  17. Investigation of Cyprus thermal tenancy using nine year MODIS LST data and Fourier analysis

    Science.gov (United States)

    Skarlatos, D.; Miliaresis, G.; Georgiou, A.

    2013-08-01

    Land Surface Temperature (LST) is an extremely important parameter that controls the exchange of long wave radiation between surface and atmosphere. It is a good indicator of the energy balance at the Earth's surface and it is one of the key parameters in the physics of land-surface processes on regional as well as global scale. This paper utilizes monthly night and day averaged LST MODIS imagery over Cyprus for a 9 year period. Fourier analysis and Least squares estimation fitting are implemented to analyze mean daily data over Cyprus in an attempt to investigate possible temperature tenancy over these years and possible differences among areas with different land cover and land use, such as Troodos Mountain and Nicosia, the main city in the center of the island. The analysis of data over a long time period, allows questions such as whether there is a tenancy to temperature increase, to be answered in a statistically better way, provided that `noise' is removed correctly. Dealing with a lot of data, always provides a more accurate estimation, but on the other hand, more noise in implemented on the data, especially when dealing with temperature which is subject to daily and annual cycles. A brief description over semi-automated data acquisition and standardization using object-oriented programming and GIS-based techniques, will be presented. The paper fully describes the time series analysis implemented, the Fourier method and how it was used to analyze and filter mean daily data with high frequency. Comparison of mean monthly daily LST against day and night LSTs is also performed over the 9 year period in order to investigate whether use of the extended data series provide significant advantage over short.

  18. Observation-based modelling of permafrost carbon fluxes with accounting for deep carbon deposits and thermokarst activity

    Science.gov (United States)

    Schneider von Deimling, T.; Grosse, G.; Strauss, J.; Schirrmeister, L.; Morgenstern, A.; Schaphoff, S.; Meinshausen, M.; Boike, J.

    2015-06-01

    High-latitude soils store vast amounts of perennially frozen and therefore inert organic matter. With rising global temperatures and consequent permafrost degradation, a part of this carbon stock will become available for microbial decay and eventual release to the atmosphere. We have developed a simplified, two-dimensional multi-pool model to estimate the strength and timing of future carbon dioxide (CO2) and methane (CH4) fluxes from newly thawed permafrost carbon (i.e. carbon thawed when temperatures rise above pre-industrial levels). We have especially simulated carbon release from deep deposits in Yedoma regions by describing abrupt thaw under newly formed thermokarst lakes. The computational efficiency of our model allowed us to run large, multi-centennial ensembles under various scenarios of future warming to express uncertainty inherent to simulations of the permafrost carbon feedback. Under moderate warming of the representative concentration pathway (RCP) 2.6 scenario, cumulated CO2 fluxes from newly thawed permafrost carbon amount to 20 to 58 petagrams of carbon (Pg-C) (68% range) by the year 2100 and reach 40 to 98 Pg-C in 2300. The much larger permafrost degradation under strong warming (RCP8.5) results in cumulated CO2 release of 42 to 141 Pg-C and 157 to 313 Pg-C (68% ranges) in the years 2100 and 2300, respectively. Our estimates only consider fluxes from newly thawed permafrost, not from soils already part of the seasonally thawed active layer under pre-industrial climate. Our simulated CH4 fluxes contribute a few percent to total permafrost carbon release yet they can cause up to 40% of total permafrost-affected radiative forcing in the 21st century (upper 68% range). We infer largest CH4 emission rates of about 50 Tg-CH4 per year around the middle of the 21st century when simulated thermokarst lake extent is at its maximum and when abrupt thaw under thermokarst lakes is taken into account. CH4 release from newly thawed carbon in wetland

  19. Observation-based modelling of permafrost carbon fluxes with accounting for deep carbon deposits and thermokarst activity

    Directory of Open Access Journals (Sweden)

    T. Schneider von Deimling

    2015-06-01

    Full Text Available High-latitude soils store vast amounts of perennially frozen and therefore inert organic matter. With rising global temperatures and consequent permafrost degradation, a part of this carbon stock will become available for microbial decay and eventual release to the atmosphere. We have developed a simplified, two-dimensional multi-pool model to estimate the strength and timing of future carbon dioxide (CO2 and methane (CH4 fluxes from newly thawed permafrost carbon (i.e. carbon thawed when temperatures rise above pre-industrial levels. We have especially simulated carbon release from deep deposits in Yedoma regions by describing abrupt thaw under newly formed thermokarst lakes. The computational efficiency of our model allowed us to run large, multi-centennial ensembles under various scenarios of future warming to express uncertainty inherent to simulations of the permafrost carbon feedback. Under moderate warming of the representative concentration pathway (RCP 2.6 scenario, cumulated CO2 fluxes from newly thawed permafrost carbon amount to 20 to 58 petagrams of carbon (Pg-C (68% range by the year 2100 and reach 40 to 98 Pg-C in 2300. The much larger permafrost degradation under strong warming (RCP8.5 results in cumulated CO2 release of 42 to 141 Pg-C and 157 to 313 Pg-C (68% ranges in the years 2100 and 2300, respectively. Our estimates only consider fluxes from newly thawed permafrost, not from soils already part of the seasonally thawed active layer under pre-industrial climate. Our simulated CH4 fluxes contribute a few percent to total permafrost carbon release yet they can cause up to 40% of total permafrost-affected radiative forcing in the 21st century (upper 68% range. We infer largest CH4 emission rates of about 50 Tg-CH4 per year around the middle of the 21st century when simulated thermokarst lake extent is at its maximum and when abrupt thaw under thermokarst lakes is taken into account. CH4 release from newly thawed carbon in

  20. Coupled Northern Hemisphere permafrost-ice-sheet evolution over the last glacial cycle

    Science.gov (United States)

    Willeit, M.; Ganopolski, A.

    2015-09-01

    Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost module is included in the Earth system model CLIMBER-2, and the coupled Northern Hemisphere (NH) permafrost-ice-sheet evolution over the last glacial cycle is explored. The model performs generally well at reproducing present-day permafrost extent and thickness. Modeled permafrost thickness is sensitive to the values of ground porosity, thermal conductivity and geothermal heat flux. Permafrost extent at the Last Glacial Maximum (LGM) agrees well with reconstructions and previous modeling estimates. Present-day permafrost thickness is far from equilibrium over deep permafrost regions. Over central Siberia and the Arctic Archipelago permafrost is presently up to 200-500 m thicker than it would be at equilibrium. In these areas, present-day permafrost depth strongly depends on the past climate history and simulations indicate that deep permafrost has a memory of surface temperature variations going back to at least 800 ka. Over the last glacial cycle permafrost has a relatively modest impact on simulated NH ice sheet volume except at LGM, when including permafrost increases ice volume by about 15 m sea level equivalent in our model. This is explained by a delayed melting of the ice base from below by the geothermal heat flux when the ice sheet sits on a porous sediment layer and permafrost has to be melted first. Permafrost affects ice sheet dynamics only when ice extends over areas covered by thick sediments, which is the case at LGM.

  1. Diagnostic and model dependent uncertainty of simulated Tibetan permafrost area

    Science.gov (United States)

    Wang, W.; Rinke, A.; Moore, J. C.; Cui, X.; Ji, D.; Li, Q.; Zhang, N.; Wang, C.; Zhang, S.; Lawrence, D. M.; McGuire, A. D.; Zhang, W.; Delire, C.; Koven, C.; Saito, K.; MacDougall, A.; Burke, E.; Decharme, B.

    2016-02-01

    We perform a land-surface model intercomparison to investigate how the simulation of permafrost area on the Tibetan Plateau (TP) varies among six modern stand-alone land-surface models (CLM4.5, CoLM, ISBA, JULES, LPJ-GUESS, UVic). We also examine the variability in simulated permafrost area and distribution introduced by five different methods of diagnosing permafrost (from modeled monthly ground temperature, mean annual ground and air temperatures, air and surface frost indexes). There is good agreement (99 to 135 × 104 km2) between the two diagnostic methods based on air temperature which are also consistent with the observation-based estimate of actual permafrost area (101 × 104 km2). However the uncertainty (1 to 128 × 104 km2) using the three methods that require simulation of ground temperature is much greater. Moreover simulated permafrost distribution on the TP is generally only fair to poor for these three methods (diagnosis of permafrost from monthly, and mean annual ground temperature, and surface frost index), while permafrost distribution using air-temperature-based methods is generally good. Model evaluation at field sites highlights specific problems in process simulations likely related to soil texture specification, vegetation types and snow cover. Models are particularly poor at simulating permafrost distribution using the definition that soil temperature remains at or below 0 °C for 24 consecutive months, which requires reliable simulation of both mean annual ground temperatures and seasonal cycle, and hence is relatively demanding. Although models can produce better permafrost maps using mean annual ground temperature and surface frost index, analysis of simulated soil temperature profiles reveals substantial biases. The current generation of land-surface models need to reduce biases in simulated soil temperature profiles before reliable contemporary permafrost maps and predictions of changes in future permafrost distribution can be made for

  2. The microbial ecology of permafrost

    DEFF Research Database (Denmark)

    Jansson, Janet; Tas, Neslihan

    2014-01-01

    Permafrost constitutes a major portion of the terrestrial cryosphere of the Earth and is a unique ecological niche for cold-adapted microorganisms. There is a relatively high microbial diversity in permafrost, although there is some variation in community composition across different permafrost......-gas emissions. This Review describes new data on the microbial ecology of permafrost and provides a platform for understanding microbial life strategies in frozen soil as well as the impact of climate change on permafrost microorganisms and their functional roles....

  3. Dynamic response of wind turbine towers in warm permafrost

    Institute of Scientific and Technical Information of China (English)

    Benjamin Still; ZhaoHui Joey Yang; Simon Evans; FuJun Niu

    2014-01-01

    Wind is a great source of renewable energy in western Alaska. Consistent winds blow across the barren tundra underlain by warm permafrost in the winter season, when the energy demand is the highest. Foundation engineering in warm permafrost has always been a challenge in wind energy development. Degrading warm permafrost poses engineering issues to design, construction, and operation of wind turbines. This paper describes the foundation design of a wind turbine built in western Alaska. It presents a sys-tem for response monitoring and load assessment, and data collected from September 2013 to March 2014. The dynamic proper-ties are assessed based on the monitoring data, and seasonal changes in the dynamic properties of the turbine tower-foundation system and likely resonance between the spinning blades and the tower structure are discussed. These analyses of a wind turbine in warm permafrost are valuable for designing or retrofitting of foundations in warm permafrost.

  4. Web-GIS visualisation of permafrost-related Remote Sensing products for ESA GlobPermafrost

    Science.gov (United States)

    Haas, A.; Heim, B.; Schaefer-Neth, C.; Laboor, S.; Nitze, I.; Grosse, G.; Bartsch, A.; Kaab, A.; Strozzi, T.; Wiesmann, A.; Seifert, F. M.

    2016-12-01

    The ESA GlobPermafrost (www.globpermafrost.info) provides a remote sensing service for permafrost research and applications. The service comprises of data product generation for various sites and regions as well as specific infrastructure allowing overview and access to datasets. Based on an online user survey conducted within the project, the user community extensively applies GIS software to handle remote sensing-derived datasets and requires preview functionalities before accessing them. In response, we develop the Permafrost Information System PerSys which is conceptualized as an open access geospatial data dissemination and visualization portal. PerSys will allow visualisation of GlobPermafrost raster and vector products such as land cover classifications, Landsat multispectral index trend datasets, lake and wetland extents, InSAR-based land surface deformation maps, rock glacier velocity fields, spatially distributed permafrost model outputs, and land surface temperature datasets. The datasets will be published as WebGIS services relying on OGC-standardized Web Mapping Service (WMS) and Web Feature Service (WFS) technologies for data display and visualization. The WebGIS environment will be hosted at the AWI computing centre where a geodata infrastructure has been implemented comprising of ArcGIS for Server 10.4, PostgreSQL 9.2 and a browser-driven data viewer based on Leaflet (http://leafletjs.com). Independently, we will provide an `Access - Restricted Data Dissemination Service', which will be available to registered users for testing frequently updated versions of project datasets. PerSys will become a core project of the Arctic Permafrost Geospatial Centre (APGC) within the ERC-funded PETA-CARB project (www.awi.de/petacarb). The APGC Data Catalogue will contain all final products of GlobPermafrost, allow in-depth dataset search via keywords, spatial and temporal coverage, data type, etc., and will provide DOI-based links to the datasets archived in the

  5. Maximising the benefits of satellite LST within the user community: ESA DUE GlobTemperature

    Science.gov (United States)

    Ghent, D.

    2014-12-01

    Land surface temperature (LST) is the mean radiative skin temperature of an area of land resulting from the mean balance of solar heating and land-atmosphere cooling fluxes. It is a basic determinant of the terrestrial thermal behaviour, as it controls the effective radiating temperature of the Earth's surface. The sensitivity of LST to soil moisture and vegetation cover means it is an important component in numerous applications. With the demand for LST data from Earth Observation currently experiencing considerable growth it is important that the users of this data are appropriately engaged by the LST data providers. The GlobTemperature project under the Data User Element of ESA's 4th Earth Observation Envelope Programme (2013-2017) aims to promote the wider uptake of global-scale satellite LST by the research and operational user communities; the key to success depending on the coherence and openness of the interactions between the LST and user communities. By incorporating detailed user input into the specifications, their subsequent testing of the LST data sets, and sustained access to data in a user-friendly manner through common data formats GlobTemperature is enhancing the portfolio of LST products from Earth Observation, while concurrently breaking down the barriers to successful application of such data through its programme of dialogue between the data providers and data users. Here we present the outcomes from the first phase of the project, which is achieving some innovative developments: a globally representative and consistent matchup database enabling validation and intercomparison of multi-sensor LST data sets; a prototype combined geostationary earth orbit (GEO) and low earth orbit (LEO) global data set for LST to resolve the diurnal cycle which is a key request from users of LST data; the delivery of the first LST data sets via a dedicated Data Portal in harmonised data format; and the establishment, in collaboration with international colleagues

  6. Mars: Detaching of the Free Water Signature (FWS) Presence Regions on the Base of HEND/ODYSSEY Data and Their Correlation with Some Permafrost Features from MOC Data

    Science.gov (United States)

    Kuzmin, R. O.; Mitrofanov, I. G.; Litvak, M. L.; Boynton, M. V.; Saunders, R. S.

    2003-01-01

    The first results from global mapping of the neutron albedo from Mars by HEND instrument have shown the noticeable deficit of both the epithermal (EN) and the fast (FN) neutrons counts rate in the high latitudes regions of both hemispheres of the planet. The deficit is indicative for high enriching of the surface regolith by hydrogen, which may correspond to amount of any water phases and forms. The objectives of our study are the spatial and temporal variations of the free water (ice) signature in the Martian surface layer on the base of HEND/ODYSSEY data and their correlation with spatial spreading of some permafrost features, mapped on the base of MOC images. For the study we used the results of the global mapping (pixel 5 x5 ) of EN and FN albedo, realized by HEND/ODYSSEY in the period from 17 February to 10 December 2002 year.

  7. Permafrost Monitoring Sonnblick

    Science.gov (United States)

    Reisenhofer, Stefan; Riedl, Claudia

    2014-05-01

    Within the project 'Permafrost Monitoring Sonnblick' (PERSON) the spatial distribution of permafrost is investigated by the 'Zentralanstalt für Meteorologie und Geodynamik' (ZAMG) in the Sonnblick area, in the Hohe Tauern in Austria. The aim of PERSON is to identify parameters affecting permafrost (geological, geomorphological, orographical and climatic factors), to determine its spatio-temporal behaviour under present day climate conditions and to estimate its possible future extension under a climate change scenario. PERSON makes use of a permafrost monitoring network that was installed 2005 in the Sonnblick area and is made up by four study sites: On the one hand the spatial extension of permafrost was focused at the ice-dammed lake Pilatus and the rock glacier Zirmsee. On the other hand, at two sites, namely Goldbergspitze and Wintergasse measurements of 'Ground-Surface Temperature' (GST) and 'Bottom Temperatures of the Snow cover' (BTS) are measured. In order to record temperatures in the uppermost layer of the ground and avoid heating by direct solar radiation loggers were buried a few centimetres into the ground or installed in boreholes at depths between 2 and 140 cm. Each of the 'Near Surface Temperature' (NST) borehole mouths is closed up with insulating foam to protect the measurements from atmospheric influence. In addition to these measurements, continuous temperature records from three 20 m deep boreholes located at the southern slope of Hoher Sonnblick are available since 2007, which represent the longest series of its kind in Austria. Furthermore, data from seismic and geoelectric measurements, temperature sensors readings at the surface and extensive meteorological observations from the Sonnblick Observatory are available. Already collected and evaluated data indicate that the thickness of the debris layer around the boreholes reaches a depth of 2 m but no more. The active layer thickness measured in the borehole next to the glacier ranges between

  8. Computing a ground appropriateness index for route selection in permafrost regions

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2017-10-01

    Full Text Available The reasonable calculation of ground appropriateness index in permafrost region is the precondition of highway route design in permafrost region. The theory of knowledge base and fuzzy mathematics are applied, and the damage effect of permafrost is considered in the paper. Based on the idea of protecting permafrost the calculation method of ground appropriateness index is put forward. Firstly, based on the actual environment conditions, the paper determines the factors affecting the road layout in permafrost areas by qualitative and quantitative analysis, including the annual slope, the average annual ground temperature of permafrost, the amount of ice in frozen soil, and the interference engineering. Secondly, based on the knowledge base theory and the use of Delphi method, the paper establishes the knowledge base, the rule base of the permafrost region and inference mechanism. The method of selecting the road in permafrost region is completed and realized by using the software platform. Thirdly, taking the Tuotuo River to Kaixin Mountain section of permafrost region as an example, the application of the method is studied by using an ArcGIS platform. Results show that the route plan determined by the method of selecting the road in permafrost region can avoid the high temperature and high ice content area, conform the terrain changes and evade the heat disturbance among the existing projects. A reasonable route plan can be achieved, and it can provide the basis for the next engineering construction.

  9. The WATERMED field experiment: validation of the AATSR LST product with in situ measurements

    Science.gov (United States)

    Noyes, E.; Soria, G.; Sobrino, J.; Remedios, J.; Llewellyn-Jones, D.; Corlett, G.

    The Advanced Along-Track Scanning Radiometer (AATSR) onboard ESA's Envisat Satellite, is the third in a series of a precision radiometers designed to measure Sea Surface Temperature (SST) with accuracies of better than ± 0.3 K (within 1-sigma limit). Since its launch in March 2001, a prototype AATSR Land Surface Temperature (LST) product has been produced for validation purposes only, with the product becoming operational from mid-2004. The (A)ATSR instrument design is unique in that it has both a nadir- and a forward-view, allowing the Earth's surface to be viewed along two different atmospheric path lengths, thus enabling an improved atmospheric correction to be made when retrieving surface temperature. It also uses an innovative and exceptionally stable on-board calibration system for its infrared channels, which, together with actively cooled detectors, gives extremely high radiometric sensitivity and precision. In this presentation, results from a comparison of the prototype LST product with ground-based measurements obtained at the WATERMED (WATer use Efficiency in natural vegetation and agricultural areas by Remote sensing in the MEDiterranean basin) field site near Marrakech, Morocco, are presented. The comparison shows that the AATSR has a positive bias of + 1.5 K, with a standard deviation of 0.7 K, indicating that the product is operating within the target specification (± 2.5 K) over the WATERMED field site. However, several anomalous validation points were observed during the analysis and we will discuss possible reasons for the occurrence of these data, including their coincidence with the presence of an Envisat blanking pulse (indicating the presence of a radar pulse at the time of AATSR pixel integration). Further investigation into this matter is required as previous investigations have always indicated that the presence of a payload radar pulse does not have any effect on (A)ATSR data quality.

  10. Permafrost Stores a Globally Significant Amount of Mercury

    Science.gov (United States)

    Schuster, Paul F.; Schaefer, Kevin M.; Aiken, George R.; Antweiler, Ronald C.; Dewild, John F.; Gryziec, Joshua D.; Gusmeroli, Alessio; Hugelius, Gustaf; Jafarov, Elchin; Krabbenhoft, David P.; Liu, Lin; Herman-Mercer, Nicole; Mu, Cuicui; Roth, David A.; Schaefer, Tim; Striegl, Robert G.; Wickland, Kimberly P.; Zhang, Tingjun

    2018-02-01

    Changing climate in northern regions is causing permafrost to thaw with major implications for the global mercury (Hg) cycle. We estimated Hg in permafrost regions based on in situ measurements of sediment total mercury (STHg), soil organic carbon (SOC), and the Hg to carbon ratio (RHgC) combined with maps of soil carbon. We measured a median STHg of 43 ± 30 ng Hg g soil-1 and a median RHgC of 1.6 ± 0.9 μg Hg g C-1, consistent with published results of STHg for tundra soils and 11,000 measurements from 4,926 temperate, nonpermafrost sites in North America and Eurasia. We estimate that the Northern Hemisphere permafrost regions contain 1,656 ± 962 Gg Hg, of which 793 ± 461 Gg Hg is frozen in permafrost. Permafrost soils store nearly twice as much Hg as all other soils, the ocean, and the atmosphere combined, and this Hg is vulnerable to release as permafrost thaws over the next century. Existing estimates greatly underestimate Hg in permafrost soils, indicating a need to reevaluate the role of the Arctic regions in the global Hg cycle.

  11. Permafrost stores a globally significant amount of mercury

    Science.gov (United States)

    Schuster, Paul F.; Schaefer, Kevin; Aiken, George R.; Antweiler, Ronald C.; DeWild, John F.; Gryziec, Joshua D.; Gusmeroli, Alessio; Hugelius, Gustaf; Jafarov, Elchin E.; Krabbenhoft, David P.; Liu, Lin; Herman-Mercer, Nicole M.; Mu, Cuicui; Roth, David A.; Schaefer, Tim; Striegl, Robert G.; Wickland, Kimberly P.; Zhang, Tingjun

    2018-01-01

    Changing climate in northern regions is causing permafrost to thaw with major implications for the global mercury (Hg) cycle. We estimated Hg in permafrost regions based on in situ measurements of sediment total mercury (STHg), soil organic carbon (SOC), and the Hg to carbon ratio (RHgC) combined with maps of soil carbon. We measured a median STHg of 43 ± 30 ng Hg g soil−1 and a median RHgC of 1.6 ± 0.9 μg Hg g C−1, consistent with published results of STHg for tundra soils and 11,000 measurements from 4,926 temperate, nonpermafrost sites in North America and Eurasia. We estimate that the Northern Hemisphere permafrost regions contain 1,656 ± 962 Gg Hg, of which 793 ± 461 Gg Hg is frozen in permafrost. Permafrost soils store nearly twice as much Hg as all other soils, the ocean, and the atmosphere combined, and this Hg is vulnerable to release as permafrost thaws over the next century. Existing estimates greatly underestimate Hg in permafrost soils, indicating a need to reevaluate the role of the Arctic regions in the global Hg cycle.

  12. Improving permafrost distribution modelling using feature selection algorithms

    Science.gov (United States)

    Deluigi, Nicola; Lambiel, Christophe; Kanevski, Mikhail

    2016-04-01

    The availability of an increasing number of spatial data on the occurrence of mountain permafrost allows the employment of machine learning (ML) classification algorithms for modelling the distribution of the phenomenon. One of the major problems when dealing with high-dimensional dataset is the number of input features (variables) involved. Application of ML classification algorithms to this large number of variables leads to the risk of overfitting, with the consequence of a poor generalization/prediction. For this reason, applying feature selection (FS) techniques helps simplifying the amount of factors required and improves the knowledge on adopted features and their relation with the studied phenomenon. Moreover, taking away irrelevant or redundant variables from the dataset effectively improves the quality of the ML prediction. This research deals with a comparative analysis of permafrost distribution models supported by FS variable importance assessment. The input dataset (dimension = 20-25, 10 m spatial resolution) was constructed using landcover maps, climate data and DEM derived variables (altitude, aspect, slope, terrain curvature, solar radiation, etc.). It was completed with permafrost evidences (geophysical and thermal data and rock glacier inventories) that serve as training permafrost data. Used FS algorithms informed about variables that appeared less statistically important for permafrost presence/absence. Three different algorithms were compared: Information Gain (IG), Correlation-based Feature Selection (CFS) and Random Forest (RF). IG is a filter technique that evaluates the worth of a predictor by measuring the information gain with respect to the permafrost presence/absence. Conversely, CFS is a wrapper technique that evaluates the worth of a subset of predictors by considering the individual predictive ability of each variable along with the degree of redundancy between them. Finally, RF is a ML algorithm that performs FS as part of its

  13. Permafrost Hazards and Linear Infrastructure

    Science.gov (United States)

    Stanilovskaya, Julia; Sergeev, Dmitry

    2014-05-01

    The international experience of linear infrastructure planning, construction and exploitation in permafrost zone is being directly tied to the permafrost hazard assessment. That procedure should also consider the factors of climate impact and infrastructure protection. The current global climate change hotspots are currently polar and mountain areas. Temperature rise, precipitation and land ice conditions change, early springs occur more often. The big linear infrastructure objects cross the territories with different permafrost conditions which are sensitive to the changes in air temperature, hydrology, and snow accumulation which are connected to climatic dynamics. One of the most extensive linear structures built on permafrost worldwide are Trans Alaskan Pipeline (USA), Alaska Highway (Canada), Qinghai-Xizang Railway (China) and Eastern Siberia - Pacific Ocean Oil Pipeline (Russia). Those are currently being influenced by the regional climate change and permafrost impact which may act differently from place to place. Thermokarst is deemed to be the most dangerous process for linear engineering structures. Its formation and development depend on the linear structure type: road or pipeline, elevated or buried one. Zonal climate and geocryological conditions are also of the determining importance here. All the projects are of the different age and some of them were implemented under different climatic conditions. The effects of permafrost thawing have been recorded every year since then. The exploration and transportation companies from different countries maintain the linear infrastructure from permafrost degradation in different ways. The highways in Alaska are in a good condition due to governmental expenses on annual reconstructions. The Chara-China Railroad in Russia is under non-standard condition due to intensive permafrost response. Standards for engineering and construction should be reviewed and updated to account for permafrost hazards caused by the

  14. Grey relation projection model for evaluating permafrost environment in the Muli coal mining area, China

    Energy Technology Data Exchange (ETDEWEB)

    Wei Cao; Yu Sheng; Yinghong Qin; Jing Li; Jichun Wu [Chinese Academy of Sciences, Lanzhou (China). State Key Laboratory of Frozen Soil Engineering

    2010-12-15

    This study attempts to estimate the current stage of the permafrost environment in the Muli coal mining area, an opencast mining site in the Qinghai-Tibet plateau, China. The estimation is done by regarding this site's permafrost environment as a system which was divided into three subsystems consisting of permafrost freeze-thaw erosion sensibility, permafrost thermal stability, and permafrost ecological fragility. The subsystems were characterized with their influencing indicators, each of which was assigned with a weight according to analytic hierarchy process. The relationship between these indictors is established using an environmental evaluation model based on grey system theory. The evaluated results show that currently the normalised grey relation projection values (GRPV) of permafrost freezing-thawing erosion sensibility, permafrost thermal stability, permafrost ecological fragility and permafrost environment are 0.58 (general situation), 0.47 (bad situation), 0.63 (general situation) and 0.56 (general situation), respectively. These values imply that the permafrost environment has been deteriorated to a certain degree by human activities and potentially could be further degraded. However, at this degree, a new equilibrium could be achieved if the current environmental degradation ratio is held and if effective treatments are constructed against further damages.

  15. Discovery of a novel methanogen prevalent in thawing permafrost.

    Science.gov (United States)

    Mondav, Rhiannon; Woodcroft, Ben J; Kim, Eun-Hae; McCalley, Carmody K; Hodgkins, Suzanne B; Crill, Patrick M; Chanton, Jeffrey; Hurst, Gregory B; VerBerkmoes, Nathan C; Saleska, Scott R; Hugenholtz, Philip; Rich, Virginia I; Tyson, Gene W

    2014-01-01

    Thawing permafrost promotes microbial degradation of cryo-sequestered and new carbon leading to the biogenic production of methane, creating a positive feedback to climate change. Here we determine microbial community composition along a permafrost thaw gradient in northern Sweden. Partially thawed sites were frequently dominated by a single archaeal phylotype, Candidatus 'Methanoflorens stordalenmirensis' gen. nov. sp. nov., belonging to the uncultivated lineage 'Rice Cluster II' (Candidatus 'Methanoflorentaceae' fam. nov.). Metagenomic sequencing led to the recovery of its near-complete genome, revealing the genes necessary for hydrogenotrophic methanogenesis. These genes are highly expressed and methane carbon isotope data are consistent with hydrogenotrophic production of methane in the partially thawed site. In addition to permafrost wetlands, 'Methanoflorentaceae' are widespread in high methane-flux habitats suggesting that this lineage is both prevalent and a major contributor to global methane production. In thawing permafrost, Candidatus 'M. stordalenmirensis' appears to be a key mediator of methane-based positive feedback to climate warming.

  16. Diagnostic and model dependent uncertainty of simulated Tibetan permafrost area

    Science.gov (United States)

    Wang, A.; Moore, J.C.; Cui, Xingquan; Ji, D.; Li, Q.; Zhang, N.; Wang, C.; Zhang, S.; Lawrence, D.M.; McGuire, A.D.; Zhang, W.; Delire, C.; Koven, C.; Saito, K.; MacDougall, A.; Burke, E.; Decharme, B.

    2016-01-01

     We perform a land-surface model intercomparison to investigate how the simulation of permafrost area on the Tibetan Plateau (TP) varies among six modern stand-alone land-surface models (CLM4.5, CoLM, ISBA, JULES, LPJ-GUESS, UVic). We also examine the variability in simulated permafrost area and distribution introduced by five different methods of diagnosing permafrost (from modeled monthly ground temperature, mean annual ground and air temperatures, air and surface frost indexes). There is good agreement (99 to 135  ×  104 km2) between the two diagnostic methods based on air temperature which are also consistent with the observation-based estimate of actual permafrost area (101  × 104 km2). However the uncertainty (1 to 128  ×  104 km2) using the three methods that require simulation of ground temperature is much greater. Moreover simulated permafrost distribution on the TP is generally only fair to poor for these three methods (diagnosis of permafrost from monthly, and mean annual ground temperature, and surface frost index), while permafrost distribution using air-temperature-based methods is generally good. Model evaluation at field sites highlights specific problems in process simulations likely related to soil texture specification, vegetation types and snow cover. Models are particularly poor at simulating permafrost distribution using the definition that soil temperature remains at or below 0 °C for 24 consecutive months, which requires reliable simulation of both mean annual ground temperatures and seasonal cycle, and hence is relatively demanding. Although models can produce better permafrost maps using mean annual ground temperature and surface frost index, analysis of simulated soil temperature profiles reveals substantial biases. The current generation of land-surface models need to reduce biases in simulated soil temperature profiles before reliable contemporary permafrost maps and predictions of changes in future

  17. Permafrost Thaw increases Emissions of Nitrous Oxide from Subarctic Peatlands

    Science.gov (United States)

    Voigt, C.; Marushchak, M. E.; Lamprecht, R. E.; Jackowicz-Korczynski, M.; Lindgren, A.; Mastepanov, M.; Christensen, T. R.; Granlund, L.; Tahvanainen, T.; Martikainen, P. J.; Biasi, C.

    2017-12-01

    Permafrost soils in the Arctic are thawing, exposing not only carbon but also large nitrogen stocks. The decomposition of this vast pool of long-term immobile C and N stocks results in the release of greenhouse gases to the atmosphere. Among these, carbon dioxide (CO2) and methane (CH4) are being studied extensively, and gaseous C release from thawing permafrost is known to be substantial. Most recent studies, however, show that Arctic soils may further be a relevant source of the strong greenhouse gas nitrous oxide (N2O). As N2O is almost 300 times more powerful in warming the climate than CO2 based on a 100-yr time horizon, the release of N2O from thawing permafrost could create a significant non-carbon permafrost-climate feedback. To study the effect of permafrost thaw on N2O fluxes, we collected peat mesocosms from a Subarctic permafrost peatland, and subjected these intact soil-plant systems to sequential thawing from the top of the active layer down to the upper permafrost layer. Measurements of N2O fluxes were coupled with detailed soil analyses and process studies. Since N2O fluxes are highly dependent on moisture conditions and vegetation cover, we applied two distinct moisture treatments (dry vs. wet) and simulated permafrost thaw in vegetated as well as in naturally bare mesocosms. Under dry conditions, permafrost thaw clearly increased N2O emissions. We observed the largest post-thaw emissions from bare peat surfaces, a typical landform in subarctic peatlands previously identified as hot spots for Arctic N2O emissions. There, permafrost thaw caused a five-fold increase in emissions (0.56 vs. 2.81 mg N2O m-2 d-1). While water-logged conditions suppressed N2O emissions, the presence of vegetation lowered, but did not prevent post-thaw N2O release. Based on these findings, we show that one fourth of the Arctic land area could be vulnerable for N2O emissions when permafrost thaws. Our results demonstrate that Arctic N2O emissions may be larger than

  18. NORPERM, the Norwegian Permafrost Database - a TSP NORWAY IPY legacy

    Science.gov (United States)

    Juliussen, H.; Christiansen, H. H.; Strand, G. S.; Iversen, S.; Midttømme, K.; Rønning, J. S.

    2010-10-01

    NORPERM, the Norwegian Permafrost Database, was developed at the Geological Survey of Norway during the International Polar Year (IPY) 2007-2009 as the main data legacy of the IPY research project Permafrost Observatory Project: A Contribution to the Thermal State of Permafrost in Norway and Svalbard (TSP NORWAY). Its structural and technical design is described in this paper along with the ground temperature data infrastructure in Norway and Svalbard, focussing on the TSP NORWAY permafrost observatory installations in the North Scandinavian Permafrost Observatory and Nordenskiöld Land Permafrost Observatory, being the primary data providers of NORPERM. Further developments of the database, possibly towards a regional database for the Nordic area, are also discussed. The purpose of NORPERM is to store ground temperature data safely and in a standard format for use in future research. The IPY data policy of open, free, full and timely release of IPY data is followed, and the borehole metadata description follows the Global Terrestrial Network for Permafrost (GTN-P) standard. NORPERM is purely a temperature database, and the data is stored in a relation database management system and made publically available online through a map-based graphical user interface. The datasets include temperature time series from various depths in boreholes and from the air, snow cover, ground-surface or upper ground layer recorded by miniature temperature data-loggers, and temperature profiles with depth in boreholes obtained by occasional manual logging. All the temperature data from the TSP NORWAY research project is included in the database, totalling 32 temperature time series from boreholes, 98 time series of micrometeorological temperature conditions, and 6 temperature depth profiles obtained by manual logging in boreholes. The database content will gradually increase as data from previous and future projects are added. Links to near real-time permafrost temperatures, obtained

  19. Thermokarst transformation of permafrost preserved glaciated landscapes.

    Science.gov (United States)

    Kokelj, S.; Tunnicliffe, J. F.; Fraser, R.; Kokoszka, J.; Lacelle, D.; Lantz, T. C.; Lamoureux, S. F.; Rudy, A.; Shakil, S.; Tank, S. E.; van der Sluijs, J.; Wolfe, S.; Zolkos, S.

    2017-12-01

    Thermokarst is the fundamental mechanism of landscape change and a primary driver of downstream effects in a warming circumpolar world. Permafrost degradation is inherently non-linear because latent heat effects can inhibit thawing. However, once this thermal transition is crossed thermokarst can accelerate due to the interaction of thermal, physical and ecological feedbacks. In this paper we highlight recent climate and precipitation-driven intensification of thaw slumping that is transforming permafrost preserved glaciated landscapes in northwestern Canada. The continental distribution of slump affected terrain reflects glacial extents and recessional positions of the Laurentide Ice sheet. On this basis and in conjunction with intense thermokarst in cold polar environments, we highlight the critical roles of geological legacy and climate history in dictating the sensitivity of permafrost terrain. These glaciated landscapes, maintained in a quasi-stable state throughout much of the late Holocene are now being transformed into remarkably dynamic environments by climate-driven thermokarst. Individual disturbances displace millions of cubic metres of previously frozen material downslope, converting upland sedimentary stores into major source areas. Precipitation-driven evacuation of sediment by fluidized mass flows perpetuates non-linear enlargement of disturbances. The infilling of valleys with debris deposits tens of metres thick increases stream base-levels and promotes rapid valley-side erosion. These processes destabilize adjacent slopes and proliferate disturbance effects. Physically-based modeling of thaw slump development provides insight into the trajectories of landscape change, and the mapping of fluvial linkages portrays the cascade of effects across watershed scales. Post-glacial or "paraglacial" models of landscape evolution provide a useful framework for understanding the nature and magnitude of climate-driven changes in permafrost preserved glaciated

  20. Subsea Permafrost Mapped Across the U.S. Beaufort Sea Using Multichannel Seismic Data

    Science.gov (United States)

    Brothers, L.; Hart, P. E.; Ruppel, C. D.

    2011-12-01

    Circum-Arctic continental shelves at water depths less than ~100 m were subaerial permafrost prior to the onset of sea-level rise starting in the late Pleistocene. Rapid transgression and the resulting temperature increase at the sediment surface have led to thawing of the inundated permafrost, landward retreat of the leading edge of the permafrost, and dissociation of permafrost-associated gas hydrates. Past numerical modeling has shown that gas hydrate dissociation is particularly pronounced at the permafrost-to-no permafrost transition offshore. On the U.S. Beaufort margin, subsea permafrost has never been systematically mapped, and the best insights about permafrost and associated gas hydrate have been based on a limited number of offshore boreholes and numerical studies, with sometimes contrasting predictions of the permafrost's seaward extent. We bring together 5370 km of multichannel seismic (MCS) data acquired during various proprietary exploration industry and public domain government surveys between 1977 and 1992 to map a velocity anomaly diagnostic of submerged permafrost along 500 km of the US Beaufort coastline. These high-velocity (>~2.8 km/s) refractions (HVR), which are evident in prestack MCS shot records, reveal laterally continuous layers of shallow, ice-bonded, coarse-grained sediments beneath the inner continental shelf. The HVR occur in less than 5% of the tracklines, and calculated HVR depths range from 60 to 350 m below seafloor. The velocity anomaly is not observed seaward of the 20 m isobath, and is only found within 30 km of the current shoreline. These results can be used to: 1) create a map of the minimum distribution of remaining US Beaufort shelf subsea permafrost; 2) reconcile discrepancies between model-predicted and borehole-verified offshore permafrost distribution; and 3) constrain where to expect hydrate dissociation.

  1. Effect of permafrost properties on gas hydrate petroleum system in the Qilian Mountains, Qinghai, Northwest China.

    Science.gov (United States)

    Wang, Pingkang; Zhang, Xuhui; Zhu, Youhai; Li, Bing; Huang, Xia; Pang, Shouji; Zhang, Shuai; Lu, Cheng; Xiao, Rui

    2014-12-01

    The gas hydrate petroleum system in the permafrost of the Qilian Mountains, which exists as an epigenetic hydrocarbon reservoir above a deep-seated hydrocarbon reservoir, has been dynamic since the end of the Late Pleistocene because of climate change. The permafrost limits the occurrence of gas hydrate reservoirs by changing the pressure-temperature (P-T) conditions, and it affects the migration of the underlying hydrocarbon gas because of its strong sealing ability. In this study, we reconstructed the permafrost structure of the Qilian Mountains using a combination of methods and measured methane permeability in ice-bearing sediment permafrost. A relationship between the ice saturation of permafrost and methane permeability was established, which permitted the quantitative evaluation of the sealing ability of permafrost with regard to methane migration. The test results showed that when ice saturation is >80%, methane gas can be completely sealed within the permafrost. Based on the permafrost properties and genesis of shallow gas, we suggest that a shallow "gas pool" occurred in the gas hydrate petroleum system in the Qilian Mountains. Its formation was related to a metastable gas hydrate reservoir controlled by the P-T conditions, sealing ability of the permafrost, fault system, and climatic warming. From an energy perspective, the increasing volume of the gas pool means that it will likely become a shallow gas resource available for exploitation; however, for the environment, the gas pool is an underground "time bomb" that is a potential source of greenhouse gas.

  2. Quantifying uncertainties of permafrost carbon–climate feedbacks

    Directory of Open Access Journals (Sweden)

    E. J. Burke

    2017-06-01

    Full Text Available The land surface models JULES (Joint UK Land Environment Simulator, two versions and ORCHIDEE-MICT (Organizing Carbon and Hydrology in Dynamic Ecosystems, each with a revised representation of permafrost carbon, were coupled to the Integrated Model Of Global Effects of climatic aNomalies (IMOGEN intermediate-complexity climate and ocean carbon uptake model. IMOGEN calculates atmospheric carbon dioxide (CO2 and local monthly surface climate for a given emission scenario with the land–atmosphere CO2 flux exchange from either JULES or ORCHIDEE-MICT. These simulations include feedbacks associated with permafrost carbon changes in a warming world. Both IMOGEN–JULES and IMOGEN–ORCHIDEE-MICT were forced by historical and three alternative future-CO2-emission scenarios. Those simulations were performed for different climate sensitivities and regional climate change patterns based on 22 different Earth system models (ESMs used for CMIP3 (phase 3 of the Coupled Model Intercomparison Project, allowing us to explore climate uncertainties in the context of permafrost carbon–climate feedbacks. Three future emission scenarios consistent with three representative concentration pathways were used: RCP2.6, RCP4.5 and RCP8.5. Paired simulations with and without frozen carbon processes were required to quantify the impact of the permafrost carbon feedback on climate change. The additional warming from the permafrost carbon feedback is between 0.2 and 12 % of the change in the global mean temperature (ΔT by the year 2100 and 0.5 and 17 % of ΔT by 2300, with these ranges reflecting differences in land surface models, climate models and emissions pathway. As a percentage of ΔT, the permafrost carbon feedback has a greater impact on the low-emissions scenario (RCP2.6 than on the higher-emissions scenarios, suggesting that permafrost carbon should be taken into account when evaluating scenarios of heavy mitigation and stabilization

  3. Distinct summer and winter bacterial communities in the active layer of Svalbard permafrost revealed by DNA- and RNA-based analyses

    Science.gov (United States)

    Schostag, Morten; Stibal, Marek; Jacobsen, Carsten S.; Bælum, Jacob; Taş, Neslihan; Elberling, Bo; Jansson, Janet K.; Semenchuk, Philipp; Priemé, Anders

    2015-01-01

    The active layer of soil overlaying permafrost in the Arctic is subjected to dramatic annual changes in temperature and soil chemistry, which likely affect bacterial activity and community structure. We studied seasonal variations in the bacterial community of active layer soil from Svalbard (78°N) by co-extracting DNA and RNA from 12 soil cores collected monthly over a year. PCR amplicons of 16S rRNA genes (DNA) and reverse transcribed transcripts (cDNA) were quantified and sequenced to test for the effect of low winter temperature and seasonal variation in concentration of easily degradable organic matter on the bacterial communities. The copy number of 16S rRNA genes and transcripts revealed no distinct seasonal changes indicating potential bacterial activity during winter despite soil temperatures well below −10°C. Multivariate statistical analysis of the bacterial diversity data (DNA and cDNA libraries) revealed a season-based clustering of the samples, and, e.g., the relative abundance of potentially active Cyanobacteria peaked in June and Alphaproteobacteria increased over the summer and then declined from October to November. The structure of the bulk (DNA-based) community was significantly correlated with pH and dissolved organic carbon, while the potentially active (RNA-based) community structure was not significantly correlated with any of the measured soil parameters. A large fraction of the 16S rRNA transcripts was assigned to nitrogen-fixing bacteria (up to 24% in June) and phototrophic organisms (up to 48% in June) illustrating the potential importance of nitrogen fixation in otherwise nitrogen poor Arctic ecosystems and of phototrophic bacterial activity on the soil surface. PMID:25983731

  4. Permafrost and organic layer interactions over a climate gradient in a discontinuous permafrost zone

    Science.gov (United States)

    Kristofer D. Johnson; Jennifer W. Harden; A. David McGuire; Mark Clark; Fengming Yuan; Andrew O. Finley

    2013-01-01

    Permafrost is tightly coupled to the organic soil layer, an interaction that mediates permafrost degradation in response to regional warming. We analyzed changes in permafrost occurrence and organic layer thickness (OLT) using more than 3000 soil pedons across a mean annual temperature (MAT) gradient. Cause and effect relationships between permafrost probability (PF),...

  5. Quantifying shallow and deep permafrost changes using radar remote sensing

    Science.gov (United States)

    Teshebaeva, K.; van Huissteden, K. J.

    2017-12-01

    Widespread thawing of permafrost in the northern Eurasian continent cause severe problems for infrastructure and global climate. Permafrost thaw by climate warming creates land surface instability, resulting in severe problems for infrastructure, and release of organic matter to the atmosphere as CO2 and CH4. Recent discoveries of CH4 seeps in lakes, in the Arctic Ocean, and CH4 emitting craters in the permafrost. These features indicate that permafrost destabilization might no longer be a surface feature only, but that also deeper layers of the permafrost, up to tens of meters, may be affected by warming. We study two potential areas in Siberian arctic; one of the test site is the Kytalyk research station near Chokurdagh town affected with a recent inundation of the Indigirka river in July 2017, which resulted in standing surface water for the period over a month. The wet soil and standing water may cause changes in active layer thickness and influence the thermal regime of the permafrost for the next decades in the region. The second test site is Yamal peninsula with recently CH4 emitting craters, which may start to contribute to emission hotspots. We hypothesize that these deeper subsurface processes also can be detected by mapping surface elevation changes using advanced SAR techniques. We test the potential of SAR imagery to enhance detection of these features, including surface movement related to permafrost active layer changes using InSAR time-series analysis. We also apply radar backscatter signal to detect seasonal changes related to the freeze-thaw cycles. The PRISM elevation data are used to estimate elevation changes in the region along with ground-based geophysical and geodetical fieldwork.

  6. Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

    DEFF Research Database (Denmark)

    Swindles, Graeme T.; Amesbury, Matthew J.; Turner, T. Edward

    2015-01-01

    The melting of high-latitude permafrost peatlands is a major concern due to a potential positive feedback on global climate change. We examine the ecology of testate amoebae in permafrost peatlands, based on sites in Sweden (similar to 200 km north of the Arctic Circle). Multivariate statistical ...

  7. Circumpolar Active-Layer Permafrost System (CAPS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Circumpolar Active-Layer Permafrost System (CAPS) contains over 100 data sets pertaining to permafrost and frozen ground topics. It also contains detailed...

  8. Permafrost Meta-Omics and Climate Change

    DEFF Research Database (Denmark)

    Mackelprang, Rachel; Saleska, Scott R.; Jacobsen, Carsten Suhr

    2016-01-01

    Permanently frozen soil, or permafrost, covers a large portion of the Earth's terrestrial surface and represents a unique environment for cold-adapted microorganisms. As permafrost thaws, previously protected organic matter becomes available for microbial degradation. Microbes that decompose soil...

  9. Spatio-temporal prediction of daily temperatures using time-series of MODIS LST images

    NARCIS (Netherlands)

    Hengl, T.; Heuvelink, G.B.M.; Percec Tadic, M.; Pebesma, E.J.

    2012-01-01

    A computational framework to generate daily temperature maps using time-series of publicly available MODIS MOD11A2 product Land Surface Temperature (LST) images (1 km resolution; 8-day composites) is illustrated using temperature measurements from the national network of meteorological stations

  10. Mapping air temperature using time series analysis of LST : The SINTESI approach

    NARCIS (Netherlands)

    Alfieri, S.M.; De Lorenzi, F.; Menenti, M.

    2013-01-01

    This paper presents a new procedure to map time series of air temperature (Ta) at fine spatial resolution using time series analysis of satellite-derived land surface temperature (LST) observations. The method assumes that air temperature is known at a single (reference) location such as in gridded

  11. CREST-SAFE: Snow LST validation, wetness profiler creation, and depth/SWE product development

    Science.gov (United States)

    Perez Diaz, C. L.; Lakhankar, T.; Romanov, P.; Khanbilvardi, R.; Munoz Barreto, J.; Yu, Y.

    2017-12-01

    CREST-SAFE: Snow LST validation, wetness profiler creation, and depth/SWE product development The Field Snow Research Station (also referred to as Snow Analysis and Field Experiment, SAFE) is operated by the NOAA Center for Earth System Sciences and Remote Sensing Technologies (CREST) in the City University of New York (CUNY). The field station is located within the premises of the Caribou Municipal Airport (46°52'59'' N, 68°01'07'' W) and in close proximity to the National Weather Service (NWS) Regional Forecast Office. The station was established in 2010 to support studies in snow physics and snow remote sensing. The Visible Infrared Imager Radiometer Suite (VIIRS) Land Surface Temperature (LST) Environmental Data Record (EDR) and Moderate Resolution Imaging Spectroradiometer (MODIS) LST product (provided by the Terra and Aqua Earth Observing System satellites) were validated using in situ LST (T-skin) and near-surface air temperature (T-air) observations recorded at CREST-SAFE for the winters of 2013 and 2014. Results indicate that T-air correlates better than T-skin with VIIRS LST data and that the accuracy of nighttime LST retrievals is considerably better than that of daytime. Several trends in the MODIS LST data were observed, including the underestimation of daytime values and night-time values. Results indicate that, although all the data sets showed high correlation with ground measurements, day values yielded slightly higher accuracy ( 1°C). Additionally, we created a liquid water content (LWC)-profiling instrument using time-domain reflectometry (TDR) at CREST-SAFE and tested it during the snow melt period (February-April) immediately after installation in 2014. Results displayed high agreement when compared to LWC estimates obtained using empirical formulas developed in previous studies, and minor improvement over wet snow LWC estimates. Lastly, to improve on global snow cover mapping, a snow product capable of estimating snow depth and snow water

  12. The BaBar LST Detector High Voltage System: Design And Implementation

    International Nuclear Information System (INIS)

    Benelli, G.; Honscheid, K.; Lewis, E.A.; Regensburger, J.J.; Smith, D.S.; Ohio State U.

    2006-01-01

    In 2004, the first two sextants of the new Limited Streamer Tube (LST) detector were installed in the BABAR experiment to replace the ageing Resistive Plate Chambers (RPCs) as active detectors for the BABAR Instrumented Flux Return (IFR) muon system. Each streamer tube of the new detector consists of 8 cells. The cell walls are coated with graphite paint and a 100 (micro)m wire forms the anode. These wires are coupled in pairs inside the tubes resulting in 4 independent two-cell segments per LST. High voltage (HV) is applied to the 4 segments through a custom connector that also provides the decoupling capacitor to pick up the detector signals from the anode wires. The BABAR LST detector is operated at 5.5 kV. The high voltage system for the LST detector was designed and built at The Ohio State University (OSU HVPS). Each of the 25 supplies built for BaBar provides 80 output channels with individual current monitoring and overcurrent protection. For each group of 20 channels the HV can be adjusted between 0 and 6 kV. A 4-fold fan-out is integrated in the power supplies to provide a total of 320 outputs. The power supplies are controlled through built-in CANbus and Ethernet (TCP/IP) interfaces. In this presentation we will discuss the design and novel features of the OSU HVPS system and its integration into the BABAR EPICS detector control framework. Experience with the supplies operation during the LST extensive quality control program and their performance during the initial data taking period will be discussed

  13. Permafrost degradation in West Greenland

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Ingeman-Nielsen, Thomas

    2012-01-01

    Important aspects of civil engineering in West Greenland relate to the presence of permafrost and mapping of the annual and future changes in the active layer due to the ongoing climatically changes in the Arctic. The Arctic Technology Centre (ARTEK) has worked more than 10 years on this topic...... and the first author has been involved since 1970 in engineering geology, geotechnical engineering and permafrost related studies for foundation construction and infrastructures in towns and communities mainly in West Greenland. We have since 2006 together with the Danish Meteorological Institute, Greenland...... Survey (ASIAQ) and the University of Alaska Fairbanks carried out the US NSF funded project ARC-0612533: Recent and future permafrost variability, retreat and degradation in Greenland and Alaska: An integrated approach. This contribution will present data and observations from the towns Ilulissat...

  14. Continuous recording of seismic signals in Alpine permafrost

    Science.gov (United States)

    Hausmann, H.; Krainer, K.; Staudinger, M.; Brückl, E.

    2009-04-01

    Over the past years various geophysical methods were applied to study the internal structure and the temporal variation of permafrost whereof seismic is of importance. For most seismic investigations in Alpine permafrost 24-channel equipment in combination with long data and trigger cables is used. Due to the harsh environment source and geophone layouts are often limited to 2D profiles. With prospect for future 3D-layouts we introduce an alternative of seismic equipment that can be used for several applications in Alpine permafrost. This study is focussed on controlled and natural source seismic experiments in Alpine permafrost using continuous data recording. With recent data from an ongoing project ("Permafrost in Austria") we will highlight the potential of the used seismic equipment for three applications: (a) seismic permafrost mapping of unconsolidated sediments, (b) seismic tomography in rock mass, and (c) passive seismic monitoring of rock falls. Single recording units (REFTEK 130, 6 channels) are used to continuously record the waveforms of both the seismic signals and a trigger signal. The combination of a small number of recording units with different types of geophones or a trigger allow numerous applications in Alpine permafrost with regard to a high efficiency and flexible seismic layouts (2D, 3D, 4D). The efficiency of the light and robust seismic equipment is achieved by the simple acquisition and the flexible and fast deployment of the (omni-directional) geophones. Further advantages are short (data and trigger) cables and the prevention of trigger errors. The processing of the data is aided by 'Seismon' which is an open source software project based on Matlab® and MySQL (see SM1.0). For active-source experiments automatic stacking of the seismic signals is implemented. For passive data a program for automatic detection of events (e.g. rock falls) is available which allows event localization. In summer 2008 the seismic equipment was used for the

  15. International Field School on Permafrost, Polar Urals, 2012

    Science.gov (United States)

    Streletskiy, D. A.; Grebenets, V.; Ivanov, M.; Sheinkman, V.; Shiklomanov, N. I.; Shmelev, D.

    2012-12-01

    The international field school on permafrost was held in the Polar Urals region from June, 30 to July 9, 2012 right after the Tenth International Conference on Permafrost which was held in Salekhard, Russia. The travel and accommodation support generously provided by government of Yamal-Nenets Autonomous Region allowed participation of 150 permafrost young research scientists, out of which 35 students from seven countries participated in the field school. The field school was organized under umbrella of International Permafrost Association and Permafrost Young Research Network. The students represented diverse educational backgrounds including hydrologists, engineers, geologists, soil scientists, geocryologists, glaciologists and geomorphologists. The base school camp was located near the Harp settlement in the vicinity of Polar Urals foothills. This unique location presented an opportunity to study a diversity of cryogenic processes and permafrost conditions characteristic for mountain and plain regions as well as transition between glacial and periglacial environments. A series of excursions was organized according to the following topics: structural geology of the Polar Urals and West Siberian Plain (Chromite mine "Centralnaya" and Core Storage in Labitnangy city); quaternary geomorphology (investigation of moraine complexes and glacial conditions of Ronamantikov and Topographov glaciers); principles of construction and maintains of structures built on permafrost (Labitnangy city and Obskaya-Bovanenkovo Railroad); methods of temperature and active-layer monitoring in tundra and forest-tundra; cryosols and soil formation in diverse landscape condition; periglacial geomorphology; types of ground ice, etc. Every evening students and professors gave a series of presentations on climate, vegetation, hydrology, soil conditions, permafrost and cryogenic processes of the region as well as on history, economic development, endogenous population of the Siberia and the

  16. a Research on Monitoring Surface Deformation and Relationships with Surface Parameters in Qinghai Tibetan Plateau Permafrost

    Science.gov (United States)

    Mi, S. J.; Li, Y. T.; Wang, F.; Li, L.; Ge, Y.; Luo, L.; Zhang, C. L.; Chen, J. B.

    2017-09-01

    The Qinghai Tibetan Plateau permafrost has been the largest permafrost region in middle-low latitude in the world for its high altitude. For the large area permafrost, especially surface deformation brought by it, have serious influence on the road engineering, road maintaining and regional economic development. Consequently, it is essential to monitor the surface deformation and study factors that influent it. We monitored an area named Wudaoliang from July 25, 2015 to June 1, 2016 and 15 Sentinel images were obtained during this time. The area we chose is about 35 kilometers long and 2 kilometers wide, and the national road 109 of China passes through the area. The traditional PS-INSAR (Persistent Scatterer Interferometric Synthetic Aperture Radar) method is not suitable because less historical images in the research area and leading to the number of PS (Persistent Scatterer) points is not enough to obtain accurate deformation results. Therefore, in this paper, we used another method which named QUASI-PSInSAR (QUASI Persistent Scatterer Interferometric Synthetic Aperture Radar) to acquire deformation for it has the advantage to weaken or eliminate the effects of spatial and temporal correlation, which has proved by other scholar. After processing 15 images in the SARproz software, we got the conclusions that, 1) the biggest deformation velocity in the whole area was about 127.9mm/year and about 109.3 mm/year in the road; 2) apparent deformation which have surface deformation more than 30mm/year was about 1.7Km in the road. Meanwhile, soil moisture(SM), Land surface temperature (LST) and surface water(SW), which are primary parameters of the land surface over the same time were reversed by using Sentinel data, Landsat data and ZY-3 data, respectively. After analyzing SM, LST , SW and deformation, we obtained that wet areas which had bigger SM, lower LST and more SW, had greater percentage of severe deformation than arid areas; besides, deformation pattern were

  17. Detecting geothermal anomalies and evaluating LST geothermal component by combining thermal remote sensing time series and land surface model data

    Science.gov (United States)

    Romaguera, Mireia; Vaughan, R. Greg; Ettema, J.; Izquierdo-Verdiguier, E.; Hecker, C. A.; van der Meer, F.D.

    2018-01-01

    This paper explores for the first time the possibilities to use two land surface temperature (LST) time series of different origins (geostationary Meteosat Second Generation satellite data and Noah land surface modelling, LSM), to detect geothermal anomalies and extract the geothermal component of LST, the LSTgt. We hypothesize that in geothermal areas the LSM time series will underestimate the LST as compared to the remote sensing data, since the former does not account for the geothermal component in its model.In order to extract LSTgt, two approaches of different nature (physical based and data mining) were developed and tested in an area of about 560 × 560 km2 centered at the Kenyan Rift. Pre-dawn data in the study area during the first 45 days of 2012 were analyzed.The results show consistent spatial and temporal LSTgt patterns between the two approaches, and systematic differences of about 2 K. A geothermal area map from surface studies was used to assess LSTgt inside and outside the geothermal boundaries. Spatial means were found to be higher inside the geothermal limits, as well as the relative frequency of occurrence of high LSTgt. Results further show that areas with strong topography can result in anomalously high LSTgt values (false positives), which suggests the need for a slope and aspect correction in the inputs to achieve realistic results in those areas. The uncertainty analysis indicates that large uncertainties of the input parameters may limit detection of LSTgt anomalies. To validate the approaches, higher spatial resolution images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data over the Olkaria geothermal field were used. An established method to estimate radiant geothermal flux was applied providing values between 9 and 24 W/m2 in the geothermal area, which coincides with the LSTgt flux rates obtained with the proposed approaches.The proposed approaches are a first step in estimating LSTgt

  18. The microbial diversity, distribution, and ecology of permafrost in China: a review.

    Science.gov (United States)

    Hu, Weigang; Zhang, Qi; Tian, Tian; Cheng, Guodong; An, Lizhe; Feng, Huyuan

    2015-07-01

    Permafrost in China mainly located in high-altitude areas. It represents a unique and suitable ecological niche that can be colonized by abundant microbes. Permafrost microbial community varies across geographically separated locations in China, and some lineages are novel and possible endemic. Besides, Chinese permafrost is a reservoir of functional microbial groups involved in key biogeochemical cycling processes. In future, more work is necessary to determine if these phylogenetic groups detected by DNA-based methods are part of the viable microbial community, and their functional roles and how they potentially respond to climate change. This review summaries recent studies describing microbial biodiversity found in permafrost and associated environments in China, and provides a framework for better understanding the microbial ecology of permafrost.

  19. Mapping ice-bonded permafrost with electrical methods in Sisimiut, West Greenland

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas

    2006-01-01

    Permafrost delineation and thickness determination is of great importance in engineering related projects in arctic areas. In this paper, 2D geoelectrical measurements are applied and evaluated for permafrost mapping in an area in West Greenland. Multi-electrode resistivity profiles (MEP) have been...... collected and are compared with borehole information. It is shown that the permafrost thickness in this case is grossly overestimated by a factor of two to three. The difference between the inverted 2D resistivity sections and the borehole information is explained by macro-anisotropy due to the presence...... of horizontal ice-lenses in the frozen clay deposits. It is concluded that where the resistivity method perform well for lateral permafrost mapping, great care should be taken in evaluating permafrost thickness based on 2D resistivity profiles alone. Additional information from boreholes or other geophysical...

  20. Permafrost at Lupin. Interpretation of SAMPO electromagnetic soundings at Lupin

    International Nuclear Information System (INIS)

    Paananen, M.; Ruskeeniemi, T.

    2003-01-01

    The Permafrost Project at the Lupin Mine in northern Canada is an international project, aiming to improve the understanding of behaviour and processes of crystalline bedrock under permafrost conditions. As a part of this project, the Geological Survey of Finland carried out electromagnetic SAMPO soundings in the vicinity of the mine between 11th and 23rd of June 2002 in order to give additional information on the permafrost depth, the location and electrical characteristics of fracture zones and possible talik structures. The total number of sounding points was 214, forming 17 separate survey lines. Used coil separation was 100 - 800 m. According to the temperature data from Lupin Mine, the base of the permafrost is at the depth of 540 m. However, there is no information about the depth distribution outside the mine. The starting point of this survey was the possible existence of a saline water horizon below the permafrost, resulting from repeated segregation and enrichment of salts in front of advancing freezing front. The main result of the survey was a deep conductor, observed at numerous sounding points irrespectively of the measurement configuration. These sounding anomalies form a subhorizontal layer at the depths between 400 and 700 m, in contrast to the vertical orientation of the geological units in the area. According to the results, the conductor gets weaker or deeper close to the Lake Contwoyto and seems to be absent below the lake. There also seems to be a lithological control, since the conducting layer is not observed in granodiorite. It is assumed that the conducting layer represents saline or brackish waters at the base of the permafrost; their calculated TDS-values are in a realistic range for such waters (5000-30 000 mg/l). The subvertical fracture zone VI, previously interpreted from the seismic survey, could be observed as a slight decrease in resistivity in 3 survey profiles using a coil separation of 100 m. (orig.)

  1. Permafrost at Lupin. Interpretation of SAMPO electromagnetic soundings at Lupin

    Energy Technology Data Exchange (ETDEWEB)

    Paananen, M.; Ruskeeniemi, T

    2003-07-01

    The Permafrost Project at the Lupin Mine in northern Canada is an international project, aiming to improve the understanding of behaviour and processes of crystalline bedrock under permafrost conditions. As a part of this project, the Geological Survey of Finland carried out electromagnetic SAMPO soundings in the vicinity of the mine between 11th and 23rd of June 2002 in order to give additional information on the permafrost depth, the location and electrical characteristics of fracture zones and possible talik structures. The total number of sounding points was 214, forming 17 separate survey lines. Used coil separation was 100 - 800 m. According to the temperature data from Lupin Mine, the base of the permafrost is at the depth of 540 m. However, there is no information about the depth distribution outside the mine. The starting point of this survey was the possible existence of a saline water horizon below the permafrost, resulting from repeated segregation and enrichment of salts in front of advancing freezing front. The main result of the survey was a deep conductor, observed at numerous sounding points irrespectively of the measurement configuration. These sounding anomalies form a subhorizontal layer at the depths between 400 and 700 m, in contrast to the vertical orientation of the geological units in the area. According to the results, the conductor gets weaker or deeper close to the Lake Contwoyto and seems to be absent below the lake. There also seems to be a lithological control, since the conducting layer is not observed in granodiorite. It is assumed that the conducting layer represents saline or brackish waters at the base of the permafrost; their calculated TDS-values are in a realistic range for such waters (5000-30 000 mg/l). The subvertical fracture zone VI, previously interpreted from the seismic survey, could be observed as a slight decrease in resistivity in 3 survey profiles using a coil separation of 100 m. (orig.)

  2. Historical and Possible Future Changes in Permafrost and Active Layer Thickness in Alaska: Implications to Landscape Changes and Permafrost Carbon Pool.

    Science.gov (United States)

    Marchenko, S. S.; Helene, G.; Euskirchen, E. S.; Breen, A. L.; McGuire, D.; Rupp, S. T.; Romanovsky, V. E.; Walsh, J. E.

    2017-12-01

    The Soil Temperature and Active Layer Thickness (ALT) Gridded Data was developed to quantify the nature and rate of permafrost degradation and its impact on ecosystems, infrastructure, CO2 and CH4 fluxes and net C storage following permafrost thaw across Alaska. To develop this database, we used the process-based permafrost dynamics model GIPL2 developed in the Geophysical Institute Permafrost Lab, UAF and which is the permafrost module of the Integrated Ecosystem Model (IEM) for Alaska and Northwest Canada. The climate forcing data for simulations were developed by the Scenarios Network for Alaska and Arctic Planning (SNAP, http://www.snap.uaf.edu/). These data are based on the historical CRU3.1 data set for the retrospective analysis period (1901-2009) and the five model averaged data were derived from the five CMIP5/AR5 IPCC Global Circulation Models that performed the best in Alaska and other northern regions: NCAR-CCSM4, GFDL-CM3, GISS-E2-R, IPSL-CM5A-LR, MRI-CGCM3. A composite of all five-model outputs for the RCP4.5 and RCP8.5 were used in these particular permafrost dynamics simulations. Data sets were downscaled to a 771 m resolution, using the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climatology. Additional input data (snow characteristics, soil thermal properties, soil water content, organic matter accumulation or its loss due to fire, etc.) came from the Terrestrial Ecosystem Model (TEM) and the ALFRESCO (ALaska FRame-based EcoSystem COde) model simulations. We estimated the dynamics of permafrost temperature, active layer thickness, area occupied by permafrost, and volume of seasonally thawed soils within the 4.75 upper meters (original TEM soil column) across the Alaska domain. Simulations of future changes in permafrost indicate that, by the end of the 21st century, late-Holocene permafrost in Alaska will be actively thawing at all locations and that some Late Pleistocene carbon-rich peatlands underlain by permafrost will

  3. Permafrost: occurrence and physiochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Ahonen, L. [Geological Survey of Finland, Espoo (Finland)

    2001-10-01

    Bedrock of the Northern Hemisphere areas to the north of about the 60th latitude are nowadays dominated by permafrost conditions. Fennoscandia is a major exception being characterised by temperate climate. In studying deep geological disposal of long-living nuclear waste, long-term climatic changes have to be taken into account. One of the scenarios to be studied is the extension of the deep permafrost conditions to the disposal site. Quaternary climatic fluctuations and their possible reasons are discussed shortly. The author's conclusion is that future climatic changes cannot be undoubtedly derived from the past variations, mainly because of the current anthropogenic involvement and of the poorly known dynamics of the major climate-affecting factors like ocean currents, which cannot be treated in a deterministic way. In low-porosity crystalline rocks permafrost may propagate to the depth of about 500 metres in some thousands to ten thousands of years. On the other hand, the major effects of permafrost are related to the freezing of water in the pores. Water expands about 9 percent in freezing, and the increasing stress may lead to pressure melting of ice. Dissolved salts in water do not accommodate into the solid ice, but they form saline water or brine segregations having freezing point of even less than minus ten degrees. A front of saline water may develop beneath the frozen bedrock. Pockets of saline water may also occur in ice, and unfrozen adsorption water may occur on the grain boundaries. With respect to the radionuclide transport processes, permafrost as such is a barrier, while the unfrozen domains (taliks) beneath major lake and river systems are potential flow paths. (orig.)

  4. Permafrost: occurrence and physiochemical processes

    International Nuclear Information System (INIS)

    Ahonen, L.

    2001-10-01

    Bedrock of the Northern Hemisphere areas to the north of about the 60th latitude are nowadays dominated by permafrost conditions. Fennoscandia is a major exception being characterised by temperate climate. In studying deep geological disposal of long-living nuclear waste, long-term climatic changes have to be taken into account. One of the scenarios to be studied is the extension of the deep permafrost conditions to the disposal site. Quaternary climatic fluctuations and their possible reasons are discussed shortly. The author's conclusion is that future climatic changes cannot be undoubtedly derived from the past variations, mainly because of the current anthropogenic involvement and of the poorly known dynamics of the major climate-affecting factors like ocean currents, which cannot be treated in a deterministic way. In low-porosity crystalline rocks permafrost may propagate to the depth of about 500 metres in some thousands to ten thousands of years. On the other hand, the major effects of permafrost are related to the freezing of water in the pores. Water expands about 9 percent in freezing, and the increasing stress may lead to pressure melting of ice. Dissolved salts in water do not accommodate into the solid ice, but they form saline water or brine segregations having freezing point of even less than minus ten degrees. A front of saline water may develop beneath the frozen bedrock. Pockets of saline water may also occur in ice, and unfrozen adsorption water may occur on the grain boundaries. With respect to the radionuclide transport processes, permafrost as such is a barrier, while the unfrozen domains (taliks) beneath major lake and river systems are potential flow paths. (orig.)

  5. Quantifying Permafrost Extent, Condition, and Degradation at Department of Defense Installations in the Arctic

    Science.gov (United States)

    Edlund, C. A.

    2017-12-01

    The Department of Defense (DoD) is planning over $500M in military construction on Eielson Air Force Base (AFB) within the next three fiscal years. This construction program will expand the footprint of facilities and change the storm water management scheme, which will have second order effects on the underlying permafrost layer. These changes in permafrost will drive engineering decision making at local and regional levels, and help shape the overall strategy for military readiness in the Arctic. Although many studies have attempted to predict climate change induced permafrost degradation, very little site-specific knowledge exists on the anthropogenic effects to permafrost at this location. In 2016, the permafrost degradation rates at Eielson AFB were modeled using the Geophysics Institute Permafrost Laboratory (GIPL) 2.1 model and limited available geotechnical and climate data. Model results indicated a degradation of the discontinuous permafrost layer at Eielson AFB of up to 7 meters in depth over the next century. To further refine an understanding of the geophysics at Eielson AFB and help engineers and commanders make more informed decisions on engineering and operations in the arctic, this project established two permafrost monitoring stations near the future construction sites. Installation of the stations occurred in July 2017. Permafrost was located and characterized using two Electrical Resistivity Tomography surveys, as well as direct frost probe measurements. Using this data, the research team optimized the placement location and depth of two long term ground temperature monitoring stations, and then installed the stations for data collection. The data set generated by these stations are the first of their kind at Eielson AFB, and represent the first systematic effort in the DoD to quantify permafrost condition before, during, and after construction and other anthropogenic activities in order to fully understand the effects of that activity in the

  6. Interactions between Shrubs and Permafrost in the Torngat Mountains, Northern Labrador, Canada

    Science.gov (United States)

    Lewkowicz, A.; Way, R. G.; Hermanutz, L.; Trant, A.; Siegwart Collier, L.; Whitaker, D.

    2017-12-01

    Discontinuous permafrost is acutely sensitive to climate warming and vegetation dynamics. Shrub height is positively correlated with accumulation of snow in the tundra resulting in warming of the ground in winter, and greater shading and lower surface temperatures in summer. Rapid greening due to climate warming has been observed throughout northeastern Canada and particularly in the coastal mountainous terrain of the Torngat Mountains National Park. Our research examines how this shrubification in the Torngat Mountains is modifying permafrost characteristics using observations which extend over a 100 km south-north transect from the sporadic zone (Saglek, Torr Bay) to where permafrost is widespread (Nakvak Brook, Kangalaksiorvik Lake) and potentially continuous (Komaktorvik River). We use air and ground temperature monitoring, vegetation surveys, dendrochronology, frost probing and electrical resistivity tomography (ERT) to describe the complex interactions between shrub growth, geomorphology, climate and permafrost in a region where climate warming is rapidly altering the landscape. Preliminary analysis of field data shows low resistivity anomalies in the ERT profiles at some sites with thin permafrost, interpreted as unfrozen zones correlated with areas of tall shrubs (Alnus spp., Salix spp. and Betula glandulosa; ranging from prostrate to 2 m). Elsewhere, high resistivities extend to the base of the ERT profiles, indicating thicker permafrost, and no obvious impact of medium to low-prostrate shrubs (Salix spp., Betula glandulosa, Rhododendron spp., and Vaccinium spp.; up to 50 cm). Permafrost is interpreted to be present at most sites with low or prostrate shrubs, except where hydrological conditions favour warmer ground temperatures. We infer that the net impact of increasing shrub heights on the active layer and permafrost depends on antecedent ground temperatures and surficial geology. Increasing shrub heights may cause permafrost degradation at sites where

  7. Evolutionary conservation of TORC1 components, TOR, Raptor, and LST8, between rice and yeast.

    Science.gov (United States)

    Maegawa, Kentaro; Takii, Rumi; Ushimaru, Takashi; Kozaki, Akiko

    2015-10-01

    Target of rapamycin (TOR) is a conserved eukaryotic serine/threonine kinase that functions as a central controller of cell growth. TOR protein is structurally defined by the presence several conserved domains such as the HEAT repeat, focal adhesion target (FAT), FKBP12/rapamycin binding (FRB), kinase, and FATC domains starting from the N-terminus. In most eukaryotes, TOR forms two distinct physical and functional complexes, which are termed as TOR complex 1 (TORC1) and TORC2. However, plants contain only TORC1 components, i.e., TOR, Raptor, and LST8. In this study, we analyzed the gene structure and functions of TORC components in rice to understand the properties of the TOR complex in plants. Comparison of the locations of introns in these genes among rice and other eukaryotes showed that they were well conserved among plants except for Chlamydomonas. Moreover, the intron positions in the coding sequence of human Raptor and LST8 were closer to those of plants than of fly or nematode. Complementation tests of rice TOR (OsTOR) components in yeast showed that although OsTOR did not complement yeast tor mutants, chimeric TOR, which consisted of the HEAT repeat and FAT domain from yeast and other regions from rice, rescued the tor mutants, indicating that the HEAT repeat and FAT domains are important for species-specific signaling. OsRaptor perfectly complemented a kog1 (yeast Raptor homolog) mutant, and OsLST8 partially complemented an lst8 mutant. Together, these data suggest the importance of the N-terminal region of the TOR, HEAT, and FAT domains for functional diversification of the TOR complex.

  8. The Impact of Global Warming on the Carbon Cycle of Arctic Permafrost: An Experimental and Field Based Study

    Energy Technology Data Exchange (ETDEWEB)

    Onstott, Tullis C [Princeton University; Pffifner, Susan M; Chourey, Karuna [Oak Ridge National Laboratory

    2014-11-07

    Our results to date indicate that CO2 and CH4 fluxes from organic poor, Arctic cryosols on Axel Heiberg Island are net CH4 sinks and CO2 emitters in contrast to organic-rich peat deposits at sub-Arctic latitudes. This is based upon field observations and a 1.5 year long thawing experiment performed upon one meter long intact cores. The results of the core thawing experiments are in good agreement with field measurements. Metagenomic, metatranscriptomic and metaproteomic analyses indicate that high affinity aerobic methanotrophs belong to the uncultivated USCalpha are present in <1% abundance in these cryosols are are active in the field during the summer and in the core thawing experiments. The methanotrophs are 100 times more abundant than the methanogens. As a result mineral cryosols, which comprise 87% of Arctic tundra, are net methane sinks. Their presence and activity may account for the discrepancies observed between the atmospheric methane concentrations observed in the Arctic predicted by climate models and the observed seasonal fluctuations and decadal trends. This has not been done yet.

  9. Quantifying Permafrost Characteristics with DCR-ERT

    Science.gov (United States)

    Schnabel, W.; Trochim, E.; Munk, J.; Kanevskiy, M. Z.; Shur, Y.; Fortier, R.

    2012-12-01

    Geophysical methods are an efficient method for quantifying permafrost characteristics for Arctic road design and engineering. In the Alaskan Arctic construction and maintenance of roads requires integration of permafrost; ground that is below 0 degrees C for two or more years. Features such as ice content and temperature are critical for understanding current and future ground conditions for planning, design and evaluation of engineering applications. This study focused on the proposed Foothills West Transportation Access project corridor where the purpose is to construct a new all-season road connecting the Dalton Highway to Umiat. Four major areas were chosen that represented a range of conditions including gravel bars, alluvial plains, tussock tundra (both unburned and burned conditions), high and low centered ice-wedge polygons and an active thermokarst feature. Direct-current resistivity using galvanic contact (DCR-ERT) was applied over transects. In conjunction complimentary site data including boreholes, active layer depths, vegetation descriptions and site photographs was obtained. The boreholes provided information on soil morphology, ice texture and gravimetric moisture content. Horizontal and vertical resolutions in the DCR-ERT were varied to determine the presence or absence of ground ice; subsurface heterogeneity; and the depth to groundwater (if present). The four main DCR-ERT methods used were: 84 electrodes with 2 m spacing; 42 electrodes with 0.5 m spacing; 42 electrodes with 2 m spacing; and 84 electrodes with 1 m spacing. In terms of identifying the ground ice characteristics the higher horizontal resolution DCR-ERT transects with either 42 or 84 electrodes and 0.5 or 1 m spacing were best able to differentiate wedge-ice. This evaluation is based on a combination of both borehole stratigraphy and surface characteristics. Simulated apparent resistivity values for permafrost areas varied from a low of 4582 Ω m to a high of 10034 Ω m. Previous

  10. Microorganisms Trapped Within Permafrost Ice In The Fox Permafrost Tunnel, Alaska

    Science.gov (United States)

    Katayama, T.; Tanaka, M.; Douglas, T. A.; Cai, Y.; Tomita, F.; Asano, K.; Fukuda, M.

    2008-12-01

    Several different types of massive ice are common in permafrost. Ice wedges are easily recognized by their shape and foliated structure. They grow syngenetically or epigenetically as a result of repeated cycles of frost cracking followed by the infiltration of snow, melt water, soil or other material into the open frost cracks. Material incorporated into ice wedges becomes frozen and preserved. Pool ice, another massive ice type, is formed by the freezing of water resting on top of frozen thermokarst sediment or melting wedges and is not foliated. The Fox Permafrost Tunnel in Fairbanks was excavated within the discontinuous permafrost zone of central Alaska and it contains permafrost, ice wedges, and pool ice preserved at roughly -3°C. We collected samples from five ice wedges and three pool ice structures in the Fox Permafrost Tunnel. If the microorganisms were incorporated into the ice during its formation, a community analysis of the microorganisms could elucidate the environment in which the ice was formed. Organic material from sediments in the tunnel was radiocarbon-dated between 14,000 and 30,000 years BP. However, it is still not clear when the ice wedges were formed or subsequently deformed because they are only partially exposed and their upper surfaces are above the tunnel walls. The objectives of our study were to determine the biogeochemical conditions during massive ice formation and to analyze the microbial community within the ices by incubation-based and DNA-based analyses. The geochemical profile and the PCR-DGGE band patterns of bacteria among five ice wedge and 3 portions of pool ice samples were markedly different. The DGGE band patterns of fungi were simple with a few bands of fungi or yeast. The dominant bands of ice wedge and pool ice samples were affiliated with the genus Geomyces and Doratomyces, respectively. Phylogenetic analysis using rRNA gene ITS regions indicated isolates of Geomyces spp. from different ice wedges were affiliated

  11. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Land Surface Temperature (LST) Environmental Data Record (EDR) from IDPS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of Land Surface Temperature (LST) from the Visible Infrared Imaging Radiometer Suite...

  12. Mid-Wisconsin to Holocene permafrost and landscape dynamics based on a drained lake basin core from the northern Seward Peninsula, northwest Alaska

    Science.gov (United States)

    Lenz, Josefine; Grosse, Guido; Jones, Benjamin M.; Anthony, Katey M. Walter; Bobrov, Anatoly; Wulf, Sabine; Wetterich, Sebastian

    2016-01-01

    Permafrost-related processes drive regional landscape dynamics in the Arctic terrestrial system. A better understanding of past periods indicative of permafrost degradation and aggradation is important for predicting the future response of Arctic landscapes to climate change. Here, we used a multi-proxy approach to analyse a ~ 4 m long sediment core from a drained thermokarst lake basin on the northern Seward Peninsula in western Arctic Alaska (USA). Sedimentological, biogeochemical, geochronological, micropalaeontological (ostracoda, testate amoebae) and tephra analyses were used to determine the long-term environmental Early-Wisconsin to Holocene history preserved in our core for central Beringia. Yedoma accumulation dominated throughout the Early to Late-Wisconsin but was interrupted by wetland formation from 44.5 to 41.5 ka BP. The latter was terminated by the deposition of 1 m of volcanic tephra, most likely originating from the South Killeak Maar eruption at about 42 ka BP. Yedoma deposition continued until 22.5 ka BP and was followed by a depositional hiatus in the sediment core between 22.5 and 0.23 ka BP. We interpret this hiatus as due to intense thermokarst activity in the areas surrounding the site, which served as a sediment source during the Late-Wisconsin to Holocene climate transition. The lake forming the modern basin on the upland initiated around 0.23 ka BP and drained catastrophically in spring 2005. The present study emphasises that Arctic lake systems and periglacial landscapes are highly dynamic and that permafrost formation as well as degradation in central Beringia was controlled by regional to global climate patterns as well as by local disturbances.

  13. Permafrost distribution in the European Alps: calculation and evaluation of an index map and summary statistics

    Directory of Open Access Journals (Sweden)

    L. Boeckli

    2012-07-01

    Full Text Available The objective of this study is the production of an Alpine Permafrost Index Map (APIM covering the entire European Alps. A unified statistical model that is based on Alpine-wide permafrost observations is used for debris and bedrock surfaces across the entire Alps. The explanatory variables of the model are mean annual air temperatures, potential incoming solar radiation and precipitation. Offset terms were applied to make model predictions for topographic and geomorphic conditions that differ from the terrain features used for model fitting. These offsets are based on literature review and involve some degree of subjective choice during model building. The assessment of the APIM is challenging because limited independent test data are available for comparison and these observations represent point information in a spatially highly variable topography. The APIM provides an index that describes the spatial distribution of permafrost and comes together with an interpretation key that helps to assess map uncertainties and to relate map contents to their actual expression in the terrain. The map can be used as a first resource to estimate permafrost conditions at any given location in the European Alps in a variety of contexts such as research and spatial planning.

    Results show that Switzerland likely is the country with the largest permafrost area in the Alps, followed by Italy, Austria, France and Germany. Slovenia and Liechtenstein may have marginal permafrost areas. In all countries the permafrost area is expected to be larger than the glacier-covered area.

  14. Permafrost and lakes control river isotope composition across a boreal Arctic transect in the Western Siberian lowlands

    Science.gov (United States)

    Ala-aho, P.; Soulsby, C.; Pokrovsky, O. S.; Kirpotin, S. N.; Karlsson, J.; Serikova, S.; Manasypov, R.; Lim, A.; Krickov, I.; Kolesnichenko, L. G.; Laudon, H.; Tetzlaff, D.

    2018-03-01

    The Western Siberian Lowlands (WSL) store large quantities of organic carbon that will be exposed and mobilized by the thawing of permafrost. The fate of mobilized carbon, however, is not well understood, partly because of inadequate knowledge of hydrological controls in the region which has a vast low-relief surface area, extensive lake and wetland coverage and gradually increasing permafrost influence. We used stable water isotopes to improve our understanding of dominant landscape controls on the hydrology of the WSL. We sampled rivers along a 1700 km South-North transect from permafrost-free to continuous permafrost repeatedly over three years, and derived isotope proxies for catchment hydrological responsiveness and connectivity. We found correlations between the isotope proxies and catchment characteristics, suggesting that lakes and wetlands are intimately connected to rivers, and that permafrost increases the responsiveness of the catchment to rainfall and snowmelt events, reducing catchment mean transit times. Our work provides rare isotope-based field evidence that permafrost and lakes/wetlands influence hydrological pathways across a wide range of spatial scales (10-105 km2) and permafrost coverage (0%-70%). This has important implications, because both permafrost extent and lake/wetland coverage are affected by permafrost thaw in the changing climate. Changes in these hydrological landscape controls are likely to alter carbon export and emission via inland waters, which may be of global significance.

  15. Confocal Raman microspectroscopy reveals a convergence of the chemical composition in methanogenic archaea from a Siberian permafrost-affected soil.

    Science.gov (United States)

    Serrano, Paloma; Hermelink, Antje; Lasch, Peter; de Vera, Jean-Pierre; König, Nicole; Burckhardt, Oliver; Wagner, Dirk

    2015-12-01

    Methanogenic archaea are widespread anaerobic microorganisms responsible for the production of biogenic methane. Several new species of psychrotolerant methanogenic archaea were recently isolated from a permafrost-affected soil in the Lena Delta (Siberia, Russia), showing an exceptional resistance against desiccation, osmotic stress, low temperatures, starvation, UV and ionizing radiation when compared to methanogens from non-permafrost environments. To gain a deeper insight into the differences observed in their resistance, we described the chemical composition of methanogenic strains from permafrost and non-permafrost environments using confocal Raman microspectroscopy (CRM). CRM is a powerful tool for microbial identification and provides fingerprint-like information about the chemical composition of the cells. Our results show that the chemical composition of methanogens from permafrost-affected soils presents a high homology and is remarkably different from strains inhabiting non-permafrost environments. In addition, we performed a phylogenetic reconstruction of the studied strains based on the functional gene mcrA to prove the different evolutionary relationship of the permafrost strains. We conclude that the permafrost methanogenic strains show a convergent chemical composition regardless of their genotype. This fact is likely to be the consequence of a complex adaptive process to the Siberian permafrost environment and might be the reason underlying their resistant nature. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Changes to the Carbon and Energy fluxes in a Northern Peatland with Thawing Permafrost

    Science.gov (United States)

    Harder, S. R.; Roulet, N. T.; Crill, P. M.; Strachan, I. B.

    2017-12-01

    The maintenance of thaw of high carbon density landscapes in the permafrost region ultimately depends of how the energy balance is partitioned as temperatures and precipitation change, yet there are comparatively few energy balance studies, especially in peatlands that contain permafrost. While permafrost peatlands are currently net sinks of carbon, as Arctic temperatures rise and permafrost thaws, the future of these ecosystems and their capacity for carbon uptake is in question. Since 2012 we have been measuring the spatially integrated CO2, energy and water vapour fluxes from the Stordalen peatland (68°22'N, 19°03'E) using eddy covariance (EC). The Stordalen peatland is a heterogeneous peatland in the discontinuous permafrost zone where permafrost thaw is actively occurring, resulting in large changes to the landscape from year to year. Areas where permafrost is present are elevated by up to 1.5 m compared to the areas where permafrost has thawed causing differences in water table depth, peat temperatures, snow distribution, vegetation community and therefore in the carbon and energy fluxes. Our EC tower is located on the edge of a permafrost peat plateau (or palsa) where one fetch measures fluxes from an area underlain by permafrost and the other fetch sees the portion of the peatland where the permafrost has thawed. Within each sector, we have an array of soil temperature and water content sensors to determine the physical characteristics of each fetch. Extensive vegetation surveys (based on plant functional types or PFTs) have also been conducted to run a footprint analysis on the flux data to complete a comparative analysis of the magnitude and variability of the carbon and energy exchanges from PFT. The footprint analysis allows us to explain the difference in energy and carbon fluxes by examining the ecological, biogeochemical and physical characteristics within each footprint. We see distinctly different energy partitioning between the fetches

  17. A Framework for Mapping Global Evapotranspiration using 375-m VIIRS LST

    Science.gov (United States)

    Hain, C.; Anderson, M. C.; Schull, M. A.; Neale, C. M. U.

    2017-12-01

    As the world's water resources come under increasing tension due to dual stressors of climate change and population growth, accurate knowledge of water consumption through evapotranspiration (ET) over a range in spatial scales will be critical in developing adaptation strategies. Remote sensing methods for monitoring consumptive water use are becoming increasingly important, especially in areas of food insecurity. One method to estimate ET from satellite-based methods, the Atmosphere Land Exchange Inverse (ALEXI) model uses the change in morning land surface temperature to estimate the partitioning of sensible/latent heat fluxes which are then used to estimate daily ET. This presentation will outline several recent enhancements to the ALEXI modeling system, with a focus on global ET and drought monitoring. Until recently, ALEXI has been limited to areas with high resolution temporal sampling of geostationary sensors. The use of geostationary sensors makes global mapping a complicated process, especially for real-time applications, as data from as many as five different sensors are required to be ingested and harmonized to create a global mosaic. However, our research team has developed a new and novel method of using twice-daily observations from polar-orbiting sensors such as MODIS and VIIRS to estimate the mid-morning rise in LST that is used to drive the energy balance estimations within ALEXI. This allows the method to be applied globally using a single sensor rather than a global compositing of all available geostationary data. Other advantages of this new method include the higher spatial resolution provided by MODIS and VIIRS and the increased sampling at high latitudes where oblique view angles limit the utility of geostationary sensors. Improvements to the spatial resolution of the thermal infrared wavelengths on the VIIRS instrument, as compared to MODIS (375-m VIIRS vs. 1-km MODIS), allows for a much higher resolution ALEXI product than has been

  18. Permafrost-associated gas hydrate: is it really approximately 1% of the global system?

    Science.gov (United States)

    Ruppel, Carolyn

    2015-01-01

    Permafrost-associated gas hydrates are often assumed to contain ∼1 % of the global gas-in-place in gas hydrates based on a study26 published over three decades ago. As knowledge of permafrost-associated gas hydrates has grown, it has become clear that many permafrost-associated gas hydrates are inextricably linked to an associated conventional petroleum system, and that their formation history (trapping of migrated gas in situ during Pleistocene cooling) is consistent with having been sourced at least partially in nearby thermogenic gas deposits. Using modern data sets that constrain the distribution of continuous permafrost onshore5 and subsea permafrost on circum-Arctic Ocean continental shelves offshore and that estimate undiscovered conventional gas within arctic assessment units,16 the done here reveals where permafrost-associated gas hydrates are most likely to occur, concluding that Arctic Alaska and the West Siberian Basin are the best prospects. A conservative estimate is that 20 Gt C (2.7·1013 kg CH4) may be sequestered in permafrost-associated gas hydrates if methane were the only hydrate-former. This value is slightly more than 1 % of modern estimates (corresponding to 1600 Gt C to 1800 Gt C2,22) for global gas-in-place in methane hydrates and about double the absolute estimate (11.2 Gt C) made in 1981.26

  19. Amount and timing of permafrost carbon release in response to climate warming

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Kevin; Zhang, Tingjun; Barrett, Andrew P. (National Snow and Ice Data Center, Cooperative Inst. for Research in Environmental Sciences, Univ. of Colorado at Boulder, Boulder (United States)), e-mail: kevin.schaefer@nsidc.org; Bruhwiler, Lori (National Oceanic and Atmospheric Administration, Earth System Research Laboratory, Boulder (United States))

    2011-04-15

    The thaw and release of carbon currently frozen in permafrost will increase atmospheric CO{sub 2} concentrations and amplify surface warming to initiate a positive permafrost carbon feedback (PCF) on climate.We use surface weather from three global climate models based on the moderate warming, A1B Intergovernmental Panel on Climate Change emissions scenario and the SiBCASA land surface model to estimate the strength and timing of the PCF and associated uncertainty. By 2200, we predict a 29-59% decrease in permafrost area and a 53-97 cm increase in active layer thickness. By 2200, the PCF strength in terms of cumulative permafrost carbon flux to the atmosphere is 190 +- 64 Gt C. This estimate may be low because it does not account for amplified surface warming due to the PCF itself and excludes some discontinuous permafrost regions where SiBCASA did not simulate permafrost. We predict that the PCF will change the arctic from a carbon sink to a source after the mid-2020s and is strong enough to cancel 42-88% of the total global land sink. The thaw and decay of permafrost carbon is irreversible and accounting for the PCF will require larger reductions in fossil fuel emissions to reach a target atmospheric CO{sub 2} concentration

  20. Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 2. Borehole constraints

    Science.gov (United States)

    Ruppel, Carolyn D.; Herman, Bruce M.; Brothers, Laura L.; Hart, Patrick E.

    2016-01-01

    Borehole logging data from legacy wells directly constrain the contemporary distribution of subsea permafrost in the sedimentary section at discrete locations on the U.S. Beaufort Margin and complement recent regional analyses of exploration seismic data to delineate the permafrost's offshore extent. Most usable borehole data were acquired on a ∼500 km stretch of the margin and within 30 km of the contemporary coastline from north of Lake Teshekpuk to nearly the U.S.-Canada border. Relying primarily on deep resistivity logs that should be largely unaffected by drilling fluids and hole conditions, the analysis reveals the persistence of several hundred vertical meters of ice-bonded permafrost in nearshore wells near Prudhoe Bay and Foggy Island Bay, with less permafrost detected to the east and west. Permafrost is inferred beneath many barrier islands and in some nearshore and lagoonal (back-barrier) wells. The analysis of borehole logs confirms the offshore pattern of ice-bearing subsea permafrost distribution determined based on regional seismic analyses and reveals that ice content generally diminishes with distance from the coastline. Lacking better well distribution, it is not possible to determine the absolute seaward extent of ice-bearing permafrost, nor the distribution of permafrost beneath the present-day continental shelf at the end of the Pleistocene. However, the recovery of gas hydrate from an outer shelf well (Belcher) and previous delineation of a log signature possibly indicating gas hydrate in an inner shelf well (Hammerhead 2) imply that permafrost may once have extended across much of the shelf offshore Camden Bay.

  1. Impact of Black Dust Pollution on Permafrost Temperature Regime in Pechora Basin

    Science.gov (United States)

    Khilimonyuk, V.; Pustovoit, G.; Filatova, M.

    2011-12-01

    Pechora Coal basin locates in North- Easter part of Europe within permafrost zone. The coal mining and post processing lead to emission of black dust (BD) and pollution of Earth surface. The scale of snow pollution surrounding Vorkuta city reaches to 260 g/sq.m of dust that is about 1000 ppmm BD concentration in snow before melting period. Such a large concentration of dust reduces snow reflectivity (Warren and Wiscombe, 1980; Chýlek et al., 1983,Gorbacheva, 1984, Zender et al, 2010) and can thereby trigger albedo feedbacks. The goal of this study is to evaluate the role of dirty surface albedo in the observed changing of permafrost regime in this basin. Two key sites: Workuta (North permafrost zone) and Inta (South permafrost zone) areas were selected for this study. For each site the zoning of territory by typical conditions of permafrost formation was performed. For the selected typical landscapes 1-D vertical heat transfer model coupled with the surface radiation-thermal balance equation at topsoil was simulated. The simulation was performed for the soil profile of 20 m depth during 20 years period with periodical input data at dirty surface averaged on monthly base. The initial measured not disturbed soil temperature profile was used for assessment the soil thermal property for the given landscape and natural surface radiation-thermal balance. The annual cycle of albedo change for dirty surface was taken from experimental measurement (Gorbacheva, 1984) for both sites as the function of the distance from the dust source. The simulation results next were used for mapping the vulnerability of permafrost thermal regime due to black dust pollution. Generally the simulation results show that South permafrost zone with mean temperature of permafrost (-0.5 -0.1C) is more vulnerable to albedo change than North permafrost zone with mean temperature (-2.5 -2C) for the same order of dust impact on albedo.

  2. Spatio-temporal prediction of daily temperatures using time-series of MODIS LST images

    Science.gov (United States)

    Hengl, Tomislav; Heuvelink, Gerard B. M.; Perčec Tadić, Melita; Pebesma, Edzer J.

    2012-01-01

    A computational framework to generate daily temperature maps using time-series of publicly available MODIS MOD11A2 product Land Surface Temperature (LST) images (1 km resolution; 8-day composites) is illustrated using temperature measurements from the national network of meteorological stations (159) in Croatia. The input data set contains 57,282 ground measurements of daily temperature for the year 2008. Temperature was modeled as a function of latitude, longitude, distance from the sea, elevation, time, insolation, and the MODIS LST images. The original rasters were first converted to principal components to reduce noise and filter missing pixels in the LST images. The residual were next analyzed for spatio-temporal auto-correlation; sum-metric separable variograms were fitted to account for zonal and geometric space-time anisotropy. The final predictions were generated for time-slices of a 3D space-time cube, constructed in the R environment for statistical computing. The results show that the space-time regression model can explain a significant part of the variation in station-data (84%). MODIS LST 8-day (cloud-free) images are unbiased estimator of the daily temperature, but with relatively low precision (±4.1°C); however their added value is that they systematically improve detection of local changes in land surface temperature due to local meteorological conditions and/or active heat sources (urban areas, land cover classes). The results of 10-fold cross-validation show that use of spatio-temporal regression-kriging and incorporation of time-series of remote sensing images leads to significantly more accurate maps of temperature than if plain spatial techniques were used. The average (global) accuracy of mapping temperature was ±2.4°C. The regression-kriging explained 91% of variability in daily temperatures, compared to 44% for ordinary kriging. Further software advancement—interactive space-time variogram exploration and automated retrieval

  3. Mountain Permafrost in the Yukon Territory, Canada: Mapping and Modelling

    Science.gov (United States)

    Lewkowicz, A. G.; Bonnaventure, P.; Schultz, E.; Etzelmuller, B.

    2006-12-01

    The distribution and characteristics of mountain permafrost in North America are poorly known compared to lowland permafrost, and predictions of climatic change impacts are therefore subject to a higher degree of uncertainty. Recent DC resistivity soundings in association with borehole temperature information in the Yukon Territory, show the wide range of permafrost conditions that can exist at sites separated by short distances. To provide baseline information for future modelling, efforts are underway to produce a detailed map of permafrost probability in the mountains of the southern half of the Yukon Territory (60-65°N), an area greater than 200 x 103km2. The methodology is based on the Basal Temperature of Snow (BTS) technique, first developed in the European Alps. Ground surface temperatures measured at the base of snow > 80 cm thick in late winter are an indicator of permafrost presence or absence. We have used this method successfully in three study areas of about 200 km2: first, Wolf Creek basin near Whitehorse (Lewkowicz and Ednie, 2004) and now the western side of the Ruby Range adjacent to Kluane Lake, and the Haines Summit area in northwestern British Columbia. In each area, (1) we installed miniature temperature loggers at the ground surface and in the air to check on the timing of the BTS measurements; (2) we measured BTS values in the elevation zone across which permafrost was expected to become widespread; (3) we modelled the BTS spatial field using elevation (from a 30 m DEM) and potential incoming solar radiation (PISR) as the independent variables; and (4) we used logistic regression to compare the modelled BTS values with pit observations made in late-summer of the presence or absence of frozen ground. Both elevation and PISR were significant in the Wolf Creek and Ruby Range sites which have relatively continental climates and fall within the Upper Yukon-Stikine Basin climatic region (Wahl et al., 1987). For the Haines Summit area, however

  4. Derivation and analysis of a high-resolution estimate of global permafrost zonation

    Directory of Open Access Journals (Sweden)

    S. Gruber

    2012-02-01

    Full Text Available Permafrost underlies much of Earth's surface and interacts with climate, eco-systems and human systems. It is a complex phenomenon controlled by climate and (sub- surface properties and reacts to change with variable delay. Heterogeneity and sparse data challenge the modeling of its spatial distribution. Currently, there is no data set to adequately inform global studies of permafrost. The available data set for the Northern Hemisphere is frequently used for model evaluation, but its quality and consistency are difficult to assess. Here, a global model of permafrost extent and dataset of permafrost zonation are presented and discussed, extending earlier studies by including the Southern Hemisphere, by consistent data and methods, by attention to uncertainty and scaling. Established relationships between air temperature and the occurrence of permafrost are re-formulated into a model that is parametrized using published estimates. It is run with a high-resolution (<1 km global elevation data and air temperatures based on the NCAR-NCEP reanalysis and CRU TS 2.0. The resulting data provide more spatial detail and a consistent extrapolation to remote regions, while aggregated values resemble previous studies. The estimated uncertainties affect regional patterns and aggregate number, and provide interesting insight. The permafrost area, i.e. the actual surface area underlain by permafrost, north of 60° S is estimated to be 13–18 × 106 km2 or 9–14 % of the exposed land surface. The global permafrost area including Antarctic and sub-sea permafrost is estimated to be 16–21 × 106 km2. The global permafrost region, i.e. the exposed land surface below which some permafrost can be expected, is estimated to be 22 ± 3 × 106 km2. A large proportion of this exhibits considerable topography and spatially-discontinuous permafrost, underscoring the importance of attention to scaling issues

  5. Data analysis and mapping of the mountain permafrost distribution

    Science.gov (United States)

    Deluigi, Nicola; Lambiel, Christophe; Kanevski, Mikhail

    2017-04-01

    In Alpine environments mountain permafrost is defined as a thermal state of the ground and corresponds to any lithosphere material that is at or below 0°C for, at least, two years. Its degradation is potentially leading to an increasing rock fall activity, rock glacier accelerations and an increase in the sediment transfer rates. During the last 15 years, knowledge on this phenomenon has significantly increased thanks to many studies and monitoring projects. They revealed a spatial distribution extremely heterogeneous and complex. As a consequence, modelling the potential extent of the mountain permafrost recently became a very important task. Although existing statistical models generally offer a good overview at a regional scale, they are not always able to reproduce its strong spatial discontinuity at the micro scale. To overcome this lack, the objective of this study is to propose an alternative modelling approach using three classification algorithms belonging to statistics and machine learning: Logistic regression (LR), Support Vector Machines (SVM) and Random forests (RF). The former is a linear parametric classifier that commonly used as a benchmark classification algorithm to be employed before using more complex classifiers. Non-linear SVM is a non-parametric learning algorithm and it is a member of the so-called kernel methods. RF are an ensemble learning method based on bootstrap aggregating and offer an embedded measure of the variable importance. Permafrost evidences were selected in a 588 km2 area of the Western Swiss Alps and serve as training examples. They were mapped from field data (thermal and geoelectrical data) and ortho-image interpretation (rock glacier inventorying). The dataset was completed with environmental predictors such as altitude, mean annual air temperature, aspect, slope, potential incoming solar radiation, normalized difference vegetation index and planar, profile and combined terrain curvature indices. Aiming at predicting

  6. Distinct summer and winter bacterial communities in the active layer of Svalbard permafrost revealed by DNA- and RNA-based analyses

    DEFF Research Database (Denmark)

    Schostag, Morten; Stibal, Marek; Jacobsen, Carsten S.

    2015-01-01

    organic matter on the bacterial communities. The copy number of 16S rRNA genes and transcripts revealed no distinct seasonal changes indicating potential bacterial activity during winter despite soil temperatures well below -10ºC. Multivariate statistical analysis of the bacterial diversity data (DNA......The active layer of soil overlaying permafrost in the Arctic is subjected to dramatic annual changes in temperature and soil chemistry, which likely affect bacterial activity and community structure. We studied seasonal variations in the bacterial community of active layer soil from Svalbard (78º......N) by co-extracting DNA and RNA from 12 soil cores collected monthly over a year. PCR amplicons of 16S rRNA genes (DNA) and reverse transcribed transcripts (cDNA) were quantified and sequenced to test for the effect of low winter temperature and seasonal variation in concentration of easily degradable...

  7. Evaluating the use of testate amoebae for palaeohydrological reconstruction in permafrost peatlands

    OpenAIRE

    Swindles, Graeme T.; Amesbury, Matthew J.; Turner, T. Edward; Carrivick, Jonathan L.; Woulds, Clare; Raby, Cassandra; Mullan, Donal; Roland, Thomas P.; Galloway, Jennifer M.; Parry, Lauren; Kokfelt, Ulla; Garneau, Michelle; Charman, Dan J.; Holden, Joseph

    2015-01-01

    The melting of high-latitude permafrost peatlands is a major concern due to a potential positive feedback on global climate change. We examine the ecology of testate amoebae in permafrost peatlands, based on sites in Sweden (~ 200 km north of the Arctic Circle). Multivariate statistical analysis confirms that water-table depth and moisture content are the dominant controls on the distribution of testate amoebae, corroborating the results from studies in mid-latitude peatlands. We present a ne...

  8. Inversion of Land Surface Temperature (LST Using Terra ASTER Data: A Comparison of Three Algorithms

    Directory of Open Access Journals (Sweden)

    Milton Isaya Ndossi

    2016-12-01

    Full Text Available Land Surface Temperature (LST is an important measurement in studies related to the Earth surface’s processes. The Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER instrument onboard the Terra spacecraft is the currently available Thermal Infrared (TIR imaging sensor with the highest spatial resolution. This study involves the comparison of LSTs inverted from the sensor using the Split Window Algorithm (SWA, the Single Channel Algorithm (SCA and the Planck function. This study has used the National Oceanic and Atmospheric Administration’s (NOAA data to model and compare the results from the three algorithms. The data from the sensor have been processed by the Python programming language in a free and open source software package (QGIS to enable users to make use of the algorithms. The study revealed that the three algorithms are suitable for LST inversion, whereby the Planck function showed the highest level of accuracy, the SWA had moderate level of accuracy and the SCA had the least accuracy. The algorithms produced results with Root Mean Square Errors (RMSE of 2.29 K, 3.77 K and 2.88 K for the Planck function, the SCA and SWA respectively.

  9. Permafrost Active Layer Seismic Interferometry Experiment (PALSIE).

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knox, Hunter Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); James, Stephanie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Rebekah [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cole, Chris [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We present findings from a novel field experiment conducted at Poker Flat Research Range in Fairbanks, Alaska that was designed to monitor changes in active layer thickness in real time. Results are derived primarily from seismic data streaming from seven Nanometric Trillium Posthole seismometers directly buried in the upper section of the permafrost. The data were evaluated using two analysis methods: Horizontal to Vertical Spectral Ratio (HVSR) and ambient noise seismic interferometry. Results from the HVSR conclusively illustrated the method's effectiveness at determining the active layer's thickness with a single station. Investigations with the multi-station method (ambient noise seismic interferometry) are continuing at the University of Florida and have not yet conclusively determined active layer thickness changes. Further work continues with the Bureau of Land Management (BLM) to determine if the ground based measurements can constrain satellite imagery, which provide measurements on a much larger spatial scale.

  10. Climate Change and Thawing Permafrost in Two Iñupiaq Communities of Alaska's Arctic: Observations, Implications, and Resilience

    Science.gov (United States)

    Woodward, A.; Kofinas, G.

    2013-12-01

    For thousands of years the Iñupiat of northern Alaska have relied on ecosystems underlain by permafrost for material and cultural resources. As permafrost thaws across the Arctic, these social-ecological systems are changing rapidly. Community-based research and extensive local knowledge of Iñupiaq villagers offer unique and valuable contributions to understanding permafrost change and its implications for humans. We partnered with two Iñupiaq communities in Alaska's Arctic to investigate current and potential effects of thawing permafrost on social-ecological systems. Anaktuvuk Pass is situated on thaw-stable consolidated gravel in the Brooks Range, while Selawik rests on ice-rich permafrost in Beringia lowland tundra. Using the transdisciplinary approach of resilience theory and mixed geophysical and ethnographic methods, we measured active layer thaw depths and documented local knowledge about climate and permafrost change. Thaw depths were greater overall in Selawik. Residents of both communities reported a variety of changes in surface features, hydrology, weather, flora, and fauna that they attribute to thawing permafrost and / or climate change. Overall, Selawik residents described more numerous and extreme examples of such changes, expressed higher degrees of certainty that change is occurring, and anticipated more significant and negative implications for their way of life than did residents of Anaktuvuk Pass. Of the two villages, Selawik faces greater and more immediate challenges to the resilience of its social-ecological system as permafrost thaws.

  11. Exploring the ground ice recharge near permafrost table on the central Qinghai-Tibet Plateau using chemical and isotopic data

    Science.gov (United States)

    Wang, Weihua; Wu, Tonghua; Zhao, Lin; Li, Ren; Zhu, Xiaofan; Wang, Wanrui; Yang, Shuhua; Qin, Yanhui; Hao, Junmin

    2018-05-01

    Thawing permafrost on the Qinghai-Tibet Plateau (QTP) has great impacts on the local hydrological process by way of causing ground ice to thaw. Until now there is little knowledge on ground ice hydrology near permafrost table under a warming climate. This study applied stable tracers (isotopes and chloride) and hydrograph separation model to quantify the sources of ground ice near permafrost table in continuous permafrost regions of the central QTP. The results indicated that the ground ice near permafrost table was mainly supplied by active layer water and permafrost water, accounting for 58.9 to 87.0% and 13.0 to 41.1%, respectively, which implying that the active layer was the dominant source. The contribution rates from the active layer to the ground ice in alpine meadow (59 to 69%) was less than that in alpine steppe (70 to 87%). It showed well-developed hydrogeochemical depth gradients, presenting depleted isotopes and positive chemical gradients with depth within the soil layer. The effects of evaporation and freeze-out fractionation on the soil water and ground ice were evident. The results provide additional insights into ground ice sources and cycling near permafrost table in permafrost terrain, and would be helpful for improving process-based detailed hydrologic models under the occurring global warming.

  12. Estimation of permafrost thawing rates in a sub-arctic catchment using recession flow analysis

    Directory of Open Access Journals (Sweden)

    S. W. Lyon

    2009-05-01

    Full Text Available Permafrost thawing is likely to change the flow pathways taken by water as it moves through arctic and sub-arctic landscapes. The location and distribution of these pathways directly influence the carbon and other biogeochemical cycling in northern latitude catchments. While permafrost thawing due to climate change has been observed in the arctic and sub-arctic, direct observations of permafrost depth are difficult to perform at scales larger than a local scale. Using recession flow analysis, it may be possible to detect and estimate the rate of permafrost thawing based on a long-term streamflow record. We demonstrate the application of this approach to the sub-arctic Abiskojokken catchment in northern Sweden. Based on recession flow analysis, we estimate that permafrost in this catchment may be thawing at an average rate of about 0.9 cm/yr during the past 90 years. This estimated thawing rate is consistent with direct observations of permafrost thawing rates, ranging from 0.7 to 1.3 cm/yr over the past 30 years in the region.

  13. Detection of geothermal anomalies in Tengchong, Yunnan Province, China from MODIS multi-temporal night LST imagery

    Science.gov (United States)

    Li, H.; Kusky, T. M.; Peng, S.; Zhu, M.

    2012-12-01

    Thermal infrared (TIR) remote sensing is an important technique in the exploration of geothermal resources. In this study, a geothermal survey is conducted in Tengchong area of Yunnan province in China using multi-temporal MODIS LST (Land Surface Temperature). The monthly night MODIS LST data from Mar. 2000 to Mar. 2011 of the study area were collected and analyzed. The 132 month average LST map was derived and three geothermal anomalies were identified. The findings of this study agree well with the results from relative geothermal gradient measurements. Finally, we conclude that TIR remote sensing is a cost-effective technique to detect geothermal anomalies. Combining TIR remote sensing with geological analysis and the understanding of geothermal mechanism is an accurate and efficient approach to geothermal area detection.

  14. Use of LST images from MODIS/AQUA sensor as an indication of frost occurrence in RS

    Directory of Open Access Journals (Sweden)

    Débora de S. Simões

    2015-10-01

    Full Text Available ABSTRACTAlthough frost occurrence causes severe losses in agriculture, especially in the south of Brazil, the data of minimum air temperature (Tmin currently available for monitoring and predicting frosts show insufficient spatial distribution. This study aimed to evaluate the MDY11A1 (LST – Land Surface Temperature product, from the MODIS sensor on board the AQUA satellite as an estimator of frost occurrence in the southeast of the state of Rio Grande do Sul, Brazil. LST images from the nighttime overpass of the MODIS/AQUA sensor for the months of June, July and August from 2006 to 2012, and data from three conventional weather stations of the National Institute of Meteorology (INMET were used. Consistency was observed between Tmin data measured in weather stations and LST data obtained from the MODIS sensor. According to the results, LSTs below 3 ºC recorded by the MODIS/AQUA sensor are an indication of a favorable scenario to frost occurrence.

  15. Climate warming over the past half century has led to thermal degradation of permafrost on the Qinghai-Tibet Plateau

    Science.gov (United States)

    Ran, Youhua; Li, Xin; Cheng, Guodong

    2018-02-01

    Air temperature increases thermally degrade permafrost, which has widespread impacts on engineering design, resource development, and environmental protection in cold regions. This study evaluates the potential thermal degradation of permafrost over the Qinghai-Tibet Plateau (QTP) from the 1960s to the 2000s using estimated decadal mean annual air temperatures (MAATs) by integrating remote-sensing-based estimates of mean annual land surface temperatures (MASTs), leaf area index (LAI) and fractional snow cover values, and decadal mean MAAT date from 152 weather stations with a geographically weighted regression (GWR). The results reflect a continuous rise of approximately 0.04 °C a-1 in the decadal mean MAAT values over the past half century. A thermal-condition classification matrix is used to convert modelled MAATs to permafrost thermal type. Results show that the climate warming has led to a thermal degradation of permafrost in the past half century. The total area of thermally degraded permafrost is approximately 153.76 × 104 km2, which corresponds to 88 % of the permafrost area in the 1960s. The thermal condition of 75.2 % of the very cold permafrost, 89.6 % of the cold permafrost, 90.3 % of the cool permafrost, 92.3 % of the warm permafrost, and 32.8 % of the very warm permafrost has been degraded to lower levels of thermal condition. Approximately 49.4 % of the very warm permafrost and 96 % of the likely thawing permafrost has degraded to seasonally frozen ground. The mean elevations of the very cold, cold, cool, warm, very warm, and likely thawing permafrost areas increased by 88, 97, 155, 185, 161, and 250 m, respectively. The degradation mainly occurred from the 1960s to the 1970s and from the 1990s to the 2000s. This degradation may lead to increased risks to infrastructure, reductions in ecosystem resilience, increased flood risks, and positive climate feedback effects. It therefore affects the well-being of millions of people

  16. International Permafrost Field Courses in Siberia: the Synthesis of Research and Education

    Science.gov (United States)

    Ablyazina, D.; Boitsov, A.; Grebenets, V.; Kaverin, D.; Klene, A.; Kurchatova, A.; Pfeiffer, E. M.; Zschocke, A.; Shiklomanov, N.; Streletskiy, D.

    2009-04-01

    During summers of 2007 and 2008 a series of International University Courses on Permafrost (IUCP) were conducted in West Siberia, Russia. Courses were organized as part of the International Permafrost Association (IPA) International Polar Year activities. The North of West Siberia region was selected to represent diverse permafrost, climatic and landscape conditions. The courses were jointly organized by the Moscow State University (MSU) and the Tumen' Oil and Gas University (TOGU) with the help from German and U.S. institutions. The program attracted undergraduate and graduate students with diverse interests and backgrounds from Germany, Russia and the U.S. and involved instructors specializing in different aspects of permafrost research. Courses were designed to address three major topics of permafrost-related research: a) permafrost environments characteristic of the discontinuous and continuous zones; b) field instrumentation and techniques; c) permafrost engineering and problems of development in permafrost regions. Methodologically, courses consisted of systematic permafrost investigations at long-term monitoring sites and survey-type expeditions. Systematic, process-based investigations were conducted at a network of sites which constitute the TEPO established by TOGU in collaboration with the gas company NadymGasProm. The observation complex includes an array of 30-m deep boreholes equipped with automatic data collection systems and representing characteristic permafrost landscapes of West Siberia. Boreholes are complemented by sites for snow cover, vegetation, soil, ground ice, and geomorphologic investigations. As part of student research activities, four new Circumpolar Active Layer Monitoring (CALM) sites were established in proximity to boreholes for monitoring spatial distribution and long-term dynamic of the active layer. New sites represent diverse landscapes characteristic of the West Siberian previously underrepresented in the CALM network

  17. Use Of Amino Acid Racemization To Investigate The Metabolic Activity Of ?Dormant? Microorganisms In Siberian Permafrost

    Science.gov (United States)

    Tsapin, A.; McDonald, G.

    2002-12-01

    search for extraterrestrial life or its remnants is based on studying the most probable environments in which life (extant or extinct) may be found, and determining the maximum period of time over which such life could be preserved. The terrestrial permafrost, inhabited by cold adapted microbes, can be considered as an extraterrestrial analog environment. The cells and their metabolic end-products in Earth's permafrost can be used in the search for possible ecosystems and potential inhabitants on extraterrestrial cryogenic bodies. The study of microorganisms (or their remnants) that were buried for a few million years in permafrost provides us with a unique opportunity to determine the long-term viability of (micro)organisms. We have analyzed the degree of racemization of aspartic acid in permafrost samples from Northern Siberia (Brinton et al. 2002, Astrobiology 2, 77), an area from which microorganisms of apparent ages up to a few million years have previously been isolated and cultured. We find that the extent of aspartic acid racemization in permafrost cores increases very slowly up to an age of approximately 25,000 years (around 5 m depth). The apparent temperature of racemization over the age range 0-25,000 years, determined using measured aspartic acid racemization rate constants, is ?19 C. This apparent racemization temperature is significantly lower than the measured environmental temperature (?11 to ?13 C), and suggests active recycling of D-aspartic acid in Siberian permafrost up to an age of around 25,000 years. This indicates that permafrost organisms are capable of repairing some molecular damage incurred while they are in a ?dormant? state over geologic time.

  18. Dynamics of the larch taiga-permafrost coupled system in Siberia under climate change

    International Nuclear Information System (INIS)

    Zhang Ningning; Yasunari, Tetsuzo; Ohta, Takeshi

    2011-01-01

    Larch taiga, also known as Siberian boreal forest, plays an important role in global and regional water-energy-carbon (WEC) cycles and in the climate system. Recent in situ observations have suggested that larch-dominated taiga and permafrost behave as a coupled eco-climate system across a broad boreal zone of Siberia. However, neither field-based observations nor modeling experiments have clarified the synthesized dynamics of this system. Here, using a new dynamic vegetation model coupled with a permafrost model, we reveal the processes of interaction between the taiga and permafrost. The model demonstrates that under the present climate conditions in eastern Siberia, larch trees maintain permafrost by controlling the seasonal thawing of permafrost, which in turn maintains the taiga by providing sufficient water to the larch trees. The experiment without permafrost processes showed that larch would decrease in biomass and be replaced by a dominance of pine and other species that suffer drier hydroclimatic conditions. In the coupled system, fire not only plays a destructive role in the forest, but also, in some cases, preserves larch domination in forests. Climate warming sensitivity experiments show that this coupled system cannot be maintained under warming of about 2 deg. C or more. Under such conditions, a forest with typical boreal tree species (dark conifer and deciduous species) would become dominant, decoupled from the permafrost processes. This study thus suggests that future global warming could drastically alter the larch-dominated taiga-permafrost coupled system in Siberia, with associated changes of WEC processes and feedback to climate.

  19. Dynamics of the larch taiga-permafrost coupled system in Siberia under climate change

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ningning [Graduate School of Environmental Studies, Nagoya University, Nagoya, Aichi 464-8601 (Japan); Yasunari, Tetsuzo [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya 464-8601 (Japan); Ohta, Takeshi, E-mail: zhangningning@lasg.iap.ac.cn [Study Consortium for Earth-Life Interactive Systems (SELIS) of Nagoya University, Nagoya (Japan)

    2011-04-15

    Larch taiga, also known as Siberian boreal forest, plays an important role in global and regional water-energy-carbon (WEC) cycles and in the climate system. Recent in situ observations have suggested that larch-dominated taiga and permafrost behave as a coupled eco-climate system across a broad boreal zone of Siberia. However, neither field-based observations nor modeling experiments have clarified the synthesized dynamics of this system. Here, using a new dynamic vegetation model coupled with a permafrost model, we reveal the processes of interaction between the taiga and permafrost. The model demonstrates that under the present climate conditions in eastern Siberia, larch trees maintain permafrost by controlling the seasonal thawing of permafrost, which in turn maintains the taiga by providing sufficient water to the larch trees. The experiment without permafrost processes showed that larch would decrease in biomass and be replaced by a dominance of pine and other species that suffer drier hydroclimatic conditions. In the coupled system, fire not only plays a destructive role in the forest, but also, in some cases, preserves larch domination in forests. Climate warming sensitivity experiments show that this coupled system cannot be maintained under warming of about 2 deg. C or more. Under such conditions, a forest with typical boreal tree species (dark conifer and deciduous species) would become dominant, decoupled from the permafrost processes. This study thus suggests that future global warming could drastically alter the larch-dominated taiga-permafrost coupled system in Siberia, with associated changes of WEC processes and feedback to climate.

  20. [Consequences for labile blood products of leukocyte depletion by whole blood filtration using the Leucoflex LST1 in-line filter. Evaluation of the Leucoflex LST1 filter].

    Science.gov (United States)

    Janus, G; Samson, T; Faudon, R; Renaudeau, C; Joussemet, M; Fabre, G

    1997-12-01

    The aim of this study is to evaluate the effects of whole blood filtration after a storage time of 20-24 hours at laboratory temperature using the in line filter Leucoflex LST1. The study concerns 49 blood donations in which we studied leukocyte depletion, proteins (IgG, IgA, IgM, haptoglobin, C3, C4), coagulation factors (fibrinogen, factors XII, XI, IX, VIII, V, proteins S and C, plasminogen, tPA, D-Dimers, PDF) at day 1, the parameters of conservation (ATP, 2-3 DPG, extra cellular potassium, haemolysis, pH) of red blood cell concentrates (RCCs) and bacteriological sterility at day 1 and 42. Despite a correct leukocyte depletion (mean depletion of 3.96 log), a 10 fold higher mean level of residual leukocytes/unit than with buffy coat poor RCC filtration (0.514.10(6) vs 0.051.10(6)) is observed. Moreover a lot of concentrates are not in accordance with French regulations (7/42 with more than 1.10(6) leukocytes/unit). The variation of the rates of IgG, IgA, IgM, haptoglobin, C4 and protein C is not significant. For the others there is a slight decrease with a mean level remaining in a physiological range. No sign of activation is noted. The sterility assays remain negative and the RCC conservation is not altered. In conclusion, even if the quality of the leukocyte depletion is not satisfactory in our study and has to be stated more precisely by multicenter studies, the whole blood filtration does not alter the quality of the derived components and allows us obtain RCC in a bigger volume and containing more haemoglobin than with the classical procedure after removing the buffy-coat [10].

  1. Scaling-up permafrost thermal measurements in western Alaska using an ecotype approach

    Directory of Open Access Journals (Sweden)

    W. L. Cable

    2016-10-01

    Full Text Available Permafrost temperatures are increasing in Alaska due to climate change and in some cases permafrost is thawing and degrading. In areas where degradation has already occurred the effects can be dramatic, resulting in changing ecosystems, carbon release, and damage to infrastructure. However, in many areas we lack baseline data, such as subsurface temperatures, needed to assess future changes and potential risk areas. Besides climate, the physical properties of the vegetation cover and subsurface material have a major influence on the thermal state of permafrost. These properties are often directly related to the type of ecosystem overlaying permafrost. In this paper we demonstrate that classifying the landscape into general ecotypes is an effective way to scale up permafrost thermal data collected from field monitoring sites. Additionally, we find that within some ecotypes the absence of a moss layer is indicative of the absence of near-surface permafrost. As a proof of concept, we used the ground temperature data collected from the field sites to recode an ecotype land cover map into a map of mean annual ground temperature ranges at 1 m depth based on analysis and clustering of observed thermal regimes. The map should be useful for decision making with respect to land use and understanding how the landscape might change under future climate scenarios.

  2. Permafrost Meta-Omics and Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Mackelprang, Rachel; Saleska, Scott R.; Jacobsen, Carsten Suhr; Jansson, Janet K.; Taş, Neslihan

    2016-06-29

    Permafrost (i.e., soil that has been frozen for at least 2 consecutive years) represents a habitat for microbial life at subzero temperatures (Gilichinsky et al. 2008). Approximately one quarter of the Earth’s surface is underlain by permafrost, which contains 25-50% of the total global soil carbon pool (Schuur et al. 2008, Tarnocai et al. 2009). This carbon is largely protected from microbial decomposition by reduced microbial activity in frozen conditions, but climate change is threatening to induce large-scale permafrost thaw thus exposing it to degradation. The resulting emissions of greenhouse gasses (GHGs) can produce a positive feedback loop and significantly amplify the effects of global warming. Increasing temperatures at high latitudes, changes in precipitation patterns, and frequent fire events have already initiated a widespread degradation of permafrost (Schuur et al. 2015).

  3. Detecting geothermal anomalies and evaluating LST geothermal component by combining thermal remote sensing time series and land surface model data

    NARCIS (Netherlands)

    Romaguera, M.; Vaughan, R. G.; Ettema, J.; Izquierdo-Verdiguier, E.; Hecker, C. A.; van der Meer, F. D.

    This paper explores for the first time the possibilities to use two land surface temperature (LST) time series of different origins (geostationary Meteosat Second Generation satellite data and Noah land surface modelling, LSM), to detect geothermal anomalies and extract the geothermal component of

  4. Detecting geothermal anomalies and evaluating LST geothermal component by combining thermal remote sensing time series and land surface model data

    NARCIS (Netherlands)

    Romaguera, M.; Vaughan, R. G.; Ettema, J.; Izquierdo-Verdiguier, E.; Hecker, C. A.; van der Meer, F. D.

    2017-01-01

    This paper explores for the first time the possibilities to use two land surface temperature (LST) time series of different origins (geostationary Meteosat Second Generation satellite data and Noah land surface modelling, LSM), to detect geothermal anomalies and extract the geothermal component of

  5. Monitoring of thermal regime of permafrost in the coastal zone of Western Yamal

    Science.gov (United States)

    Vasiliev, A.

    2009-04-01

    Data on thermal regime of permafrost are required for estimation of the climate change influence on permafrost dynamics. Monitoring of thermal regime of permafrost was arranged in the area of weather station "Marre-Sale", western Yamal. In terms of geomorphology, the area of our observations belongs to the second and third marine terraces; the surface of these terraces has been partly modified by recent cryogenic processes. The elevation varies from 10 to 30 m a.s.l. Marine clays lie at the base of the geological section of the coastal deposits. Their upper part was eroded and uneven surface of marine sediments is overlain by continental sandy sediments. Marine clays are saline. In the southern part of study area, low accumulative islands are forming. Their heights above sea level do not exceed 0.5 meters, and during high tides their surface is covered by sea water. The sediments accumulating at these islands are saline silty clays. Western Yamal region is located within continuous permafrost zone with thickness of 150 to 200 meters. Study of thermal regime in the on-shore zone has been performed since 1979 using the 10-12-m-deep boreholes. In 2007, five boreholes were included in the work program of the Thermal State of Permafrost (TSP) project developed as a part of IPY scientific activities. According to TSP program, temperature sensors were installed at depths 2, 3, 5, and 10 meters; measurements have been performed every six hours. In this presentation, results of our observations related to climate change are discussed. For different terrain units, increase of mean annual permafrost temperature during the last 30 years has reached 0.6 to 1.5 deg. C. In the transit zone, monitoring of thermal regime have been performed since 2006. Sensors were installed at depths 0, 0.25, 0.6, 0.75, 1.25, 1.75, and 2.25 meters. The active layer depth here reaches 1.9 meters, thus the 2.25-m-sensor is located within permafrost. Monitoring data show the sharp increase in mean

  6. Hydrogeology, chemical and microbial activity measurement through deep permafrost

    Energy Technology Data Exchange (ETDEWEB)

    Stotler, R.L.; Frape, S.K.; Freifeld, B.M.; Holden, B.; Onstott, T.C.; Ruskeeniemi, T.; Chan, E.

    2010-04-01

    Little is known about hydrogeochemical conditions beneath thick permafrost, particularly in fractured crystalline rock, due to difficulty in accessing this environment. The purpose of this investigation was to develop methods to obtain physical, chemical, and microbial information about the subpermafrost environment from a surface-drilled borehole. Using a U-tube, gas and water samples were collected, along with temperature, pressure, and hydraulic conductivity measurements, 420 m below ground surface, within a 535 m long, angled borehole at High Lake, Nunavut, Canada, in an area with 460-m-thick permafrost. Piezometric head was well above the base of the permafrost, near land surface. Initial water samples were contaminated with drill fluid, with later samples <40% drill fluid. The salinity of the non-drill fluid component was <20,000 mg/L, had a Ca/Na ratio above 1, with {delta}{sup 18}O values {approx}5{per_thousand} lower than the local surface water. The fluid isotopic composition was affected by the permafrost-formation process. Nonbacteriogenic CH{sub 4} was present and the sample location was within methane hydrate stability field. Sampling lines froze before uncontaminated samples from the subpermafrost environment could be obtained, yet the available time to obtain water samples was extended compared to previous studies. Temperature measurements collected from a distributed temperature sensor indicated that this issue can be overcome easily in the future. The lack of methanogenic CH{sub 4} is consistent with the high sulfate concentrations observed in cores. The combined surface-drilled borehole/U-tube approach can provide a large amount of physical, chemical, and microbial data from the subpermafrost environment with few, controllable, sources of contamination.

  7. Hydrogeology, chemical and microbial activity measurement through deep permafrost.

    Science.gov (United States)

    Stotler, Randy L; Frape, Shaun K; Freifeld, Barry M; Holden, Brian; Onstott, Tullis C; Ruskeeniemi, Timo; Chan, Eric

    2011-01-01

    Little is known about hydrogeochemical conditions beneath thick permafrost, particularly in fractured crystalline rock, due to difficulty in accessing this environment. The purpose of this investigation was to develop methods to obtain physical, chemical, and microbial information about the subpermafrost environment from a surface-drilled borehole. Using a U-tube, gas and water samples were collected, along with temperature, pressure, and hydraulic conductivity measurements, 420 m below ground surface, within a 535 m long, angled borehole at High Lake, Nunavut, Canada, in an area with 460-m-thick permafrost. Piezometric head was well above the base of the permafrost, near land surface. Initial water samples were contaminated with drill fluid, with later samples <40% drill fluid. The salinity of the non-drill fluid component was <20,000 mg/L, had a Ca/Na ratio above 1, with δ(18) O values ∼5‰ lower than the local surface water. The fluid isotopic composition was affected by the permafrost-formation process. Nonbacteriogenic CH(4) was present and the sample location was within methane hydrate stability field. Sampling lines froze before uncontaminated samples from the subpermafrost environment could be obtained, yet the available time to obtain water samples was extended compared to previous studies. Temperature measurements collected from a distributed temperature sensor indicated that this issue can be overcome easily in the future. The lack of methanogenic CH(4) is consistent with the high sulfate concentrations observed in cores. The combined surface-drilled borehole/U-tube approach can provide a large amount of physical, chemical, and microbial data from the subpermafrost environment with few, controllable, sources of contamination. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  8. Numerical simulation of permafrost depth during a future glaciation, Campine area, Northern Belgium

    International Nuclear Information System (INIS)

    Govaerts, Joan; Weetjens, Eef; Beerten, Koen

    2012-01-01

    Document available in extended abstract form only. Given the long time frames involved and their potential detrimental effects, climate changes are considered in the safety assessment of long-term geological disposal of radioactive waste. One such effect that climate changes may govern is the re-appearance of permafrost in north-western Europe. This condition already existed during previous glaciations (e.g., Weichselian glacial, 115-11 ka BP), and may have several consequences for the hydrosphere, geosphere, biosphere and repository. Here, we present calculations of permafrost depth based on the climatic scenario with the Weichselian (last glacial) as an analog to estimate the permafrost depth during a future glaciation. Whereas the lateral extent of permafrost can be deduced from surface features, not much is known about the maximum depth of permafrost during a cold stage in the Campine region. Realistic values of the latent heat of melting of pure water, and thermal conductivity of dry or frozen and unfrozen saturated sand and clay are used as input parameters. In addition, detailed and refined climatic scenarios for the last glacial are used to improve the quality of boundary conditions, together with a more advanced description of freezing/thawing processes. To describe heat transport in the subsoil of the Mol site, the one-dimensional enthalpy conservation equation is used with heat transport only occurring by conduction. In the first calculation case, the temperature at the top of the soil layer is set equal to the air temperatures of a realistic glacial cycle (Weichselian glaciation). In a second calculation case, the insulating effects of the surface cover are considered, and the air temperatures are converted into surface temperatures by making use of the 'n-factor concept', which yields an empirical relationship between the mean annual surface temperature, T s , and the mean annual air temperature, T a . In Figure 1 the permafrost pro-gradation front

  9. Simulations of permafrost evolution at Olkiluoto

    Energy Technology Data Exchange (ETDEWEB)

    Hartikainen, J. [Aalto Univ., Espoo (Finland)

    2013-07-15

    This report provides numerical estimations of the evolution of permafrost and perennially frozen ground at Olkiluoto on time-scales of 60,000 and 125,000 years using Olkiluoto's site-specific information on time histories of ground level temperatures, ice sheet thickness, basal conditions, shoreline migration, soil and vegetation cover as well as heat generation from the spent fuel at a depth of 420 metres. When considering environmental conditions akin to the last glacial cycle for a 125,000 years long period, the maximum permafrost depth over the repository area can exceed the depth of 300 m and the maximum depth of perennially frozen ground the depth of 270 m. If Olkiluoto, after a 50,000 years long temperate phase of boreal climate, was subjected to a 10,000 years long periglacial period with air temperature decreased between -5 deg C and -10 deg C, the maximum permafrost depth would range between 60 and 240 m and the maximum depth of perennially frozen ground between 50 and 220 m. Furthermore, permafrost would reach the repository depth in 10,000 years, if the air temperature was lowered down to -15 deg C and the ground surface had a very thin vegetation and snow cover. Alternatively, if Olkiluoto experienced a 125,000 years long glacial cycle with a very long periglacial periods of low air temperatures and thin vegetation and snow cover and without any ice sheet development, permafrost would reach the depth of 400 m in 98,000 years and perennially frozen ground in 101,000 years. The areal distribution of permafrost and perennially frozen ground are broadly affected by the snow cover, lakes and the peat areas, especially when an extensive peat growth occurs. The lack of snow cover can enhance the evolution of the maximum depth of permafrost and perennially frozen ground by over 50 %. In addition, ground thermal conditions and the heat generation from the spent fuel modify the spatial and temporal development of permafrost and perennially frozen ground. A

  10. Simulations of permafrost evolution at Olkiluoto

    International Nuclear Information System (INIS)

    Hartikainen, J.

    2013-07-01

    This report provides numerical estimations of the evolution of permafrost and perennially frozen ground at Olkiluoto on time-scales of 60,000 and 125,000 years using Olkiluoto's site-specific information on time histories of ground level temperatures, ice sheet thickness, basal conditions, shoreline migration, soil and vegetation cover as well as heat generation from the spent fuel at a depth of 420 metres. When considering environmental conditions akin to the last glacial cycle for a 125,000 years long period, the maximum permafrost depth over the repository area can exceed the depth of 300 m and the maximum depth of perennially frozen ground the depth of 270 m. If Olkiluoto, after a 50,000 years long temperate phase of boreal climate, was subjected to a 10,000 years long periglacial period with air temperature decreased between -5 deg C and -10 deg C, the maximum permafrost depth would range between 60 and 240 m and the maximum depth of perennially frozen ground between 50 and 220 m. Furthermore, permafrost would reach the repository depth in 10,000 years, if the air temperature was lowered down to -15 deg C and the ground surface had a very thin vegetation and snow cover. Alternatively, if Olkiluoto experienced a 125,000 years long glacial cycle with a very long periglacial periods of low air temperatures and thin vegetation and snow cover and without any ice sheet development, permafrost would reach the depth of 400 m in 98,000 years and perennially frozen ground in 101,000 years. The areal distribution of permafrost and perennially frozen ground are broadly affected by the snow cover, lakes and the peat areas, especially when an extensive peat growth occurs. The lack of snow cover can enhance the evolution of the maximum depth of permafrost and perennially frozen ground by over 50 %. In addition, ground thermal conditions and the heat generation from the spent fuel modify the spatial and temporal development of permafrost and perennially frozen ground. A

  11. Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses

    Science.gov (United States)

    Harris, Charles; Arenson, Lukas U.; Christiansen, Hanne H.; Etzelmüller, Bernd; Frauenfelder, Regula; Gruber, Stephan; Haeberli, Wilfried; Hauck, Christian; Hölzle, Martin; Humlum, Ole; Isaksen, Ketil; Kääb, Andreas; Kern-Lütschg, Martina A.; Lehning, Michael; Matsuoka, Norikazu; Murton, Julian B.; Nötzli, Jeanette; Phillips, Marcia; Ross, Neil; Seppälä, Matti; Springman, Sarah M.; Vonder Mühll, Daniel

    2009-02-01

    We present a review of the changing state of European permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of Svalbard and the discontinuous high altitude mountain permafrost of Iceland, Fennoscandia and the Alps. The paper focuses on methodological developments and data collection over the last decade or so, including research associated with the continent-scale network of instrumented permafrost boreholes established between 1998 and 2001 under the European Union PACE project. Data indicate recent warming trends, with greatest warming at higher latitudes. Equally important are the impacts of shorter-term extreme climatic events, most immediately reflected in changes in active layer thickness. A large number of complex variables, including altitude, topography, insolation and snow distribution, determine permafrost temperatures. The development of regionally calibrated empirical-statistical models, and physically based process-oriented models, is described, and it is shown that, though more complex and data dependent, process-oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography. Mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed. We report on recent research into ground ice formation, including ice segregation within bedrock and vein ice formation within ice wedge systems. The potential impacts of climate change on rock weathering, permafrost creep, landslides, rock falls, debris flows and slow mass movements are also discussed. Recent engineering responses to the potentially damaging effects of climate warming are outlined, and risk assessment strategies to minimise geological hazards are described. We conclude that forecasting changes in hazard occurrence, magnitude and frequency is likely to depend on process-based modelling, demanding improved

  12. Analysing the environmental harms caused by coal mining and its protection measures in permafrost regions of Qinghai–Tibet Plateau

    Directory of Open Access Journals (Sweden)

    Wei Cao

    2017-09-01

    Full Text Available The coal mining has brought a series of ecological problems and environmental problems in permafrost regions. Taking Muli coal-mining area as an example, this article attempts to analyse the environmental harms caused by coal mining and its protection measures in permafrost regions of Qinghai–Tibet Plateau. This article analyses the influence of open mining on the surrounding permafrost around the open pit by using the numerical simulation. The results show that (1 based on the interrelation between coal mining and permafrost environment, these main environmental harm include the permafrost change and the natural environment change in cold regions; (2 once the surface temperature rises due to open mining, the permafrost will disappear with the increase of exploitation life. If considering the solar radiation, the climate conditions and the geological condition around the pit edge, the maximum thaw depth will be more than 2 m; (3 the protection measures are proposed to avoid the disadvantage impact on the permafrost environment caused by coal mining. It will provide a scientific basis for the resource development and environment protection in cold regions.

  13. Degradation and Local Survival of Permafrost Through the Last Interglaciation in Interior Alaska and Yukon Territory

    Science.gov (United States)

    Reyes, A. V.; Froese, D. G.; Jensen, B. J.

    2006-12-01

    Permafrost in northern North America is warming, and recent modeling efforts have predicted the widespread disappearance of permafrost through much of the northern hemisphere over the next century. However, little is known of the impacts of past sustained warm intervals on permafrost dynamics, antiquity, and distribution due to difficulties in establishing reliable chronologies. Permafrost thus remains the last element of the Arctic cryosphere for which there is poor understanding of its adaptability to past warmer-than-present climate. Here we present observations from three sites in the region of interior Alaska and Yukon Territory that remained ice-free during Plio-Pleistocene glaciations, which collectively demonstrate the variable nature of the response of permafrost to warming during the last interglaciation. Chronology for all sites is based on identification of Old Crow tephra (OCt; 140±10 ka) by glass major element composition. Throughout the study region, OCt is consistently associated with organic-rich sediments that represent the last interglaciation on the basis of pollen, insect, and macrofossil assemblages. At the Palisades site on the Yukon River, 250 km west of Fairbanks, OCt is 1.5-3.5 m below thick (>1m) organic-rich silts and peats that are locally rich in beaver-chewed wood and large wood stumps, some of which are in growth position. In contrast, placer mining at Thistle Creek in central Yukon Territory exposes a dramatic thaw unconformity that is presumably related to local, but incomplete, permafrost degradation during the last interglaciation. In upslope positions at Thistle Creek, OCt is incorporated into a steeply dipping, 30 cm thick, organic-rich silt horizon that truncates at least one intact, relict ice wedge. The steeply dipping organic- rich horizon grades downslope into organic-rich silt with dense accumulations of wood fragments, including tree stems up to 2 m long. Evidence for similar permafrost degradation during the last

  14. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Richard Sigal; Kent Newsham; Thomas Williams; Barry Freifeld; Timothy Kneafsey; Carl Sondergeld; Shandra Rai; Jonathan Kwan; Stephen Kirby; Robert Kleinberg; Doug Griffin

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. The work scope drilled and cored a well The Hot Ice No. 1 on Anadarko leases beginning in FY 2003 and completed in 2004. An on-site core analysis laboratory was built and utilized for determining the physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. The final efforts of the project are to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists developing reservoir models. No gas hydrates were encountered in this well; however, a wealth of information was generated and is contained in this report. The Hot Ice No. 1 well was drilled from the surface to a measured depth of 2300 ft. There was almost 100% core recovery from the bottom of surface casing at 107 ft to total depth. Based on the best estimate of the bottom of the methane hydrate stability zone (which used new data obtained from Hot Ice No. 1 and new analysis of data from adjacent wells), core was recovered over its complete range. Approximately 580 ft of porous, mostly frozen, sandstone and 155 of conglomerate were recovered in the Ugnu Formation and approximately 215 ft of porous sandstone were recovered in the West Sak Formation. There were gas shows in the bottom

  15. The impacts of recent permafrost thaw on land–atmosphere greenhouse gas exchange

    International Nuclear Information System (INIS)

    Hayes, Daniel J; Yuan, Fengming; Wullschleger, Stan D; Kicklighter, David W; Melillo, Jerry M; McGuire, A David; Chen, Min; Zhuang, Qianlai

    2014-01-01

    Permafrost thaw and the subsequent mobilization of carbon (C) stored in previously frozen soil organic matter (SOM) have the potential to be a strong positive feedback to climate. As the northern permafrost region experiences as much as a doubling of the rate of warming as the rest of the Earth, the vast amount of C in permafrost soils is vulnerable to thaw, decomposition and release as atmospheric greenhouse gases. Diagnostic and predictive estimates of high-latitude terrestrial C fluxes vary widely among different models depending on how dynamics in permafrost, and the seasonally thawed ‘active layer’ above it, are represented. Here, we employ a process-based model simulation experiment to assess the net effect of active layer dynamics on this ‘permafrost carbon feedback’ in recent decades, from 1970 to 2006, over the circumpolar domain of continuous and discontinuous permafrost. Over this time period, the model estimates a mean increase of 6.8 cm in active layer thickness across the domain, which exposes a total of 11.6 Pg C of thawed SOM to decomposition. According to our simulation experiment, mobilization of this previously frozen C results in an estimated cumulative net source of 3.7 Pg C to the atmosphere since 1970 directly tied to active layer dynamics. Enhanced decomposition from the newly exposed SOM accounts for the release of both CO 2 (4.0 Pg C) and CH 4 (0.03 Pg C), but is partially compensated by CO 2 uptake (0.3 Pg C) associated with enhanced net primary production of vegetation. This estimated net C transfer to the atmosphere from permafrost thaw represents a significant factor in the overall ecosystem carbon budget of the Pan-Arctic, and a non-trivial additional contribution on top of the combined fossil fuel emissions from the eight Arctic nations over this time period. (paper)

  16. The impacts of recent permafrost thaw on land-atmosphere greenhouse gas exchange

    Science.gov (United States)

    Hayes, Daniel J.; Kicklighter, David W.; McGuire, A. David; Chen, Min; Zhuang, Qianlai; Yuan, Fengming; Melillo, Jerry M.; Wullschleger, Stan D.

    2014-01-01

    Permafrost thaw and the subsequent mobilization of carbon (C) stored in previously frozen soil organic matter (SOM) have the potential to be a strong positive feedback to climate. As the northern permafrost region experiences as much as a doubling of the rate of warming as the rest of the Earth, the vast amount of C in permafrost soils is vulnerable to thaw, decomposition and release as atmospheric greenhouse gases. Diagnostic and predictive estimates of high-latitude terrestrial C fluxes vary widely among different models depending on how dynamics in permafrost, and the seasonally thawed 'active layer' above it, are represented. Here, we employ a process-based model simulation experiment to assess the net effect of active layer dynamics on this 'permafrost carbon feedback' in recent decades, from 1970 to 2006, over the circumpolar domain of continuous and discontinuous permafrost. Over this time period, the model estimates a mean increase of 6.8 cm in active layer thickness across the domain, which exposes a total of 11.6 Pg C of thawed SOM to decomposition. According to our simulation experiment, mobilization of this previously frozen C results in an estimated cumulative net source of 3.7 Pg C to the atmosphere since 1970 directly tied to active layer dynamics. Enhanced decomposition from the newly exposed SOM accounts for the release of both CO2 (4.0 Pg C) and CH4 (0.03 Pg C), but is partially compensated by CO2 uptake (0.3 Pg C) associated with enhanced net primary production of vegetation. This estimated net C transfer to the atmosphere from permafrost thaw represents a significant factor in the overall ecosystem carbon budget of the Pan-Arctic, and a non-trivial additional contribution on top of the combined fossil fuel emissions from the eight Arctic nations over this time period.

  17. Permafrost and urban Development in Norilsk Russia.

    Science.gov (United States)

    Shiklomanov, N. I.; Streletskiy, D. A.; Grebenets, V. I.

    2017-12-01

    The city of Norilsk was established in 1935 as a GULAG mining and metallurgy work camp to explore the rich deposits of non-ferrous metals. By the 1989, the population of Norilsk reached 179,757 people. Two additional cities were developed in proximity to Norilsk in the 1960s-1980s: Talnakh (1989 population 65,710); and Kaerkan (1989 population 29,824) making the Norilsk region a major Arctic metropolis. While such rapid growth is not unusual for developing industrial cities, the geographic location makes Norilsk rather unique among world urban centers. It was built in Central Siberia at 69°51' N latitude (above the Arctic Circle), in region characterized by harsh subarctic climate (mean annual temperature around -10 oC), over forest tundra/tundra transitional landscapes underlined by perennially frozen ground (permafrost). Throughout its existence, the Norilsk region was highly isolated: it is not connected to Russian road and railroad systems. The harsh environmental conditions provided significant and rather unique challenges to Norilsk development. Specifically, the presence of ice-rich permafrost imposed restrictions on application of standard urban planning and engineering practices. This presentation analyzes the history of permafrost construction in Norilsk. It shows how though initial trial and errors, a set of guiding principles and engineering methods of construction on permafrost were developed allowing a rapid urbanization of the area during the 1960-1980s. However, despite significant advances in permafrost engineering, the pronounced permafrost degradation has become evident in Norilsk by the mid 1980s and has accelerated rapidly since the mid 1990s resulting in widespread deformation of buildings. Climatic changes are frequently identified as a major cause of accelerated deterioration of infrastructure build on permafrost. However, we argue that other factors, including the complexity of interactions between deferent components of urban

  18. Classification of permafrost active layer depth from remotely sensed and topographic evidence

    International Nuclear Information System (INIS)

    Peddle, D.R.; Franklin, S.E.

    1993-01-01

    The remote detection of permafrost (perennially frozen ground) has important implications to environmental resource development, engineering studies, natural hazard prediction, and climate change research. In this study, the authors present results from two experiments into the classification of permafrost active layer depth within the zone of discontinuous permafrost in northern Canada. A new software system based on evidential reasoning was implemented to permit the integrated classification of multisource data consisting of landcover, terrain aspect, and equivalent latitude, each of which possessed different formats, data types, or statistical properties that could not be handled by conventional classification algorithms available to this study. In the first experiment, four active layer depth classes were classified using ground based measurements of the three variables with an accuracy of 83% compared to in situ soil probe determination of permafrost active layer depth at over 500 field sites. This confirmed the environmental significance of the variables selected, and provided a baseline result to which a remote sensing classification could be compared. In the second experiment, evidence for each input variable was obtained from image processing of digital SPOT imagery and a photogrammetric digital elevation model, and used to classify active layer depth with an accuracy of 79%. These results suggest the classification of evidence from remotely sensed measures of spectral response and topography may provide suitable indicators of permafrost active layer depth

  19. Comparisons of Satellite Soil Moisture, an Energy Balance Model Driven by LST Data and Point Measurements

    Science.gov (United States)

    Laiolo, Paola; Gabellani, Simone; Rudari, Roberto; Boni, Giorgio; Puca, Silvia

    2013-04-01

    Soil moisture plays a fundamental role in the partitioning of mass and energy fluxes between land surface and atmosphere, thereby influencing climate and weather, and it is important in determining the rainfall-runoff response of catchments; moreover, in hydrological modelling and flood forecasting, a correct definition of moisture conditions is a key factor for accurate predictions. Different sources of information for the estimation of the soil moisture state are currently available: satellite data, point measurements and model predictions. All are affected by intrinsic uncertainty. Among different satellite sensors that can be used for soil moisture estimation three major groups can be distinguished: passive microwave sensors (e.g., SSMI), active sensors (e.g. SAR, Scatterometers), and optical sensors (e.g. Spectroradiometers). The last two families, mainly because of their temporal and spatial resolution seem the most suitable for hydrological applications In this work soil moisture point measurements from 10 sensors in the Italian territory are compared of with the satellite products both from the HSAF project SM-OBS-2, derived from the ASCAT scatterometer, and from ACHAB, an operative energy balance model that assimilate LST data derived from MSG and furnishes daily an evaporative fraction index related to soil moisture content for all the Italian region. Distributed comparison of the ACHAB and SM-OBS-2 on the whole Italian territory are performed too.

  20. Association of CAD, a multifunctional protein involved in pyrimidine synthesis, with mLST8, a component of the mTOR complexes

    Science.gov (United States)

    2013-01-01

    Background mTOR is a genetically conserved serine/threonine protein kinase, which controls cell growth, proliferation, and survival. A multifunctional protein CAD, catalyzing the initial three steps in de novo pyrimidine synthesis, is regulated by the phosphorylation reaction with different protein kinases, but the relationship with mTOR protein kinase has not been known. Results CAD was recovered as a binding protein with mLST8, a component of the mTOR complexes, from HEK293 cells transfected with the FLAG-mLST8 vector. Association of these two proteins was confirmed by the co-immuoprecipitaiton followed by immunoblot analysis of transfected myc-CAD and FLAG-mLST8 as well as that of the endogenous proteins in the cells. Analysis using mutant constructs suggested that CAD has more than one region for the binding with mLST8, and that mLST8 recognizes CAD and mTOR in distinct ways. The CAD enzymatic activity decreased in the cells depleted of amino acids and serum, in which the mTOR activity is suppressed. Conclusion The results obtained indicate that mLST8 bridges between CAD and mTOR, and plays a role in the signaling mechanism where CAD is regulated in the mTOR pathway through the association with mLST8. PMID:23594158

  1. High biolability of ancient permafrost carbon upon thaw

    NARCIS (Netherlands)

    Vonk, J.E.; Mann, P.J.; Davydov, S.; Davydova, A.; Spencer, R.G.M.; Schade, J.; Sobczak, W.V.; Zimov, S.; Bulygina, E.; Eglinton, T.I.; Holmes, R.M.

    2013-01-01

    Ongoing climate warming in the Arctic will thaw permafrost and remobilize substantial terrestrial organic carbon (OC) pools. Around a quarter of northern permafrost OC resides in Siberian Yedoma deposits, the oldest form of permafrost carbon. However, our understanding of the degradation and

  2. High biolability of ancient permafrost carbon upon thaw

    NARCIS (Netherlands)

    Vonk, Jorien E.; Mann, Paul J.; Davydov, Sergey; Davydova, Anna; Spencer, Robert G. M.; Schade, John; Sobczak, William V.; Zimov, Nikita; Zimov, Sergei; Bulygina, Ekaterina; Eglinton, Timothy I.; Holmes, Robert M.

    2013-01-01

    Ongoing climate warming in the Arctic will thaw permafrost and remobilize substantial terrestrial organic carbon (OC) pools. Around a quarter of northern permafrost OC resides in Siberian Yedoma deposits, the oldest form of permafrost carbon. However, our understanding of the degradation and fate of

  3. Potential remobilization of belowground permafrost carbon under future global warming

    Science.gov (United States)

    P. Kuhry; E. Dorrepaal; G. Hugelius; E.A.G. Schuur; C. Tarnocai

    2010-01-01

    Research on permafrost carbon has dramatically increased in the past few years. A new estimate of 1672 Pg C of belowground organic carbon in the northern circumpolar permafrost region more than doubles the previous value and highlights the potential role of permafrost carbon in the Earth System. Uncertainties in this new estimate remain due to relatively few available...

  4. Frozen in Time? Microbial strategies for survival and carbon metabolism over geologic time in a Pleistocene permafrost chronosequence

    Science.gov (United States)

    Mackelprang, R.; Douglas, T. A.; Waldrop, M. P.

    2014-12-01

    Permafrost soils have received tremendous interest due to their importance as a global carbon store with the potential to be thawed over the coming centuries. Instead of being 'frozen in time,' permafrost contains active microbes. Most metagenomic studies have focused on Holocene aged permafrost. Here, we target Pleistocene aged ice and carbon rich permafrost (Yedoma), which can differ in carbon content and stage of decay. Our aim was to understand how microbes in the permafrost transform organic matter over geologic time and to identify physiological and biochemical adaptations that enable long-term survival. We used next-generation sequencing to characterize microbial communities along a permafrost age gradient. Samples were collected from the Cold Regions Research and Engineering Laboratory (CRREL) Permafrost Tunnel near Fox, AK, which penetrates a hillside providing access to permafrost ranging in age from 12 to 40 kyr. DNA was extracted directly from unthawed samples. 16S rRNA amplicon (16S) and shotgun metagenome sequencing revealed significant age-driven differences. First, microbial diversity declines with permafrost age, likely due to long-term exposure to environmental stresses and a reduction in metabolic resources. Second, we observed taxonomic differences among ages, with an increasing abundance of Firmicutes (endospore-formers) in older samples, suggesting that dormancy is a common survival strategy in older permafrost. Ordination of 16S and metagenome data revealed age-based clustering. Genes differing significantly between age categories included those involved in lipopolysaccharide assembly, cold-response, and carbon processing. These data point to the physiological adaptations to long-term frozen conditions and to the metabolic processes utilized in ancient permafrost. In fact, a gene common in older samples is involved in cadaverine production, which could potentially explain the putrefied smell of Pleistocene aged permafrost. Coupled with soil

  5. Landscape effects of wildfire on permafrost distribution in interior Alaska derived from remote sensing

    Science.gov (United States)

    Brown, Dana R. N.; Jorgenson, M. Torre; Kielland, Knut; Verbyla, David L.; Prakash, Anupma; Koch, Joshua C.

    2016-01-01

    Climate change coupled with an intensifying wildfire regime is becoming an important driver of permafrost loss and ecosystem change in the northern boreal forest. There is a growing need to understand the effects of fire on the spatial distribution of permafrost and its associated ecological consequences. We focus on the effects of fire a decade after disturbance in a rocky upland landscape in the interior Alaskan boreal forest. Our main objectives were to (1) map near-surface permafrost distribution and drainage classes and (2) analyze the controls over landscape-scale patterns of post-fire permafrost degradation. Relationships among remote sensing variables and field-based data on soil properties (temperature, moisture, organic layer thickness) and vegetation (plant community composition) were analyzed using correlation, regression, and ordination analyses. The remote sensing data we considered included spectral indices from optical datasets (Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI)), the principal components of a time series of radar backscatter (Advanced Land Observing Satellite—Phased Array type L-band Synthetic Aperture Radar (ALOS-PALSAR)), and topographic variables from a Light Detection and Ranging (LiDAR)-derived digital elevation model (DEM). We found strong empirical relationships between the normalized difference infrared index (NDII) and post-fire vegetation, soil moisture, and soil temperature, enabling us to indirectly map permafrost status and drainage class using regression-based models. The thickness of the insulating surface organic layer after fire, a measure of burn severity, was an important control over the extent of permafrost degradation. According to our classifications, 90% of the area considered to have experienced high severity burn (using the difference normalized burn ratio (dNBR)) lacked permafrost after fire. Permafrost thaw, in turn, likely increased drainage and resulted in

  6. Landscape Effects of Wildfire on Permafrost Distribution in Interior Alaska Derived from Remote Sensing

    Directory of Open Access Journals (Sweden)

    Dana R.N. Brown

    2016-08-01

    Full Text Available Climate change coupled with an intensifying wildfire regime is becoming an important driver of permafrost loss and ecosystem change in the northern boreal forest. There is a growing need to understand the effects of fire on the spatial distribution of permafrost and its associated ecological consequences. We focus on the effects of fire a decade after disturbance in a rocky upland landscape in the interior Alaskan boreal forest. Our main objectives were to (1 map near-surface permafrost distribution and drainage classes and (2 analyze the controls over landscape-scale patterns of post-fire permafrost degradation. Relationships among remote sensing variables and field-based data on soil properties (temperature, moisture, organic layer thickness and vegetation (plant community composition were analyzed using correlation, regression, and ordination analyses. The remote sensing data we considered included spectral indices from optical datasets (Landsat 7 Enhanced Thematic Mapper Plus (ETM+ and Landsat 8 Operational Land Imager (OLI, the principal components of a time series of radar backscatter (Advanced Land Observing Satellite—Phased Array type L-band Synthetic Aperture Radar (ALOS-PALSAR, and topographic variables from a Light Detection and Ranging (LiDAR-derived digital elevation model (DEM. We found strong empirical relationships between the normalized difference infrared index (NDII and post-fire vegetation, soil moisture, and soil temperature, enabling us to indirectly map permafrost status and drainage class using regression-based models. The thickness of the insulating surface organic layer after fire, a measure of burn severity, was an important control over the extent of permafrost degradation. According to our classifications, 90% of the area considered to have experienced high severity burn (using the difference normalized burn ratio (dNBR lacked permafrost after fire. Permafrost thaw, in turn, likely increased drainage and resulted

  7. Extraction of Water from Lunar Permafrost

    Science.gov (United States)

    Ethridge, Edwin C.; Kaukler, William

    2009-01-01

    Remote sensing indicates the presence of hydrogen rich regions associated with the lunar poles. The logical hypothesis is that there is cryogenically trapped water ice located in craters at the lunar poles. Some of the craters have been in permanent darkness for a billion years. The presence of water at the poles as well as other scientific advantages of a polar base, have influenced NASA plans for the lunar outpost. The lunar outpost has water and oxygen requirements on the order of 1 ton per year scaling up to as much as 5 tons per year. Microwave heating of the frozen permafrost has unique advantages for water extraction. Proof of principle experiments have successfully demonstrated that microwaves will couple to the cryogenic soil in a vacuum and the sublimed water vapor can be successfully captured on a cold trap. Dielectric property measurements of lunar soil simulant have been measured. Microwave absorption and attenuation in lunar soil simulant has been correlated with measured dielectric properties. Future work will be discussed.

  8. The Last Permafrost Maximum (LPM) map of the northern hemisphere: permafrost extent and mean annual air temperatures, 25-17 ka BP

    NARCIS (Netherlands)

    Vandenberghe, J.; French, H.M.; Gorbunov, A.; Velichko, A.A.; Jin, H.; Cui, Z.; Zhang, T.; Wan, X.

    2014-01-01

    This paper accompanies a map that shows the extent of permafrost in the Northern Hemisphere between 25 and 17 thousand years ago. The map is based upon existing archival data, common throughout the Northern Hemisphere, that include ice-wedge pseudomorphs, sand wedges and large cryoturbations. Where

  9. Thermal stability analysis under embankment with asphalt pavement and cement pavement in permafrost regions.

    Science.gov (United States)

    Junwei, Zhang; Jinping, Li; Xiaojuan, Quan

    2013-01-01

    The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8 m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results.

  10. Strong geologic methane emissions from discontinuous terrestrial permafrost in the Mackenzie Delta, Canada.

    Science.gov (United States)

    Kohnert, Katrin; Serafimovich, Andrei; Metzger, Stefan; Hartmann, Jörg; Sachs, Torsten

    2017-07-19

    Arctic permafrost caps vast amounts of old, geologic methane (CH 4 ) in subsurface reservoirs. Thawing permafrost opens pathways for this CH 4 to migrate to the surface. However, the occurrence of geologic emissions and their contribution to the CH 4 budget in addition to recent, biogenic CH 4 is uncertain. Here we present a high-resolution (100 m × 100 m) regional (10,000 km²) CH 4 flux map of the Mackenzie Delta, Canada, based on airborne CH 4 flux data from July 2012 and 2013. We identify strong, likely geologic emissions solely where the permafrost is discontinuous. These peaks are 13 times larger than typical biogenic emissions. Whereas microbial CH 4 production largely depends on recent air and soil temperature, geologic CH 4 was produced over millions of years and can be released year-round provided open pathways exist. Therefore, even though they only occur on about 1% of the area, geologic hotspots contribute 17% to the annual CH 4 emission estimate of our study area. We suggest that this share may increase if ongoing permafrost thaw opens new pathways. We conclude that, due to permafrost thaw, hydrocarbon-rich areas, prevalent in the Arctic, may see increased emission of geologic CH 4 in the future, in addition to enhanced microbial CH 4 production.

  11. Climate change and the permafrost carbon feedback.

    Science.gov (United States)

    Schuur, E A G; McGuire, A D; Schädel, C; Grosse, G; Harden, J W; Hayes, D J; Hugelius, G; Koven, C D; Kuhry, P; Lawrence, D M; Natali, S M; Olefeldt, D; Romanovsky, V E; Schaefer, K; Turetsky, M R; Treat, C C; Vonk, J E

    2015-04-09

    Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emission from these regions and their impact on climate change remain uncertain. Here we find that current evidence suggests a gradual and prolonged release of greenhouse gas emissions in a warming climate and present a research strategy with which to target poorly understood aspects of permafrost carbon dynamics.

  12. Examining Environmental Gradients with satellite data in permafrost regions - the current state of the ESA GlobPermafrost initative

    Science.gov (United States)

    Grosse, G.; Bartsch, A.; Kääb, A.; Westermann, S.; Strozzi, T.; Wiesmann, A.; Duguay, C. R.; Seifert, F. M.; Obu, J.; Nitze, I.; Heim, B.; Haas, A.; Widhalm, B.

    2017-12-01

    Permafrost cannot be directly detected from space, but many surface features of permafrost terrains and typical periglacial landforms are observable with a variety of EO sensors ranging from very high to medium resolution at various wavelengths. In addition, landscape dynamics associated with permafrost changes and geophysical variables relevant for characterizing the state of permafrost, such as land surface temperature or freeze-thaw state can be observed with spaceborne Earth Observation. Suitable regions to examine environmental gradients across the Arctic have been defined in a community white paper (Bartsch et al. 2014, hdl:10013/epic.45648.d001). These transects have been revised and adjusted within the DUE GlobPermafrost initiative of the European Space Agency. The ESA DUE GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. Prototype product cases will cover different aspects of permafrost by integrating in situ measurements of subsurface and surface properties, Earth Observation, and modelling to provide a better understanding of permafrost today. The project will extend local process and permafrost monitoring to broader spatial domains, support permafrost distribution modelling, and help to implement permafrost landscape and feature mapping in a GIS framework. It will also complement active layer and thermal observing networks. Both lowland (latitudinal) and mountain (altitudinal) permafrost issues are addressed. The status of the Permafrost Information System and first results will be presented. Prototypes of GlobPermafrost datasets include: Modelled mean annual ground temperature by use of land surface temperature and snow water equivalent from satellites Land surface characterization including shrub height, land cover and parameters related to surface roughness Trends from

  13. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire

    DEFF Research Database (Denmark)

    Abbott, Benjamin W.; Jones, Jeremy B.; Schuur, Edward A. G.

    2016-01-01

    estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost......-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments...... indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty...

  14. Reparation and Immunomodulating Properties of Bacillus sp. Metabolites from Permafrost.

    Science.gov (United States)

    Kalenova, L F; Melnikov, V P; Besedin, I M; Bazhin, A S; Gabdulin, M A; Kolyvanova, S S

    2017-09-01

    An ointment containing metabolites of Bacillus sp. microorganisms isolated from permafrost samples was applied onto the skin wound of BALB/c mice. Metabolites isolated during culturing of Bacillus sp. at 37°C produced a potent therapeutic effect and promoted wound epithelialization by 30% in comparison with the control (ointment base) and by 20% in comparison with Solcoseryl. Treatment with Bacillus sp. metabolites stimulated predominantly humoral immunity, reduced the time of wound contraction and the volume of scar tissue, and promoted complete hair recovery. These metabolites can be considered as modulators of the wound process with predominance of regeneration mechanisms.

  15. Thin, Conductive Permafrost Surrounding Lake Fryxell Indicates Salts From Past Lakes, McMurdo Dry Valleys, Antarctica

    Science.gov (United States)

    Foley, N.; Tulaczyk, S. M.; Gooseff, M. N.; Myers, K. F.; Doran, P. T.; Auken, E.; Dugan, H. A.; Mikucki, J.; Virginia, R. A.

    2017-12-01

    In the McMurdo Dry Valleys (MDV), permafrost should be thick and liquid water rare. However, despite the well below zero mean annual temperature in this cryospheric desert, liquid water can be found in lakes, summer melt streams, subglacial outflow, and - recent work has shown - underneath anomalously thin permafrost. In part, this niche hydrosphere is maintained by the presence of salts, which depress the freezing point of water to perhaps as cold as -10° Celsius. We detected widespread salty water across the MDV in lakes and at depth using a helicopter-borne Time Domain Electromagnetic (TDEM) sensor. By using the presence of brines to mark the transition from frozen permafrost (near the surface) to unfrozen ground (at depth), we have created a map of permafrost thickness in Lower Taylor Valley (LTV), a large MDV with a complex history of glaciation and occupation by lakes. Our results show that permafrost is thinner ( 200m) than would be expected based on geothermal gradient measurements (up to 1000m), a result of the freezing point depression caused by salt and potentially enhanced by an unfinished transient freezing process. Near Lake Fryxell, a large, brackish lake in the center of LTV, permafrost is very thin (about 30-40m) and notably more electrically conductive than more distal permafrost. This thin ring of conductive permafrost surrounding the lake basin most likely reflects the high presence of salts in the subsurface, preventing complete freezing. These salts may be a remnant of the salty bottom waters of a historic larger lake (LGM glacially dammed Lake Washburn) or the remnant of salty basal water from a past advance of Taylor Glacier, which now sits many km up-valley but is known to contain brines which currently flow onto the surface and directly into the subsurface aquifer.

  16. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire: an expert assessment

    Science.gov (United States)

    Benjamin W. Abbott,; Jeremy B. Jones,; Edward A.G. Schuur,; F.S. Chapin, III; Bowden, William B.; M. Syndonia Bret-Harte,; Howard E. Epstein,; Michael D. Flannigan,; Tamara K. Harms,; Teresa N. Hollingsworth,; Mack, Michelle C.; McGuire, A. David; Susan M. Natali,; Adrian V. Rocha,; Tank, Suzanne E.; Merrit R. Turetsky,; Jorien E. Vonk,; Wickland, Kimberly P.; Aiken, George R.

    2016-01-01

    As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%–85% of permafrost carbon release can still be avoided if human emissions are actively reduced.

  17. Responses of alpine grassland on Qinghai–Tibetan plateau to climate warming and permafrost degradation: a modeling perspective

    International Nuclear Information System (INIS)

    Yi, Shuhua; Wang, Xiaoyun; Qin, Yu; Ding, Yongjian; Xiang, Bo

    2014-01-01

    Permafrost plays a critical role in soil hydrology. Thus, the degradation of permafrost under warming climate conditions may affect the alpine grassland ecosystem on the Qinghai–Tibetan Plateau. Previous space-for-time studies using plot and basin scales have reached contradictory conclusions. In this study, we applied a process-based ecosystem model (DOS-TEM) with a state-of-the-art permafrost hydrology scheme to examine this issue. Our results showed that 1) the DOS-TEM model could properly simulate the responses of soil thermal and hydrological dynamics and of ecosystem dynamics to climate warming and spatial differences in precipitation; 2) the simulated results were consistent with plot-scale studies showing that warming caused an increase in maximum unfrozen thickness, a reduction in vegetation and soil carbon pools as a whole, and decreases in soil water content, net primary production, and heterotrophic respiration; and 3) the simulated results were also consistent with basin-scale studies showing that the ecosystem responses to warming were different in regions with different combinations of water and energy constraints. Permafrost prevents water from draining into water reservoirs. However, the degradation of permafrost in response to warming is a long-term process that also enhances evapotranspiration. Thus, the degradation of the alpine grassland ecosystem on the Qinghai–Tibetan Plateau (releasing carbon) cannot be mainly attributed to the disappearing waterproofing function of permafrost. (letter)

  18. Evaluating permafrost thaw vulnerabilities and hydrologic impacts in boreal Alaska (USA) watersheds using field data and cryohydrogeologic modeling

    Science.gov (United States)

    Walvoord, M. A.; Voss, C.; Ebel, B. A.; Minsley, B. J.

    2017-12-01

    Permafrost environments undergo changes in hydraulic, thermal, chemical, and mechanical subsurface properties upon thaw. These property changes must be considered in addition to alterations in hydrologic, thermal, and topographic boundary conditions when evaluating shifts in the movement and storage of water in arctic and sub-arctic boreal regions. Advances have been made in the last several years with respect to multiscale geophysical characterization of the subsurface and coupled fluid and energy transport modeling of permafrost systems. Ongoing efforts are presented that integrate field data with cryohydrogeologic modeling to better understand and anticipate changes in subsurface water resources, fluxes, and flowpaths caused by climate warming and permafrost thawing. Analyses are based on field data from several sites in interior Alaska (USA) that span a broad north-south transition from continuous to discontinuous permafrost. These data include soil hydraulic and thermal properties and shallow permafrost distribution. The data guide coupled fluid and energy flow simulations that incorporate porewater liquid/ice phase change and the accompanying modifications in hydraulic and thermal subsurface properties. Simulations are designed to assess conditions conducive to active layer thickening and talik development, both of which are expected to affect groundwater storage and flow. Model results provide a framework for identifying factors that control the rates of permafrost thaw and associated hydrologic responses, which in turn influence the fate and transport of carbon.

  19. Viral impacts on microbial carbon cycling in thawing permafrost soils

    Science.gov (United States)

    Trubl, G. G.; Roux, S.; Bolduc, B.; Jang, H. B.; Emerson, J. B.; Solonenko, N.; Li, F.; Solden, L. M.; Vik, D. R.; Wrighton, K. C.; Saleska, S. R.; Sullivan, M. B.; Rich, V. I.

    2017-12-01

    Permafrost contains 30-50% of global soil carbon (C) and is rapidly thawing. While the fate of this C is unknown, it will be shaped in part by microbes and their associated viruses, which modulate host activities via mortality and metabolic control. To date, viral research in soils has been outpaced by that in aquatic environments, due to the technical challenges of accessing viruses as well as the dramatic physicochemical heterogeneity in soils. Here, we describe advances in soil viromics from our research on permafrost-associated soils, and their implications for associated terrestrial C cycling. First, we optimized viral resuspension-DNA extraction methods for a range of soil types. Second, we applied cutting-edge viral-specific informatics methods to recover viral populations, define their gene content, connect them to potential hosts, and analyze their relationships to environmental parameters. A total of 781 viral populations were recovered from size-fractionated virus samples of three soils along a permafrost thaw gradient. Ecological analyses revealed endemism as recovered viral populations were largely unique to each habitat and unlike those in aquatic communities. Genome- and network-based classification assigned these viruses into 226 viral clusters (VCs; genus-level taxonomy), 55% of which were novel. This increases the number of VCs by a third and triples the number of soil viral populations in the RefSeq database (currently contains 256 VCs and 316 soil viral populations). Genomic analyses revealed 85% of the genes were functionally unknown, though 5% of the annotatable genes contained C-related auxiliary metabolic genes (AMGs; e.g. glycoside hydrolases). Using sequence-based features and microbial population genomes, we were able to in silico predict hosts for 30% of the viral populations. The identified hosts spanned 3 phyla and 6 genera but suggested these viruses have species-specific host ranges as >80% of hosts for a given virus were in the same

  20. Subsidence from an artificial permafrost warming experiment.

    Science.gov (United States)

    Gelvin, A.; Wagner, A. M.; Lindsey, N.; Dou, S.; Martin, E. R.; Ekblaw, I.; Ulrich, C.; James, S. R.; Freifeld, B. M.; Daley, T. M.; Saari, S.; Ajo Franklin, J. B.

    2017-12-01

    Using fiber optic sensing technologies (seismic, strain, and temperature) we installed a geophysical detection system to predict thaw subsidence in Fairbanks, Alaska, United States. Approximately 5 km of fiber optic was buried in shallow trenches (20 cm depth), in an area with discontinuous permafrost, where the top of the permafrost is approximately 4 - 4.5m below the surface. The thaw subsidence was enforced by 122 60-Watt vertical heaters installed over a 140 m2 area where seismic, strain, and temperature were continuously monitored throughout the length of the fiber. Several vertical thermistor strings were also recording ground temperatures to a depth of 10 m in parallel to the fiber optic to verify the measurements collected from the fiber optic cable. GPS, Electronic Distance Measurement (EDM) Traditional and LiDAR (Light and Detection and Ranging) scanning were used to investigate the surface subsidence. The heaters were operating for approximately a three month period starting in August, 2016. During the heating process the soil temperatures at the heater element increased from 3.5 to 45 °C at a depth of 3 - 4 m. It took approximately 7 months for the temperature at the heater elements to recover to their initial temperature. The depth to the permafrost table was deepened by about 1 m during the heating process. By the end of the active heating, the surface had subsided approximately 8 cm in the heating section where permafrost was closest to the surface. This was conclusively confirmed with GPS, EDM, and LiDAR. An additional LiDAR survey was performed about seven months after the heaters were turned off (in May 2017). A total subsidence of approximately 20 cm was measured by the end of the passive heating process. This project successfully demonstrates that this is a viable approach for simulating both deep permafrost thaw and the resulting surface subsidence.

  1. Coupling of snow and permafrost processes using the Basic Modeling Interface (BMI)

    Science.gov (United States)

    Wang, K.; Overeem, I.; Jafarov, E. E.; Piper, M.; Stewart, S.; Clow, G. D.; Schaefer, K. M.

    2017-12-01

    We developed a permafrost modeling tool based by implementing the Kudryavtsev empirical permafrost active layer depth model (the so-called "Ku" component). The model is specifically set up to have a basic model interface (BMI), which enhances the potential coupling to other earth surface processes model components. This model is accessible through the Web Modeling Tool in Community Surface Dynamics Modeling System (CSDMS). The Kudryavtsev model has been applied for entire Alaska to model permafrost distribution at high spatial resolution and model predictions have been verified by Circumpolar Active Layer Monitoring (CALM) in-situ observations. The Ku component uses monthly meteorological forcing, including air temperature, snow depth, and snow density, and predicts active layer thickness (ALT) and temperature on the top of permafrost (TTOP), which are important factors in snow-hydrological processes. BMI provides an easy approach to couple the models with each other. Here, we provide a case of coupling the Ku component to snow process components, including the Snow-Degree-Day (SDD) method and Snow-Energy-Balance (SEB) method, which are existing components in the hydrological model TOPOFLOW. The work flow is (1) get variables from meteorology component, set the values to snow process component, and advance the snow process component, (2) get variables from meteorology and snow component, provide these to the Ku component and advance, (3) get variables from snow process component, set the values to meteorology component, and advance the meteorology component. The next phase is to couple the permafrost component with fully BMI-compliant TOPOFLOW hydrological model, which could provide a useful tool to investigate the permafrost hydrological effect.

  2. The effects of permafrost thaw on soil hydrologic, thermal, and carbon dynamics in an Alaskan peatland

    Science.gov (United States)

    O'Donnell, Jonathan A.; Jorgenson, M. Torre; Harden, Jennifer W.; McGuire, A. David; Kanevskiy, Mikhail Z.; Wickland, Kimberly P.

    2012-01-01

    Recent warming at high-latitudes has accelerated permafrost thaw in northern peatlands, and thaw can have profound effects on local hydrology and ecosystem carbon balance. To assess the impact of permafrost thaw on soil organic carbon (OC) dynamics, we measured soil hydrologic and thermal dynamics and soil OC stocks across a collapse-scar bog chronosequence in interior Alaska. We observed dramatic changes in the distribution of soil water associated with thawing of ice-rich frozen peat. The impoundment of warm water in collapse-scar bogs initiated talik formation and the lateral expansion of bogs over time. On average, Permafrost Plateaus stored 137 ± 37 kg C m-2, whereas OC storage in Young Bogs and Old Bogs averaged 84 ± 13 kg C m-2. Based on our reconstructions, the accumulation of OC in near-surface bog peat continued for nearly 1,000 years following permafrost thaw, at which point accumulation rates slowed. Rapid decomposition of thawed forest peat reduced deep OC stocks by nearly half during the first 100 years following thaw. Using a simple mass-balance model, we show that accumulation rates at the bog surface were not sufficient to balance deep OC losses, resulting in a net loss of OC from the entire peat column. An uncertainty analysis also revealed that the magnitude and timing of soil OC loss from thawed forest peat depends substantially on variation in OC input rates to bog peat and variation in decay constants for shallow and deep OC stocks. These findings suggest that permafrost thaw and the subsequent release of OC from thawed peat will likely reduce the strength of northern permafrost-affected peatlands as a carbon dioxide sink, and consequently, will likely accelerate rates of atmospheric warming.

  3. Modelling the Effects of Temperature and Cloud Cover Change on Mountain Permafrost Distribution, Northwest Canada

    Science.gov (United States)

    Bonnaventure, P. P.; Lewkowicz, A. G.

    2008-12-01

    Spatial models of permafrost probability for three study areas in northwest Canada between 59°N and 61°N were perturbed to investigate climate change impacts. The models are empirical-statistical in nature, based on basal temperature of snow (BTS) measurements in winter, and summer ground-truthing of the presence or absence of frozen ground. Predictions of BTS values are made using independent variables of elevation and potential incoming solar radiation (PISR), both derived from a 30 m DEM. These are then transformed into the probability of the presence or absence of permafrost through logistic regression. Under present climate conditions, permafrost percentages in the study areas are 44% for Haines Summit, British Columbia, 38% for Wolf Creek, Yukon, and 69% for part of the Ruby Range, Yukon (Bonnaventure and Lewkowicz, 2008; Lewkowicz and Bonaventure, 2008). Scenarios of air temperature change from -2K (approximating Neoglacial conditions) to +5K (possible within the next century according to the IPCC) were examined for the three sites. Manipulations were carried out by lowering or raising the terrain within the DEM assuming a mean environmental lapse rate of 6.5K/km. Under a -2K scenario, permafrost extent increased by 22-43% in the three study areas. Under a +5K warming, permafrost essentially disappeared in Haines Summit and Wolf Creek, while in the Ruby Range less than 12% of the area remained perennially frozen. It should be emphasized that these model predictions are for equilibrium conditions which might not be attained for several decades or longer in areas of cold permafrost. Cloud cover changes of -10% to +10% were examined through adjusting the partitioning of direct beam and diffuse radiation in the PISR input field. Changes to permafrost extent were small, ranging from -2% to -4% for greater cloudiness with changes of the opposite magnitude for less cloud. The results show that air temperature change has a much greater potential to affect mountain

  4. Surface and subsurface conditions in permafrost areas - a literature review

    International Nuclear Information System (INIS)

    Vidstrand, Patrik

    2003-02-01

    This report contains a summary of some of the information within existing technical and scientific literature on permafrost. Permafrost is viewed as one of the future climate driven process domains that may exist in Scandinavia, and that may give rise to significantly different surface and subsurface conditions than the present. Except for changes in the biosphere, permafrost may impact hydraulic, mechanical, and chemical subsurface processes and conditions. Permafrost and its influences on the subsurface conditions are thus of interest for the performance and safety assessments of deep geological waste repositories. The definition of permafrost is 'ground that stays at or below 0 deg C for at least two consecutive years'. Permafrost will effect the geological subsurface to some depth. How deep the permafrost may grow is a function of the heat balance, thermal conditions at the surface and within the ground, and the geothermal heat flux from the Earth's inner parts. The main chapters of the report summaries the knowledge on permafrost evolution, occurrence and distribution, and extracts information concerning hydrology and mechanical and chemical impacts due to permafrost related conditions. The results of a literature review are always dependent on the available literature. Concerning permafrost there is some literature available from investigations in the field of long-term repositories and some from mining industries. However, reports of these investigations are few and the bulk of permafrost literature comes from the science departments concerned with surficial processes (e.g. geomorphology, hydrology, agriculture, etc) and from engineering concerns, such as foundation of constructions and pipeline design. This focus within the permafrost research inevitably yields a biased but also an abundant amount of information on localised surficial processes and a limited amount on regional and deep permafrost characteristics. Possible conclusions are that there is

  5. A New Wave of Permafrost Warming in the Alaskan Interior?

    Science.gov (United States)

    Romanovsky, V. E.; Nicolsky, D.; Cable, W.; Kholodov, A. L.; Panda, S. K.

    2017-12-01

    The impact of climate warming on permafrost and the potential of climate feedbacks resulting from permafrost thawing have recently received a great deal of attention. Ground temperatures are a primary indicator of permafrost stability. Many of the research sites in our permafrost network are located along the North American Arctic Permafrost-Ecological Transect that spans all permafrost zones in Alaska. Most of the sites in Alaska show substantial warming of permafrost since the 1980s. The magnitude of warming has varied with location, but was typically from 0.5 to 3°C. However, this warming was not linear in time and not spatially uniform. In some regions this warming even may be reversed and a slight recent cooling of permafrost has been observed recently at some locations. The Interior of Alaska is one of such regions where a slight permafrost cooling was observed starting in the late 1990s that has continued through the 2000s and in the beginning of the 2010s. The cooling has followed the substantial increase in permafrost temperatures documented for the Interior during the 1980s and 1990s. Permafrost temperatures at 15 m depth increased here by 0.3 to 0.6°C between 1983 and 1996. In most locations they reached their maximum in the second half of the 1990s. Since then, the permafrost temperatures started to decrease slowly and by 2013 this decrease at some locations was as much as 0.3°C at 15 m depth. There are some indications that the warming trend in the Alaskan Interior permafrost resumed during the last four years. By 2016, new record highs for the entire period of measurements of permafrost temperatures at 15 m depth were recorded at several locations. The latest observed permafrost warming in the Interior was combined with higher than normal summer precipitations. This combination has triggered near-surface permafrost degradation in many locations with adverse consequences for the ground surface stability affecting ecosystems and infrastructure. In

  6. Surface and subsurface conditions in permafrost areas - a literature review

    Energy Technology Data Exchange (ETDEWEB)

    Vidstrand, Patrik [Bergab, Goeteborg (Sweden)

    2003-02-01

    This report contains a summary of some of the information within existing technical and scientific literature on permafrost. Permafrost is viewed as one of the future climate driven process domains that may exist in Scandinavia, and that may give rise to significantly different surface and subsurface conditions than the present. Except for changes in the biosphere, permafrost may impact hydraulic, mechanical, and chemical subsurface processes and conditions. Permafrost and its influences on the subsurface conditions are thus of interest for the performance and safety assessments of deep geological waste repositories. The definition of permafrost is 'ground that stays at or below 0 deg C for at least two consecutive years'. Permafrost will effect the geological subsurface to some depth. How deep the permafrost may grow is a function of the heat balance, thermal conditions at the surface and within the ground, and the geothermal heat flux from the Earth's inner parts. The main chapters of the report summaries the knowledge on permafrost evolution, occurrence and distribution, and extracts information concerning hydrology and mechanical and chemical impacts due to permafrost related conditions. The results of a literature review are always dependent on the available literature. Concerning permafrost there is some literature available from investigations in the field of long-term repositories and some from mining industries. However, reports of these investigations are few and the bulk of permafrost literature comes from the science departments concerned with surficial processes (e.g. geomorphology, hydrology, agriculture, etc) and from engineering concerns, such as foundation of constructions and pipeline design. This focus within the permafrost research inevitably yields a biased but also an abundant amount of information on localised surficial processes and a limited amount on regional and deep permafrost characteristics. Possible conclusions are that

  7. Permafrost conditions at the Upper Kuskokwim river area and its influence on local communities.

    Science.gov (United States)

    Kholodov, A. L.; Panda, S. K.; Hanson, T.

    2017-12-01

    Research area located within the zone of discontinuous permafrost distribution. Recent mean annual air temperature here is close to the 0C. It means, that taking in consideration warming influence of the snow cower during winter, mean annual temperature at the ground surface is well above freezing point. It means that presence or absence of permafrost here completely controlled by the ecological conditions. Based on remote sensing data and the surveys conducted in 2016-17 we selected 6 main ecotypes typical for this area: black spruce boreal forest, wetlands, low and tall shrubs, deciduous and mixed forest. Most of them (low shrubs, deciduous and mixed forest) represent different stages of area recovering after forest fires that was confirmed by the presence of ashy layer close to ground surface in soil pits had been dug within these landscapes. Permafrost was observed only within 2 of them: low shrubs and black spruce boreal forest. Within these types of terrain temperature at the bottom of active layer varies from -0.2/-0.5C at the areas of low shrubs, recovered after relatively recent (approximately 30-50 years old) fires to -1/-1.5 within black spruce forest. Active (seasonally thawed) layer as thick as 0.6 to 0.8 m. Warmest ecotypes for the area are tall shrubs and deciduous forest, temperature at the depth close to 1 m is about +3C. At the mixed forest temperature at the same depth consists of +1/+2C. Active (seasonally frozen) layer thickness within permafrost free areas is 1-1.5 m at the drained sites and about 0.5 within wetlands. Ice-rich permafrost underlying the active layer was noticed only within the black spruce forest. Areas which are free of permafrost are much better drained, typical moisture of mineral soil is less than 30% versus 45-50% in seasonally thawed layer. The current state of permafrost and the fact that it presence completely depends on ecosystems limits land use abilities of local inhabitants. Any changes of forest coverage or organic

  8. Design and Build of the Qinghai-Tibet Railway considering the Impacts of Warming Climate and Permafrost

    Science.gov (United States)

    Ma, W.; Jin, H.; Cheng, G.; Wu, Q.; Lai, Y.

    2005-12-01

    During the period from 1960 to 2000, an 1°C increase of air temperature has been observed along the Qinghai-Tibet Railway (QTR) traversing 632 km of warm and ice-rich permafrost through the interior of the Qinghai-Tibet Plateau. Correspondingly, mean annual ground temperatures (MAGTs) of warm (>-1 °C) permafrost on average increased about 0.3 to 0.5°C during 1970s-1990, while that of colder permafrost had increased by 0.1 to 0.3°C. During 1996-2004, ground temperatures at the permafrost table were increasing at the rates of 0.01-0.08°C a-1, and the permafrost table was lowering at the rates of 2.6 to 6.6 cm a-1; and the ground temperatures at depths of 6 to 8 m were warming at the rates of 0.02 to 0.05°C a-1. Consequently, the strengths of permafrost as the foundation of the QTR would be weakened if proper engineering measures were not taken. Based on the experiences and lessons learned from the road construction in permafrost regions from Alaska, Canada and Russia, and northeastern China, and taking into consideration of possible climatic warming along the QTR during the next 100 years, the design and construction of the QTR adopted the principle of``cooling the roadbed'' because most of the permafrost along the route is too deep to be thawed, too thermally sensitive to climatic warming and too critical to have appreciable thaw settlements. About 550 km of QTR is in continuous permafrost zone, 82 km is in discontinuous permafrost zone; 275 km is in warm permafrost areas, and 110 km of permafrost is ice-rich. The QTR is designed for safe operations during the next 100 years during which a warming of 2.2 to 2.6°C by 2050 is projected. Without engineering measures to keep ground frozen or maintain the settlement within the acceptable limits, thaw settlement in the foundation soils, and induced environmental instability would threaten the integrity and safety of QTR operation. However, only increasing therma resistance, such as increasing fill thickness or

  9. Effects of post-fire wood management strategies on vegetation recovery and land surface temperature (LST) estimated from Landsat images

    Science.gov (United States)

    Vlassova, Lidia; Pérez-Cabello, Fernando

    2016-02-01

    The study contributes remote sensing data to the discussion about effects of post-fire wood management strategies on forest regeneration. Land surface temperature (LST) and Normalized Differenced Vegetation Index (NDVI), estimated from Landsat-8 images are used as indicators of Pinus halepensis ecosystem recovery after 2008 fire in areas of three post-fire treatments: (1) salvage logging with wood extraction from the site on skidders in suspended position (SL); (2) snag shredding in situ leaving wood debris in place (SS) performed two years after the event; and (3) non-intervention control areas (CL) where all snags were left standing. Six years after the fire NDVI values ∼0.5 estimated from satellite images and field radiometry indicate considerable vegetation recovery due to efficient regeneration traits developed by the dominant plant species. However, two years after management activities in part of the burnt area, the effect of SL and SS on ecosystem recovery is observed in terms of both LST and NDVI. Statistically significant differences are detected between the intervened areas (SL and SS) and control areas of non-intervention (CL); no difference is registered between zones of different intervention types (SL and SS). CL areas are on average 1 °C cooler and 10% greener than those corresponding to either SL or SS, because of the beneficial effects of burnt wood residuals, which favor forest recovery through (i) enhanced nutrient cycling in soils, (ii) avoidance of soil surface disturbance and mechanical damage of seedlings typical to the managed areas, and (iii) ameliorated microclimate. The results of the study show that in fire-resilient ecosystems, such as P. halepensis forests, NDVI is higher and LST is lower in areas with no management intervention, being an indication of more favorable conditions for vegetation regeneration.

  10. Permafrost Degradation Risk Zone Assessment using Simulation Models

    DEFF Research Database (Denmark)

    Daanen, R.P.; Ingeman-Nielsen, Thomas; Marchenko, S.

    2011-01-01

    In this proof-of-concept study we focus on linking large scale climate and permafrost simulations to small scale engineering projects by bridging the gap between climate and permafrost sciences on the one hand and on the other technical recommendation for adaptation of planned infrastructures...... to climate change in a region generally underlain by permafrost. We present the current and future state of permafrost in Greenland as modelled numerically with the GIPL model driven by HIRHAM climate projections up to 2080. We develop a concept called Permafrost Thaw Potential (PTP), defined...... as the potential active layer increase due to climate warming and surface alterations. PTP is then used in a simple risk assessment procedure useful for engineering applications. The modelling shows that climate warming will result in continuing wide-spread permafrost warming and degradation in Greenland...

  11. Geophysical Investigations of Saline Permafrost at Ilulissat, Greenland

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas; Foged, Niels Nielsen; Butzbach, Rune

    2008-01-01

    The technical properties and general state of permafrost in Greenland is not well documented. A new coordinated investigation has been initiated, for ground temperature measurements and permafrost mapping in Greenlandic towns in sporadic, discontinuous and continuous permafrost zones. We present...... investigation results from one of the sites, located at Ilulissat, in an area of discontinuous saline permafrost. We have established ground temperature measurement stations and conducted a shallow geoelectrical study. Our results show that the sediments in the studied area mainly consist of very frost...... susceptible silty clays. The area has permafrost with a maximum active layer thickness between 0.9 and 1 m. In spite of low permafrost temperatures a considerable part of the pore water is unfrozen, due to high residual salt concentrations. Consequently, the unfrozen water content dominates the technical...

  12. Permafrost and organic layer interactions over a climate gradient in a discontinuous permafrost zone

    Science.gov (United States)

    Johnson, Kristofer D.; Harden, Jennifer W.; McGuire, A. David; Clark, Mark; Yuan, Fengming; Finley, Andrew O.

    2013-09-01

    Permafrost is tightly coupled to the organic soil layer, an interaction that mediates permafrost degradation in response to regional warming. We analyzed changes in permafrost occurrence and organic layer thickness (OLT) using more than 3000 soil pedons across a mean annual temperature (MAT) gradient. Cause and effect relationships between permafrost probability (PF), OLT, and other topographic factors were investigated using structural equation modeling in a multi-group analysis. Groups were defined by slope, soil texture type, and shallow (OLT increase in shallow OLT soils (OLTs) due to an insulation effect, but PF decreased in deep OLT soils (OLTd) by 0.06 for every 10-cm increase. Across the MAT gradient, PF in sandy soils varied little, but PF in loamy and silty soils decreased substantially from cooler to warmer temperatures. The change in OLT was more heterogeneous across soil texture types—in some there was no change while in others OLTs soils thinned and/or OLTd soils thickened at warmer locations. Furthermore, when soil organic carbon was estimated using a relationship with thickness, the average increase in carbon in OLTd soils was almost four times greater compared to the average decrease in carbon in OLTs soils across all soil types. If soils follow a trajectory of warming that mimics the spatial gradients found today, then heterogeneities of permafrost degradation and organic layer thinning and thickening should be considered in the regional carbon balance.

  13. Data-driven mapping of the potential mountain permafrost distribution.

    Science.gov (United States)

    Deluigi, Nicola; Lambiel, Christophe; Kanevski, Mikhail

    2017-07-15

    Existing mountain permafrost distribution models generally offer a good overview of the potential extent of this phenomenon at a regional scale. They are however not always able to reproduce the high spatial discontinuity of permafrost at the micro-scale (scale of a specific landform; ten to several hundreds of meters). To overcome this lack, we tested an alternative modelling approach using three classification algorithms belonging to statistics and machine learning: Logistic regression, Support Vector Machines and Random forests. These supervised learning techniques infer a classification function from labelled training data (pixels of permafrost absence and presence) with the aim of predicting the permafrost occurrence where it is unknown. The research was carried out in a 588km 2 area of the Western Swiss Alps. Permafrost evidences were mapped from ortho-image interpretation (rock glacier inventorying) and field data (mainly geoelectrical and thermal data). The relationship between selected permafrost evidences and permafrost controlling factors was computed with the mentioned techniques. Classification performances, assessed with AUROC, range between 0.81 for Logistic regression, 0.85 with Support Vector Machines and 0.88 with Random forests. The adopted machine learning algorithms have demonstrated to be efficient for permafrost distribution modelling thanks to consistent results compared to the field reality. The high resolution of the input dataset (10m) allows elaborating maps at the micro-scale with a modelled permafrost spatial distribution less optimistic than classic spatial models. Moreover, the probability output of adopted algorithms offers a more precise overview of the potential distribution of mountain permafrost than proposing simple indexes of the permafrost favorability. These encouraging results also open the way to new possibilities of permafrost data analysis and mapping. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A central database for the Global Terrestrial Network for Permafrost (GTN-P)

    Science.gov (United States)

    Elger, Kirsten; Lanckman, Jean-Pierre; Lantuit, Hugues; Karlsson, Ævar Karl; Johannsson, Halldór

    2013-04-01

    used by as many researchers as intended by the initiators of these global programs. The European Union project PAGE21 created opportunities to develop this central database for GTN-P data during the duration of the project and beyond. The database aims to be the one location where the researcher can find data, metadata and information of all relevant parameters for a specific site. Each component of the Data Management System (DMS), including parameters, data levels and metadata formats were developed in cooperation with GTN-P and the IPA. The general framework of the GTN-P DMS is based on an object-oriented model (OOM) and implemented into a spatial database. To ensure interoperability and enable potential inter-database search, field names are following international metadata standards. The outputs of the DMS will be tailored to the needs of the modeling community but also to the ones of other stakeholders. In particular, new products will be developed in partnership with the IPA and other relevant international organizations to raise awareness on permafrost in the policy-making arena. The DMS will be released to a broader public in May 2013 and we expect to have the first active data upload - via an online interface - after 2013's summer field season.

  15. Permafrost in the Himalayas: specific characteristics, evolution vs. climate change and impacts on potential natural hazards

    Science.gov (United States)

    Fort, Monique

    2015-04-01

    Mountain environments are very sensitive to climate change, yet assessing the potential impacts of these changes is not easy because of the complexity and diversity of mountain systems. The Himalayan permafrost belt presents three main specificities: (1) it develops in a geodynamically active mountain, which means that the controlling factors are not only temperature but also seismo-tectonic activity; (2) due to the steepness of the southern flank of the Greater Himalaya and potential large scale rock failures, permafrost evidence manifests itself best in the inner valleys and on the northern, arid side of the Himalayas (elevations >4000m); (3) the east-west strike of the mountain range creates large spatial discontinuity in the "cold" belt, mostly related to precipitation nature and availability. Only limited studies have been carried to date, and there is no permanent "field laboratory", nor continuous records but a few local studies. Based on preliminary observations in the Nepal Himalayas (mostly in Mustang and Dolpo districts), and Indian Ladakh, we present the main features indicating the existence of permafrost (either continuous or discontinuous). Rock-glaciers are quite well represented, though their presence may be interpreted as a combined result from both ground ice and large rock collapse. The precise altitudinal zonation of permafrost belt (specifying potential permafrost, probable permafrost, observed permafrost belts) still requires careful investigations in selected areas. Several questions arise when considering the evolution of permafrost in a context of climate change, with its impacts on the development of potential natural hazards that may affect the mountain population. Firstly, permafrost degradation (ground ice melting) is a cause of mountain slope destabilization. When the steep catchments are developed in frost/water sensitive bedrock (shales and marls) and extend to high elevations (as observed in Mustang or Dolpo), it would supply more

  16. Data Integration Tool: Permafrost Data Debugging

    Science.gov (United States)

    Wilcox, H.; Schaefer, K. M.; Jafarov, E. E.; Pulsifer, P. L.; Strawhacker, C.; Yarmey, L.; Basak, R.

    2017-12-01

    We developed a Data Integration Tool (DIT) to significantly speed up the time of manual processing needed to translate inconsistent, scattered historical permafrost data into files ready to ingest directly into the Global Terrestrial Network-Permafrost (GTN-P). The United States National Science Foundation funded this project through the National Snow and Ice Data Center (NSIDC) with the GTN-P to improve permafrost data access and discovery. We leverage this data to support science research and policy decisions. DIT is a workflow manager that divides data preparation and analysis into a series of steps or operations called widgets (https://github.com/PermaData/DIT). Each widget does a specific operation, such as read, multiply by a constant, sort, plot, and write data. DIT allows the user to select and order the widgets as desired to meet their specific needs, incrementally interact with and evolve the widget workflows, and save those workflows for reproducibility. Taking ideas from visual programming found in the art and design domain, debugging and iterative design principles from software engineering, and the scientific data processing and analysis power of Fortran and Python it was written for interactive, iterative data manipulation, quality control, processing, and analysis of inconsistent data in an easily installable application. DIT was used to completely translate one dataset (133 sites) that was successfully added to GTN-P, nearly translate three datasets (270 sites), and is scheduled to translate 10 more datasets ( 1000 sites) from the legacy inactive site data holdings of the Frozen Ground Data Center (FGDC). Iterative development has provided the permafrost and wider scientific community with an extendable tool designed specifically for the iterative process of translating unruly data.

  17. Microbial diversity in European alpine permafrost and active layers.

    Science.gov (United States)

    Frey, Beat; Rime, Thomas; Phillips, Marcia; Stierli, Beat; Hajdas, Irka; Widmer, Franco; Hartmann, Martin

    2016-03-01

    Permafrost represents a largely understudied genetic resource. Thawing of permafrost with global warming will not only promote microbial carbon turnover with direct feedback on greenhouse gases, but also unlock an unknown microbial diversity. Pioneering metagenomic efforts have shed light on the permafrost microbiome in polar regions, but temperate mountain permafrost is largely understudied. We applied a unique experimental design coupled to high-throughput sequencing of ribosomal markers to characterize the microbiota at the long-term alpine permafrost study site 'Muot-da-Barba-Peider' in eastern Switzerland with an approximate radiocarbon age of 12 000 years. Compared to the active layers, the permafrost community was more diverse and enriched with members of the superphylum Patescibacteria (OD1, TM7, GN02 and OP11). These understudied phyla with no cultured representatives proposedly feature small streamlined genomes with reduced metabolic capabilities, adaptations to anaerobic fermentative metabolisms and potential ectosymbiotic lifestyles. The permafrost microbiota was also enriched with yeasts and lichenized fungi known to harbour various structural and functional adaptation mechanisms to survive under extreme sub-zero conditions. These data yield an unprecedented view on microbial life in temperate mountain permafrost, which is increasingly important for understanding the biological dynamics of permafrost in order to anticipate potential ecological trajectories in a warming world. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Gas hydrates and permafrost in continental northern West Siberia; Gashydrate und Permafrost im kontinentalen noerdlichen Westsibirien

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, B. [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany); Braun, A.; Poelchau, H.S. [Forschungszentrum Juelich (Germany). Inst. fuer Erdoel und Organische Geochemie; Littke, R. [RWTH Aachen (Germany). Lehrstuhl fuer Geologie, Geochemie und Lagerstaetten des Erdoels und der Kohle

    1997-12-31

    The largest natural gas pool in the world is located in northern part of the West Siberian Basin. During the Quaternary this reservoir became overlaid with several hundreds of metres of permafrost. The pressure and temperature conditions prevailing under this permafrost zone have led to the development of gas hydrates. As far as is known today there is no genetic relationship between the formation of the gas pool and the development of gas hydrates. The present contribution deals with these questions in detail. (MSK) [Deutsch] Im Nordteil des westsibirischen Beckens liegt die groesste Erdgaslagerstaette der Erde. Darueber hat sich im Quartaer ein mehrere hundert Meter maechtiger Permafrost gebildet. Die unter der Premafrostzone herrschenden Druck-und Temperaturbedingungen ermoeglichten die Bildung von Gashydraten. Nach heutigen Erkenntnisse besteht kein genetischer Zusammenhang zwischen Lagerstaettenbildung und Gashydraten. Im Folgenden werden Einzelheiten geschildert.

  19. Borehole permafrost data, Kumtor and Taragai Valleys, Tienshan, Kazakhstan, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset includes observations of the permafrost temperatures in the Inner Tien Shan were started in 1986 by Kazakhstan Alpine Permafrost Laboratory....

  20. Permafrost and organic layer interactions over a climate gradient in a discontinuous permafrost zone

    International Nuclear Information System (INIS)

    Johnson, Kristofer D; Harden, Jennifer W; David McGuire, A; Clark, Mark; Yuan, Fengming; Finley, Andrew O

    2013-01-01

    Permafrost is tightly coupled to the organic soil layer, an interaction that mediates permafrost degradation in response to regional warming. We analyzed changes in permafrost occurrence and organic layer thickness (OLT) using more than 3000 soil pedons across a mean annual temperature (MAT) gradient. Cause and effect relationships between permafrost probability (PF), OLT, and other topographic factors were investigated using structural equation modeling in a multi-group analysis. Groups were defined by slope, soil texture type, and shallow (<28 cm) versus deep organic (≥28 cm) layers. The probability of observing permafrost sharply increased by 0.32 for every 10-cm OLT increase in shallow OLT soils (OLTs) due to an insulation effect, but PF decreased in deep OLT soils (OLTd) by 0.06 for every 10-cm increase. Across the MAT gradient, PF in sandy soils varied little, but PF in loamy and silty soils decreased substantially from cooler to warmer temperatures. The change in OLT was more heterogeneous across soil texture types—in some there was no change while in others OLTs soils thinned and/or OLTd soils thickened at warmer locations. Furthermore, when soil organic carbon was estimated using a relationship with thickness, the average increase in carbon in OLTd soils was almost four times greater compared to the average decrease in carbon in OLTs soils across all soil types. If soils follow a trajectory of warming that mimics the spatial gradients found today, then heterogeneities of permafrost degradation and organic layer thinning and thickening should be considered in the regional carbon balance. (letter)

  1. Field Biogeochemical Measurements in Support of Remote Sensing Signatures and Characterization of Permafrost Terrain: Integrated Technologies for Delineating Permafrost and Ground-State Conditions

    Science.gov (United States)

    2015-03-01

    Characterization of Permafrost Terrain Integrated Technologies for Delineating Permafrost and Ground-State Conditions En gi ne er R es ea rc h an d...Signatures and Characterization of Permafrost Terrain Integrated Technologies for Delineating Permafrost and Ground-State Conditions Robyn A. Barbato...Center-Directed Research Project, “Integrated Technologies for Delineating Permafrost and Ground-State Conditions” ERDC TR-15-1 ii Abstract This

  2. A comparison of radiometric correction techniques in the evaluation of the relationship between LST and NDVI in Landsat imagery.

    Science.gov (United States)

    Tan, Kok Chooi; Lim, Hwee San; Matjafri, Mohd Zubir; Abdullah, Khiruddin

    2012-06-01

    Atmospheric corrections for multi-temporal optical satellite images are necessary, especially in change detection analyses, such as normalized difference vegetation index (NDVI) rationing. Abrupt change detection analysis using remote-sensing techniques requires radiometric congruity and atmospheric correction to monitor terrestrial surfaces over time. Two atmospheric correction methods were used for this study: relative radiometric normalization and the simplified method for atmospheric correction (SMAC) in the solar spectrum. A multi-temporal data set consisting of two sets of Landsat images from the period between 1991 and 2002 of Penang Island, Malaysia, was used to compare NDVI maps, which were generated using the proposed atmospheric correction methods. Land surface temperature (LST) was retrieved using ATCOR3_T in PCI Geomatica 10.1 image processing software. Linear regression analysis was utilized to analyze the relationship between NDVI and LST. This study reveals that both of the proposed atmospheric correction methods yielded high accuracy through examination of the linear correlation coefficients. To check for the accuracy of the equation obtained through linear regression analysis for every single satellite image, 20 points were randomly chosen. The results showed that the SMAC method yielded a constant value (in terms of error) to predict the NDVI value from linear regression analysis-derived equation. The errors (average) from both proposed atmospheric correction methods were less than 10%.

  3. Threshold sensitivity of shallow Arctic lakes and sublake permafrost to changing winter climate

    Science.gov (United States)

    Arp, Christopher D.; Jones, Benjamin M.; Grosse, Guido; Bondurant, Allen C.; Romanovksy, Vladimir E.; Hinkel, Kenneth M.; Parsekian, Andrew D.

    2016-01-01

    Interactions and feedbacks between abundant surface waters and permafrost fundamentally shape lowland Arctic landscapes. Sublake permafrost is maintained when the maximum ice thickness (MIT) exceeds lake depth and mean annual bed temperatures (MABTs) remain below freezing. However, declining MIT since the 1970s is likely causing talik development below shallow lakes. Here we show high-temperature sensitivity to winter ice growth at the water-sediment interface of shallow lakes based on year-round lake sensor data. Empirical model experiments suggest that shallow (1 m depth) lakes have warmed substantially over the last 30 years (2.4°C), with MABT above freezing 5 of the last 7 years. This is in comparison to slower rates of warming in deeper (3 m) lakes (0.9°C), with already well-developed taliks. Our findings indicate that permafrost below shallow lakes has already begun crossing a critical thawing threshold approximately 70 years prior to predicted terrestrial permafrost thaw in northern Alaska.

  4. Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

    Science.gov (United States)

    Mewes, Benjamin; Hilbich, Christin; Delaloye, Reynald; Hauck, Christian

    2017-12-01

    Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity). Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

  5. Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

    Directory of Open Access Journals (Sweden)

    B. Mewes

    2017-12-01

    Full Text Available Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity. Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

  6. Climate hazards caused by thawing permafrost? Background information of the Federal Environmental Agency; Klimagefahr durch tauenden Permafrost? UBA-Hintergrundpapier

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-08-15

    The thawing of permafrost regions is supposed to increase climatic change processes due to the released methane. During the last decades the temperature of permafrost soils has increased by several tenths of degree up to 2 deg C. It is supposed that 10 to 20% of the permafrost regions will thaw during the next 100 years. The southern boundary of the permafrost region will move several hundred kilometers toward the north. Besides the increased risk for the climate system there will also be disadvantageous consequences for the ecosystems. Negative economic consequences are already observed and will be enhanced in the futures with significant cost for the public.

  7. Quality and Distribution of Frozen Organic Matter (Old, Deep, Fossil Carbon) in Siberian Permafrost

    Science.gov (United States)

    Schirrmeister, Lutz; Strauss, Jens; Wetterich, Sebastian; Grosse, Guido; Overduin, Pier Paul

    2013-04-01

    Permafrost deposits constitute a large organic carbon (OC) pool vulnerable to degradation and potential carbon release due to global warming. Permafrost sections along coastal and river bank exposures and subsea cores in northeastern Siberia were studied for organic matter (OM) characteristics and ice content. OM stored in Quaternary permafrost grew, accumulated, froze, partly decomposed, and refroze under different periglacial environments, reflected in specific biogeochemical and cryolithological features. For the studied individual strata (Saalian ice-rich deposits, Pre-Eemian floodplain, Eemian lake deposits, Early to Middle Weichselian fluvial deposits, Middle Weichselian Yedoma, Late Weichselian Yedoma , Taberites, Holocene cover, Holocene thermokarst, Holocene thermoerosional valley and submerged lagoon and fluvial deposits) OM accumulation, preservation, and distribution are strongly linked to a broad variety of paleoenvironmental factors and specific surface and subsurface conditions before inclusion of OM into the permafrost. OM in permafrost includes twigs, leaves, peat, grass roots, plant detritus, and particulate and dissolved OM. The vertical distribution of total OC (TOC) in exposures varies from 0.1 wt % of the dry sediment in fluvial deposits to 45 wt % in Holocene peats. High TOC, high C/N, and low d13C reflect less decomposed OM accumulated under wet, anaerobic soil conditions characteristic of interglacial and interstadial periods. Glacial and stadial periods are characterized by less variable, low TOC, low C/N, and high d13C values indicating stable environments with reduced bioproductivity and stronger OM decomposition under dryer, aerobic soil conditions. Based on TOC data and updated information on bulk densities, we estimate average OC inventories for different stratigraphic units in northeastern Siberia, ranging from 7 kg C/m³ for Early Weichselian fluvial deposits, to 33 kg C/m³ for Middle Weichselian Yedoma deposits, to 75 kg C/m³ for

  8. Soil data from fire and permafrost-thaw chronosequences in upland Picea mariana stands near Hess Creek and Tok, interior Alaska

    Science.gov (United States)

    O'Donnell, Jonathan A.; Harden, Jennifer W.; Manies, Kristen L.; Jorgenson, M. Torre; Kanevskiy, Mikhail; Xu, Xiaomei

    2013-01-01

    Soils of the Northern Circumpolar Permafrost region harbor 1,672 petagrams (Pg) (1 Pg = 1,000,000,000 kilograms) of organic carbon (OC), nearly 50 percent of the global belowground OC pool (Tarnocai and others, 2009). Of that soil OC, nearly 88 percent is presently stored in perennially frozen ground. Recent climate warming at northern latitudes has resulted in warming and thawing of permafrost in many regions (Osterkamp, 2007), which might mobilize OC stocks from associated soil reservoirs via decomposition, leaching, or erosion. Warming also has increased the magnitude and severity of wildfires in the boreal region (Turetsky and others, 2011), which might exacerbate rates of permafrost degradation relative to warming alone. Given the size and vulnerability of the soil OC pool in permafrost soils, permafrost thaw will likely function as a strong positive feedback to the climate system (Koven and others, 2011; Schaefer and others, 2011). In this report, we report soil OC inventories from two upland fire chronosequences located near Hess Creek and Tok in Interior Alaska. We sampled organic and mineral soils in the top 2 meters (m) across a range of stand ages to evaluate the effects of wildfire and permafrost thaw on soil C dynamics. These data were used to parameterize a simple process-based fire-permafrost-carbon model, which is described in detail by O’Donnell and others (2011a, b). Model simulations examine long-term changes in soil OC storage in response to fire, permafrost thaw, and climate change. These data also have been used in other papers, including Harden and others (2012), which examines C recovery post-fire, and Johnson and others (2011), which synthesizes data within the Alaska Soil Carbon Database. Findings from these studies highlight the importance of climate and disturbance (wildfire, permafrost thaw) on soil C storage, and loss of soil C from high-latitude ecosystems.

  9. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Donn McGuire; Steve Runyon; Richard Sigal; Bill Liddell; Thomas Williams; George Moridis

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. Hot Ice No. 1 was planned to test the Ugnu and West Sak sequences for gas hydrates and a concomitant free gas accumulation on Anadarko's 100% working interest acreage in section 30 of Township 9N, Range 8E of the Harrison Bay quadrangle of the North Slope of Alaska. The Ugnu and West Sak intervals are favorably positioned in the hydrate-stability zone over an area extending from Anadarko's acreage westward to the vicinity of the aforementioned gas-hydrate occurrences. This suggests that a large, north-to-south trending gas-hydrate accumulation may exist in that area. The presence of gas shows in the Ugnu and West Sak reservoirs in wells situated eastward and down dip of the Hot Ice location indicate that a free-gas accumulation may be trapped by gas hydrates. The Hot Ice No. 1 well was designed to core from the surface to the base of the West Sak interval using the

  10. Controls on ecosystem and root respiration across a permafrost and wetland gradient in interior Alaska

    Science.gov (United States)

    McConnell, Nicole A.; Turetsky, Merritt R.; McGuire, A. David; Kane, Evan S.; Waldrop, Mark P.; Harden, Jennifer W.

    2013-01-01

    Permafrost is common to many northern wetlands given the insulation of thick organic soil layers, although soil saturation in wetlands can lead to warmer soils and increased thaw depth. We analyzed five years of soil CO2 fluxes along a wetland gradient that varied in permafrost and soil moisture conditions. We predicted that communities with permafrost would have reduced ecosystem respiration (ER) but greater temperature sensitivity than communities without permafrost. These predictions were partially supported. The colder communities underlain by shallow permafrost had lower ecosystem respiration (ER) than communities with greater active layer thickness. However, the apparent Q10 of monthly averaged ER was similar in most of the vegetation communities except the rich fen, which had smaller Q10 values. Across the gradient there was a negative relationship between water table position and apparent Q10, showing that ER was more temperature sensitive under drier soil conditions. We explored whether root respiration could account for differences in ER between two adjacent communities (sedge marsh and rich fen), which corresponded to the highest and lowest ER, respectively. Despite differences in root respiration rates, roots contributed equally (~40%) to ER in both communities. Also, despite similar plant biomass, ER in the rich fen was positively related to root biomass, while ER in the sedge marsh appeared to be related more to vascular green area. Our results suggest that ER across this wetland gradient was temperature-limited, until conditions became so wet that respiration became oxygen-limited and influenced less by temperature. But even in sites with similar hydrology and thaw depth, ER varied significantly likely based on factors such as soil redox status and vegetation composition.

  11. Bacterial community structure in two permafrost wetlands on the Tibetan Plateau and Sanjiang Plain, China.

    Science.gov (United States)

    Yun, Juanli; Ju, Yiwen; Deng, Yongcui; Zhang, Hongxun

    2014-08-01

    Permafrost wetlands are important methane emission sources and fragile ecosystems sensitive to climate change. Presently, there remains a lack of knowledge regarding bacterial communities, especially methanotrophs in vast areas of permafrost on the Tibetan Plateau in Northwest China and the Sanjiang Plain (SJ) in Northeast China. In this study, 16S rRNA-based quantitative PCR (qPCR) and 454 pyrosequencing were used to identify bacterial communities in soils sampled from a littoral wetland of Lake Namco on the Tibetan Plateau (NMC) and an alluvial wetland on the SJ. Additionally, methanotroph-specific primers targeting particulate methane monooxygenase subunit A gene (pmoA) were used for qPCR and pyrosequencing analysis of methanotrophic community structure in NMC soils. qPCR analysis revealed the presence of 10(10) 16S rRNA gene copies per gram of wet soil in both wetlands, with 10(8) pmoA copies per gram of wet soil in NMC. The two permafrost wetlands showed similar bacterial community compositions, which differed from those reported in other cold environments. Proteobacteria, Actinobacteria , and Chloroflexi were the most abundant phyla in both wetlands, whereas Acidobacteria was prevalent in the acidic wetland SJ only. These four phyla constituted more than 80 % of total bacterial community diversity in permafrost wetland soils, and Methylobacter of type I methanotrophs was overwhelmingly dominant in NMC soils. This study is the first major bacterial sequencing effort of permafrost in the NMC and SJ wetlands, which provides fundamental data for further studies of microbial function in extreme ecosystems under climate change scenarios.

  12. Remote sensing of glacier- and permafrost-related hazards in high mountains: an overview

    Directory of Open Access Journals (Sweden)

    A. Kääb

    2005-01-01

    Full Text Available Process interactions and chain reactions, the present shift of cryospheric hazard zones due to atmospheric warming, and the potential far reach of glacier disasters make it necessary to apply modern remote sensing techniques for the assessment of glacier and permafrost hazards in high-mountains. Typically, related hazard source areas are situated in remote regions, often difficult to access for physical and/or political reasons. In this contribution we provide an overview of air- and spaceborne remote sensing methods suitable for glacier and permafrost hazard assessment and disaster management. A number of image classification and change detection techniques support high-mountain hazard studies. Digital terrain models (DTMs, derived from optical stereo data, synthetic aperture radar or laserscanning, represent one of the most important data sets for investigating high-mountain processes. Fusion of satellite stereo-derived DTMs with the DTM from the Shuttle Radar Topography Mission (SRTM is a promising way to combine the advantages of both technologies. Large changes in terrain volume such as from avalanche deposits can indeed be measured even by repeat satellite DTMs. Multitemporal data can be used to derive surface displacements on glaciers, permafrost and landslides. Combining DTMs, results from spectral image classification, and multitemporal data from change detection and displacement measurements significantly improves the detection of hazard potentials. Modelling of hazardous processes based on geographic information systems (GIS complements the remote sensing analyses towards an integrated assessment of glacier and permafrost hazards in mountains. Major present limitations in the application of remote sensing to glacier and permafrost hazards in mountains are, on the one hand, of technical nature (e.g. combination and fusion of different methods and data; improved understanding of microwave backscatter. On the other hand, better

  13. Numerical modeling of permafrost dynamics in Alaska using a high spatial resolution dataset

    Directory of Open Access Journals (Sweden)

    E. E. Jafarov

    2012-06-01

    Full Text Available Climate projections for the 21st century indicate that there could be a pronounced warming and permafrost degradation in the Arctic and sub-Arctic regions. Climate warming is likely to cause permafrost thawing with subsequent effects on surface albedo, hydrology, soil organic matter storage and greenhouse gas emissions.

    To assess possible changes in the permafrost thermal state and active layer thickness, we implemented the GIPL2-MPI transient numerical model for the entire Alaska permafrost domain. The model input parameters are spatial datasets of mean monthly air temperature and precipitation, prescribed thermal properties of the multilayered soil column, and water content that are specific for each soil class and geographical location. As a climate forcing, we used the composite of five IPCC Global Circulation Models that has been downscaled to 2 by 2 km spatial resolution by Scenarios Network for Alaska Planning (SNAP group.

    In this paper, we present the modeling results based on input of a five-model composite with A1B carbon emission scenario. The model has been calibrated according to the annual borehole temperature measurements for the State of Alaska. We also performed more detailed calibration for fifteen shallow borehole stations where high quality data are available on daily basis. To validate the model performance, we compared simulated active layer thicknesses with observed data from Circumpolar Active Layer Monitoring (CALM stations. The calibrated model was used to address possible ground temperature changes for the 21st century. The model simulation results show widespread permafrost degradation in Alaska could begin between 2040–2099 within the vast area southward from the Brooks Range, except for the high altitude regions of the Alaska Range and Wrangell Mountains.

  14. Resilience and vulnerability of permafrost to climate change

    Science.gov (United States)

    M.Torre Jorgenson; Vladimir Romanovsky; Jennifer Harden; Yuri Shur; Jonathan O' Donnell; Edward A.G. Schuur; Mikhail Kanevskiy; Sergei. Marchenko

    2010-01-01

    The resilience and vulnerability of permafrost to climate change depends on complex interactions among topography, water, soil, vegetation, and snow, which allow permafrost to persist at mean annual air temperatures (MAATs) as high as +2 °C and degrade at MAATs as low as -20°C. To assess these interactions, we compiled existing data and tested effects of varying...

  15. Future permafrost conditions along environmental gradients in Zackenberg, Greenland

    DEFF Research Database (Denmark)

    Westermann, Sebastian; Elberling, Bo; Pedersen, Stine Højlund

    2015-01-01

    The future development of ground temperatures in permafrost areas is determined by a number of factors varying on different spatial and temporal scales. For sound projections of impacts of permafrost thaw, scaling procedures are of paramount importance. We present numerical simulations of present...

  16. Evidence for nonuniform permafrost degradation after fire in boreal landscapes

    Science.gov (United States)

    Minsley, Burke J.; Pastick, Neal J.; Wylie, Bruce K.; Brown, Dana R.N.; Kass, M. Andy

    2016-01-01

    Fire can be a significant driver of permafrost change in boreal landscapes, altering the availability of soil carbon and nutrients that have important implications for future climate and ecological succession. However, not all landscapes are equally susceptible to fire-induced change. As fire frequency is expected to increase in the high latitudes, methods to understand the vulnerability and resilience of different landscapes to permafrost degradation are needed. We present a combination of multiscale remote sensing, geophysical, and field observations that reveal details of both near-surface (1 m) impacts of fire on permafrost. Along 11 transects that span burned-unburned boundaries in different landscape settings within interior Alaska, subsurface electrical resistivity and nuclear magnetic resonance data indicate locations where permafrost appears to be resilient to disturbance from fire, areas where warm permafrost conditions exist that may be most vulnerable to future change, and also areas where permafrost has thawed. High-resolution geophysical data corroborate remote sensing interpretations of near-surface permafrost and also add new high-fidelity details of spatial heterogeneity that extend from the shallow subsurface to depths of about 10 m. Results show that postfire impacts on permafrost can be variable and depend on multiple factors such as fire severity, soil texture, soil moisture, and time since fire.

  17. Methane emissions from permafrost thaw lakes limited by lake drainage.

    NARCIS (Netherlands)

    van Huissteden, J.; Berrittella, C.; Parmentier, F.J.W.; Mi, Y.; Maximov, T.C.; Dolman, A.J.

    2011-01-01

    Thaw lakes in permafrost areas are sources of the strong greenhouse gas methane. They develop mostly in sedimentary lowlands with permafrost and a high excess ground ice volume, resulting in large areas covered with lakes and drained thaw-lake basins (DTLBs; refs,). Their expansion is enhanced by

  18. Permafrost: An International Approach to 21th Century Challenges

    Science.gov (United States)

    Brown, J.

    2003-12-01

    Whereas glaciers are easily discernible to the human eye and satellites, permafrost terrains and their physical components are not easily detected from the surface without supplemental knowledge and measurements. In the Northern Hemisphere, approximately 17 million km2 of exposed land contains some extent of permafrost or ground that remains frozen for more than two years. The vast majority, or 11 million km2, of permafrost terrain has temperatures of 5° C or below, with perennially frozen ground underlying essentially all ground surfaces to considerable depths. Permafrost in the remaining regions, including mid-latitude mountains, is both warmer and is spatially variable (discontinuous). As climate warms the uppermost permafrost is subjected to increase thaw with resulting ground subsidence, accelerated erosion, and related biogeochemical modifications. The challenging questions to geocryologists, modelers and the public relate to the rate of change and the spatial variability of the projected thaw, particularly in the warmer zones where actual areal and subareal distribution of permafrost is poorly known. An international network of active layer measurements and borehole sites now exists under the Global Climate Observing System (GCOS), but requires additional sites for representative coverage. This Global Terrestrial Network for Permafrost (GTN-P) is coordinated by the 24-member, International Permafrost Association. At the Eighth International Conference on Permafrost (ICOP) in Zurich in July 2003, the IPA Council agreed on the scope of new activities for the next five years, many of which will be undertaken in cooperation with other international organizations (e.g. WCRP/CliC; ICSI, IASC, SCAR, IGU, IUGS). Examples of the activities of the IPA Working Groups are: 1. Antarctic Permafrost and Periglacial Environments (active layer processes, maps, database). 2. Coastal and Offshore Permafrost (sediment and organic transfers, subsea permafrost dynamics). 3

  19. Diversity and Distribution of Archaea Community along a Stratigraphic Permafrost Profile from Qinghai-Tibetan Plateau, China

    Directory of Open Access Journals (Sweden)

    Shiping Wei

    2014-01-01

    Full Text Available Accompanying the thawing permafrost expected to result from the climate change, microbial decomposition of the massive amounts of frozen organic carbon stored in permafrost is a potential emission source of greenhouse gases, possibly leading to positive feedbacks to the greenhouse effect. In this study, the community composition of archaea in stratigraphic soils from an alpine permafrost of Qinghai-Tibetan Plateau was investigated. Phylogenic analysis of 16S rRNA sequences revealed that the community was predominantly constituted by Crenarchaeota and Euryarchaeota. The active layer contained a proportion of Crenarchaeota at 51.2%, with the proportion of Euryarchaeota at 48.8%, whereas the permafrost contained 41.2% Crenarchaeota and 58.8% Euryarchaeota, based on 16S rRNA gene sequence analysis. OTU1 and OTU11, affiliated to Group 1.3b/MCG-A within Crenarchaeota and the unclassified group within Euryarchaeota, respectively, were widely distributed in all sediment layers. However, OTU5 affiliated to Group 1.3b/MCG-A was primarily distributed in the active layers. Sequence analysis of the DGGE bands from the 16S rRNAs of methanogenic archaea showed that the majority of methanogens belonged to Methanosarcinales and Methanomicrobiales affiliated to Euryarchaeota and the uncultured ZC-I cluster affiliated to Methanosarcinales distributed in all the depths along the permafrost profile, which indicated a dominant group of methanogens occurring in the cold ecosystems.

  20. Transient thermal effects in Alpine permafrost

    Directory of Open Access Journals (Sweden)

    J. Noetzli

    2009-04-01

    Full Text Available In high mountain areas, permafrost is important because it influences the occurrence of natural hazards, because it has to be considered in construction practices, and because it is sensitive to climate change. The assessment of its distribution and evolution is challenging because of highly variable conditions at and below the surface, steep topography and varying climatic conditions. This paper presents a systematic investigation of effects of topography and climate variability that are important for subsurface temperatures in Alpine bedrock permafrost. We studied the effects of both, past and projected future ground surface temperature variations on the basis of numerical experimentation with simplified mountain topography in order to demonstrate the principal effects. The modeling approach applied combines a distributed surface energy balance model and a three-dimensional subsurface heat conduction scheme. Results show that the past climate variations that essentially influence present-day permafrost temperatures at depth of the idealized mountains are the last glacial period and the major fluctuations in the past millennium. Transient effects from projected future warming, however, are likely larger than those from past climate conditions because larger temperature changes at the surface occur in shorter time periods. We further demonstrate the accelerating influence of multi-lateral warming in steep and complex topography for a temperature signal entering the subsurface as compared to the situation in flat areas. The effects of varying and uncertain material properties (i.e., thermal properties, porosity, and freezing characteristics on the subsurface temperature field were examined in sensitivity studies. A considerable influence of latent heat due to water in low-porosity bedrock was only shown for simulations over time periods of decades to centuries. At the end, the model was applied to the topographic setting of the Matterhorn

  1. The GTN-P Data Management System: A central database for permafrost monitoring parameters of the Global Terrestrial Network for Permafrost (GTN-P) and beyond

    Science.gov (United States)

    Lanckman, Jean-Pierre; Elger, Kirsten; Karlsson, Ævar Karl; Johannsson, Halldór; Lantuit, Hugues

    2013-04-01

    Permafrost is a direct indicator of climate change and has been identified as Essential Climate Variable (ECV) by the global observing community. The monitoring of permafrost temperatures, active-layer thicknesses and other parameters has been performed for several decades already, but it was brought together within the Global Terrestrial Network for Permafrost (GTN-P) in the 1990's only, including the development of measurement protocols to provide standardized data. GTN-P is the primary international observing network for permafrost sponsored by the Global Climate Observing System (GCOS) and the Global Terrestrial Observing System (GTOS), and managed by the International Permafrost Association (IPA). All GTN-P data was outfitted with an "open data policy" with free data access via the World Wide Web. The existing data, however, is far from being homogeneous: it is not yet optimized for databases, there is no framework for data reporting or archival and data documentation is incomplete. As a result, and despite the utmost relevance of permafrost in the Earth's climate system, the data has not been used by as many researchers as intended by the initiators of the programs. While the monitoring of many other ECVs has been tackled by organized international networks (e.g. FLUXNET), there is still no central database for all permafrost-related parameters. The European Union project PAGE21 created opportunities to develop this central database for permafrost monitoring parameters of GTN-P during the duration of the project and beyond. The database aims to be the one location where the researcher can find data, metadata, and information of all relevant parameters for a specific site. Each component of the Data Management System (DMS), including parameters, data levels and metadata formats were developed in cooperation with the GTN-P and the IPA. The general framework of the GTN-P DMS is based on an object oriented model (OOM), open for as many parameters as possible, and

  2. Baseline characteristics of climate, permafrost and land cover from a new permafrost observatory in the Lena River Delta, Siberia (1998–2011

    Directory of Open Access Journals (Sweden)

    J. Boike

    2013-03-01

    Full Text Available Samoylov Island is centrally located within the Lena River Delta at 72° N, 126° E and lies within the Siberian zone of continuous permafrost. The landscape on Samoylov Island consists mainly of late Holocene river terraces with polygonal tundra, ponds and lakes, and an active floodplain. The island has been the focus of numerous multidisciplinary studies since 1993, which have focused on climate, land cover, ecology, hydrology, permafrost and limnology. This paper aims to provide a framework for future studies by describing the characteristics of the island's meteorological parameters (temperature, radiation and snow cover, soil temperature, and soil moisture. The land surface characteristics have been described using high resolution aerial images in combination with data from ground-based observations. Of note is that deeper permafrost temperatures have increased between 0.3 to 1.3 °C over the last five years. However, no clear warming of air and active layer temperatures is detected since 1998, though winter air temperatures during recent years have not been as cold as in earlier years. Data related to this article are archived under: http://doi. pangaea.de/10.1594/PANGAEA.806233 .

  3. The International Permafrost Association: current initiatives for cryospheric research

    Science.gov (United States)

    Schollaen, Karina; Lewkowicz, Antoni G.; Christiansen, Hanne H.; Romanovsky, Vladimir E.; Lantuit, Hugues; Schrott, Lothar; Sergeev, Dimitry; Wei, Ma

    2015-04-01

    The International Permafrost Association (IPA), founded in 1983, has as its objectives to foster the dissemination of knowledge concerning permafrost and to promote cooperation among persons and national or international organizations engaged in scientific investigation and engineering work on permafrost. The IPA's primary responsibilities are convening International Permafrost Conferences, undertaking special projects such as preparing databases, maps, bibliographies, and glossaries, and coordinating international field programs and networks. Membership is through adhering national or multinational organizations or as individuals in countries where no Adhering Body exists. The IPA is governed by its Executive Committee and a Council consisting of representatives from 26 Adhering Bodies having interests in some aspect of theoretical, basic and applied frozen ground research, including permafrost, seasonal frost, artificial freezing and periglacial phenomena. This presentation details the IPA core products, achievements and activities as well as current projects in cryospheric research. One of the most important core products is the circumpolar permafrost map. The IPA also fosters and supports the activities of the Global Terrestrial Network on Permafrost (GTN-P) sponsored by the Global Terrestrial Observing System, GTOS, and the Global Climate Observing System, GCOS, whose long-term goal is to obtain a comprehensive view of the spatial structure, trends, and variability of changes in the active layer thickness and permafrost temperature. A further important initiative of the IPA are the biannually competitively-funded Action Groups which work towards the production of well-defined products over a period of two years. Current IPA Action Groups are working on highly topical and interdisciplinary issues, such as the development of a regional Palaeo-map of Permafrost in Eurasia, the integration of multidisciplinary knowledge about the use of thermokarst and permafrost

  4. NEW PERMAFROST FEATURE – DEP CRATER IN CENTRAL YAMAL (WEST SIBERIA, RUSIA AS A RESPONSE TO LOCAL CLIMATE FLUCTUATIONS

    Directory of Open Access Journals (Sweden)

    Marina O. Leibman

    2014-01-01

    Full Text Available This paper is based on field data obtained during short visits to a newly formed permafrost feature in a form of relatively narrow, deep crater. Excluding impossible and improbable versions of the crater’s development, the authors conclude that it originated from warmerground temperatures and an increase in unfrozen water content, leading to an increase in pressure from gas emissions from permafrost and ground ice. This conclusion is also supported by known processes in the palaeo-geography of Yamal lakes and recent studies of gas-hydrate behavior and subsea processes in gas-bearing provinces.

  5. Anaerobic methanotrophic communities thrive in deep submarine permafrost.

    Science.gov (United States)

    Winkel, Matthias; Mitzscherling, Julia; Overduin, Pier P; Horn, Fabian; Winterfeld, Maria; Rijkers, Ruud; Grigoriev, Mikhail N; Knoblauch, Christian; Mangelsdorf, Kai; Wagner, Dirk; Liebner, Susanne

    2018-01-22

    Thawing submarine permafrost is a source of methane to the subsurface biosphere. Methane oxidation in submarine permafrost sediments has been proposed, but the responsible microorganisms remain uncharacterized. We analyzed archaeal communities and identified distinct anaerobic methanotrophic assemblages of marine and terrestrial origin (ANME-2a/b, ANME-2d) both in frozen and completely thawed submarine permafrost sediments. Besides archaea potentially involved in anaerobic oxidation of methane (AOM) we found a large diversity of archaea mainly belonging to Bathyarchaeota, Thaumarchaeota, and Euryarchaeota. Methane concentrations and δ 13 C-methane signatures distinguish horizons of potential AOM coupled either to sulfate reduction in a sulfate-methane transition zone (SMTZ) or to the reduction of other electron acceptors, such as iron, manganese or nitrate. Analysis of functional marker genes (mcrA) and fluorescence in situ hybridization (FISH) corroborate potential activity of AOM communities in submarine permafrost sediments at low temperatures. Modeled potential AOM consumes 72-100% of submarine permafrost methane and up to 1.2 Tg of carbon per year for the total expected area of submarine permafrost. This is comparable with AOM habitats such as cold seeps. We thus propose that AOM is active where submarine permafrost thaws, which should be included in global methane budgets.

  6. Permafrost stores a globally significant amount of mercury

    Science.gov (United States)

    Schaefer, K. M.; Schuster, P. F.; Antweiler, R.; Aiken, G.; DeWild, J.; Gryziec, J. D.; Gusmeroli, A.; Hugelius, G.; Jafarov, E.; Krabbenhoft, D. P.; Liu, L.; Herman-Mercer, N. M.; Mu, C.; Roth, D. A.; Schaefer, T.; Striegl, R. G.; Wickland, K.; Zhang, T.

    2017-12-01

    Changing climate in northern regions is causing permafrost to thaw with major implications for the cycling of mercury in arctic and subarctic ecosystems. Permafrost occurs in nearly one quarter of the Earth's Northern Hemisphere. We measured total soil mercury concentration in 588 samples from 13 soil permafrost cores from the interior and the North Slope of Alaska. The median concentration was 47.7±23.4 ng Hg g soil-1 and the median ratio of Hg to carbon was 1.56±0.86 µg Hg g C-1. We estimate Alaskan permafrost stores 56±32 kilotons of mercury and the entire northern hemisphere permafrost land mass stores 773±441 kilotons of mercury. This increases estimates of mercury stored in soils by 60%, making permafrost the second largest reservoir of mercury on the planet. Climate projections indicate extensive permafrost thawing, releasing mercury into the environment through a variety of mechanisms, for example, terrestrial transport via dissolved organic carbon (DOC), gaseous elemental mercury (GEM) evasion, forest fires, atmospheric mixing processes with ozone, and Springtime atmospheric Hg depletion after the polar sunrise. These findings have major implications for terrestrial and aquatic life, the world's fisheries, and ultimately human health.

  7. Tundra permafrost thaw causes significant shifts in energy partitioning

    Directory of Open Access Journals (Sweden)

    Christian Stiegler

    2016-04-01

    Full Text Available Permafrost, a key component of the arctic and global climate system, is highly sensitive to climate change. Observed and ongoing permafrost degradation influences arctic hydrology, ecology and biogeochemistry, and models predict that rapid warming is expected to significantly reduce near-surface permafrost and seasonally frozen ground during the 21st century. These changes raise concern of how permafrost thaw affects the exchange of water and energy with the atmosphere. However, associated impacts of permafrost thaw on the surface energy balance and possible feedbacks on the climate system are largely unknown. In this study, we show that in northern subarctic Sweden, permafrost thaw and related degradation of peat plateaus significantly change the surface energy balance of three peatland complexes by enhancing latent heat flux and, to less degree, also ground heat flux at the cost of sensible heat flux. This effect is valid at all radiation levels but more pronounced at higher radiation levels. The observed differences in flux partitioning mainly result from the strong coupling between soil moisture availability, vegetation composition, albedo and surface structure. Our results suggest that ongoing and predicted permafrost degradation in northern subarctic Sweden ultimately result in changes in land–atmosphere coupling due to changes in the partitioning between latent and sensible heat fluxes. This in turn has crucial implications for how predictive climate models for the Arctic are further developed.

  8. The Langley Stability and Transition Analysis Code (LASTRAC) : LST, Linear and Nonlinear PSE for 2-D, Axisymmetric, and Infinite Swept Wing Boundary Layers

    Science.gov (United States)

    Chang, Chau-Lyan

    2003-01-01

    During the past two decades, our understanding of laminar-turbulent transition flow physics has advanced significantly owing to, in a large part, the NASA program support such as the National Aerospace Plane (NASP), High-speed Civil Transport (HSCT), and Advanced Subsonic Technology (AST). Experimental, theoretical, as well as computational efforts on various issues such as receptivity and linear and nonlinear evolution of instability waves take part in broadening our knowledge base for this intricate flow phenomenon. Despite all these advances, transition prediction remains a nontrivial task for engineers due to the lack of a widely available, robust, and efficient prediction tool. The design and development of the LASTRAC code is aimed at providing one such engineering tool that is easy to use and yet capable of dealing with a broad range of transition related issues. LASTRAC was written from scratch based on the state-of-the-art numerical methods for stability analysis and modem software technologies. At low fidelity, it allows users to perform linear stability analysis and N-factor transition correlation for a broad range of flow regimes and configurations by using either the linear stability theory (LST) or linear parabolized stability equations (LPSE) method. At high fidelity, users may use nonlinear PSE to track finite-amplitude disturbances until the skin friction rise. Coupled with the built-in receptivity model that is currently under development, the nonlinear PSE method offers a synergistic approach to predict transition onset for a given disturbance environment based on first principles. This paper describes the governing equations, numerical methods, code development, and case studies for the current release of LASTRAC. Practical applications of LASTRAC are demonstrated for linear stability calculations, N-factor transition correlation, non-linear breakdown simulations, and controls of stationary crossflow instability in supersonic swept wing boundary

  9. Transient thermal modeling of permafrost conditions in Southern Norway

    Directory of Open Access Journals (Sweden)

    S. Westermann

    2013-04-01

    Full Text Available Thermal modeling is a powerful tool to infer the temperature regime of the ground in permafrost areas. We present a transient permafrost model, CryoGrid 2, that calculates ground temperatures according to conductive heat transfer in the soil and in the snowpack. CryoGrid 2 is forced by operational air temperature and snow-depth products for potential permafrost areas in Southern Norway for the period 1958 to 2009 at 1 km2 spatial resolution. In total, an area of about 80 000 km2 is covered. The model results are validated against borehole temperatures, permafrost probability maps from "bottom temperature of snow" measurements and inventories of landforms indicative of permafrost occurrence. The validation demonstrates that CryoGrid 2 can reproduce the observed lower permafrost limit to within 100 m at all validation sites, while the agreement between simulated and measured borehole temperatures is within 1 K for most sites. The number of grid cells with simulated permafrost does not change significantly between the 1960s and 1990s. In the 2000s, a significant reduction of about 40% of the area with average 2 m ground temperatures below 0 °C is found, which mostly corresponds to degrading permafrost with still negative temperatures in deeper ground layers. The thermal conductivity of the snow is the largest source of uncertainty in CryoGrid 2, strongly affecting the simulated permafrost area. Finally, the prospects of employing CryoGrid 2 as an operational soil-temperature product for Norway are discussed.

  10. Monitoring Seasonal Changes in Permafrost Using Seismic Interferometry

    Science.gov (United States)

    James, S. R.; Knox, H. A.; Abbott, R. E.

    2015-12-01

    The effects of climate change in polar regions and their incorporation in global climate models has recently become an area of great interest. Permafrost holds entrapped greenhouse gases, e.g. CO2 and CH4, which are released to the atmosphere upon thawing, creating a positive feedback mechanism. Knowledge of seasonal changes in active layer thickness as well as long term degradation of permafrost is critical to the management of high latitude infrastructures, hazard mitigation, and increasing the accuracy of climate predictions. Methods for effectively imaging the spatial extent, depth, thickness, and discontinuous nature of permafrost over large areas are needed. Furthermore, continuous monitoring of permafrost over annual time scales would provide valuable insight into permafrost degradation. Seismic interferometry using ambient seismic noise has proven effective for recording velocity changes within the subsurface for a variety of applications, but has yet to be applied to permafrost studies. To this end, we deployed 7 Nanometrics Trillium posthole broadband seismometers within Poker Flat Research Range, located 30 miles north of Fairbanks, Alaska in a zone of discontinuous permafrost. Approximately 2 years worth of nearly continuous ambient noise data was collected. Using the python package MSNoise, relative changes in velocity were calculated. Results show high amounts of variability throughout the study period. General trends of negative relative velocity shifts can be seen between August and October followed by a positive relative velocity shift between November and February. Differences in relative velocity changes with both frequency and spatial location are also observed, suggesting this technique is sensitive to permafrost variation with depth and extent. Overall, short and long term changes in shallow subsurface velocity can be recovered using this method proposing seismic interferometry is a promising new technique for permafrost monitoring. Sandia

  11. Circumpolar assessment of permafrost C quality and its vulnerability over time using long-term incubation data.

    Science.gov (United States)

    Schädel, Christina; Schuur, Edward A G; Bracho, Rosvel; Elberling, Bo; Knoblauch, Christian; Lee, Hanna; Luo, Yiqi; Shaver, Gaius R; Turetsky, Merritt R

    2014-02-01

    High-latitude ecosystems store approximately 1700 Pg of soil carbon (C), which is twice as much C as is currently contained in the atmosphere. Permafrost thaw and subsequent microbial decomposition of permafrost organic matter could add large amounts of C to the atmosphere, thereby influencing the global C cycle. The rates at which C is being released from the permafrost zone at different soil depths and across different physiographic regions are poorly understood but crucial in understanding future changes in permafrost C storage with climate change. We assessed the inherent decomposability of C from the permafrost zone by assembling a database of long-term (>1 year) aerobic soil incubations from 121 individual samples from 23 high-latitude ecosystems located across the northern circumpolar permafrost zone. Using a three-pool (i.e., fast, slow and passive) decomposition model, we estimated pool sizes for C fractions with different turnover times and their inherent decomposition rates using a reference temperature of 5 °C. Fast cycling C accounted for less than 5% of all C in both organic and mineral soils whereas the pool size of slow cycling C increased with C : N. Turnover time at 5 °C of fast cycling C typically was below 1 year, between 5 and 15 years for slow turning over C, and more than 500 years for passive C. We project that between 20 and 90% of the organic C could potentially be mineralized to CO2 within 50 incubation years at a constant temperature of 5 °C, with vulnerability to loss increasing in soils with higher C : N. These results demonstrate the variation in the vulnerability of C stored in permafrost soils based on inherent differences in organic matter decomposability, and point toward C : N as an index of decomposability that has the potential to be used to scale permafrost C loss across landscapes. © 2013 John Wiley & Sons Ltd.

  12. Adaptation to permafrost in the Canadian north: Present and future

    International Nuclear Information System (INIS)

    Woo Mingko; Rouse, W.R.; Young, K.L.; Lewkowicz, A.G.

    1993-01-01

    Human-induced climate warming is believed to be imminent, although its exact magnitude is uncertain. Such a warming will have a dramatic effect on permafrost, which underlies about half of Canada's land mass. Adaptation of the land to climatic warming will include diminution of permafrost both in lateral and vertical extent, with concomitant responses in the landscape such as development of thermokarst, slides and slumping in hilly terrain, and altering of hydrologic regimes. Since northern development has relied on special techniques that preserve permafrost to ensure foundation stability, climatic warming will demand adjustment in engineering designs for new facilities and alteration of maintenance procedures for existing facilities. Recommendations are presented for future research, both on permafrost and its linkages to climatic and other environmental factors, and on risk analyses of engineering projects

  13. Assessment of three mitigation techniques for permafrost protection

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr

    The presence of permafrost is an important aspect in civil engineering in arctic regions. The construction of engineering structures, such as road and airfield embankments, will change the thermal regime of the ground, and may lead to permafrost degradation under or adjacent to such structures....... This problem, has in the last decades, been amplified by the climate warming, which has been most evident in the arctic regions. The construction of a road embankment usually results in an increased mean annual surface temperature, which will increase the thawing of permafrost and expose the road embankment...... objective has been to study the three above-mentioned techniques and evaluate their potential for minimizing the problems with thaw settlements in permafrost areas. The air convection embankment and heat drain techniques have been tested for the implementation in the shoulders of road and airfield...

  14. Dalton Highway 9 to 11 Mile expedient resistivity permafrost investigation.

    Science.gov (United States)

    2014-01-01

    This project performed capacitive coupled resistivity surveys over a roadway reconstruction project in Interior Alaska, for the determination of permafrost extent. The : objective was to ascertain the ability of an expedient earth resistivity survey ...

  15. Searching for eukaryotic life preserved in Antarctic permafrost

    DEFF Research Database (Denmark)

    Zucconi, L.; Selbmann, L.; Buzzini, P.

    2012-01-01

    Fungi and yeasts isolated in pure culture from Antarctic permafrost collected at different depths in the McMurdo Dry Valleys were identified with cultural, physiological and molecular methods. Fungi belonged to the genera Penicillium, Eurotium, Cladosporium, Alternaria, Engyodonthium, Aureobasidium...

  16. The behaviour of petroleum spills in permafrost soils

    International Nuclear Information System (INIS)

    Biggar, K. W.; Nahir, M.

    1999-01-01

    Recent laboratory and field investigations of the migration of non-aqueous phase liquids into frozen soil dispelled the general assumption that permafrost provides an impermeable barrier, thus preventing the migration of spilled hydrocarbons into the frozen soil. In actual fact, these investigations confirm gravity-driven downward migration in the presence of air voids within the frozen soil matrix. This paper reviews the results of research on the migration of hydrocarbons into permafrost and frozen soils, and explains the mechanisms believed to be responsible for the phenomenon. To date, unfrozen portion of the pore water in permafrost, air voids in unsaturated fill installed for construction pads, and the network of fissures that develop as a result of frozen soil undergoing thermal contraction as temperature decreases, have been identified as conduits facilitating the migration of free phase petroleum hydrocarbons into permafrost or frozen soils. Each of these mechanisms and their potential impact are discussed. 4 refs., 5 figs

  17. Four years of UAS Imagery Reveals Vegetation Change Due to Permafrost Thaw

    Science.gov (United States)

    DelGreco, J. L.; Herrick, C.; Varner, R. K.; McArthur, K. J.; McCalley, C. K.; Garnello, A.; Finnell, D.; Anderson, S. M.; Crill, P. M.; Palace, M. W.

    2017-12-01

    Warming trends in sub-arctic regions have resulted in thawing of permafrost which in turn induces change in vegetation across peatlands. Collapse of palsas (i.e. permafrost plateaus) has also been correlated to increases in methane (CH4) emissions to the atmosphere. Vegetation change provides new microenvironments that promote CH4 production and emission, specifically through plant interactions and structure. By quantifying the changes in vegetation at the landscape scale, we will be able to understand the impact of thaw on CH4 emissions in these complex and climate sensitive northern ecosystems. We combine field-based measurements of vegetation composition and high resolution Unmanned Aerial Systems (UAS) imagery to characterize vegetation change in a sub-arctic mire. At Stordalen Mire (1 km x 0.5 km), Abisko, Sweden, we flew a fixed-wing UAS in July of each year between 2014 and 2017. High precision GPS ground control points were used to georeference the imagery. Seventy-five randomized square-meter plots were measured for vegetation composition and individually classified into one of five cover types, each representing a different stage of permafrost degradation. With this training data, each year of imagery was classified by cover type. The developed cover type maps were also used to estimate CH4 emissions across the mire based on average flux CH4 rates from each cover type obtained from flux chamber measurements collected at the mire. This four year comparison of vegetation cover and methane emissions has indicated a rapid response to permafrost thaw and changes in emissions. Estimation of vegetation cover types is vital in our understanding of the evolution of northern peatlands and its future role in the global carbon cycle.

  18. Comparing the sensitivity of permafrost and marine gas hydrate to climate warming

    International Nuclear Information System (INIS)

    Taylor, A.E.; Dallimore, S.R.; Hyndman, R.D.; Wright, F.

    2005-01-01

    The sensitivity of Arctic subpermafrost gas hydrate at the Mallik borehole was compared to temperate marine gas hydrate located offshore southwestern Canada. In particular, a finite element geothermal model was used to determine the sensitivity to the end of the ice age, and contemporary climate warming of a 30 m thick methane hydrate layer lying at the base of a gas hydrate stability zone prior to 13.5 kiloannum (ka) before present (BP). It was suggested that the 30 m gas-hydrate-bearing layer would have disappeared by now, according to the thermal signal alone. However, the same gas-hydrate-bearing layer underlying permafrost would persist until at least 4 ka after present, even with contemporary climate warming. The longer time for subpermafrost gas hydrate comes from the thawing pore ice at the base of permafrost, at the expense of dissociation of the deeper gas hydrate. The dissociation of underlying gas hydrate from climate surface warming is buffered by the overlying permafrost

  19. Computer Science in K-12 School Curricula of the 2lst Century: Why, What and When?

    Science.gov (United States)

    Webb, Mary; Davis, Niki; Bell, Tim; Katz, Yaacov J.; Reynolds, Nicholas; Chambers, Dianne P.; Syslo, Maciej M.

    2017-01-01

    In this paper we have examined the position and roles of Computer Science in curricula in the light of recent calls for curriculum change and we have proposed principles and issues to consider in curriculum design as well as identifying priority areas for further research. The paper is based on discussions within and beyond the International…

  20. Sensitivity of airborne geophysical data to sublacustrine and near-surface permafrost thaw

    Science.gov (United States)

    Minsley, Burke J.; Wellman, Tristan; Walvoord, Michelle Ann; Revil, Andre

    2014-01-01

    A coupled hydrogeophysical forward and inverse modeling approach is developed to illustrate the ability of frequency-domain airborne electromagnetic (AEM) data to characterize subsurface physical properties associated with sublacustrine permafrost thaw during lake-talik formation. Numerical modeling scenarios are evaluated that consider non-isothermal hydrologic responses to variable forcing from different lake depths and for different hydrologic gradients. A novel physical property relationship connects the dynamic distribution of electrical resistivity to ice saturation and temperature outputs from the SUTRA groundwater simulator with freeze–thaw physics. The influence of lithology on electrical resistivity is controlled by a surface conduction term in the physical property relationship. Resistivity models, which reflect changes in subsurface conditions, are used as inputs to simulate AEM data in order to explore the sensitivity of geophysical observations to permafrost thaw. Simulations of sublacustrine talik formation over a 1000-year period are modeled after conditions found in the Yukon Flats, Alaska. Synthetic AEM data are analyzed with a Bayesian Markov chain Monte Carlo algorithm that quantifies geophysical parameter uncertainty and resolution. Major lithological and permafrost features are well resolved by AEM data in the examples considered. The subtle geometry of partial ice saturation beneath lakes during talik formation cannot be resolved using AEM data, but the gross characteristics of sub-lake resistivity models reflect bulk changes in ice content and can identify the presence of a talik. A final synthetic example compares AEM and ground-based electromagnetic responses for their ability to resolve shallow permafrost and thaw features in the upper 1–2 m below ground outside the lake margin.

  1. Development of capability for microtopography-resolving simulations of hydrologic processes in permafrost affected regions

    Science.gov (United States)

    Painter, S.; Moulton, J. D.; Berndt, M.; Coon, E.; Garimella, R.; Lewis, K. C.; Manzini, G.; Mishra, P.; Travis, B. J.; Wilson, C. J.

    2012-12-01

    The frozen soils of the Arctic and subarctic regions contain vast amounts of stored organic carbon. This carbon is vulnerable to release to the atmosphere as temperatures warm and permafrost degrades. Understanding the response of the subsurface and surface hydrologic system to degrading permafrost is key to understanding the rate, timing, and chemical form of potential carbon releases to the atmosphere. Simulating the hydrologic system in degrading permafrost regions is challenging because of the potential for topographic evolution and associated drainage network reorganization as permafrost thaws and massive ground ice melts. The critical process models required for simulating hydrology include subsurface thermal hydrology of freezing/thawing soils, thermal processes within ice wedges, mechanical deformation processes, overland flow, and surface energy balances including snow dynamics. A new simulation tool, the Arctic Terrestrial Simulator (ATS), is being developed to simulate these coupled processes. The computational infrastructure must accommodate fully unstructured grids that track evolving topography, allow accurate solutions on distorted grids, provide robust and efficient solutions on highly parallel computer architectures, and enable flexibility in the strategies for coupling among the various processes. The ATS is based on Amanzi (Moulton et al. 2012), an object-oriented multi-process simulator written in C++ that provides much of the necessary computational infrastructure. Status and plans for the ATS including major hydrologic process models and validation strategies will be presented. Highly parallel simulations of overland flow using high-resolution digital elevation maps of polygonal patterned ground landscapes demonstrate the feasibility of the approach. Simulations coupling three-phase subsurface thermal hydrology with a simple thaw-induced subsidence model illustrate the strong feedbacks among the processes. D. Moulton, M. Berndt, M. Day, J

  2. Methanogen community composition and rates of methane consumption in Canadian High Arctic permafrost soils.

    Science.gov (United States)

    Allan, J; Ronholm, J; Mykytczuk, N C S; Greer, C W; Onstott, T C; Whyte, L G

    2014-04-01

    Increasing permafrost thaw, driven by climate change, has the potential to result in organic carbon stores being mineralized into carbon dioxide (CO2) and methane (CH4) through microbial activity. This study examines the effect of increasing temperature on community structure and metabolic activity of methanogens from the Canadian High Arctic, in an attempt to predict how warming will affect microbially controlled CH4 soil flux. In situ CO2 and CH4 flux, measured in 2010 and 2011 from ice-wedge polygons, indicate that these soil formations are a net source of CO2 emissions, but a CH4 sink. Permafrost and active layer soil samples were collected at the same sites and incubated under anaerobic conditions at warmer temperatures, with and without substrate amendment. Gas flux was measured regularly and indicated an increase in CH4 flux after extended incubation. Pyrosequencing was used to examine the effects of an extended thaw cycle on methanogen diversity and the results indicate that in situ methanogen diversity, based on the relative abundance of the 16S ribosomal ribonucleic acid (rRNA) gene associated with known methanogens, is higher in the permafrost than in the active layer. Methanogen diversity was also shown to increase in both the active layer and permafrost soil after an extended thaw. This study provides evidence that although High Arctic ice-wedge polygons are currently a sink for CH4, higher arctic temperatures and anaerobic conditions, a possible result of climate change, could result in this soil becoming a source for CH4 gas flux. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  3. Decadal changes of surface elevation over permafrost area estimated using reflected GPS signals

    Science.gov (United States)

    Liu, Lin; Larson, Kristine M.

    2018-02-01

    Conventional benchmark-based survey and Global Positioning System (GPS) have been used to measure surface elevation changes over permafrost areas, usually once or a few times a year. Here we use reflected GPS signals to measure temporal changes of ground surface elevation due to dynamics of the active layer and near-surface permafrost. Applying the GPS interferometric reflectometry technique to the multipath signal-to-noise ratio data collected by a continuously operating GPS receiver mounted deep in permafrost in Barrow, Alaska, we can retrieve the vertical distance between the antenna and reflecting surface. Using this unique kind of observables, we obtain daily changes of surface elevation during July and August from 2004 to 2015. Our results show distinct temporal variations at three timescales: regular thaw settlement within each summer, strong interannual variability that is characterized by a sub-decadal subsidence trend followed by a brief uplift trend, and a secular subsidence trend of 0.26 ± 0.02 cm year-1 during 2004 and 2015. This method provides a new way to fully utilize data from continuously operating GPS sites in cold regions for studying dynamics of the frozen ground consistently and sustainably over a long time.

  4. The LST analog read-out system of the ZEUS muon detector

    International Nuclear Information System (INIS)

    De Giorgi, M.; Abbiendi, G.; Bertolin, A.; Borsato, E.; Brugnera, R.; Carlin, R.; Dal Corso, F.; Dosselli, U.; Gasparini, F.; Limentani, S.; Morandin, M.; Pitacco, G.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Zuin, F.

    1996-01-01

    A muon position detector based on limited streamer tubes has been built for the ZEUS experiment at the HERA e-p collider at Desy. The tubes are arranged in chambers equipped with electronics circuitry providing an analog read-out of induced signals on strips set orthogonal to the tube wires. The electronic module for charge amplification and conversion will be described including some results obtained from the complete system. (orig.)

  5. Assessing hazard risk, cost of adaptation and traditional land use activities in the context of permafrost thaw in communities in Yukon and the Northwest Territories, Canada

    Science.gov (United States)

    Benkert, B.; Perrin, A.; Calmels, F.

    2015-12-01

    Together with its partners, the Northern Climate ExChange (NCE, part of the Yukon Research Centre at Yukon College) has been mapping permafrost-related hazard risk in northern communities since 2010. By integrating geoscience and climate project data, we have developed a series of community-scale hazard risk maps. The maps depict hazard risk in stoplight colours for easy interpretation, and support community-based, future-focused adaptation planning. Communities, First Nations, consultants and local regulatory agencies have used the hazard risk maps to site small-scale infrastructure projects, guide land planning processes, and assess suitability of land development applications. However, we know that assessing risk is only one step in integrating the implications of permafrost degradation in societal responses to environmental change. To build on our permafrost hazard risk maps, we are integrating economic principles and traditional land use elements. To assess economic implications of adaptation to permafrost change, we are working with geotechnical engineers to identify adaptation options (e.g., modified building techniques, permafrost thaw mitigation approaches) that suit the risks captured by our existing hazard risk maps. We layer this with an economic analysis of the costs associated with identified adaptation options, providing end-users with a more comprehensive basis upon which to make decisions related to infrastructure. NCE researchers have also integrated traditional land use activities in assessments of permafrost thaw risk, in a project led by Jean Marie River First Nation in the Northwest Territories. Here, the implications of permafrost degradation on food security and land use priorities were assessed by layering key game and gathering areas on permafrost thaw vulnerability maps. Results indicated that close to one quarter of big and small game habitats, and close to twenty percent of key furbearer and gathering areas within the First Nation

  6. Terrestrial Permafrost Models of Martian Habitats and Inhabitants

    Science.gov (United States)

    Gilichinsky, D.

    2011-12-01

    The terrestrial permafrost is the only rich depository of viable ancient microorganisms on Earth, and can be used as a bridge to possible Martian life forms and shallow subsurface habitats where the probability of finding life is highest. Since there is a place for water, the requisite condition for life, the analogous models are more or less realistic. If life ever existed on Mars, traces might have been preserved and could be found at depth within permafrost. The age of the terrestrial isolates corresponds to the longevity of the frozen state of the embedding strata, with the oldest known dating back to the late Pliocene in Arctic and late Miocene in Antarctica. Permafrost on Earth and Mars vary in age, from a few million years on Earth to a few billion years on Mars. Such a difference in time scale would have a significant impact on the possibility of preserving life on Mars, which is why the longevity of life forms preserved within terrestrial permafrost can only be an approximate model for Mars. 1. A number of studies indicate that the Antarctic cryosphere began to develop on the Eocene-Oligocene boundary, after the isolation of the continent. Permafrost degradation is only possible if mean annual ground temperature, -28°C now, rise above freezing, i.e., a significant warming to above 25°C is required. There is no evidence of such sharp temperature increase, which indicates that the climate and geological history was favorable to persistence of pre-Pliocene permafrost. These oldest relics (~30Myr) are possibly to be found at high hypsometric levels of ice-free areas (Dry Valleys and nearby mountains). It is desirable to test the layers for the presence of viable cells. The limiting age, if one exists, within this ancient permafrost, where the viable organisms were no longer present, could be established as the limit for life preservation below 0oC. Positive results will extend the known temporal limits of life in permafrost. 2. Even in this case, the age of

  7. Exploring Viral Mediated Carbon Cycling in Thawing Permafrost Microbial Communities

    Science.gov (United States)

    Trubl, G. G.; Solonenko, N.; Moreno, M.; Sullivan, M. B.; Rich, V. I.

    2014-12-01

    Viruses are the most abundant biological entities on Earth and their impact on carbon cycling in permafrost habitats is poorly understood. Arctic C cycling is particularly important to interpret due to the rapid climate change occurring and the large amount of C stockpiled there (~1/3 of global soil C is stored in permafrost). Viruses of microbes (i.e. phages) play central roles in C cycling in the oceans, through cellular lysis (phage drive the largest ocean C flux about 150 Gt yr-1, dwarfing all others by >5-fold), production of associated DOC, as well as transport and expression during infection (1029 transduction events day-1). C cycling in thawing permafrost systems is critical in understanding the climate trajectory and phages may be as important for C cycling here as they are in the ocean. The thawed C may become a food source for microbes, producing CO2 and potentially CH4, both potent greenhouse gases. To address the potential role of phage in C cycling in these dynamic systems, we are examining phage from an arctic permafrost thaw gradient in northern Sweden. We have developed a protocol for successfully extracting phage from peat soils and are quantifying phage in 15 peat and 2 lake sediment cores, with the goal of sequencing viromes. Preliminary data suggest that phage are present at 109 g-1 across the permafrost thaw gradient (compared to the typical marine count ~105 ml-1), implying a potentially robust phage-host interaction web in these changing environments. We are examining phage from 11 depth intervals (covering the active and permafrost layer) in the cores to assess phage-host community dynamics. Phage morphology and abundance for each layer and environment are being determined using qTEM and EFM. Understanding the phage that infect bacteria and archaea in these rapidly changing habitats will provide insight into the controls on current and future CH4 and CO2 emissions in permafrost habitats.

  8. Improving Soil Moisture Estimation with a Dual Ensemble Kalman Smoother by Jointly Assimilating AMSR-E Brightness Temperature and MODIS LST

    Directory of Open Access Journals (Sweden)

    Weijing Chen

    2017-03-01

    Full Text Available Uncertainties in model parameters can easily result in systematic differences between model states and observations, which significantly affect the accuracy of soil moisture estimation in data assimilation systems. In this research, a soil moisture assimilation scheme is developed to jointly assimilate AMSR-E (Advanced Microwave Scanning Radiometer-Earth Observing System brightness temperature (TB and MODIS (Moderate Resolution Imaging Spectroradiometer Land Surface Temperature (LST products, which also corrects model bias by simultaneously updating model states and parameters with a dual ensemble Kalman filter (DEnKS. Common Land Model (CoLM and a Radiative Transfer Model (RTM are adopted as model and observation operator, respectively. The assimilation experiment was conducted in Naqu on the Tibet Plateau from 31 May to 27 September 2011. The updated soil temperature at surface obtained by assimilating MODIS LST serving as inputs of RTM is to reduce the differences between the simulated and observed TB, then AMSR-E TB is assimilated to update soil moisture and model parameters. Compared with in situ measurements, the accuracy of soil moisture estimation derived from the assimilation experiment has been tremendously improved at a variety of scales. The updated parameters effectively reduce the states bias of CoLM. The results demonstrate the potential of assimilating AMSR-E TB and MODIS LST to improve the estimation of soil moisture and related parameters. Furthermore, this study indicates that the developed scheme is an effective way to retrieve downscaled soil moisture when assimilating the coarse-scale microwave TB.

  9. River Export of Dissolved and Particulate Organic Carbon from Permafrost and Peat Deposits across the Siberian Arctic

    Science.gov (United States)

    Wild, B.; Andersson, A.; Bröder, L.; Vonk, J.; Hugelius, G.; McClelland, J. W.; Raymond, P. A.; Gustafsson, O.

    2017-12-01

    Permafrost and peat deposits of northern high latitudes store more than 1300 Pg of organic carbon. This carbon has been preserved for thousands of years by cold and moist conditions, but is now increasingly mobilized as temperatures rise. While part will be degraded to CO2 and CH4 and amplify global warming, part will be exported by rivers to the Arctic Ocean where it can be degraded or re-buried by sedimentation. We here use the four large Siberian rivers Ob, Yenisey, Lena, and Kolyma as natural integrators of carbon mobilization in their catchments. We apply isotope based source apportionments and Markov Chain Monte Carlo Simulations to quantify contributions of organic carbon from permafrost and peat deposits to organic carbon exported by these rivers. More specifically, we compare the 14C signatures of dissolved and particulate organic carbon (DOC, POC) sampled close to the river mouths with those of five potential carbon sources; (1) recent aquatic and (2) terrestrial primary production, (3) the active layer of permafrost soils, (4) deep Holocene deposits (including thermokarst and peat deposits) and (5) Ice Complex Deposits. 14C signatures of these endmembers were constrained based on extensive literature review. We estimate that the four rivers together exported 2.4-4.5 Tg organic carbon from permafrost and peat deposits per year. While total organic carbon export was dominated by DOC (90%), the export of organic carbon from permafrost and peat deposits was more equally distributed between DOC (56%) and POC (44%). Recent models predict that ca. 200 Pg carbon will be lost as CO2 or CH4 by 2100 (RCP8.5) from the circumarctic permafrost area, of which roughly a quarter is drained by the Ob, Yenisey, Lena, and Kolyma rivers. Our comparatively low estimates of river carbon export thus suggest limited transfer of organic carbon from permafrost and peat deposits to high latitude rivers, or its rapid degradation within rivers. Our findings highlight the importance

  10. Suggested best practice for geotechnical characterisation of permafrost in the Nordic countries

    DEFF Research Database (Denmark)

    Agergaard, Frederik Ancker; Ingeman-Nielsen, Thomas; Foged, Niels Nielsen

    2012-01-01

    Even though permafrost is a specialty within Nordic geotechnical engineering, engineers and researcher will be faced with managing the consequences of projected climatic influences to construction design in permafrost areas. This requires the determination of the frozen soil engineering propertie...

  11. Permafrost hydrology in changing climatic conditions: seasonal variability of stable isotope composition in rivers in discontinuous permafrost

    International Nuclear Information System (INIS)

    Streletskiy, Dmitry A; Shiklomanov, Nikolay I; Nyland, Kelsey E; Tananaev, Nikita I; Opel, Thomas; Streletskaya, Irina D; Tokarev, Igor’; Shiklomanov, Alexandr I

    2015-01-01

    Role of changing climatic conditions on permafrost degradation and hydrology was investigated in the transition zone between the tundra and forest ecotones at the boundary of continuous and discontinuous permafrost of the lower Yenisei River. Three watersheds of various sizes were chosen to represent the characteristics of the regional landscape conditions. Samples of river flow, precipitation, snow cover, and permafrost ground ice were collected over the watersheds to determine isotopic composition of potential sources of water in a river flow over a two year period. Increases in air temperature over the last forty years have resulted in permafrost degradation and a decrease in the seasonal frost which is evident from soil temperature measurements, permafrost and active-layer monitoring, and analysis of satellite imagery. The lowering of the permafrost table has led to an increased storage capacity of permafrost affected soils and a higher contribution of ground water to river discharge during winter months. A progressive decrease in the thickness of the layer of seasonal freezing allows more water storage and pathways for water during the winter low period making winter discharge dependent on the timing and amount of late summer precipitation. There is a substantial seasonal variability of stable isotopic composition of river flow. Spring flooding corresponds to the isotopic composition of snow cover prior to the snowmelt. Isotopic composition of river flow during the summer period follows the variability of precipitation in smaller creeks, while the water flow of larger watersheds is influenced by the secondary evaporation of water temporarily stored in thermokarst lakes and bogs. Late summer precipitation determines the isotopic composition of texture ice within the active layer in tundra landscapes and the seasonal freezing layer in forested landscapes as well as the composition of the water flow during winter months. (letter)

  12. Collaboration in Education: International Field Class on Permafrost

    Science.gov (United States)

    Streletskiy, D. A.; Shiklomanov, N. I.; Grebenets, V. I.

    2011-12-01

    Field work is a dominant research component in the earth sciences. Understanding and proper use of field methods can enhance the quality of research, while lack of understanding in acquiring data can lead to misleading interpretation of results. Early involvement in field work helps students to bridge the gap between theoretical knowledge and practical applications and to be better prepared for future jobs. However, many University curriculums lack adequate, required field methods courses. Presented are results of collaboration between the George Washington and Moscow State Universities in organization of field courses on Arctic physical and social environments. The latest field course took place in summer 2011 in the Central Siberian region and is a part of the International Permafrost Association education and outreach effort initiated during International Polar Year. The 25 day course involved fifteen Russian and US students who traveled from Moscow to Krasnoyarsk, and then along Yenisey river to Norilsk. This route was chosen as having diversity of natural conditions and variety of economic, engineering, and demographic problems associated with development. The main goal of the class was to investigate permafrost conditions of Central Siberia; dynamics of upper permafrost due to changing climate and under anthropogenic influence; and to understand factors responsible for the diversity of permafrost conditions in the region. The students and instructors were required to make presentations on a variety of topics focusing on the region or research methods, such as climate, vegetation, hydrology, history of development, economics, remote sensing, etc. The emphasis in the field was made on understanding permafrost in relation to other components of the natural system. For example, landscape conditions (including microclimatic, biogeographic and pedologic conditions) were described at every site located in natural settings. Sites located in settlements were evaluated

  13. In situ nuclear magnetic response of permafrost and active layer soil in boreal and tundra ecosystems

    DEFF Research Database (Denmark)

    Kass, Mason Andrew; Irons, Trevor; Minsley, Burke J.

    2017-01-01

    Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience...... of the nuclear magnetic resonance (NMR) response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show...

  14. What's down below? Current and potential future applications of geophysical techniques to identify subsurface permafrost conditions (Invited)

    Science.gov (United States)

    Douglas, T. A.; Bjella, K.; Campbell, S. W.

    2013-12-01

    can be used to delineate subsurface permafrost geomorphology. This presentation will include examples of projects in Alaska and Greenland where a combination of geophysical and other measurement techniques have been used to identify subsurface conditions. These include projects at multiple locations around Interior Alaska where a variety of ground based and standoff measurements are being used to identify subsurface conditions, and infrastructure projects at Thule, Greenland, where geophysical measurements are being used to cut costs for new construction and maintenance. The expansion of the Cold Regions Research and Engineering Laboratories' Fox Permafrost Tunnel is to provide a three dimensional test bed for geophysical measurements, and construction is aided by geophysical measurements. The array of geophysical research tools used to interrogate the subsurface in permafrost terrains can likely provide worthwhile information in non-frozen ground terrains to support sensor development and geomorphological interpretation.

  15. Using Modeling Tools to Better Understand Permafrost Hydrology

    Directory of Open Access Journals (Sweden)

    Clément Fabre

    2017-06-01

    Full Text Available Modification of the hydrological cycle and, subsequently, of other global cycles is expected in Arctic watersheds owing to global change. Future climate scenarios imply widespread permafrost degradation caused by an increase in air temperature, and the expected effect on permafrost hydrology is immense. This study aims at analyzing, and quantifying the daily water transfer in the largest Arctic river system, the Yenisei River in central Siberia, Russia, partially underlain by permafrost. The semi-distributed SWAT (Soil and Water Assessment Tool hydrological model has been calibrated and validated at a daily time step in historical discharge simulations for the 2003–2014 period. The model parameters have been adjusted to embrace the hydrological features of permafrost. SWAT is shown capable to estimate water fluxes at a daily time step, especially during unfrozen periods, once are considered specific climatic and soils conditions adapted to a permafrost watershed. The model simulates average annual contribution to runoff of 263 millimeters per year (mm yr−1 distributed as 152 mm yr−1 (58% of surface runoff, 103 mm yr−1 (39% of lateral flow and 8 mm yr−1 (3% of return flow from the aquifer. These results are integrated on a reduced basin area downstream from large dams and are closer to observations than previous modeling exercises.

  16. CRYOLINK: Monitoring of permafrost and seasonal frost in southern Norway

    Science.gov (United States)

    Farbrot, Herman; Hipp, Tobias; Etzelmüller, Bernd; Humlum, Ole; Isaksen, Ketil; Strand Ødegârd, Rune

    2010-05-01

    The modern southern boundary for Scandinavian permafrost is located in the mountains of Southern Norway. Permafrost and seasonal frost are considered key components of the cryosphere, and the climate-permafrost relation has acquired added importance with the increasing awareness and concern of rising air temperatures. The three-year research project CRYOLINK ("Permafrost and seasonal frost in southern Norway") aims at improving knowledge on past and present ground temperatures, seasonal frost, and distribution of mountain permafrost in Southern Norway by addressing the fundamental problem of heat transfer between the atmosphere and the ground surface. Hence, several shallow boreholes have been drilled in August 2008 in three areas (Juvvass, Jetta and Tron) situated along a west-east transect. On most borehole sites air and ground temperatures are measured. Further, vertical arrays of Miniature Temperature Dataloggers (MTDs; Thermochron iBottons®) at fixed heights above the ground surface have been installed to roughly determine the snow depths at the sites, which is also indicated by digital cameras providing daily pictures of snow and weather conditions. In addition individual MTDs have been placed out to measure ground surface temperature at different aspects and snow settings. This presentation will focus on the field set up and give examples of data obtained from the sites.

  17. Trace elements transport in western Siberia rivers across a permafrost gradient

    Science.gov (United States)

    Pokrovsky, O. S.; Manasypov, R. M.; Loiko, S.; Krickov, I. A.; Kopysov, S. G.; Kolesnichenko, L. G.; Vorobyev, S. N.; Kirpotin, S. N.

    2015-11-01

    decreased significantly northward during all seasons. Overall, the rank of environmental factors on TE concentration in western Siberian rivers was latitude (3 permafrost zones) > season > watershed size. The effect of the latitude was minimal in spring for most TE but highly visible for Sr, Mo, Sb and U. The main factors controlling the shift of river feeding from surface and subsurface flow to deep underground flow in the permafrost-bearing zone were the depth of the active (unfrozen) seasonal layer and its position in organic or mineral horizons of the soil profile. In the permafrost-free zone, the relative role of carbonate mineral-bearing base rock feeding vs. bog water feeding determined the pattern of trace element concentration and fluxes in rivers of various size as a function of season. Comparison of obtained TE fluxes in WSL rivers with those of other subarctic rivers demonstrated reasonable agreement for most trace elements; the lithology of base rocks was the major factor controlling the magnitude of TE fluxes. The climate change in western Siberia and permafrost boundary migration will affect essentially the elements controlled by underground water feeding (DIC, alkaline-earth elements (Ca, Sr), oxyanions (Mo, Sb, As) and U). The thickening of the active layer may increase the export of trivalent and tetravalent hydrolysates in the form of organo-ferric colloids. Plant litter-originated divalent metals present as organic complexes may be retained via adsorption on mineral horizon. However, due to various counterbalanced processes controlling element source and sinks in plants - peat - mineral soil - river systems, the overall impact of the permafrost thaw on TE export from the land to the ocean may be smaller than that foreseen by merely active layer thickening and permafrost boundary shift.

  18. Trace element transport in western Siberian rivers across a permafrost gradient

    Science.gov (United States)

    Pokrovsky, Oleg S.; Manasypov, Rinat M.; Loiko, Sergey V.; Krickov, Ivan A.; Kopysov, Sergey G.; Kolesnichenko, Larisa G.; Vorobyev, Sergey N.; Kirpotin, Sergey N.

    2016-03-01

    . The effect of the latitude was minimal in spring for most TEs but highly visible for Sr, Mo, Sb and U. The main factors controlling the shift of river feeding from surface and subsurface flow to deep underground flow in the permafrost-bearing zone were the depth of the active (unfrozen) seasonal layer and its position in organic or mineral horizons of the soil profile. In the permafrost-free zone, the relative role of carbonate mineral-bearing base rock feeding versus bog water feeding determined the pattern of TE concentration and fluxes in rivers of various sizes as a function of season. Comparison of obtained TE fluxes in WSL rivers with those of other subarctic rivers demonstrated reasonable agreement for most TEs; the lithology of base rocks was the major factor controlling the magnitude of TE fluxes. Climate change in western Siberia and permafrost boundary migration will essentially affect the elements controlled by underground water feeding (DIC, alkaline earth elements (Ca, Sr), oxyanions (Mo, Sb, As) and U). The thickening of the active layer may increase the export of trivalent and tetravalent hydrolysates in the form of organo-ferric colloids. Plant litter-originated divalent metals present as organic complexes may be retained via adsorption on mineral horizon. However, due to various counterbalanced processes controlling element source and sinks in plant-peat-mineral soil-river systems, the overall impact of the permafrost thaw on TE export from the land to the ocean may be smaller than that foreseen with merely active layer thickening and permafrost boundary shift.

  19. Permafrost and infrastructure in the Usa Basin (Northeast European Russia) : Possible impacts of global warming

    NARCIS (Netherlands)

    Mazhitova, G.; Karstkarel, N.; Oberman, N.; Romanovsky, V.; Kuhry, P.

    The relationship between permafrost conditions and the distribution of infrastructure in the Usa Basin, Northeast European Russia, is analyzed. About 75% of the Basin is underlain by permafrost terrain with various degrees of continuity (isolated patches to continuous permafrost). The region has a

  20. Brief Communication : Future avenues for permafrost science from the perspective of early career researchers

    NARCIS (Netherlands)

    Fritz, M.; Deshpande, B. N.; Bouchard, F.; Högström, E.; Malenfant-Lepage, J.; Morgenstern, A.; Nieuwendam, A.; Oliva, M.; Paquette, M.; Rudy, A. C A; Siewert, M. B.; Sjöberg, Y.; Weege, S.

    2015-01-01

    Accelerating climate change and increased economic and environmental interests in permafrost-affected regions have resulted in an acute need for more directed permafrost research. In June 2014, 88 early career researchers convened to identify future priorities for permafrost research. This

  1. Fossil organic matter characteristics in permafrost deposits of the northeast Siberian Arctic

    Science.gov (United States)

    Lutz Schirrmeister; Guido Grosse; Sebastian Wetterich; Pier Paul Overduin; Jens Straub; Edward A.G. Schuur; Hans-Wolfgang. Hubberton

    2011-01-01

    Permafrost deposits constitute a large organic carbon pool highly vulnerable to degradation and potential carbon release due to global warming. Permafrost sections along coastal and river bank exposures in NE Siberia were studied for organic matter (OM) characteristics and ice content. OM stored in Quaternary permafrost grew, accumulated, froze, partly decomposed, and...

  2. Soil CO2 production in upland tundra where permafrost is thawing

    Science.gov (United States)

    Hanna Lee; Edward A.G. Schuur; Jason G. Vogel

    2010-01-01

    Permafrost soils store nearly half of global soil carbon (C), and therefore permafrost thawing could lead to large amounts of greenhouse gas emissions via decomposition of soil organic matter. When ice-rich permafrost thaws, it creates a localized surface subsidence called thermokarst terrain, which changes the soil microenvironment. We used soil profile CO2...

  3. Dependence of the evolution of carbon dynamics in the northern permafrost region on the trajectory of climate change.

    Science.gov (United States)

    McGuire, A David; Lawrence, David M; Koven, Charles; Clein, Joy S; Burke, Eleanor; Chen, Guangsheng; Jafarov, Elchin; MacDougall, Andrew H; Marchenko, Sergey; Nicolsky, Dmitry; Peng, Shushi; Rinke, Annette; Ciais, Philippe; Gouttevin, Isabelle; Hayes, Daniel J; Ji, Duoying; Krinner, Gerhard; Moore, John C; Romanovsky, Vladimir; Schädel, Christina; Schaefer, Kevin; Schuur, Edward A G; Zhuang, Qianlai

    2018-04-10

    We conducted a model-based assessment of changes in permafrost area and carbon storage for simulations driven by RCP4.5 and RCP8.5 projections between 2010 and 2299 for the northern permafrost region. All models simulating carbon represented soil with depth, a critical structural feature needed to represent the permafrost carbon-climate feedback, but that is not a universal feature of all climate models. Between 2010 and 2299, simulations indicated losses of permafrost between 3 and 5 million km 2 for the RCP4.5 climate and between 6 and 16 million km 2 for the RCP8.5 climate. For the RCP4.5 projection, cumulative change in soil carbon varied between 66-Pg C (10 15 -g carbon) loss to 70-Pg C gain. For the RCP8.5 projection, losses in soil carbon varied between 74 and 652 Pg C (mean loss, 341 Pg C). For the RCP4.5 projection, gains in vegetation carbon were largely responsible for the overall projected net gains in ecosystem carbon by 2299 (8- to 244-Pg C gains). In contrast, for the RCP8.5 projection, gains in vegetation carbon were not great enough to compensate for the losses of carbon projected by four of the five models; changes in ecosystem carbon ranged from a 641-Pg C loss to a 167-Pg C gain (mean, 208-Pg C loss). The models indicate that substantial net losses of ecosystem carbon would not occur until after 2100. This assessment suggests that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon-climate feedback. Copyright © 2018 the Author(s). Published by PNAS.

  4. Dependence of the evolution of carbon dynamics in the northern permafrost region on the trajectory of climate change

    Science.gov (United States)

    McGuire, A. David; Lawrence, David M.; Koven, Charles; Clein, Joy S.; Burke, Eleanor J.; Chen, Guangsheng; Jafarov, Elchin; MacDougall, Andrew H.; Marchenko, Sergey S.; Nicolsky, Dmitry J.; Peng, Shushi; Rinke, Annette; Ciais, Philippe; Gouttevin, Isabelle; Hayes, Daniel J.; Ji, Duoying; Krinner, Gerhard; Moore, John C.; Romanovsky, Vladimir; Schadel, Christina; Schaefer, Kevin; Schuur, Edward A.G.; Zhuang, Qianlai

    2018-01-01

    We conducted a model-based assessment of changes in permafrost area and carbon storage for simulations driven by RCP4.5 and RCP8.5 projections between 2010 and 2299 for the northern permafrost region. All models simulating carbon represented soil with depth, a critical structural feature needed to represent the permafrost carbon–climate feedback, but that is not a universal feature of all climate models. Between 2010 and 2299, simulations indicated losses of permafrost between 3 and 5 million km2 for the RCP4.5 climate and between 6 and 16 million km2 for the RCP8.5 climate. For the RCP4.5 projection, cumulative change in soil carbon varied between 66-Pg C (1015-g carbon) loss to 70-Pg C gain. For the RCP8.5 projection, losses in soil carbon varied between 74 and 652 Pg C (mean loss, 341 Pg C). For the RCP4.5 projection, gains in vegetation carbon were largely responsible for the overall projected net gains in ecosystem carbon by 2299 (8- to 244-Pg C gains). In contrast, for the RCP8.5 projection, gains in vegetation carbon were not great enough to compensate for the losses of carbon projected by four of the five models; changes in ecosystem carbon ranged from a 641-Pg C loss to a 167-Pg C gain (mean, 208-Pg C loss). The models indicate that substantial net losses of ecosystem carbon would not occur until after 2100. This assessment suggests that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon–climate feedback.

  5. Using dissolved organic matter age and composition to detect permafrost thaw in boreal watersheds of interior Alaska

    Science.gov (United States)

    O'Donnell, Jonathan A.; Aiken, George R.; Walvoord, Michelle A.; Raymond, Peter A.; Butler, Kenna D.; Dornblaser, Mark M.; Heckman, Katherine

    2014-11-01

    Recent warming at high latitudes has accelerated permafrost thaw, which can modify soil carbon dynamics and watershed hydrology. The flux and composition of dissolved organic matter (DOM) from soils to rivers are sensitive to permafrost configuration and its impact on subsurface hydrology and groundwater discharge. Here, we evaluate the utility of DOM composition and age as a tool for detecting permafrost thaw in three rivers (Beaver, Birch, and Hess Creeks) within the discontinuous permafrost zone of interior Alaska. We observed strong temporal controls on Δ14C content of hydrophobic acid isolates (Δ14C-HPOA) across all rivers, with the most enriched values occurring during spring snowmelt (75 ± 8‰) and most depleted during winter flow (-21 ± 8‰). Radiocarbon ages of winter flow samples ranged from 35 to 445 yr BP, closely tracking estimated median base flow travel times for this region (335 years). During spring snowmelt, young DOM was composed of highly aromatic, high molecular-weight compounds, whereas older DOM of winter flow had lower aromaticity and molecular weight. We observed a significant correlation between Δ14C-HPOA and UV absorbance coefficient at 254 nm (α254) across all study rivers. Using α254 as an optical indicator for Δ14C-HPOA, we also observed a long-term decline in α254 during maximum annual thaw depth over the last decade at the Hess Creek study site. These findings suggest a shift in watershed hydrology associated with increasing active layer thickness. Further development of DOM optical indicators may serve as a novel and inexpensive tool for detecting permafrost degradation in northern watersheds.

  6. Evidence From Hydrogen Isotopes in Meteorites for a Martian Permafrost

    Science.gov (United States)

    Usui, T.; Alexander, C. M. O'D.; Wang, J.; Simon, J. I.; Jones, J. H.

    2014-01-01

    Fluvial landforms on Mars suggest that it was once warm enough to maintain persistent liquid water on its surface. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. We have investigated the evolution of surface water/ ice and its interaction with the atmosphere by measurements of hydrogen isotope ratios (D/H: deuterium/ hydrogen) of martian meteorites. Hydrogen is a major component of water (H2O) and its isotopes fractionate significantly during hydrological cycling between the atmosphere, surface waters, ground ice, and polar cap ice. Based on in situ ion microprobe analyses of three geochemically different shergottites, we reported that there is a water/ice reservoir with an intermediate D/H ratio (delta D = 1,000?2500 %) on Mars. Here we present the possibility that this water/ice reservoir represents a ground-ice/permafrost that has existed relatively intact over geologic time.

  7. Variability in the sensitivity among model simulations of permafrost and carbon dynamics in the permafrost region between 1960 and 2009

    Science.gov (United States)

    McGuire, A. David; Koven, Charles; Lawrence, David M.; Clein, Joy S.; Xia, Jiangyang; Beer, Christian; Burke, Eleanor J.; Chen, Guangsheng; Chen, Xiaodong; Delire, Christine; Jafarov, Elchin; MacDougall, Andrew H.; Marchenko, Sergey S.; Nicolsky, Dmitry J.; Peng, Shushi; Rinke, Annette; Saito, Kazuyuki; Zhang, Wenxin; Alkama, Ramdane; Bohn, Theodore J.; Ciais, Philippe; Decharme, Bertrand; Ekici, Altug; Gouttevin, Isabelle; Hajima, Tomohiro; Hayes, Daniel J.; Ji, Duoying; Krinner, Gerhard; Lettenmaier, Dennis P.; Luo, Yiqi; Miller, Paul A.; Moore, John C.; Romanovsky, Vladimir; Schädel, Christina; Schaefer, Kevin; Schuur, Edward A.G.; Smith, Benjamin; Sueyoshi, Tetsuo; Zhuang, Qianlai

    2016-01-01

    A significant portion of the large amount of carbon (C) currently stored in soils of the permafrost region in the Northern Hemisphere has the potential to be emitted as the greenhouse gases CO2and CH4 under a warmer climate. In this study we evaluated the variability in the sensitivity of permafrost and C in recent decades among land surface model simulations over the permafrost region between 1960 and 2009. The 15 model simulations all predict a loss of near-surface permafrost (within 3 m) area over the region, but there are large differences in the magnitude of the simulated rates of loss among the models (0.2 to 58.8 × 103 km2 yr−1). Sensitivity simulations indicated that changes in air temperature largely explained changes in permafrost area, although interactions among changes in other environmental variables also played a role. All of the models indicate that both vegetation and soil C storage together have increased by 156 to 954 Tg C yr−1between 1960 and 2009 over the permafrost region even though model analyses indicate that warming alone would decrease soil C storage. Increases in gross primary production (GPP) largely explain the simulated increases in vegetation and soil C. The sensitivity of GPP to increases in atmospheric CO2 was the dominant cause of increases in GPP across the models, but comparison of simulated GPP trends across the 1982–2009 period with that of a global GPP data set indicates that all of the models overestimate the trend in GPP. Disturbance also appears to be an important factor affecting C storage, as models that consider disturbance had lower increases in C storage than models that did not consider disturbance. To improve the modeling of C in the permafrost region, there is the need for the modeling community to standardize structural representation of permafrost and carbon dynamics among models that are used to evaluate the permafrost C feedback and for the modeling and observational communities to

  8. GAPHAZ: improving knowledge management of glacier and permafrost hazards and risks in mountains

    Science.gov (United States)

    Huggel, Christian; Burn, Chris; Clague, John J.; Hewitt, Ken; Kääb, Andreas; Krautblatter, Michael; Kargel, Jeffrey S.; Reynolds, John; Sokratov, Sergey

    2014-05-01

    -researched and monitored regions to the more extensive and diverse regions needs to be addressed.. Standards are required to ensure an adequate level of quality and to avoid incorrect assessments with potentially adverse consequences, as experiences in the past have shown. Concepts and terminologies related to hazard and risk assessments must follow recently issued consensus statements, such as those of UN-ISDR and IPCC. Hazard assessments must be undertaken routinely and regularly, combined with appropriate ground-based and remote sensing monitoring. Assessments need to adequately consider the physical processes and their interactions. Integrative risk assessments should be achieved by interdisciplinary cooperation. There is still a lack of integration of physical/engineering and social aspects of glacier and permafrost hazards; therefore communication and exchange between natural and social science experts must be strengthened. In the design and implementation of risk reduction and adaptation measures, a close collaboration among scientists, policy makers, and local populations is necessary. Recognizing different perceptions of risks among actors are particularly important if risk reduction efforts are to be successful. Measures should generally be adapted to the local social, cultural, economic, political, and institutional context. Early warning systems are becoming increasingly important, and a growing number of experiences are available also for high-mountain environments. A systematic analysis and exchange of experiences using dedicated expert networks will be fostered by GAPHAZ in collaboration with other initiatives and actors.

  9. Petroleum contamination movement into permafrost in the high Arctic

    International Nuclear Information System (INIS)

    Biggar, K.W.

    1997-01-01

    The extent of petroleum hydrocarbon contamination that has penetrated the active layer into the permafrost at sites where spills have occurred in Canada's Arctic was discussed. There was evidence to suggest that hydrocarbon contamination may enter the permafrost layer through gravity drainage and cap suction through fissures in the frozen soil, and perhaps by diffusion through the unfrozen water of fine-grained soils. Core samples were taken in frozen silty clay to be sectioned and analyzed for total petroleum hydrocarbons, using ultrasonic solvent extraction and gas chromatography and mass spectrometry analysis. It was concluded that it is possible for petroleum contamination in permafrost to migrate by gravity drainage down soil fissures and then diffuse into surrounding soil. 2 figs

  10. The Ecological Situation in the Russian Arctic Permafrost Zone

    Directory of Open Access Journals (Sweden)

    Petrov Sergei

    2016-01-01

    Full Text Available The paper describes innovative approaches to ensure environmental safety in the production of hydrocarbon material in a permafrost zone. Studies the anthropogenic environmental factors, climatic and geographical and geological conditions of Purovskiy district of Yamalo-Nenets Autonomous Area (YaNAO. We consider the chemical characteristics of wastewater discharged into surface water objects, polluting emissions into the atmosphere. The conclusions of the environmental situation in Purovskiy and Ustpurovsk-Tazovskiy permafrost areas. Calculate the concentration of pollutants in the control section of the water object and the maximum ground-level concentrations of pollutants in the atmospheric air. The conclusions about the exceeding the maximum permissible concentration (MPC in the atmospheric air for solids, carbon monoxide, nitrogen dioxide. Was examined the climatic conditions of the Far North. Correlational analysis was performed between human factors and temperature conditions of the northern territories, as well as between the climate and natural features cryological and disturbed permafrost soils.

  11. Improving Permafrost Hydrology Prediction Through Data-Model Integration

    Science.gov (United States)

    Wilson, C. J.; Andresen, C. G.; Atchley, A. L.; Bolton, W. R.; Busey, R.; Coon, E.; Charsley-Groffman, L.

    2017-12-01

    The CMIP5 Earth System Models were unable to adequately predict the fate of the 16GT of permafrost carbon in a warming climate due to poor representation of Arctic ecosystem processes. The DOE Office of Science Next Generation Ecosystem Experiment, NGEE-Arctic project aims to reduce uncertainty in the Arctic carbon cycle and its impact on the Earth's climate system by improved representation of the coupled physical, chemical and biological processes that drive how much buried carbon will be converted to CO2 and CH4, how fast this will happen, which form will dominate, and the degree to which increased plant productivity will offset increased soil carbon emissions. These processes fundamentally depend on permafrost thaw rate and its influence on surface and subsurface hydrology through thermal erosion, land subsidence and changes to groundwater flow pathways as soil, bedrock and alluvial pore ice and massive ground ice melts. LANL and its NGEE colleagues are co-developing data and models to better understand controls on permafrost degradation and improve prediction of the evolution of permafrost and its impact on Arctic hydrology. The LANL Advanced Terrestrial Simulator was built using a state of the art HPC software framework to enable the first fully coupled 3-dimensional surface-subsurface thermal-hydrology and land surface deformation simulations to simulate the evolution of the physical Arctic environment. Here we show how field data including hydrology, snow, vegetation, geochemistry and soil properties, are informing the development and application of the ATS to improve understanding of controls on permafrost stability and permafrost hydrology. The ATS is being used to inform parameterizations of complex coupled physical, ecological and biogeochemical processes for implementation in the DOE ACME land model, to better predict the role of changing Arctic hydrology on the global climate system. LA-UR-17-26566.

  12. Methane Ebullition During Simulated Lake Expansion and Permafrost Degradation

    Science.gov (United States)

    Mazéas, O.; von Fischer, J. C.; Whelan, M.; Rhew, R.

    2007-12-01

    Methane, a potent greenhouse gas, is emitted by Arctic tundra and lakes. Ebullition, or bubbling, of methane from Arctic lakes has been shown to be a major transport mechanism from the sediment to the atmosphere, and ebullition rates are greatest near the edges of the lakes where active erosion is occurring. In regions of continuous permafrost, Arctic lakes have been expanding in recent decades, attributed to permafrost melting and development of thermokarst. Lake expansion occurs when the margins erode into water, supplying large amounts of organic rich material to the sediment-water interface. This allows carbon that was previously stored in the soil (active layer and permafrost) to become bioavailable and subject to decomposition. An increase in Arctic methane emissions as a result of permafrost thawing and lake expansion would constitute a positive feedback to Arctic warming. In order to better understand these processes, an experiment was initiated in July 2007 at the Barrow Environmental Observatory, Barrow, AK. Different layers of locally collected tundra soil were placed into incubation chambers at the bottom of a shallow (about 1 m deep) lake. Each experimental chamber consists of a bucket fixed underneath an inverted funnel, with a sampling port on top to capture and collect the emitted gases. Gas samples are analyzed for methane and carbon dioxide concentrations, as well as relevant isotopic compositions. Gas sampling has occurred at frequent intervals during the late summer and will continue through the early winter. Three replicates of each layer (active layer, seasonally frozen active layer and permafrost) were incubated, as well as an empty control chamber. An additional chamber containing thawed permafrost and cellulose-rich sawdust was placed for comparison, as cellulose is a major component of plant tissue and the fermentation of the cellulose should yield substrates for methanogenesis. Total production of methane versus organic carbon content of

  13. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. Williams; Keith Millheim; Bill Liddell

    2005-03-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Oil-field engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in Arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrates agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is a cost-shared partnership between Maurer Technology, Anadarko Petroleum, Noble Corporation, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to help identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. As part of the project work scope, team members drilled and cored the HOT ICE No. 1 on Anadarko leases beginning in January 2003 and completed in March 2004. Due to scheduling constraints imposed by the Arctic drilling season, operations at the site were suspended between April 21, 2003 and January 30, 2004. An on-site core analysis laboratory was designed, constructed and used for determining physical characteristics of frozen core immediately after it was retrieved from the well. The well was drilled from a new and innovative Anadarko Arctic Platform that has a greatly reduced footprint and environmental impact. Final efforts of the project were to correlate geology, geophysics, logs, and drilling and production data and provide this information to scientists for future hydrate operations. Unfortunately, no gas hydrates were encountered in this well; however, a wealth of information was generated

  14. Impact of physical permafrost processes on hydrological change

    Science.gov (United States)

    Hagemann, Stefan; Blome, Tanja; Beer, Christian; Ekici, Altug

    2015-04-01

    Permafrost or perennially frozen ground is an important part of the terrestrial cryosphere; roughly one quarter of Earth's land surface is underlain by permafrost. As it is a thermal phenomenon, its characteristics are highly dependent on climatic factors. The impact of the currently observed warming, which is projected to persist during the coming decades due to anthropogenic CO2 input, certainly has effects for the vast permafrost areas of the high northern latitudes. The quantification of these effects, however, is scientifically still an open question. This is partly due to the complexity of the system, where several feedbacks are interacting between land and atmosphere, sometimes counterbalancing each other. Moreover, until recently, many global circulation models (GCMs) and Earth system models (ESMs) lacked the sufficient representation of permafrost physics in their land surface schemes. Within the European Union FP7 project PAGE21, the land surface scheme JSBACH of the Max-Planck-Institute for Meteorology ESM (MPI-ESM) has been equipped with the representation of relevant physical processes for permafrost studies. These processes include the effects of freezing and thawing of soil water for both energy and water cycles, thermal properties depending on soil water and ice contents, and soil moisture movement being influenced by the presence of soil ice. In the present study, it will be analysed how these permafrost relevant processes impact projected hydrological changes over northern hemisphere high latitude land areas. For this analysis, the atmosphere-land part of MPI-ESM, ECHAM6-JSBACH, is driven by prescribed SST and sea ice in an AMIP2-type setup with and without the newly implemented permafrost processes. Observed SST and sea ice for 1979-1999 are used to consider induced changes in the simulated hydrological cycle. In addition, simulated SST and sea ice are taken from a MPI-ESM simulation conducted for CMIP5 following the RCP8.5 scenario. The

  15. Review and synthesis: Changing permafrost in a warming world and feedbacks to the Earth System

    Science.gov (United States)

    Grosse, Guido; Goetz, Scott; McGuire, A. David; Romanovsky, Vladimir E.; Schuur, Edward A.G.

    2016-01-01

    The permafrost component of the cryosphere is changing dramatically, but the permafrost region is not well monitored and the consequences of change are not well understood. Changing permafrost interacts with ecosystems and climate on various spatial and temporal scales. The feedbacks resulting from these interactions range from local impacts on topography, hydrology, and biology to complex influences on global scale biogeochemical cycling. This review contributes to this focus issue by synthesizing its 28 multidisciplinary studies which provide field evidence, remote sensing observations, and modeling results on various scales. We synthesize study results from a diverse range of permafrost landscapes and ecosystems by reporting key observations and modeling outcomes for permafrost thaw dynamics, identifying feedbacks between permafrost and ecosystem processes, and highlighting biogeochemical feedbacks from permafrost thaw. We complete our synthesis by discussing the progress made, stressing remaining challenges and knowledge gaps, and providing an outlook on future needs and research opportunities in the study of permafrost–ecosystem–climate interactions.

  16. Year-round simulated methane emissions from a permafrost ecosystem in Northeast Siberia

    Science.gov (United States)

    Castro-Morales, Karel; Kleinen, Thomas; Kaiser, Sonja; Zaehle, Sönke; Kittler, Fanny; Kwon, Min Jung; Beer, Christian; Göckede, Mathias

    2018-05-01

    Wetlands of northern high latitudes are ecosystems highly vulnerable to climate change. Some degradation effects include soil hydrologic changes due to permafrost thaw, formation of deeper active layers, and rising topsoil temperatures that accelerate the degradation of permafrost carbon and increase in CO2 and CH4 emissions. In this work we present 2 years of modeled year-round CH4 emissions into the atmosphere from a Northeast Siberian region in the Russian Far East. We use a revisited version of the process-based JSBACH-methane model that includes four CH4 transport pathways: plant-mediated transport, ebullition and molecular diffusion in the presence or absence of snow. The gas is emitted through wetlands represented by grid cell inundated areas simulated with a TOPMODEL approach. The magnitude of the summertime modeled CH4 emissions is comparable to ground-based CH4 fluxes measured with the eddy covariance technique and flux chambers in the same area of study, whereas wintertime modeled values are underestimated by 1 order of magnitude. In an annual balance, the most important mechanism for transport of methane into the atmosphere is through plants (61 %). This is followed by ebullition ( ˜ 35 %), while summertime molecular diffusion is negligible (0.02 %) compared to the diffusion through the snow during winter ( ˜ 4 %). We investigate the relationship between temporal changes in the CH4 fluxes, soil temperature, and soil moisture content. Our results highlight the heterogeneity in CH4 emissions at landscape scale and suggest that further improvements to the representation of large-scale hydrological conditions in the model will facilitate a more process-oriented land surface scheme and better simulate CH4 emissions under climate change. This is especially necessary at regional scales in Arctic ecosystems influenced by permafrost thaw.

  17. Impact of downslope soil transport on carbon storage and fate in permafrost dominated landscapes

    Science.gov (United States)

    Shelef, E.; Rowland, J. C.; Wilson, C. J.; Altmann, G.; Hilley, G. E.

    2014-12-01

    A large fraction of high latitude permafrost-dominated landscapes are covered by soil mantled hillslopes. In these landscapes, soil organic carbon (SOC) accumulates and is lost through lateral transport processes. At present, these processes are not included in regional or global landsurface climate models. We present preliminary results of a soil transport and storage model over a permafrost dominated hillslope. In this model soil carbon is transported downslope within a mobile layer that thaws every summer. The model tracks soil transport and its subsequent storage at the hillslope's base. In a scenario where a carbon poor subsurface is blanketed by a carbon-rich surface layer, the progressive downslope soil transport can result in net carbon sequestration. This sequestration occurs because SOC is carried from the hilllsope's near-surface layer, where it is produced by plants and is capable of decomposing, into depositional sites at the hillslope's base where it is stored in frozen deposits such that it's decomposition rate is effectively zero. We use the model to evaluate the quantities of carbon stored in depositional settings during the Holocene, and to predict changes in sequestration rate in response to thaw depth thickening expected to occur within the next century due to climate-change. At the Holocene time scale, we show that a large amount of SOC is likely stored in depositional sites that comprise only a small fraction of arctic landscapes. The convergent topography of these sites makes them susceptible to fluvial erosion and suggests that increased fluvial incision in response to climate-change-induced thawing has the potential to release significant amounts of carbon to the river system, and potentially to the atmosphere. At the time scale of the next century, increased thaw depth may increase soil-transport rates on hillslopes and therefore increase SOC sequestration rates at a magnitude that may partly compensate for the carbon release expected from

  18. Year-round simulated methane emissions from a permafrost ecosystem in Northeast Siberia

    Directory of Open Access Journals (Sweden)

    K. Castro-Morales

    2018-05-01

    Full Text Available Wetlands of northern high latitudes are ecosystems highly vulnerable to climate change. Some degradation effects include soil hydrologic changes due to permafrost thaw, formation of deeper active layers, and rising topsoil temperatures that accelerate the degradation of permafrost carbon and increase in CO2 and CH4 emissions. In this work we present 2 years of modeled year-round CH4 emissions into the atmosphere from a Northeast Siberian region in the Russian Far East. We use a revisited version of the process-based JSBACH-methane model that includes four CH4 transport pathways: plant-mediated transport, ebullition and molecular diffusion in the presence or absence of snow. The gas is emitted through wetlands represented by grid cell inundated areas simulated with a TOPMODEL approach. The magnitude of the summertime modeled CH4 emissions is comparable to ground-based CH4 fluxes measured with the eddy covariance technique and flux chambers in the same area of study, whereas wintertime modeled values are underestimated by 1 order of magnitude. In an annual balance, the most important mechanism for transport of methane into the atmosphere is through plants (61 %. This is followed by ebullition ( ∼  35 %, while summertime molecular diffusion is negligible (0.02 % compared to the diffusion through the snow during winter ( ∼  4 %. We investigate the relationship between temporal changes in the CH4 fluxes, soil temperature, and soil moisture content. Our results highlight the heterogeneity in CH4 emissions at landscape scale and suggest that further improvements to the representation of large-scale hydrological conditions in the model will facilitate a more process-oriented land surface scheme and better simulate CH4 emissions under climate change. This is especially necessary at regional scales in Arctic ecosystems influenced by permafrost thaw.

  19. PYRN-Bib: The Permafrost Young Researchers Network Bibliography of Permafrost-Related Degree-Earning Theses

    Science.gov (United States)

    Grosse, Guido; Lantuit, Hugues; Gärtner-Roer, Isabelle

    2010-05-01

    PYRN-Bib is an international bibliographical database aiming at collecting and distributing information on all theses submitted for earning a scientific degree in permafrost-related research. PYRN-Bib is hosted by the Permafrost Young Researchers Network (PYRN, http://pyrn.ways.org), an international network of early career students and young scientists in permafrost related research with currently more than 750 members. The fully educational, non-profit project PYRN-Bib is published under the patronage of the International Permafrost Association (IPA). The bibliography covers all theses as long as they clearly treat aspects of permafrost research from such diverse fields as: Geophysics, Geology, Cryolithology, Biology, Biogeochemistry, Microbiology, Astrobiology, Chemistry, Engineering, Geomorphology, Remote Sensing, Modeling, Mineral and Hydrocarbon Exploration, and Science History and Education. The specific goals of PYRN-Bib are (1) to generate a comprehensive database that includes all degree-earning theses (e.g. Diploma, Ph.D., Master, etc.), coming from any country and any scientific field, under the single condition that the thesis is strongly related to research on permafrost and/or periglacial processes; (2) to reference unique but buried sources of information including theses published in languages other than English; (3) to make the database widely available to the scientific community and the general public; (4) to solicit PYRN membership; and (5) to provide a mean to map the evolution of permafrost research over the last decades, including regional trends, shifts in research direction, and/or the place of permafrost research in society. PYRN-Bib is available online and maintained by PYRN. The complete bibliography can be downloaded at no cost and is offered in different file formats: tagged Endnote library, XML, BibTex, and PDF. New entries are continuously provided by PYRN members and the scientific community. PYRN-Bib currently contains more than

  20. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Ali Kadaster; Bill Liddell; Tommy Thompson; Thomas Williams; Michael Niedermayr

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project was a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. The work scope included drilling and coring a well (Hot Ice No. 1) on Anadarko leases beginning in FY 2003 and completed in 2004. During the first drilling season, operations were conducted at the site between January 28, 2003 to April 30, 2003. The well was spudded and drilled to a depth of 1403 ft. Due to the onset of warmer weather, work was then suspended for the season. Operations at the site were continued after the tundra was re-opened the following season. Between January 12, 2004 and March 19, 2004, the well was drilled and cored to a final depth of 2300 ft. An on-site core analysis laboratory was built and implemented for determining physical characteristics of the hydrates and surrounding rock. The well was drilled from a new Anadarko Arctic Platform that has a minimal footprint and environmental impact. Final efforts of the project are to correlate geology, geophysics, logs, and drilling and

  1. Changing Permafrost in the Arctic and its Global Effects in the 21st Century (PAGE21): A very large international and integrated project to measure the impact of permafrost degradation on the climate system

    Science.gov (United States)

    Lantuit, Hugues; Boike, Julia; Dahms, Melanie; Hubberten, Hans-Wolfgang

    2013-04-01

    climate-change mitigation. The concept of PAGE21 is to directly address these questions through a close interaction between monitoring activities, proc-ess studies and modeling on the pertinent temporal and spatial scales. Field sites have been selected to cover a wide range of environmental conditions for the validation of large scale mod-els, the development of permafrost monitoring capabilities, the study of permafrost processes, and for overlap with existing monitoring programs. PAGE21 will contribute to upgrading the project sites with the objective of providing a measurement baseline, both for process studies and for modeling programs. PAGE21 is determined to break down the traditional barriers in permafrost sciences between observational and model-supported site studies and large-scale climate modeling. Our concept for the interaction between site-scale studies and large-scale modeling is to establish and maintain a direct link be-tween these two areas for developing and evaluating, on all spatial scales, the land-surface modules of leading European global climate models taking part in the Coupled Model Inter-comparison Project Phase 5 (CMIP5), designed to inform the IPCC process. The timing of this project is such that the main scientific results from PAGE21, and in particular the model-based assessments will build entirely on new outputs and results from the CMIP5 Climate Model Intercomparison Project designed to inform the IPCC Fifth Assessment Report. However, PAGE21 is designed to leave a legacy that will en-dure beyond the lifetime of the projections that it produces. This legacy will comprise • an improved understanding of the key processes and parameters that determine the vulnerability of arctic permafrost to climate change, • the production of a suite of major European coupled climate models including detailed and validated repre-sentations of permafrost-related processes, that will reduce uncertainties in future climate projections pro-duced well

  2. Effects of temperature on biological activity of permafrost microorganisms.

    Science.gov (United States)

    Kalyonova, L F; Novikova, M A; Subbotin, A M; Bazhin, A S

    2015-04-01

    The number and viability of microorganism specimens Bacillus spp. isolated from permafrost soil remained unchanged after incubation at temperatures of -16-37°C. Experiments on F1 CBA/Black-6 mice showed that incubation of bacteria at -5°C for 72 h promotes a decrease in their toxicity and an increase in their immunostimulating effect.

  3. Bacterial communities in ancient permafrost profiles of Svalbard, Arctic.

    Science.gov (United States)

    Singh, Purnima; Singh, Shiv M; Singh, Ram N; Naik, Simantini; Roy, Utpal; Srivastava, Alok; Bölter, Manfred

    2017-12-01

    Permafrost soils are unique habitats in polar environment and are of great ecological relevance. The present study focuses on the characterization of bacterial communities from permafrost profiles of Svalbard, Arctic. Counts of culturable bacteria range from 1.50 × 10 3 to 2.22 × 10 5 CFU g -1 , total bacterial numbers range from 1.14 × 10 5 to 5.52 × 10 5 cells g -1 soil. Bacterial isolates are identified through 16S rRNA gene sequencing. Arthrobacter and Pseudomonas are the most dominant genera, and A. sulfonivorans, A. bergeri, P. mandelii, and P. jessenii as the dominant species. Other species belong to genera Acinetobacter, Bacillus, Enterobacter, Nesterenkonia, Psychrobacter, Rhizobium, Rhodococcus, Sphingobacterium, Sphingopyxis, Stenotrophomonas, and Virgibacillus. To the best of our knowledge, genera Acinetobacter, Enterobacter, Nesterenkonia, Psychrobacter, Rhizobium, Sphingobacterium, Sphingopyxis, Stenotrophomonas, and Virgibacillus are the first northernmost records from Arctic permafrost. The present study fills the knowledge gap of culturable bacterial communities and their chronological characterization from permafrost soils of Ny-Ålesund (79°N), Arctic. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Permafrost in Marine Deposits at Ilulissat Airport in Greenland, Revisited

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Ingeman-Nielsen, Thomas

    2008-01-01

    residual salt content in the porewater. However, in the less saline top zone massive ice layers was found constituting up to 30 volume%. These formations representing a type example of saline permafrost caused the planned position of the runway to be shifted towards northwest and a removal of the layers...

  5. The effect of petroleum spills on permafrost at CFS Alert

    International Nuclear Information System (INIS)

    Haidar, S.; Jarrett, P.

    1997-01-01

    Site investigations have been carried out at two decommissioned tank farm sites at Canadian Forces Station Alert on the northern tip of Ellesmere Island. The purpose was to study the mechanism of spilt fuel movement in frozen ground and its effects on frozen soils. The investigations consisted of sampling to depths below the permafrost table to assess vertical fuel migration, hydrocarbon pollutant concentration and water content. Results showed vertical migration of spilled fuel into permafrost. The migration was attributed to gravity drainage through interconnected air voids in fill material or movement through fissures in the soil induced by thermal contraction. Unweathered contaminants were found below the liners on top of the permafrost, believed to have been caused by holes in the liner. The entrapment of the spilled fuel may have been responsible for the enhanced vertical migration of contaminants observed at these sites. It was concluded that permafrost should not be considered as an impermeable barrier to contaminants with freezing points below 0 degree C. 4 figs

  6. Permafrost knowledge to serve as foundation for Inuit community planning

    Science.gov (United States)

    Gibéryen, T.; Allard, M.

    2011-12-01

    With the recent announcement of Québec's provincial government's Plan Nord, Nunavik will see a 500 new houses sweep onto it's territory over the next 5 years. The local Inuit communities are confronted with the pressuring need to find suitable land to safely accommodate the new infrastructures in the long term. Additional to human and environmental constraints are those related to warming permafrost. Intensive studies on four Nunavik communities (Inukjuak, Puvirnituq, Akulivik, Kangirsuk) have allowed us to extensively consult local and regional authorities on their planning and management considerations. Recent and archived drilling data have been used to corroborate air photo interpretation, surficial geology and permafrost mapping. All collected information are integrated into aggregated maps that will eventually serve as community master plans. General recommendations on how to best manage and plan for community expansions on warming permafrost are made. Appropriate engineering techniques assuring long-term stable foundations are outlined and additionally mapped, taking into consideration the variable terrain conditions and simulated changes in permafrost temperature and active layer thickness according to climate change scenarios. The final purpose of our results is for them to support local and regional governments in their community planning process towards the best possible climate change adaptation strategies.

  7. Threshold loss of discontinuous permafrost and landscape evolution.

    Science.gov (United States)

    Chasmer, Laura; Hopkinson, Chris

    2017-07-01

    This study demonstrates linkages between the 1997/1998 El Niño/Southern Oscillation index and a threshold shift to increased permafrost loss within a southern Taiga Plains watershed, Northwest Territories, Canada. Three-dimensional contraction of permafrost plateaus and changes in vegetation structural characteristics are determined from multitemporal airborne Light Detection And Ranging (LiDAR) surveys in 2008, 2011 and 2015. Morphological changes in permafrost cover are compared with optical image analogues from 1970, 1977, 2000 and 2008 and time-series hydro-climate data. Results demonstrate that significant changes in air temperature, precipitation, runoff and a shortening of the snow-covered season by 35 days (1998-2014) and 50 days (1998 only) occurred after 1997. The albedo reduction associated with 35 and 50 days less snow cover leads to increases in shortwave energy receipt during the active thaw period of ~12% (3% annually) and ~16% (5% annually), respectively. From 2000 to 2015, sporadic permafrost loss accelerated from 0.19% (of total basin area) per year between 1970 and 2000 to 0.58% per year from 2000 to 2015, with a projected total loss of permafrost by ~2044. From ~1997 to 2011, we observe a corresponding shift to increased runoff ratio. However, observed increases in the proportion of snow precipitation and the volumetric contribution of permafrost loss to runoff post-1997 (0.6-6.4% per year) cannot fully explain this shift. This suggests increases in drainage efficiency and possible losses from long-term groundwater storage as a result of subtle terrain morphological and soil zone hydraulic conductivity changes. These hydrological changes appear coincident with high vegetation mortality at plateau margins combined with succession-related canopy growth in some bog and fen areas, which are presumed to be drying. Similar changes in runoff response were observed at adjacent Birch, Trout and Jean Marie River watersheds indicating that observations

  8. Characterization and Modeling Of Microbial Carbon Metabolism In Thawing Permafrost

    Science.gov (United States)

    Graham, D. E.; Phelps, T. J.; Xu, X.; Carroll, S.; Jagadamma, S.; Shakya, M.; Thornton, P. E.; Elias, D. A.

    2012-12-01

    Increased annual temperatures in the Arctic are warming the surface and subsurface, resulting in thawing permafrost. Thawing exposes large pools of buried organic carbon to microbial degradation, increasing greenhouse gas generation and emission. Most global-scale land-surface models lack depth-dependent representations of carbon conversion and GHG transport; therefore they do not adequately describe permafrost thawing or microbial mineralization processes. The current work was performed to determine how permafrost thawing at moderately elevated temperatures and anoxic conditions would affect CO2 and CH4 generation, while parameterizing depth-dependent GHG production processes with respect to temperature and pH in biogeochemical models. These enhancements will improve the accuracy of GHG emission predictions and identify key biochemical and geochemical processes for further refinement. Three core samples were obtained from discontinuous permafrost terrain in Fairbanks, AK with a mean annual temperature of -3.3 °C. Each core was sectioned into surface/near surface (0-0.8 m), active layer (0.8-1.6 m), and permafrost (1.6-2.2 m) horizons, which were homogenized for physico-chemical characterization and microcosm construction. Surface samples had low pH values (6.0), low water content (18% by weight), low organic carbon (0.8%), and high C:N ratio (43). Active layer samples had higher pH values (6.4), higher water content (34%), more organic carbon (1.4%) and a lower C:N ratio (24). Permafrost samples had the highest pH (6.5), highest water content (46%), high organic carbon (2.5%) and the lowest C:N ratio (19). Most organic carbon was quantified as labile or intermediate pool versus stable pool in each sample, and all samples had low amounts of carbonate. Surface layer microcosms, containing 20 g sediment in septum-sealed vials, were incubated under oxic conditions, while similar active and permafrost layer samples were anoxic. These microcosms were incubated at -2

  9. Effects of permafrost aggradation on peat properties as determined from a pan-Arctic synthesis of plant macrofossils

    Science.gov (United States)

    Treat, C.C.; Jones, Miriam C.; Camill, P.; Gallego-Sala, A.; Garneau, M.; Harden, Jennifer W.; Hugelius, G.; Klein, E.S.; Kokfelt, U.; Kuhry, P.; Loisel, Julie; Mathijssen, J.H.; O'Donnell, J.A.; Oksanen, P.O.; Ronkainen, T.M.; Sannel, A.B.K.; Talbot, J. J.; Tarnocal, C.M.; Valiranta, M.

    2016-01-01

    Permafrost dynamics play an important role in high-latitude peatland carbon balance and are key to understanding the future response of soil carbon stocks. Permafrost aggradation can control the magnitude of the carbon feedback in peatlands through effects on peat properties. We compiled peatland plant macrofossil records for the northern permafrost zone (515 cores from 280 sites) and classified samples by vegetation type and environmental class (fen, bog, tundra and boreal permafrost, and thawed permafrost). We examined differences in peat properties (bulk density, carbon (C), nitrogen (N) and organic matter content, and C/N ratio) and C accumulation rates among vegetation types and environmental classes. Consequences of permafrost aggradation differed between boreal and tundra biomes, including differences in vegetation composition, C/N ratios, and N content. The vegetation composition of tundra permafrost peatlands was similar to permafrost-free fens, while boreal permafrost peatlands more closely resembled permafrost-free bogs. Nitrogen content in boreal permafrost and thawed permafrost peatlands was significantly lower than in permafrost-free bogs despite similar vegetation types (0.9% versus 1.5% N). Median long-term C accumulation rates were higher in fens (23 g C m−2 yr−1) than in permafrost-free bogs (18 g C m−2 yr−1) and were lowest in boreal permafrost peatlands (14 g C m−2 yr−1). The plant macrofossil record demonstrated transitions from fens to bogs to permafrost peatlands, bogs to fens, permafrost aggradation within fens, and permafrost thaw and reaggradation. Using data synthesis, we have identified predominant peatland successional pathways, changes in vegetation type, peat properties, and C accumulation rates associated with permafrost aggradation.

  10. Collaborative Research: Quantifying Climate Feedbacks of the Terrestrial Biosphere under Thawing Permafrost Conditions in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, Jerry [Marine Biological Lab., Woods Hole, MA (United States)

    2017-12-12

    uncertainties. Based on our study results along with a review of observed and projected climate changes in Northern Eurasia by others, we have also outlined a more integrated modelling approach that may be developed and applied in future studies to better capture the influence of earth system feedbacks and human activities on the evolution of climate change effects over time. Specifically, we have examined: 1) how evapotranspiration and water availability have been changing in Northern Eurasia and may change in the future including the impact of forcing uncertainties (Liu et al., 2013, 2014, 2015); 2) how soil consumption of atmospheric methane across the globe have been influenced and may be influenced by climate change and nitrogen deposition during the 20th and 21st centuries (Zhuang et al., 2013); 3) how wetland inundation extent influences net CO2 and CH4 fluxes from northern high latitudes (Zhuang et al., 2015); 4) the relative effects of various environmental factors (including permafrost degradation) on terrestrial dissolved organic carbon (DOC) loading of river networks across the pan-Arctic and how they have changed over the 20th century (Kicklighter et al., 2013); 5) the impacts of recent and future permafrost thaw on land-atmosphere greenhouse gas exchange across the pan-Arctic (Gao et al., 2012, 2013; Hayes et al., 2014; Kicklighter et al. 2015a, 2018); 6) how climate-induced vegetation shifts may affect carbon fluxes and future land use in Northern Eurasia (Jiang et al., 2012, 2016; Kicklighter et al., 2014a) and the globe (Zhuang et al. 2015b); 7) the relative importance of legacies from past land use, future land-use change and climate change on projections of terrestrial carbon fluxes (Monier et al., 2015; Kicklighter et al., 2016); and 8) how the effects of earth system feedbacks and human activities can be better incorporated in assessments of climate change impacts (Monier et al., 2017; Groisman et al., 2018).

  11. Satellite-derived NDVI, LST, and climatic factors driving the distribution and abundance of Anopheles mosquitoes in a former malarious area in northwest Argentina.

    Science.gov (United States)

    Dantur Juri, María Julia; Estallo, Elizabet; Almirón, Walter; Santana, Mirta; Sartor, Paolo; Lamfri, Mario; Zaidenberg, Mario

    2015-06-01

    Distribution and abundance of disease vectors are directly related to climatic conditions and environmental changes. Remote sensing data have been used for monitoring environmental conditions influencing spatial patterns of vector-borne diseases. The aim of this study was to analyze the effect of the Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS), and climatic factors (temperature, humidity, wind velocity, and accumulated rainfall) on the distribution and abundance of Anopheles species in northwestern Argentina using Poisson regression analyses. Samples were collected from December, 2001 to December, 2005 at three localities, Aguas Blancas, El Oculto and San Ramón de la Nueva Orán. We collected 11,206 adult Anopheles species, with the major abundance observed at El Oculto (59.11%), followed by Aguas Blancas (22.10%) and San Ramón de la Nueva Orán (18.79%). Anopheles pseudopunctipennis was the most abundant species at El Oculto, Anopheles argyritarsis predominated in Aguas Blancas, and Anopheles strodei in San Ramón de la Nueva Orán. Samples were collected throughout the sampling period, with the highest peaks during the spring seasons. LST and mean temperature appear to be the most important variables determining the distribution patterns and major abundance of An. pseudopunctipennis and An. argyritarsis within malarious areas. © 2015 The Society for Vector Ecology.

  12. Permafrost at its limits: The most easterly evidence of existing permafrost in the European Alps as indicated by ground temperature and geoelectrical measurements

    Science.gov (United States)

    Kellerer-Pirklbauer, A.; Kühnast, B.

    2009-04-01

    Mountain permafrost is a widespread phenomenon in alpine regions in the European Alps. For instance, some 2000 km² or 4% of the Austrian Alps are underlain by permafrost. Up to recent times most research on permafrost issues in Austria focused on the central and highest section of the Austrian Alps. By contrast, knowledge concerning marginal permafrost zones is fairly limited. To increase knowledge about the easternmost limit of permafrost in the European Alps, a research project focusing on the Seckauer Tauern Mountains (14°30'E to 15°00'E) and particularly on the Hochreichart area was initiated in 2004 by the first author. Since then, different methods have been applied such as e.g. geomorphic mapping, numerical permafrost modelling, multi-annual BTS measurements (since 2004) or continuous ground surface and near ground surface temperature measurements by miniature temperature data loggers/MTDs (since 2004). In order to verify the temperature data and to extend the spatial knowledge about permafrost distribution beyond point information, a geoelectrical survey was carried out at the end of August 2008 by applying the electrical resistivity tomography (ERT) method along a 120 m long profile covering the upper part of the rooting zone of a (more-or-less) relict rock glacier and the talus slope above. For this survey the two-dimensional (2D) electrical surveys was performed using the Wenner-Alfa configuration with 2.5 m spacing and an LGM-Lippmann 4-Punkt light hp resistivity-meter. The ERT results indicate an active layer of 2 to 4 m underlain by a permafrost body along 3/4 of the entire profile with resistivity values between 50 to 100 kOhm.m and extending to a depth of 10 to 15 m. The permafrost body is substantially thicker at the lower part of the profile (rock glacier; first 50 m of profile) compared to most of the upper part (talus slope). Focusing on the talus slope, the permafrost body is thickest on the central section of the profile (~5-6 m thickness

  13. ADAPT: building conceptual models of the physical and biological processes across permafrost landscapes

    Science.gov (United States)

    Allard, M.; Vincent, W. F.; Lemay, M.

    2012-12-01

    Fundamental and applied permafrost research is called upon in Canada in support of environmental protection, economic development and for contributing to the international efforts in understanding climatic and ecological feedbacks of permafrost thawing under a warming climate. The five year "Arctic Development and Adaptation to Permafrost in Transition" program (ADAPT) funded by NSERC brings together 14 scientists from 10 Canadian universities and involves numerous collaborators from academia, territorial and provincial governments, Inuit communities and industry. The geographical coverage of the program encompasses all of the permafrost regions of Canada. Field research at a series of sites across the country is being coordinated. A common protocol for measuring ground thermal and moisture regime, characterizing terrain conditions (vegetation, topography, surface water regime and soil organic matter contents) is being applied in order to provide inputs for designing a general model to provide an understanding of transfers of energy and matter in permafrost terrain, and the implications for biological and human systems. The ADAPT mission is to produce an 'Integrated Permafrost Systems Science' framework that will be used to help generate sustainable development and adaptation strategies for the North in the context of rapid socio-economic and climate change. ADAPT has three major objectives: to examine how changing precipitation and warming temperatures affect permafrost geosystems and ecosystems, specifically by testing hypotheses concerning the influence of the snowpack, the effects of water as a conveyor of heat, sediments, and carbon in warming permafrost terrain and the processes of permafrost decay; to interact directly with Inuit communities, the public sector and the private sector for development and adaptation to changes in permafrost environments; and to train the new generation of experts and scientists in this critical domain of research in Canada

  14. Modeling sub-sea permafrost in the East Siberian Arctic Shelf: the Dmitry Laptev Strait

    International Nuclear Information System (INIS)

    Nicolsky, D; Shakhova, N

    2010-01-01

    The present state of sub-sea permafrost modeling does not agree with certain observational data on the permafrost state within the East Siberian Arctic Shelf. This suggests a need to consider other mechanisms of permafrost destabilization after the recent ocean transgression. We propose development of open taliks wherever thaw lakes and river paleo-valleys were submerged shelf-wide as a possible mechanism for the degradation of sub-sea permafrost. To test the hypothesis we performed numerical modeling of permafrost dynamics in the Dmitry Laptev Strait area. We achieved sufficient agreement with the observed distribution of thawed and frozen layers to suggest that the proposed mechanism of permafrost destabilization is plausible.

  15. The long-term fate of permafrost peatlands under rapid climate warming

    DEFF Research Database (Denmark)

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon...... stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological...... approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed...

  16. Ground thermal and geomechanical conditions in a permafrost-affected high-latitude rock avalanche site (Polvartinden, northern Norway)

    Science.gov (United States)

    Frauenfelder, Regula; Isaksen, Ketil; Lato, Matthew J.; Noetzli, Jeannette

    2018-04-01

    On 26 June 2008, a rock avalanche detached in the northeast facing slope of Polvartinden, a high-alpine mountain in Signaldalen, northern Norway. Here, we report on the observed and modelled past and present near-surface temperature regime close to the failure zone, as well as on a subsequent simulation of the subsurface temperature regime, and on initial geomechanical mapping based on laser scanning. The volume of the rock avalanche was estimated to be approximately 500 000 m3. The depth to the actual failure surface was found to range from 40 m at the back of the failure zone to 0 m at its toe. Visible in situ ice was observed in the failure zone just after the rock avalanche. Between September 2009 and August 2013, ground surface temperatures were measured with miniature temperature data loggers at 14 different localities, close to the original failure zone along the northern ridge of Polvartinden and on the valley floor. The results from these measurements and from a basic three-dimensional heat conduction model suggest that the lower altitudinal limit of permafrost at present is at 600-650 m a.s.l., which corresponds to the upper limit of the failure zone. A coupling of our in situ data with regional climate data since 1958 suggests a general gradual warming and that the period with highest mean near surface temperatures on record ended four months before the Signaldalen rock avalanche detached. A comparison with a transient permafrost model run at 10 m depth, representative for areas where snow accumulates, strengthen these findings, which are also in congruence with measurements in nearby permafrost boreholes. It is likely that permafrost in and near the failure zone is presently subject to degradation. This degradation, in combination with the extreme warm year antecedent to the rock failure, is seen to have played an important role in the detaching of the Signaldalen rock avalanche.

  17. The research station "Vaskiny Dachi", Central Yamal, West Siberia, Russia – a review of 25 years of permafrost studies

    Directory of Open Access Journals (Sweden)

    Marina O. Leibman

    2015-03-01

    Full Text Available The research station "Vaskiny Dachi" on the Yamal Peninsula was established in 1988. Activities aimed at monitoring of permafrost and related environmental features under a relatively low level of nature disturbances caused by gas field development. Cryogenic processes that may affect the environment and their structures have been of primary interest. Landslides are the most common cryogenic processes in Central Yamal in general and also in the proximity of the station. Field surveys of numerous landslides, analysis of their dependence on climatic parameters and their fluctuations resulted in novel classification of cryogenic landslides based on mechanisms of their development. Dating by radiocarbon and dendrochronology allows the separation of cycles of landslide activation. Cryogenic landslides control the development of other processes, such as thermal erosion, river channel erosion and thermokarst. It also affects topography, vegetation pattern, geochemistry of vegetation, ground water and soils. As a result, permafrost parameters, specifically active layer depth and ground temperature, moisture and ice content in the active layer, depend indirectly on landsliding. Monitoring within the framework of the main programs of the International Permafrost Association, such as Circumarctic Active Layer Monitoring (CALM, since 1993 and Thermal State of Permafrost (TSP, since 2011, play an important role among the research activities. From the collected data one can conclude that ground temperature increased on average by about 1 °C since the 1990s. At the same time, active layer fluctuations do not exactly follow the air temperature changes. Spatial changes in ground temperature are controlled by the redistribution of snow which is resulting from strong winds characteristic for tundra environments and the highly dissected relief of Central Yamal. Temporal variations rather depend on air temperature fluctuations but the rate differs in various

  18. Investigation of Soil and Vegetation Characteristics in Discontinuous Permafrost Landscapes Near Fairbanks, Alaska

    Science.gov (United States)

    2015-08-01

    ER D C TR -1 5- 7 ERDC Center-Directed Research Investigation of Soil and Vegetation Characteristics in Discontinuous Permafrost ...Characteristics in Discontinuous Permafrost Landscapes Near Fairbanks, Alaska Jacob F. Berkowitz U.S. Army Engineer Research and Development Center (ERDC...Washington, DC 20314-1000 Under ERDC Center-Directed Research project “Integrated Technologies for Delineat- ing Permafrost and Ground-State

  19. Groundwater controls on post-fire permafrost thaw: Water and energy balance effects

    OpenAIRE

    Rocha, Adrian; Mckenzie, Jeffrey; Lamontagne-Halle, Pierrick; Zipper, Samuel

    2018-01-01

    Fire frequency and severity is increasing in high latitude regions, with large impacts on the water and energy balances. However, the degree to which groundwater flow impacts the permafrost response to fire remains poorly understood and understudied. Here, we use the Anaktuvuk River Fire (Alaska, USA) as an archetypal example to investigate groundwater-permafrost interactions following fire. We identify key thermal and hydrologic parameters controlling permafrost and active layer response to ...

  20. Influences of Moisture Regimes and Functional Plant Types on Nutrient Cycling in Permafrost Regions

    Science.gov (United States)

    McCaully, R. E.; Arendt, C. A.; Newman, B. D.; Heikoop, J. M.; Wilson, C. J.; Sevanto, S.; Wales, N. A.; Wullschleger, S.

    2017-12-01

    In the permafrost-dominated Arctic, climatic feedbacks exist between permafrost, soil moisture, functional plant type and presence of nutrients. Functional plant types present within the Arctic regulate and respond to changes in hydrologic regimes and nutrient cycling. Specifically, alders are a member of the birch family that use root nodules to fix nitrogen, which is a limiting nutrient strongly linked to fertilizing Arctic ecosystems. Previous investigations in the Seward Peninsula, AK show elevated presence of nitrate within and downslope of alder patches in degraded permafrost systems, with concentrations an order of magnitude greater than that of nitrate measured above these patches. Further observations within these degraded permafrost systems are crucial to assess whether alders are drivers of, or merely respond to, nitrate fluxes. In addition to vegetative feedbacks with nitrate supply, previous studies have also linked low moisture content to high nitrate production. Within discontinuous permafrost regions, the absence of permafrost creates well-drained regions with unsaturated soils whereas the presence of permafrost limits vertical drainage of soil-pore water creating elevated soil moisture content, which likely corresponds to lower nitrate concentrations. We investigate these feedbacks further in the Seward Peninsula, AK, through research supported by the United States Department of Energy Next Generation Ecosystem Experiment (NGEE) - Arctic. Using soil moisture and thaw depth as proxies to determine the extent of permafrost degradation, we identify areas of discontinuous permafrost over a heterogeneous landscape and collect co-located soilwater chemistry samples to highlight the complex relationships that exist between alder patches, soil moisture regimes, the presence of permafrost and available nitrate supply. Understanding the role of nitrogen in degrading permafrost systems, in the context of both vegetation present and soil moisture, is crucial

  1. Long-term anoxia and release of ancient, labile carbon upon thaw of Pleistocene permafrost

    Science.gov (United States)

    Ewing, Stephanie A.; O'Donnell, Jonathan A.; Aiken, George R.; Butler, Kenna D.; Butman, David; Windham-Myers, Lisamarie; Kanevskiy, Mikhail

    2015-01-01

    The fate of permafrost carbon upon thaw will drive feedbacks to climate warming. Here we consider the character and context of dissolved organic carbon (DOC) in yedoma permafrost cores from up to 20 m depth in central Alaska. We observed high DOC concentrations (4 to 129 mM) and consistent low molecular weight organic acid concentrations in three cores. We estimate a DOC production rate of 12 µmol DOC m−2 yr−1 based on model ages of up to ~200 kyr derived from uranium isotopes. Acetate C accounted for 24 ± 1% of DOC in all samples. This proportion suggests long-term anaerobiosis and is likely to influence thaw outcomes due to biolability of acetate upon release in many environments. The combination of uranium isotopes, ammonium concentrations, and calcium concentrations explained 86% of the variation in thaw water DOC concentrations, suggesting that DOC production may be related to both reducing conditions and mineral dissolution over time.

  2. Study of stress-strain state of pipeline under permafrost conditions

    Science.gov (United States)

    Tarasenko, A. A.; Redutinskiy, M. N.; Chepur, P. V.; Gruchenkova, A. A.

    2018-05-01

    In this paper, the dependences of the stress-strain state and subsidence of pipelines on the dimensions of the subsidence zone are obtained for the sizes of pipes that have become most widespread during the construction of main oil pipelines (530x10, 820x12, 1020x12, 1020x14, 1020x16, 1220x14, 1220x16, 1220x18 mm). True values of stresses in the pipeline wall, as well as the exact location of maximum stresses for the interval of subsidence zones from 5 to 60 meters, are determined. For this purpose, the authors developed a finite element model of the pipeline that takes into account the actual interaction of the pipeline with the subgrade and allows calculating the SSS of the structure for a variable subsidence zone. Based on the obtained dependences for the underground laying of oil pipelines in permafrost areas, it is proposed to artificially limit the zone of possible subsidence by separation supports from the soil with higher building properties and physical-mechanical parameters. This technical solution would significantly reduce costs when constructing new oil pipelines in permafrost areas.

  3. Minor contribution of small thaw ponds to the pools of carbon and methane in the inland waters of the permafrost-affected part of the Western Siberian Lowland

    Science.gov (United States)

    Polishchuk, Y. M.; Bogdanov, A. N.; Muratov, I. N.; Polishchuk, V. Y.; Lim, A.; Manasypov, R. M.; Shirokova, L. S.; Pokrovsky, O. S.

    2018-04-01

    Despite the potential importance of small (permafrost-affected WSL territory based on a combination of medium-resolution Landsat-8 images and high-resolution Kanopus-V scenes on 78 test sites across the WSL in a wide range of lake sizes (from 20 to 2 × 108 m2). The results were in fair agreement with other published data for world lakes including those in circum-polar regions. Based on available measurements of CH4, CO2, and dissolved organic carbon (DOC) in thermokarst lakes and thaw ponds of the permafrost-affected part of the WSL, we found an inverse relationship between lake size and concentration, with concentrations of GHGs and DOC being highest in small thaw ponds. However, since these small ponds represent only a tiny fraction of the landscape (i.e. ~1.5% of the total lake area), their contribution to the total pool of GHG and DOC in inland lentic water of the permafrost-affected part of the WSL is less than 2%. As such, despite high concentrations of DOC and GHG in small ponds, their role in overall C storage can be negated. Ongoing lake drainage due to climate warming and permafrost thaw in the WSL may lead to a decrease in GHG emission potential from inland waters and DOC release from lakes to rivers.

  4. Vejbygning i områder med permafrost

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr

    2009-01-01

    Siden begyndelsen af 1990’erne er der registreret en markant stigning i den årlige middeltemperatur i Nunavik, Québec Canada. Dette har ført til en reduktion i udbredelsen af permafrost, hvilket truer stabiliteten af lufthavne og veje i området. I sommeren 2007 blev en teststrækning opført i...... Tasiujaq Lufthavn for at studere effekten af tre forskellige metoder, som skal være med til at reducere optøningen af permafrost under landingsbanen. De tre metoder, som er blevet undersøgt, er konvektionskøling (air convection embankment), varmeudtrækning (heat drain) samt et forsøg med ændring af...

  5. Mapping Deep Low Velocity Zones in Alaskan Arctic Coastal Permafrost using Seismic Surface Waves

    Science.gov (United States)

    Dou, S.; Ajo Franklin, J. B.; Dreger, D. S.

    2012-12-01

    Surface Waves (MASW) suggests the existence of pronounced low shear wave velocity zones that span the depth range of 2 - 30 meters; this zone has shear velocity values comparable to partially thawed soils. Such features coincide with previous findings of very low electrical resistivity structure (as low as ~10 Ohm*m at some locations) from measurements obtained in the first NGEE-Arctic geophysical field campaign (conducted in the week of September 24 - October 1, 2011). These low shear velocity zones are likely representative of regions with high unfrozen water content and thus have important implications on the rate of microbial activity and the vulnerability of deep permafrost carbon pools. Analysis of this dataset required development of a novel inversion approach based on waveform inversion. The existence of multiple closely spaced Rayleigh wave modes made traditional inversion based on mode picking virtually impossible; As a result, we selected a direct misfit evaluation based on comparing dispersion images in the phase velocity/frequency domain. The misfit function was optimized using a global search algorithm, in this case Huyer and Neumaier's Multi Coordinate Search algorithm (MCS). This combination of MCS and waveform misfit allowed recovery of the low velocity region despite the existence of closely spaced modes.

  6. Impacts of Permafrost on Infrastructure and Ecosystem Services

    Science.gov (United States)

    Trochim, E.; Schuur, E.; Schaedel, C.; Kelly, B. P.

    2017-12-01

    The Study of Environmental Arctic Change (SEARCH) program developed knowledge pyramids as a tool for advancing scientific understanding and making this information accessible for decision makers. Knowledge pyramids are being used to synthesize, curate and disseminate knowledge of changing land ice, sea ice, and permafrost in the Arctic. Each pyramid consists of a one-two page summary brief in broadly accessible language and literature organized by levels of detail including synthesizes and scientific building blocks. Three knowledge pyramids have been produced related to permafrost on carbon, infrastructure, and ecosystem services. Each brief answers key questions with high societal relevance framed in policy-relevant terms. The knowledge pyramids concerning infrastructure and ecosystem services were developed in collaboration with researchers specializing in the specific topic areas in order to identify the most pertinent issues and accurately communicate information for integration into policy and planning. For infrastructure, the main issue was the need to build consensus in the engineering and science communities for developing improved methods for incorporating data applicable to building infrastructure on permafrost. In ecosystem services, permafrost provides critical landscape properties which affect basic human needs including fuel and drinking water availability, access to hunting and harvest, and fish and wildlife habitat. Translating these broad and complex topics necessitated a systematic and iterative approach to identifying key issues and relating them succinctly to the best state of the art research. The development of the knowledge pyramids provoked collaboration and synthesis across distinct research and engineering communities. The knowledge pyramids also provide a solid basis for policy development and the format allows the content to be regularly updated as the research community advances.

  7. Effects of permafrost microorganisms on skin wound reparation.

    Science.gov (United States)

    Kalenova, L F; Novikova, M A; Subbotin, A M

    2015-02-01

    Local application of ointment with Bacillus spp. strain MG8 (15,000-20,000 living bacterial cells), isolated from permafrost specimens, on the skin wound of about 60 mm(2) stimulated the reparation processes in experimental mice. A possible mechanism stimulating the regeneration of the damaged tissues under the effect of MG8 could be modulation of the immune system reactivity with more rapid switchover to humoral immunity anti-inflammatory mechanisms aimed at de novo synthesis of protein.

  8. Physiological characteristics of bacteria isolated from water brines within permafrost

    Science.gov (United States)

    Shcherbakova, V.; Rivkina, E.; Laurinavichuis, K.; Pecheritsina, S.; Gilichinsky, D.

    2004-01-01

    In the Arctic there are lenses of overcooled water brines (cryopegs) sandwiched within permafrost marine sediments 100 120 thousand years old. We have investigated the physiological properties of the pure cultures of anaerobic Clostridium sp. strain 14D1 and two strains of aerobic bacteria Psychrobacter sp. isolated from these cryopegs. The structural and physiological characteristics of new bacteria from water brines have shown their ability to survive and develop under harsh conditions, such as subzero temperatures and high salinity.

  9. Presence of rapidly degrading permafrost plateaus in south-central Alaska

    Science.gov (United States)

    Jones, Benjamin M.; Baughman, Carson; Romanovsky, Vladimir E.; Parsekian, Andrew D.; Babcock, Esther; Stephani, Eva; Jones, Miriam C.; Grosse, Guido; Berg, Edward E

    2016-01-01

    Permafrost presence is determined by a complex interaction of climatic, topographic, and ecological conditions operating over long time scales. In particular, vegetation and organic layer characteristics may act to protect permafrost in regions with a mean annual air temperature (MAAT) above 0 °C. In this study, we document the presence of residual permafrost plateaus in the western Kenai Peninsula lowlands of south-central Alaska, a region with a MAAT of 1.5 ± 1 °C (1981–2010). Continuous ground temperature measurements between 16 September 2012 and 15 September 2015, using calibrated thermistor strings, documented the presence of warm permafrost (−0.04 to −0.08 °C). Field measurements (probing) on several plateau features during the fall of 2015 showed that the depth to the permafrost table averaged 1.48 m but at some locations was as shallow as 0.53 m. Late winter surveys (augering, coring, and GPR) in 2016 showed that the average seasonally frozen ground thickness was 0.45 m, overlying a talik above the permafrost table. Measured permafrost thickness ranged from 0.33 to  >  6.90 m. Manual interpretation of historic aerial photography acquired in 1950 indicates that residual permafrost plateaus covered 920 ha as mapped across portions of four wetland complexes encompassing 4810 ha. However, between 1950 and ca. 2010, permafrost plateau extent decreased by 60.0 %, with lateral feature degradation accounting for 85.0 % of the reduction in area. Permafrost loss on the Kenai Peninsula is likely associated with a warming climate, wildfires that remove the protective forest and organic layer cover, groundwater flow at depth, and lateral heat transfer from wetland surface waters in the summer. Better understanding the resilience and vulnerability of ecosystem-protected permafrost is critical for mapping and predicting future permafrost extent and degradation across all permafrost regions that are currently warming

  10. Mountain permafrost, glacier thinning, and slope stability - a perspective from British Columbia (and Alaska)

    Science.gov (United States)

    Geertsema, Marten

    2016-04-01

    The association of landslides with thinning glaciers and mapped, or measured, mountain permafrost is increasing. Glacier thinning debuttresses slopes and promotes joint expansion. It is relatively easy to map. Permafrost, a thermal condition, is generally not visually detectible, and is difficult to map. Much mountain permafrost may have been overlooked in hazard analysis. Identifying, and characterizing mountain permafrost, and its influence on slope instability is crucial for hazard and risk analysis in mountainous terrain. Rock falls in mountains can be the initial event in process chains. They can transform into rock avalanches, debris flows or dam burst floods, travelling many kilometres, placing infrastructure and settlements at risk.

  11. Microbial survival strategies in ancient permafrost: insights from metagenomics.

    Science.gov (United States)

    Mackelprang, Rachel; Burkert, Alexander; Haw, Monica; Mahendrarajah, Tara; Conaway, Christopher H; Douglas, Thomas A; Waldrop, Mark P

    2017-10-01

    In permafrost (perennially frozen ground) microbes survive oligotrophic conditions, sub-zero temperatures, low water availability and high salinity over millennia. Viable life exists in permafrost tens of thousands of years old but we know little about the metabolic and physiological adaptations to the challenges presented by life in frozen ground over geologic time. In this study we asked whether increasing age and the associated stressors drive adaptive changes in community composition and function. We conducted deep metagenomic and 16 S rRNA gene sequencing across a Pleistocene permafrost chronosequence from 19 000 to 33 000 years before present (kyr). We found that age markedly affected community composition and reduced diversity. Reconstruction of paleovegetation from metagenomic sequence suggests vegetation differences in the paleo record are not responsible for shifts in community composition and function. Rather, we observed shifts consistent with long-term survival strategies in extreme cryogenic environments. These include increased reliance on scavenging detrital biomass, horizontal gene transfer, chemotaxis, dormancy, environmental sensing and stress response. Our results identify traits that may enable survival in ancient cryoenvironments with no influx of energy or new materials.

  12. Metagenomic analysis of permafrost microbial community response to thaw

    Energy Technology Data Exchange (ETDEWEB)

    Mackelprang, R.; Waldrop, M.P.; DeAngelis, K.M.; David, M.M.; Chavarria, K.L.; Blazewicz, S.J.; Rubin, E.M.; Jansson, J.K.

    2011-07-01

    We employed deep metagenomic sequencing to determine the impact of thaw on microbial phylogenetic and functional genes and related this data to measurements of methane emissions. Metagenomics, the direct sequencing of DNA from the environment, allows for the examination of whole biochemical pathways and associated processes, as opposed to individual pieces of the metabolic puzzle. Our metagenome analyses revealed that during transition from a frozen to a thawed state there were rapid shifts in many microbial, phylogenetic and functional gene abundances and pathways. After one week of incubation at 5°C, permafrost metagenomes converged to be more similar to each other than while they were frozen. We found that multiple genes involved in cycling of C and nitrogen shifted rapidly during thaw. We also constructed the first draft genome from a complex soil metagenome, which corresponded to a novel methanogen. Methane previously accumulated in permafrost was released during thaw and subsequently consumed by methanotrophic bacteria. Together these data point towards the importance of rapid cycling of methane and nitrogen in thawing permafrost.

  13. Permafrost delineation for remediation planning : Fort Wainwright, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Astley, B. [Cold Regions Research and Engineering Laboratory, Anchorage, AK (United States); Snyder, C. [YEC Inc., Valley Cottage, NJ (United States); Delaney, A. [Cold Regions Research and Engineering Laboratory, Fairbanks, AK (United States); Arcone, S.; Lawson, D. [Cold Regions Research and Engineering Laboratory, Hanover, NH (United States)

    2003-07-01

    In the summer of 1999, geophysical and hydrogeological surveys were conducted at the Birch Hill Tank Farm and Truck Fill Stand in Fort Wainwright, Alaska to assess the distribution of benzene, 1,2-dichloroethane, and 1,2-dibromoethane. The Birch Hill site consists of a silt, sand and gravel fluvial deposit that overlies bedrock. Permafrost occurs discontinuously throughout the alluvium and underlying bedrock, resulting in a complex aquifer distribution. The bedrock beneath the Tank Farm is highly fractured and faulted with a weathered horizon that is 30 meters thick. The goal of this study was to map the discontinuous permafrost and aquifers in the alluvial deposits and weathered bedrock zone for the purpose of delineating bedrock depth and structural features that influence ground water flow. Several methods were used to define subsurface conditions, including borehole logs, DC resistivity, and ground-penetrating radar. A 3-D hydrogeologic model was used to develop a ground water flow model used to determine contaminant migration pathways and rates. The permafrost configuration was found to be the most important boundary condition in this model. 7 refs., 1 tab., 5 figs.

  14. Mutations in the Arabidopsis Lst8 and Raptor genes encoding partners of the TOR complex, or inhibition of TOR activity decrease abscisic acid (ABA) synthesis.

    Science.gov (United States)

    Kravchenko, Alena; Citerne, Sylvie; Jéhanno, Isabelle; Bersimbaev, Rakhmetkazhi I; Veit, Bruce; Meyer, Christian; Leprince, Anne-Sophie

    2015-11-27

    The Target of Rapamycin (TOR) kinase regulates essential processes in plant growth and development by modulation of metabolism and translation in response to environmental signals. In this study, we show that abscisic acid (ABA) metabolism is also regulated by the TOR kinase. Indeed ABA hormone level strongly decreases in Lst8-1 and Raptor3g mutant lines as well as in wild-type (WT) Arabidopsis plants treated with AZD-8055, a TOR inhibitor. However the growth and germination of these lines are more sensitive to exogenous ABA. The diminished ABA hormone accumulation is correlated with lower transcript levels of ZEP, NCED3 and AAO3 biosynthetic enzymes, and higher transcript amount of the CYP707A2 gene encoding a key-enzyme in abscisic acid catabolism. These results suggest that the TOR signaling pathway is implicated in the regulation of ABA accumulation in Arabidopsis. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Simulation of hydrodynamic effects of salt rejection due to permafrost. Hydrogeological numerical model of density-driven mixing, at a regional scale, due to a high salinity pulse

    International Nuclear Information System (INIS)

    Vidstrand, Patrik; Svensson, Urban; Follin, Sven

    2006-10-01

    The main objective of this study is to support the safety assessment of the investigated candidate sites concerning hydrogeological and hydrogeochemical issues related to permafrost. However, a more specific objective of the study is to improve the assessment of processes in relation to permafrost scenarios. The model is based on a mathematical model that includes Darcy velocities, mass conservation, matrix diffusion, and salinity distribution. Gravitational effects are thus fully accounted for. A regional groundwater flow model (POM v1.1, Simpevarp) was used as basis for the simulations. The main results of the model include salinity distributions in time. The general conclusion is that density-driven mixing processes are contained within more permeable deformation zones and that these processes are fast as compared with preliminary permafrost growth rates. The results of the simulation suggest that a repository volume in the rock mass in-between the deterministic deformation zones, approximately 150 m below the permafrost will not experience a high salinity situation due to the salt rejection process

  16. Changes in surface area of the Böön Tsagaan and Orog lakes (Mongolia, Valley of the Lakes, 1974-2013) compared to climate and permafrost changes

    Science.gov (United States)

    Szumińska, Danuta

    2016-07-01

    The main aim of the study is the analysis of changes in surface area of lake Böön Tsagaan (45°35‧N, 99°8‧E) and lake Orog (45°3‧N, 100°44‧E) taking place in the last 40 years in the context of climate conditions and permafrost degradation. The lakes, located in Central Mongolia, at the borderline of permafrost range are fed predominantly by river waters and groundwater from the surrounding mountain areas, characterized by continuous and discontinuous permafrost occurrence - mostly the Khangai. The analysis of the Böön Tsagaan and Orog lake surface area in 1974-2013 was conducted based on satellite images, whereas climate conditions were analysed using the NOAA climate data and CRU dataset. Principal Component Analysis (PCA) was used to study the relationship patterns between the climatic factors and changes in the surface area of the lakes. A tendency for a decrease in surface area, intermittent with short episodes of resupply, was observed in both studied lakes. Climate changes recorded in the analysed period had both direct and indirect impacts on water supply to lakes. Taking into account the results of PCA analysis, the most significant factors include: fluctuation of annual precipitation, increase in air temperature and thickness of snow cover. The extended duration of snow cover in the last decades of the 20th century may constitute a key factor in relation to permafrost degradation.

  17. Modeling interactions of soil hydrological dynamics and soil thermal and permafrost dynamics and their effects on carbon cycling in northern high latitudes

    Science.gov (United States)

    Zhuang, Q.; Tang, J.

    2008-12-01

    Large areas of northern high latitude ecosystems are underlain with permafrost. The warming temperature and fires deteriorate the stability of those permafrost, altering hydrological cycle, and consequently soil temperature and active layer depth. These changes will determine the fate of large carbon pools in soils and permafrost over the region. We developed a modeling framework of hydrology, permafrost, and biogeochemical dynamics based on our existing modules of these components. The framework was incorporated with a new snow dynamics module and the effects of soil moisture on soil thermal properties. The framework was tested for tundra and boreal forest ecosystems at field sites with respect to soil thermal and hydrological regimes in Alaska and was then applied to the whole Alaskan ecosystems for the period of 1923-2000 at a daily time step. Our two sets of simulations with and without considering soil moisture effects indicated that the soil temperature profile and active layer depth between two simulations are significant different. The differences of soil thermal regime would expect to result in different carbon dynamics. Next, we will verify the framework with the observed data of soil moisture and soil temperature at poor-drain, moderate-drain, and well-drain boreal forest sites in Alaska. With the verified framework, we will evaluate the effects of interactions of soil thermal and hydrological dynamics on carbon dynamics for the whole northern high latitudes.

  18. Vegetation Changes in the Permafrost Regions of the Qinghai-Tibetan Plateau from 1982-2012: Different Responses Related to Geographical Locations and Vegetation Types in High-Altitude Areas.

    Directory of Open Access Journals (Sweden)

    Zhiwei Wang

    Full Text Available The Qinghai-Tibetan Plateau (QTP contains the largest permafrost area in a high-altitude region in the world, and the unique hydrothermal environments of the active layers in this region have an important impact on vegetation growth. Geographical locations present different climatic conditions, and in combination with the permafrost environments, these conditions comprehensively affect the local vegetation activity. Therefore, the responses of vegetation to climate change in the permafrost region of the QTP may be varied differently by geographical location and vegetation condition. In this study, using the latest Global Inventory Modeling and Mapping Studies (GIMMS Normalized Difference Vegetation Index (NDVI product based on turning points (TPs, which were calculated using a piecewise linear model, 9 areas within the permafrost region of the QTP were selected to investigate the effect of geographical location and vegetation type on vegetation growth from 1982 to 2012. The following 4 vegetation types were observed in the 9 selected study areas: alpine swamp meadow, alpine meadow, alpine steppe and alpine desert. The research results show that, in these study areas, TPs mainly appeared in 2000 and 2001, and almost 55.1% and 35.0% of the TPs were located in 2000 and 2001. The global standardized precipitation evapotranspiration index (SPEI and 7 meteorological variables were selected to analyze their correlations with NDVI. We found that the main correlative variables to vegetation productivity in study areas from 1982 to 2012 were precipitation, surface downward long-wave radiation and temperature. Furthermore, NDVI changes exhibited by different vegetation types within the same study area followed similar trends. The results show that regional effects rather than vegetation type had a larger impact on changes in vegetation growth in the permafrost regions of the QTP, indicating that climatic factors had a larger impact in the permafrost

  19. Year-round methane emissions from permafrost in a North-east Siberian region

    Science.gov (United States)

    Castro-Morales, Karel; Kaiser, Sonja; Kleinen, Thomas; Kwon, Min Jung; Kittler, Fanny; Zaehle, Sönke; Beer, Christian; Göckede, Mathias

    2017-04-01

    In recent decades, permafrost regions in northern latitudes are thawing as a response of climate warming. Soils in permafrost areas contain vast amounts of organic material that is released into the environment after thaw, providing new labile material for bacterial decomposition. As a result, higher production of methane in the anoxic soil layers and within anaerobic wetlands is anticipated, and this will be further released to the atmosphere. In order to assess the current large-scale methane emissions from a wetland permafrost-thaw affected area, we present results of year-round simulated methane emissions at regional scale for a section at the Russian far Northeast in Siberia, located in the low Arctic tundra and characterized by continuous permafrost. For this we use a newly developed process-based methane model built in the framework of the land surface model JSBACH. The model contains explicit permafrost processes and an improved representation of the horizontal extent of wetlands with a hydrological model (TOPMODEL). Model simulated distribution and horizontal extent of wetlands is evaluated against high-resolution remote sensing data. Total and individual regional methane emissions by ebullition, molecular diffusion, plant-mediated and emissions through snow are presented for 2014 and 2015. The model shows a reasonable seasonal transition between the individual methane emission paths. Most of the methane emissions to the atmosphere occur in summer (July, August, September), with the peak of the emissions during August. In this month, plant-mediated transport is the dominant emission path with about 15 mg CH4 m-2 d-1 in 2014, followed by ebullition (7 mg CH4 m-2 d-1) accounting for about half of the emissions thorough plants. Molecular diffusion is a minor contributor with only 0.006 mg CH4 m-2 d-1 at the peak of the summer emissions. Methane emissions through snow occur only during spring, fall and winter months, with higher emissions in spring and autumn

  20. Permafrost thaw and wildfire: Equally important drivers of boreal tree cover changes in the Taiga Plains, Canada

    Science.gov (United States)

    Helbig, M.; Pappas, C.; Sonnentag, O.

    2016-02-01

    Boreal forests cover vast areas of the permafrost zones of North America, and changes in their composition and structure can lead to pronounced impacts on the regional and global climate. We partition the variation in regional boreal tree cover changes between 2000 and 2014 across the Taiga Plains, Canada, into its main causes: permafrost thaw, wildfire disturbance, and postfire regrowth. Moderate Resolution Imaging Spectroradiometer Percent Tree Cover (PTC) data are used in combination with maps of historic fires, and permafrost and drainage characteristics. We find that permafrost thaw is equally important as fire history to explain PTC changes. At the southern margin of the permafrost zone, PTC loss due to permafrost thaw outweighs PTC gain from postfire regrowth. These findings emphasize the importance of permafrost thaw in controlling regional boreal forest changes over the last decade, which may become more pronounced with rising air temperatures and accelerated permafrost thaw.

  1. Epilithonimonas psychrotolerans sp. nov., isolated from alpine permafrost.

    Science.gov (United States)

    Ge, Liang; Zhao, Qi; Sheng, Hongmei; Wu, Jianmin; An, Lizhe

    2015-11-01

    A bacterial strain, designated TSBY 57T, was isolated during a study on the phylogenetic diversity of culturable bacteria from alpine permafrost in Tianshan Mountains, China, and was classified by means of a polyphasic taxonomic approach. The novel strain was found to belong to the genus Epilithonimonas and was distinguished from recognized species of this genus. Strain TSBY 57T grew aerobically, at 0-30 °C, with 0-1.5% (w/v) NaCl and at pH 6-8.Cells were Gram-stain-negative, non-motile, non-spore-forming rods. Compared with the reference strains, the novel strain was psychrotolerant. The predominant fatty acids were summed feature 3 (consisting of C16:1ω7c and/or C16:1ω6c), anteiso-C15:0 and iso-C15:0.The sole respiratory quinone was MK-6.Phosphatidylethanolamine was predominant in the polar lipid profile of strain TSBY 57T. These chemotaxonomic traits were in good agreement with the characteristics of the genus Epilithonimonas. On the basis of 16S rRNA gene sequence similarity, strain TSBY 57T was a member of the genus Epilithonimonas and was closely related to Epilithonimonas tenax DSM 16811T (99.0%), Epilithonimonas ginsengisoli DCY78T (98.6%) and Epilithonimonas lactis H1T (98.5%). However, DNA-DNA reassociation values between strain TSBY 57T and E. tenax DSM 16811T, E. ginsengisoli DCY78T and E. lactis H1T were 39.5 ± 2.6, 37.7 ± 1.0 and 37.3 ± 1.1%, respectively. The G+C content of the DNA was 34.4 ± 0.2  mol%. Based on data from this polyphasic taxonomic study, strain TSBY 57T represents a novel species of the genus Epilithonimonas, for which the name Epilithonimonas psychrotolerans sp. nov. is proposed. The type strain is TSBY 57T ( = NRRL B-51307T=CCTCC AB 207182T).

  2. Variations in Growing-Season NDVI and Its Response to Permafrost Degradation in Northeast China

    Directory of Open Access Journals (Sweden)

    Jinting Guo

    2017-04-01

    Full Text Available Permafrost is extremely sensitive to climate change. The degradation of permafrost has strong and profound effects on vegetation. The permafrost zone of northeastern China is the second largest region of permafrost in China and lies on the south edge of the Eurasian cryolithozone. This study analyzed the spatiotemporal variations of the growing-season Normalization Difference Vegetation Index (NDVI in the permafrost zone of northeastern China and analyzed the correlation between NDVI and ground surface temperatures (GST during the years 1981–2014. Mean growing-season NDVI (MGS-NDVI experienced a marked increase of 0.003 year−1 across the entire permafrost zone. The spatial dynamics of vegetation cover had a high degree of heterogeneity on a per pixel scale. The MGS-NDVI value increased significantly (5% significance level in 80.57%, and this increase was mostly distributed in permafrost zone except for the western steppe region. Only 7.72% experienced a significant decrease in NDVI, mainly in the cultivated and steppe portions. In addition, MGS-NDVI increased significantly with increasing growing-season mean ground surface temperature (GS-MGST. Our results suggest that a warming of GS-MGST (permafrost degradation in the permafrost region of northeastern China played a positive role in increasing plant growth and activities. Although increasing ground surface temperature resulted in increased vegetation cover and growth in the short time of permafrost degradation, from the long term point of view, permafrost degradation or disappearance may weaken or even hinder vegetation activities.

  3. The thin brown line: The crucial role of peat in protecting permafrost in Arctic Alaska

    Science.gov (United States)

    Gaglioti, B.; Mann, D. H.; Farquharson, L. M.; Baughman, C. A.; Jones, B. M.; Romanovsky, V. E.; Williams, A. P.; Andreu-Hayles, L.

    2017-12-01

    Ongoing warming threatens to thaw Arctic permafrost and release its stored carbon, which could trigger a permafrost-carbon feedback capable of augmenting global warming. The effects of warming air temperatures on permafrost are complicated by the fact that across much of the Arctic and Subarctic a mat of living plants and decaying litter cover the ground and buffer underlying permafrost from air temperatures. For simplicity here, we refer to this organic mat as "peat". Because this peat modifies heat flow between ground and air, the rate and magnitude of permafrost responses to changing climate - and hence the permafrost-carbon feedback - are partly slaved to the peat layer's slower dynamics. To explore this relationship, we used 14C-age offsets within lake sediments in Alaskan watersheds underlain by yedoma deposits to track the changing responses of permafrost thaw to fluctuating climate as peat accumulated over the last 14,000 years. As the peat layer built up, warming events became less effective at thawing permafrost and releasing ancient carbon. Consistent with this age-offset record, the geological record shows that early in post-glacial times when the peat cover was still thin and limited in extent, warm intervals triggered extensive thermokarst that resulted in rapid aggradation of floodplains. Today in contrast, hillslopes and floodplains remain stable despite rapid warming, probably because of the buffering effects of the extensive peat cover. Another natural experiment is provided by tundra fires like the 2007 Anaktuvuk River fire that removed the peat cover from tundra underlain by continuous permafrost and resulted in widespread thermkarsting. Further support for peat's critical role in protecting permafrost comes from the results of modeling how permafrost temperatures under different peat thicknesses respond to warming air temperature. Although post-industrial warming has not yet surpassed the buffering capacity of 14,000 years of peat buildup in

  4. Dynamics of Permafrost Associated Methane Hydrate in Response to Climate Change

    Science.gov (United States)

    You, K.; Flemings, P. B.

    2014-12-01

    The formation and melting of methane hydrate and ice are intertwined in permafrost regions. A shortage of methane supply leads to formation of hydrate only at depth, below the base of permafrost. We consider a system with the ground surface initially at 0 oC with neither ice nor hydrate present. We abruptly decrease the temperature from 0 to -10 oC to simulate the effect of marine regression/ global cooling. A low methane supply rate of 0.005 kg m-2 yr-1 from depth leads to distinct ice and hydrate layers: a 100 m continuous hydrate layer is present beneath 850 m at 80 k.y.. However, a high methane supply rate of 0.1 kg m-2 yr-1 leads to 50 m ice-bonded methane hydrate at the base of permafrost, and the hydrate layer distributes between the depth of 350 and 700 m at 80 k.y.. We apply our model to illuminate future melting of hydrate at Mallik, a known Arctic hydrate accumulation. We assume a 600 m thick ice saturated (average 90%) layer extending downward from the ground surface. We increase the surface temperature linearly from -6 to 0 oC for 300 yr and then keep the surface temperature at 0 oC to reflect future climate warming caused by doubling of CO2. Hydrate melting is initiated at the base of the hydrate layer after 15 k.y.. Methane gas starts to vent to the atmosphere at 38 k.y. with an average flux of ~ 0.35 g m-2 yr-1. If the 600 m thick average ice saturation is decreased to half (45%) (or to zero), methane gas starts to vent to the atmosphere at 29 k.y. (or at 20 k.y.) with the same average flux. These results are found by a newly-developed fully-coupled multiphase multicomponent fluid flow and heat transport model. Our thermodynamic equilibrium-based model emphasizes the role of salinity in both ice and hydrate dynamics.

  5. Increasing risks related to landslides from degrading permafrost into new lakes in de-glaciating mountain ranges

    Science.gov (United States)

    Haeberli, Wilfried; Schaub, Yvonne; Huggel, Christian

    2017-09-01

    While glacier volumes in most cold mountain ranges rapidly decrease due to continued global warming, degradation of permafrost at altitudes above and below glaciers is much slower. As a consequence, many still existing glacier and permafrost landscapes probably transform within decades into new landscapes of bare bedrock, loose debris, sparse vegetation, numerous new lakes and steep slopes with slowly degrading permafrost. These new landscapes are likely to persist for centuries if not millennia to come. During variable but mostly extended future time periods, such new landscapes will be characterized by pronounced disequilibria within their geo- and ecosystems. This especially involves long-term stability reduction of steep/icy mountain slopes as a slow and delayed reaction to stress redistribution following de-buttressing by vanishing glaciers and to changes in mechanical strength and hydraulic permeability caused by permafrost degradation. Thereby, the probability of far-reaching flood waves from large mass movements into lakes systematically increases with the formation of many new lakes and systems of lakes in close neighborhood to, or even directly at the foot of, so-affected slopes. Results of recent studies in the Swiss Alps are reviewed and complemented with examples from the Cordillera Blanca in Peru and the Mount Everest region in Nepal. Hot spots of future hazards from potential flood waves caused by large rock falls into new lakes can already now be recognized. To this end, integrated spatial information on glacier/permafrost evolution and lake formation can be used together with scenario-based models for rapid mass movements, impact waves and flood propagation. The resulting information must then be combined with exposure and vulnerability considerations related to settlements and infrastructure. This enables timely planning of risk reduction options. Such risk reduction options consist of two components: Mitigation of hazards, which in the present

  6. Using in-field and remote sensing techniques for the monitoring of small-scale permafrost decline in Northern Quebec

    Science.gov (United States)

    May, Inga; Kim, Jun Su; Spannraft, Kati; Ludwig, Ralf; Hajnsek, Irena; Bernier, Monique; Allard, Michel

    2010-05-01

    Permafrost-affected soils represent about 45% of Canadian arctic and subarctic regions. Under the recently recorded changed climate conditions, the areas located in the discontinuous permafrost zones are likely to belong to the most impacted environments. Degradations of Palsas and lithalsas as being the most distinct permafrost landforms as well as an extension of wetlands have been observe during the past decades by several research teams all over the northern Arctic. These alterations, caused by longer an warmer thawing periods, are expected to become more and more frequent in the future. The effects on human beings and on the surrounding sensitive ecosystems are presumed to be momentous and of high relevance. Hence, there is a high demand for new techniques that are able to detect, and possibly even predict, the behavior of the permafrost within a changing environment. The presented study is part of an international research collaboration between LMU, INRS and UL within the framework of ArcticNet. The project intends to develop a monitoring system strongly based on remote sensing imagery and GIS-based data analysis, using a test site located in northern Quebec (Umiujaq, 56°33' N, 76°33' W). It shall be investigated to which extent the interpretation of satellite imagery is feasible to partially substitute costly and difficult geophysical point measurements, and to provide spatial knowledge about the major factors that control permafrost dynamics and ecosystem change. In a first step, these factors, mainly expected to be determined from changes in topography, vegetation cover and snow cover, are identified and validated by means of several consecutive ground truthing initiatives supporting the analysis of multi-sensoral time series of remotely sensed information. Both sources are used to generate and feed different concepts for modeling permafrost dynamics by ways of parameter retrieval and data assimilation. On this poster, the outcomes of the first project

  7. Assessment of permafrost distribution maps in the Hindu Kush Himalayan region using rock glaciers mapped in Google Earth

    NARCIS (Netherlands)

    Schmid, M.O.; Baral, P.; Gruber, S.; Shahi, S.; Shrestha, T.; Stumm, D.; Wester, P.

    2015-01-01

    The extent and distribution of permafrost in the mountainous parts of the Hindu Kush Himalayan (HKH) region are largely unknown. A long tradition of permafrost research, predominantly on rather gentle relief, exists only on the Tibetan Plateau. Two permafrost maps are available digitally that

  8. Distinct microbial communities in the active and permafrost layers on the Tibetan Plateau.

    Science.gov (United States)

    Chen, Yong-Liang; Deng, Ye; Ding, Jin-Zhi; Hu, Hang-Wei; Xu, Tian-Le; Li, Fei; Yang, Gui-Biao; Yang, Yuan-He

    2017-12-01

    Permafrost represents an important understudied genetic resource. Soil microorganisms play important roles in regulating biogeochemical cycles and maintaining ecosystem function. However, our knowledge of patterns and drivers of permafrost microbial communities is limited over broad geographic scales. Using high-throughput Illumina sequencing, this study compared soil bacterial, archaeal and fungal communities between the active and permafrost layers on the Tibetan Plateau. Our results indicated that microbial alpha diversity was significantly higher in the active layer than in the permafrost layer with the exception of fungal Shannon-Wiener index and Simpson's diversity index, and microbial community structures were significantly different between the two layers. Our results also revealed that environmental factors such as soil fertility (soil organic carbon, dissolved organic carbon and total nitrogen contents) were the primary drivers of the beta diversity of bacterial, archaeal and fungal communities in the active layer. In contrast, environmental variables such as the mean annual precipitation and total phosphorus played dominant roles in driving the microbial beta diversity in the permafrost layer. Spatial distance was important for predicting the bacterial and archaeal beta diversity in both the active and permafrost layers, but not for fungal communities. Collectively, these results demonstrated different driving factors of microbial beta diversity between the active layer and permafrost layer, implying that the drivers of the microbial beta diversity observed in the active layer cannot be used to predict the biogeographic patterns of the microbial beta diversity in the permafrost layer. © 2017 John Wiley & Sons Ltd.

  9. Chemical indicators of cryoturbation and microbial processing throughout an alaskan permafrost soil depth profile

    Science.gov (United States)

    Although permafrost soils contain vast stores of carbon, we know relatively little about the chemical composition of their constituent organic matter. Soil organic matter chemistry is an important predictor of decomposition rates, especially in the initial stages of decomposition. Permafrost, organi...

  10. Methane production as key to the greenhouse gas budget of thawing permafrost

    Science.gov (United States)

    Knoblauch, Christian; Beer, Christian; Liebner, Susanne; Grigoriev, Mikhail N.; Pfeiffer, Eva-Maria

    2018-04-01

    Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change1,2. Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils3-6 and a stronger permafrost carbon-climate feedback from drained (oxic) soils1,7. Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2-carbon equivalents (CO2-Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account8. A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 ± 58 g CO2-C kgC-1 (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2-Ce (241 ± 138 g CO2-Ce kgC-1) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.

  11. Paleo-Eskimo kitchen midden preservation in permafrost under future climate conditions at Qajaa, West Greenland

    DEFF Research Database (Denmark)

    Elberling, Bo; Matthiesen, Henning; Jørgensen, Christian Juncher

    2011-01-01

    characteristics measured in situ and from permafrost cores. Measurements of thermal properties, heat generation, oxygen consumption and CO2 production show that the kitchen midden can be characterized as peat but produces 4–7 times more heat than natural sediment. An analytical model from permafrost research has...

  12. The circuitry of ecosystem metabolism: CO2 and CH4 flux from permafrost soils

    Science.gov (United States)

    Microbial decomposition of thawed permafrost organic matter could release greenhouse gases (GHG) to the atmosphere and accelerate the carbon (C)-climate feedback. Greenhouse gas emissions from thawed permafrost are difficult to predict because they result from complex interactions between abiotic dr...

  13. Vulnerability of Permafrost Soil Carbon to Climate Warming: Evaluating Controls on Microbial Community Composition

    Science.gov (United States)

    Abstract: Despite the fact that permafrost soils contain up to half of the carbon (C) in terrestrial pools, we have a poor understanding of the controls on decomposition in thawed permafrost. Global climate models assume that decomposition increases linearly with temperature, yet decomposition in th...

  14. Draft Genome Sequence of Methylocella silvestris TVC, a Facultative Methanotroph Isolated from Permafrost

    OpenAIRE

    Wang, Jing; Geng, Kan; Farhan Ul Haque, Muhammad; Crombie, Andrew; Street, Lorna E.; Wookey, Philip A.; Ma, Ke; Murrell, J. Colin; Pratscher, Jennifer

    2018-01-01

    Permafrost environments play a crucial role in global carbon and methane cycling. We report here the draft genome sequence of Methylocella silvestris TVC, a new facultative methanotroph strain, isolated from the Siksik Creek catchment in the continuous permafrost zone of Inuvik (Northwest Territories, Canada).

  15. Draft Genome Sequence of Methylocella silvestris TVC, a Facultative Methanotroph Isolated from Permafrost.

    Science.gov (United States)

    Wang, Jing; Geng, Kan; Farhan Ul Haque, Muhammad; Crombie, Andrew; Street, Lorna E; Wookey, Philip A; Ma, Ke; Murrell, J Colin; Pratscher, Jennifer

    2018-02-22

    Permafrost environments play a crucial role in global carbon and methane cycling. We report here the draft genome sequence of Methylocella silvestris TVC, a new facultative methanotroph strain, isolated from the Siksik Creek catchment in the continuous permafrost zone of Inuvik (Northwest Territories, Canada). Copyright © 2018 Wang et al.

  16. Controls on the methane released through ebullition affected by permafrost degradation

    Science.gov (United States)

    S.J. Klapstein; M.R. Turetsky; A.D. McGuire; J.W. Harden; C.I. Czimczik; X. Xu; J.P. Chanton; J.M. Waddington

    2014-01-01

    Permafrost thaw in peat plateaus leads to the flooding of surface soils and the formation of collapse scar bogs, which have the potential to be large emitters of methane (CH4) from surface peat as well as deeper, previously frozen, permafrost carbon (C). We used a network of bubble traps, permanently installed 20 cm and 60 cm beneath the moss surface, to examine...

  17. Molecular investigations into a globally important carbon pool: permafrost-protected carbon in Alaskan soils

    Science.gov (United States)

    M.P. Waldrop; K.P. Wickland; R. White; A.A. Berhe; J.W. Harden; V.E. Romanovsky

    2010-01-01

    The fate of carbon (C) contained within permafrost in boreal forest environments is an important consideration for the current and future carbon cycle as soils warm in northern latitudes. Currently, little is known about the microbiology or chemistry of permafrost soils that may affect its decomposition once soils thaw. We tested the hypothesis that low microbial...

  18. Evaluation of Electromagnetic Induction (EMI) Resistivity Technologies for Assessing Permafrost Geomorphologies

    Science.gov (United States)

    2016-08-01

    resistivity, have been used to interrogate the subsur- face in permafrost terrains at the meters to kilometers scales. Airborne measurement techniques have...burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense... interrogate the subsurface in permafrost terrains at the meters to kilometers scales. Airborne measurement techniques have broad applicability at the

  19. Reviews and syntheses : Effects of permafrost thaw on Arctic aquatic ecosystems

    NARCIS (Netherlands)

    Vonk, J. E.; Tank, S. E.; Bowden, W.B.; Laurion, I.; Vincent, W. F.; Alekseychik, P.; Amyot, M.; Billet, M. F.; Canário, J.; Cory, R. M.; Deshpande, B. N.; Helbig, M.; Jammet, M.; Karlsson, J.; Larouche, J.; Macmillan, G.; Rautio, M.; Walter Anthony, K. M.; Wickland, K.P.

    2015-01-01

    The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new freshwater ecosystems, while at the same time modifying the existing lakes, streams, and rivers that are impacted by thaw. Here, we describe the current

  20. Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge thaw

    NARCIS (Netherlands)

    Vonk, J.E.; Mann, P.J.; Dowdy, K.L.; Davydova, A.; Davydov, S.P.; Zimov, N.; Spencer, R.G.M.; Bulygina, E.B.; Eglinton, T.I.; Holmes, R.M.

    2013-01-01

    Pleistocene Yedoma permafrost contains nearly a third of all organic matter (OM) stored in circum-arctic permafrost and is characterized by the presence of massive ice wedges. Due to its rapid formation by sediment accumulation and subsequent frozen storage, Yedoma OM is relatively well preserved

  1. Vulnerability of permafrost carbon to climate change: implications for the global carbon cycle

    Science.gov (United States)

    Edward A.G. Schuur; James Bockheim; Josep G. Canadell; Eugenie Euskirchen; Christopher B. Field; Sergey V. Goryachkin; Stefan Hagemann; Peter Kuhry; Peter M. Lafleur; Hanna Lee; Galina Mazhitova; Frederick E. Nelson; Annette Rinke; Vladimir E. Romanovsky; Nikolay Shiklomanov; Charles Tarnocai; Sergey Venevsky; Jason G. Vogel; Sergei A. Zimov

    2008-01-01

    Thawing permafrost and the resulting microbial decomposition of previously frozen organic carbon (C) is one of the most significant potential feedbacks from terrestrial ecosystems to the atmosphere in a changing climate. In this article we present an overview of the global permafrost C pool and of the processes that might transfer this C into the atmosphere, as well as...

  2. Response of CO2 exchange in a tussock tundra ecosystem to permafrost thaw and thermokarst development

    Science.gov (United States)

    Jason Vogel; Edward A.G. Schuur; Christian Trucco; Hanna. Lee

    2009-01-01

    Climate change in high latitudes can lead to permafrost thaw, which in ice-rich soils can result in ground subsidence, or thermokarst. In interior Alaska, we examined seasonal and annual ecosystem CO2 exchange using static and automatic chamber measurements in three areas of a moist acidic tundra ecosystem undergoing varying degrees of permafrost...

  3. LGM permafrost distribution: how well can the latest PMIP multi-model ensembles perform reconstruction?

    Directory of Open Access Journals (Sweden)

    K. Saito

    2013-08-01

    Full Text Available Here, global-scale frozen ground distribution from the Last Glacial Maximum (LGM has been reconstructed using multi-model ensembles of global climate models, and then compared with evidence-based knowledge and earlier numerical results. Modeled soil temperatures, taken from Paleoclimate Modelling Intercomparison Project phase III (PMIP3 simulations, were used to diagnose the subsurface thermal regime and determine underlying frozen ground types for the present day (pre-industrial; 0 kya and the LGM (21 kya. This direct method was then compared to an earlier indirect method, which categorizes underlying frozen ground type from surface air temperature, applying to both the PMIP2 (phase II and PMIP3 products. Both direct and indirect diagnoses for 0 kya showed strong agreement with the present-day observation-based map. The soil temperature ensemble showed a higher diversity around the border between permafrost and seasonally frozen ground among the models, partly due to varying subsurface processes, implementation, and settings. The area of continuous permafrost estimated by the PMIP3 multi-model analysis through the direct (indirect method was 26.0 (17.7 million km2 for LGM, in contrast to 15.1 (11.2 million km2 for the pre-industrial control, whereas seasonally frozen ground decreased from 34.5 (26.6 million km2 to 18.1 (16.0 million km2. These changes in area resulted mainly from a cooler climate at LGM, but from other factors as well, such as the presence of huge land ice sheets and the consequent expansion of total land area due to sea-level change. LGM permafrost boundaries modeled by the PMIP3 ensemble – improved over those of the PMIP2 due to higher spatial resolutions and improved climatology – also compared better to previous knowledge derived from geomorphological and geocryological evidence. Combinatorial applications of coupled climate models and detailed stand-alone physical-ecological models for the cold-region terrestrial

  4. LGM permafrost distribution: how well can the latest PMIP multi-model ensembles perform reconstruction?

    Science.gov (United States)

    Saito, K.; Sueyoshi, T.; Marchenko, S.; Romanovsky, V.; Otto-Bliesner, B.; Walsh, J.; Bigelow, N.; Hendricks, A.; Yoshikawa, K.

    2013-08-01

    Here, global-scale frozen ground distribution from the Last Glacial Maximum (LGM) has been reconstructed using multi-model ensembles of global climate models, and then compared with evidence-based knowledge and earlier numerical results. Modeled soil temperatures, taken from Paleoclimate Modelling Intercomparison Project phase III (PMIP3) simulations, were used to diagnose the subsurface thermal regime and determine underlying frozen ground types for the present day (pre-industrial; 0 kya) and the LGM (21 kya). This direct method was then compared to an earlier indirect method, which categorizes underlying frozen ground type from surface air temperature, applying to both the PMIP2 (phase II) and PMIP3 products. Both direct and indirect diagnoses for 0 kya showed strong agreement with the present-day observation-based map. The soil temperature ensemble showed a higher diversity around the border between permafrost and seasonally frozen ground among the models, partly due to varying subsurface processes, implementation, and settings. The area of continuous permafrost estimated by the PMIP3 multi-model analysis through the direct (indirect) method was 26.0 (17.7) million km2 for LGM, in contrast to 15.1 (11.2) million km2 for the pre-industrial control, whereas seasonally frozen ground decreased from 34.5 (26.6) million km2 to 18.1 (16.0) million km2. These changes in area resulted mainly from a cooler climate at LGM, but from other factors as well, such as the presence of huge land ice sheets and the consequent expansion of total land area due to sea-level change. LGM permafrost boundaries modeled by the PMIP3 ensemble - improved over those of the PMIP2 due to higher spatial resolutions and improved climatology - also compared better to previous knowledge derived from geomorphological and geocryological evidence. Combinatorial applications of coupled climate models and detailed stand-alone physical-ecological models for the cold-region terrestrial, paleo-, and modern

  5. Towards improved parameterization of a macroscale hydrologic model in a discontinuous permafrost boreal forest ecosystem

    Directory of Open Access Journals (Sweden)

    A. Endalamaw

    2017-09-01

    Full Text Available Modeling hydrological processes in the Alaskan sub-arctic is challenging because of the extreme spatial heterogeneity in soil properties and vegetation communities. Nevertheless, modeling and predicting hydrological processes is critical in this region due to its vulnerability to the effects of climate change. Coarse-spatial-resolution datasets used in land surface modeling pose a new challenge in simulating the spatially distributed and basin-integrated processes since these datasets do not adequately represent the small-scale hydrological, thermal, and ecological heterogeneity. The goal of this study is to improve the prediction capacity of mesoscale to large-scale hydrological models by introducing a small-scale parameterization scheme, which better represents the spatial heterogeneity of soil properties and vegetation cover in the Alaskan sub-arctic. The small-scale parameterization schemes are derived from observations and a sub-grid parameterization method in the two contrasting sub-basins of the Caribou Poker Creek Research Watershed (CPCRW in Interior Alaska: one nearly permafrost-free (LowP sub-basin and one permafrost-dominated (HighP sub-basin. The sub-grid parameterization method used in the small-scale parameterization scheme is derived from the watershed topography. We found that observed soil thermal and hydraulic properties – including the distribution of permafrost and vegetation cover heterogeneity – are better represented in the sub-grid parameterization method than the coarse-resolution datasets. Parameters derived from the coarse-resolution datasets and from the sub-grid parameterization method are implemented into the variable infiltration capacity (VIC mesoscale hydrological model to simulate runoff, evapotranspiration (ET, and soil moisture in the two sub-basins of the CPCRW. Simulated hydrographs based on the small-scale parameterization capture most of the peak and low flows, with similar accuracy in both sub

  6. Microbial populations in Antarctic permafrost: biodiversity, state, age, and implication for astrobiology.

    Science.gov (United States)

    Gilichinsky, D A; Wilson, G S; Friedmann, E I; McKay, C P; Sletten, R S; Rivkina, E M; Vishnivetskaya, T A; Erokhina, L G; Ivanushkina, N E; Kochkina, G A; Shcherbakova, V A; Soina, V S; Spirina, E V; Vorobyova, E A; Fyodorov-Davydov, D G; Hallet, B; Ozerskaya, S M; Sorokovikov, V A; Laurinavichyus, K S; Shatilovich, A V; Chanton, J P; Ostroumov, V E; Tiedje, J M

    2007-04-01

    Antarctic permafrost soils have not received as much geocryological and biological study as has been devoted to the ice sheet, though the permafrost is more stable and older and inhabited by more microbes. This makes these soils potentially more informative and a more significant microbial repository than ice sheets. Due to the stability of the subsurface physicochemical regime, Antarctic permafrost is not an extreme environment but a balanced natural one. Up to 10(4) viable cells/g, whose age presumably corresponds to the longevity of the permanently frozen state of the sediments, have been isolated from Antarctic permafrost. Along with the microbes, metabolic by-products are preserved. This presumed natural cryopreservation makes it possible to observe what may be the oldest microbial communities on Earth. Here, we describe the Antarctic permafrost habitat and biodiversity and provide a model for martian ecosystems.

  7. Geophysical Investigation of a Thermokarst Lake Talik in Continuous Permafrost

    Science.gov (United States)

    Creighton, A.; Parsekian, A.; Arp, C. D.; Jones, B. M.; Babcock, E.; Bondurant, A. C.

    2016-12-01

    On the Arctic Coastal Plain (ACP) of northern Alaska, shallow thermokarst lakes cover up to 25% of the landscape. These lakes occupy depressions created by the subsidence of thawed, ice-rich permafrost. Areas of unfrozen sediment, or taliks, can form under lakes that have a mean annual bottom temperature greater than 0°C. The geometry of these taliks, as well as the processes that create them, are important for understanding interactions between surface water, groundwater, and carbon cycling. Non-invasive geophysical methods are a useful means to study talik sediments as borehole studies yield few data points, and the contrast between unfrozen and frozen sediments is an ideal geophysical target. To study talik configuration associated with an actively expanding thermokarst lake, we conducted a geophysical transect across Peatball Lake. This lake has an estimated initiation age of 1400 calendar years BP. Over the past 60 years, lake surface area has increased through thermal and mechanical shoreline erosion. A talik of previously unknown thickness likely exists below Peatball Lake. We conducted a transect of transient electromagnetic soundings across the lake extending into the surrounding terrestrial environment. Since permafrost has relatively high resistivity compared to talik sediments, the interpreted electrical structure of the subsurface likely reflects talik geometry. We also conducted nuclear magnetic resonance soundings at representative locations along the transect. These measurements can provide data on sub-lake sediment properties including water content. Together, these measurements resolve the talik structure across the lake transect and showed evidence of varying talik thicknesses from the lake edge to center. These is no evidence of a talik at the terrestrial control sites. These results can help constrain talik development models and thus provide insight into Arctic and permafrost processes in the face of a changing climate.

  8. Dissolved organic carbon and nitrogen release from boreal Holocene permafrost and seasonally frozen soils of Alaska

    Science.gov (United States)

    Wickland, Kimberly P.; Waldrop, Mark P.; Aiken, George R.; Koch, Joshua C.; Torre Jorgenson, M.; Striegl, Robert G.

    2018-06-01

    Permafrost (perennially frozen) soils store vast amounts of organic carbon (C) and nitrogen (N) that are vulnerable to mobilization as dissolved organic carbon (DOC) and dissolved organic and inorganic nitrogen (DON, DIN) upon thaw. Such releases will affect the biogeochemistry of permafrost regions, yet little is known about the chemical composition and source variability of active-layer (seasonally frozen) and permafrost soil DOC, DON and DIN. We quantified DOC, total dissolved N (TDN), DON, and DIN leachate yields from deep active-layer and near-surface boreal Holocene permafrost soils in interior Alaska varying in soil C and N content and radiocarbon age to determine potential release upon thaw. Soil cores were collected at three sites distributed across the Alaska boreal region in late winter, cut in 15 cm thick sections, and deep active-layer and shallow permafrost sections were thawed and leached. Leachates were analyzed for DOC, TDN, nitrate (NO3 ‑), and ammonium (NH4 +) concentrations, dissolved organic matter optical properties, and DOC biodegradability. Soils were analyzed for C, N, and radiocarbon (14C) content. Soil DOC, TDN, DON, and DIN yields increased linearly with soil C and N content, and decreased with increasing radiocarbon age. These relationships were significantly different for active-layer and permafrost soils such that for a given soil C or N content, or radiocarbon age, permafrost soils released more DOC and TDN (mostly as DON) per gram soil than active-layer soils. Permafrost soil DOC biodegradability was significantly correlated with soil Δ14C and DOM optical properties. Our results demonstrate that near-surface Holocene permafrost soils preserve greater relative potential DOC and TDN yields than overlying seasonally frozen soils that are exposed to annual leaching and decomposition. While many factors control the fate of DOC and TDN, the greater relative yields from newly thawed Holocene permafrost soils will have the largest

  9. Influence of vertical and lateral heat transfer on permafrost thaw, peatland landscape transition, and groundwater flow

    Science.gov (United States)

    Kurylyk, Barret L.; Masaki, Masaki; Quinton, William L.; McKenzie, Jeffrey M.; Voss, Clifford I.

    2016-01-01

    Recent climate change has reduced the spatial extent and thickness of permafrost in many discontinuous permafrost regions. Rapid permafrost thaw is producing distinct landscape changes in the Taiga Plains of the Northwest Territories, Canada. As permafrost bodies underlying forested peat plateaus shrink, the landscape slowly transitions into unforested wetlands. The expansion of wetlands has enhanced the hydrologic connectivity of many watersheds via new surface and near-surface flow paths, and increased streamflow has been observed. Furthermore, the decrease in forested peat plateaus results in a net loss of boreal forest and associated ecosystems. This study investigates fundamental processes that contribute to permafrost thaw by comparing observed and simulated thaw development and landscape transition of a peat plateau-wetland complex in the Northwest Territories, Canada from 1970 to 2012. Measured climate data are first used to drive surface energy balance simulations for the wetland and peat plateau. Near-surface soil temperatures simulated in the surface energy balance model are then applied as the upper boundary condition to a three-dimensional model of subsurface water flow and coupled energy transport with freeze-thaw. Simulation results demonstrate that lateral heat transfer, which is not considered in many permafrost models, can influence permafrost thaw rates. Furthermore, the simulations indicate that landscape evolution arising from permafrost thaw acts as a positive feedback mechanism that increases the energy absorbed at the land surface and produces additional permafrost thaw. The modeling results also demonstrate that flow rates in local groundwater flow systems may be enhanced by the degradation of isolated permafrost bodies.

  10. Multi-decadal degradation and persistence of permafrost in the Alaska Highway corridor, northwest Canada

    International Nuclear Information System (INIS)

    James, Megan; Lewkowicz, Antoni G; Smith, Sharon L; Miceli, Christina M

    2013-01-01

    Changes in permafrost distribution in the southern discontinuous zone were evaluated by repeating a 1964 survey through part of the Alaska Highway corridor (56° N–61° N) in northwest Canada. A total of 55 sites from the original survey in northern British Columbia and southern Yukon were located using archival maps and photographs. Probing for frozen ground, manual excavations, air and ground temperature monitoring, borehole drilling and geophysical techniques were used to gather information on present-day permafrost and climatic conditions. Mean annual air temperatures have increased by 1.5–2.0 ° C since the mid-1970s and significant degradation of permafrost has occurred. Almost half of the permafrost sites along the entire transect which exhibited permafrost in 1964 do so no longer. This change is especially evident in the south where two-thirds of the formerly permafrost sites have thawed and the limit of permafrost appears to have shifted northward. The permafrost that persists is patchy, generally less than 15 m thick, has mean annual surface temperatures >0 ° C, mean ground temperatures between −0.5 and 0 ° C, is in peat or beneath a thick organic mat, and appears to have a thicker active layer than in 1964. Its persistence may relate to the latent heat requirements of thawing permafrost or to the large thermal offset of organic soils. The study demonstrates that degradation of permafrost has occurred in the margins of its distribution in the last few decades, a trend that is expected to continue as the climate warms. (letter)

  11. International Field School on Permafrost: Yenisei, Russian Federation - 2013

    Science.gov (United States)

    Nyland, K. E.; Streletskiy, D. A.; Grebenets, V. I.

    2013-12-01

    The International Field School on Permafrost was established in Russia as part of International Polar Year activities. The first course was offered in 2007 in Northwestern Siberia and attracted students from Russia, Germany, and the United States. Over the past seven years undergraduate and graduate students representing eight different countries in North America, Europe, and Asia have participated in the field school. This annual summer field course visits different regions of the Russian Arctic each year, but the three course foci remain consistent, which are to make in depth examinations of, 1) natural permafrost characteristics and conditions, 2) field techniques and applications, and 3) engineering practices and construction on permafrost. During these field courses students participate in excursions to local museums and exhibitions, meet with representatives from local administrations, mining and construction industries, and learn field techniques for complex permafrost investigations, including landscape and soil descriptions, temperature monitoring, active-layer measurements, cryostratigraphy, and more. During these courses students attend an evening lecture series by their professors and also give presentations on various regionally oriented topics of interest, such as the local geology, climate, or historical development of the region. This presentation will relate this summer's (July 2013) field course which took place in the Yenisei River region of central Siberia. The course took place along a bioclimatic transect from south to north along the Yenisei River and featured extended stays in the cities of Igarka and Noril'sk. This year's students (undergraduate, masters, and one PhD student) represented universities in the United States, Canada, and the Russian Federation. The organization of this course was accomplished through the cooperation of The George Washington University's Department of Geography and the Lomonosov Moscow State University

  12. Uav Photogrammetry for Mapping and Monitoring of Northern Permafrost Landscapes

    Science.gov (United States)

    Fraser, R. H.; Olthof, I.; Maloley, M.; Fernandes, R.; Prevost, C.; van der Sluijs, J.

    2015-08-01

    Northern environments are changing in response to recent climate warming, resource development, and natural disturbances. The Arctic climate has warmed by 2-3°C since the 1950's, causing a range of cryospheric changes including declines in sea ice extent, snow cover duration, and glacier mass, and warming permafrost. The terrestrial Arctic has also undergone significant temperature-driven changes in the form of increased thermokarst, larger tundra fires, and enhanced shrub growth. Monitoring these changes to inform land managers and decision makers is challenging due to the vast spatial extents involved and difficult access. Environmental monitoring in Canada's North is often based on local-scale measurements derived from aerial reconnaissance and photography, and ecological, hydrologic, and geologic sampling and surveying. Satellite remote sensing can provide a complementary tool for more spatially comprehensive monitoring but at coarser spatial resolutions. Satellite remote sensing has been used to map Arctic landscape changes related to vegetation productivity, lake expansion and drainage, glacier retreat, thermokarst, and wildfire activity. However, a current limitation with existing satellite-based techniques is the measurement gap between field measurements and high resolution satellite imagery. Bridging this gap is important for scaling up field measurements to landscape levels, and validating and calibrating satellite-based analyses. This gap can be filled to a certain extent using helicopter or fixed-wing aerial surveys, but at a cost that is often prohibitive. Unmanned aerial vehicle (UAV) technology has only recently progressed to the point where it can provide an inexpensive and efficient means of capturing imagery at this middle scale of measurement with detail that is adequate to interpret Arctic vegetation (i.e. 1-5 cm) and coverage that can be directly related to satellite imagery (1-10 km2). Unlike satellite measurements, UAVs permit frequent

  13. UAV PHOTOGRAMMETRY FOR MAPPING AND MONITORING OF NORTHERN PERMAFROST LANDSCAPES

    Directory of Open Access Journals (Sweden)

    R. H. Fraser

    2015-08-01

    Full Text Available Northern environments are changing in response to recent climate warming, resource development, and natural disturbances. The Arctic climate has warmed by 2–3°C since the 1950’s, causing a range of cryospheric changes including declines in sea ice extent, snow cover duration, and glacier mass, and warming permafrost. The terrestrial Arctic has also undergone significant temperature-driven changes in the form of increased thermokarst, larger tundra fires, and enhanced shrub growth. Monitoring these changes to inform land managers and decision makers is challenging due to the vast spatial extents involved and difficult access. Environmental monitoring in Canada’s North is often based on local-scale measurements derived from aerial reconnaissance and photography, and ecological, hydrologic, and geologic sampling and surveying. Satellite remote sensing can provide a complementary tool for more spatially comprehensive monitoring but at coarser spatial resolutions. Satellite remote sensing has been used to map Arctic landscape changes related to vegetation productivity, lake expansion and drainage, glacier retreat, thermokarst, and wildfire activity. However, a current limitation with existing satellite-based techniques is the measurement gap between field measurements and high resolution satellite imagery. Bridging this gap is important for scaling up field measurements to landscape levels, and validating and calibrating satellite-based analyses. This gap can be filled to a certain extent using helicopter or fixed-wing aerial surveys, but at a cost that is often prohibitive. Unmanned aerial vehicle (UAV technology has only recently progressed to the point where it can provide an inexpensive and efficient means of capturing imagery at this middle scale of measurement with detail that is adequate to interpret Arctic vegetation (i.e. 1–5 cm and coverage that can be directly related to satellite imagery (1–10 km2. Unlike satellite measurements

  14. [The intensity of phytodetrite decomposition in Larch Forest of the permafrost zone in central Siberia].

    Science.gov (United States)

    Prokushkin, S G; Prokushkin, A S; Sorokin, N D

    2014-01-01

    Based on the results of long-term investigations, quantitative assessment ofphytodetrite mineralization rates is provided. Their role in the biological cycle of larch stands growing in the permafrost zone of Central Evenkia is discussed. It is demonstrated that their destruction in the subshrub-sphagnum and cowberry-green moss larch stands is extremely slow, the plant litter contains the most cecalcitrant organic matter demonstrating the lowest decomposition coefficient of 0.03-0.04 year(-1), whereas fresh components of the plant litter have 3- to 4-fold higher values. An insignificant input of N and C from the analyzed mortmass to the soil has been registered. It has been revealed that the changes in N and C in the decomposition components are closely related to the quantitative dynamics (biomass) of microorganisms, such as hydrolytics and, especially, micromicetes.

  15. Water Travel Time Distributions in Permafrost-affected Catchments: Challenges, Progress and Implications

    Science.gov (United States)

    Smith, A. A.; Piovano, T. I.; Tetzlaff, D.; Ala-aho, P. O. A.; Wookey, P. A.; Soulsby, C.

    2017-12-01

    Characterising the travel times of water has been a major research focus in catchment science over the past decade. Use of isotopes to quantify the temporal dynamics of the transformation of precipitation into runoff has revealed fundamental new insights into catchment flow paths and mixing processes that influence biogeochemical transport. However, permafrost-affected catchments have received little attention, despite their global importance in terms of rapid environmental change. Such places have limited access for data collection during critical periods (e.g. early phases of snowmelt), temporal and spatially variable freeze-thaw cycles, and the development of the active layer has a time variant influence on catchment hydrology. All of these characteristics make the application of traditional transit time estimation approaches challenging. This contribution describes an isotope-based study undertaken to provide a preliminary assessment of travel times at SikSik Creek in the Canadian Arctic. We adopted a model-data fusion approach to estimate the volumes and isotopic characteristics of snowpack and meltwater. Using sampling in the spring/summer we characterise the isotopic composition of summer rainfall, melt from residual snow, soil water and stream water. In addition, soil moisture dynamics and the temporal evolution of the active layer profile were also monitored. Transit times were estimated for soil and stream water compositions using lumped convolution integral models and temporally variable inputs including snowmelt, ice thaw, and summer rainfall. Comparing transit time estimates using a variety of inputs reveals transit time is best estimated using all available inflows (i.e. snowmelt, ice thaw, and rainfall). Early spring transit times are short, dominated by snowmelt and ice thaw and limited catchment storage when soils are predominantly frozen. However, significant and increasing mixing with water in the active layer during the summer results in more

  16. LGM permafrost distribution: how well can the latest PMIP multi-model ensembles reconstruct?

    Science.gov (United States)

    Saito, K.; Sueyoshi, T.; Marchenko, S.; Romanovsky, V.; Otto-Bliesner, B.; Walsh, J.; Bigelow, N.; Hendricks, A.; Yoshikawa, K.

    2013-03-01

    Global-scale frozen ground distribution during the Last Glacial Maximum (LGM) was reconstructed using multi-model ensembles of global climate models, and then compared with evidence-based knowledge and earlier numerical results. Modeled soil temperatures, taken from Paleoclimate Modelling Intercomparison Project Phase III (PMIP3) simulations, were used to diagnose the subsurface thermal regime and determine underlying frozen ground types for the present-day (pre-industrial; 0 k) and the LGM (21 k). This direct method was then compared to the earlier indirect method, which categorizes the underlying frozen ground type from surface air temperature, applied to both the PMIP2 (phase II) and PMIP3 products. Both direct and indirect diagnoses for 0 k showed strong agreement with the present-day observation-based map, although the soil temperature ensemble showed a higher diversity among the models partly due to varying complexity of the implemented subsurface processes. The area of continuous permafrost estimated by the multi-model analysis was 25.6 million km2 for LGM, in contrast to 12.7 million km2 for the pre-industrial control, whereas seasonally, frozen ground increased from 22.5 million km2 to 32.6 million km2. These changes in area resulted mainly from a cooler climate at LGM, but other factors as well, such as the presence of huge land ice sheets and the consequent expansion of total land area due to sea-level change. LGM permafrost boundaries modeled by the PMIP3 ensemble-improved over those of the PMIP2 due to higher spatial resolutions and improved climatology-also compared better to previous knowledge derived from the geomorphological and geocryological evidences. Combinatorial applications of coupled climate models and detailed stand-alone physical-ecological models for the cold-region terrestrial, paleo-, and modern climates will advance our understanding of the functionality and variability of the frozen ground subsystem in the global eco-climate system.

  17. Review: Impacts of permafrost degradation on inorganic chemistry of surface fresh water

    Science.gov (United States)

    Colombo, Nicola; Salerno, Franco; Gruber, Stephan; Freppaz, Michele; Williams, Mark; Fratianni, Simona; Giardino, Marco

    2018-03-01

    Recent studies have shown that climate change is impacting the inorganic chemical characteristics of surface fresh water in permafrost areas and affecting aquatic ecosystems. Concentrations of major ions (e.g., Ca2 +, Mg2 +, SO42 -, NO3-) can increase following permafrost degradation with associated deepening of flow pathways and increased contributions of deep groundwater. In addition, thickening of the active layer and melting of near-surface ground ice can influence inorganic chemical fluxes from permafrost into surface water. Permafrost degradation has also the capability to modify trace element (e.g., Ni, Mn, Al, Hg, Pb) contents in surface water. Although several local and regional modifications of inorganic chemistry of surface fresh water have been attributed to permafrost degradation, a comprehensive review of the observed changes is lacking. The goal of this paper is to distil insight gained across differing permafrost settings through the identification of common patterns in previous studies, at global scale. In this review we focus on three typical permafrost configurations (pervasive permafrost degradation, thermokarst, and thawing rock glaciers) as examples and distinguish impacts on (i) major ions and (ii) trace elements. Consequences of warming climate have caused spatially-distributed progressive increases of major ion and trace element delivery to surface fresh water in both polar and mountain areas following pervasive permafrost degradation. Moreover, localised releases of major ions and trace elements to surface water due to the liberation of soluble materials sequestered in permafrost and ground ice have been found in ice-rich terrains both at high latitude (thermokarst features) and high elevation (rock glaciers). Further release of solutes and related transport to surface fresh water can be expected under warming climatic conditions. However, complex interactions among several factors able to influence the timing and magnitude of the impacts

  18. In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

    Directory of Open Access Journals (Sweden)

    M. A. Kass

    2017-12-01

    Full Text Available Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multiyear investigation into the impacts of wildfires on permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show the efficacy of borehole NMR (bNMR to permafrost studies. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR is sensitive to the nucleation of ice within soil pore spaces.

  19. The Global Terrestrial Network for Permafrost Database: metadata statistics and prospective analysis on future permafrost temperature and active layer depth monitoring site distribution

    Science.gov (United States)

    Biskaborn, B. K.; Lanckman, J.-P.; Lantuit, H.; Elger, K.; Streletskiy, D. A.; Cable, W. L.; Romanovsky, V. E.

    2015-03-01

    The Global Terrestrial Network for Permafrost (GTN-P) provides the first dynamic database associated with the Thermal State of Permafrost (TSP) and the Circumpolar Active Layer Monitoring (CALM) programs, which extensively collect permafrost temperature and active layer thickness data from Arctic, Antarctic and Mountain permafrost regions. The purpose of the database is to establish an "early warning system" for the consequences of climate change in permafrost regions and to provide standardized thermal permafrost data to global models. In this paper we perform statistical analysis of the GTN-P metadata aiming to identify the spatial gaps in the GTN-P site distribution in relation to climate-effective environmental parameters. We describe the concept and structure of the Data Management System in regard to user operability, data transfer and data policy. We outline data sources and data processing including quality control strategies. Assessment of the metadata and data quality reveals 63% metadata completeness at active layer sites and 50% metadata completeness for boreholes. Voronoi Tessellation Analysis on the spatial sample distribution of boreholes and active layer measurement sites quantifies the distribution inhomogeneity and provides potential locations of additional permafrost research sites to improve the representativeness of thermal monitoring across areas underlain by permafrost. The depth distribution of the boreholes reveals that 73% are shallower than 25 m and 27% are deeper, reaching a maximum of 1 km depth. Comparison of the GTN-P site distribution with permafrost zones, soil organic carbon contents and vegetation types exhibits different local to regional monitoring situations on maps. Preferential slope orientation at the sites most likely causes a bias in the temperature monitoring and should be taken into account when using the data for global models. The distribution of GTN-P sites within zones of projected temperature change show a high

  20. Slope instability related to permafrost changes on Mexican volcanoes

    Science.gov (United States)

    Delgado Granados, Hugo; Molina, Victor Soto

    2015-04-01

    Permafrost is present above 4,500 meters at the three highest Mexican mountains, Citlaltépetl, Popocatépetl and Iztaccihuatl (5,675, 5,452 and 5,286m asl, respectively), all active volcanoes. During the rainy season in the central region of Mexico, the occurrence of small debris-flows in the ice-free parts of the mountains, as well as small lanslides is frequent. At Popocatépetl volcano, flows are mostly related to a combination of the eruptive activity and climatic factors. However, the volcanic activity is different at Citlaltépetl and Iztaccihuatl where there is no eruptive activity, but landslides have occurred in recent years on their steep slopes because its stability has been altered as a result of an increase in the air temperature which in turn has caused variations in the thickness of the active layer of permafrost, causing as a consequence, the increase of an even more unstable soil. Additionally, cracks in the rock walls are subject to an increasing hydrostatic pressure due to continuous daily freezing and thawing of seasonal water produced by a warmer and less solid precipitation accumulating in the cracks over time and in the unconsolidated potentially unstable material.

  1. Archaeal communities of Arctic methane-containing permafrost.

    Science.gov (United States)

    Shcherbakova, Victoria; Yoshimura, Yoshitaka; Ryzhmanova, Yana; Taguchi, Yukihiro; Segawa, Takahiro; Oshurkova, Victoria; Rivkina, Elizaveta

    2016-10-01

    In the present study, we used culture-independent methods to investigate the diversity of methanogenic archaea and their distribution in five permafrost samples collected from a borehole in the Kolyma River Lowland (north-east of Russia). Total DNA was extracted from methane-containing permafrost samples of different age and amplified by PCR. The resulting DNA fragments were cloned. Phylogenetic analysis of the sequences showed the presence of archaea in all studied samples; 60%-95% of sequences belonged to the Euryarchaeota. Methanogenic archaea were novel representatives of Methanosarcinales, Methanomicrobiales, Methanobacteriales and Methanocellales orders. Bathyarchaeota (Miscellaneous Crenarchaeota Group) representatives were found among nonmethanogenic archaea in all the samples studied. The Thaumarchaeota representatives were not found in the upper sample, whereas Woesearchaeota (formerly DHVEG-6) were found in the three deepest samples. Unexpectedly, the greatest diversity of archaea was observed at a depth of 22.3 m, probably due to the availability of the labile organic carbon and/or due to the migration of the microbial cells during the freezing front towards the bottom. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Strategy of valid 14C dates choice in syngenetic permafrost

    Science.gov (United States)

    Vasil'chuk, Y. K.; Vasil'chuk, A. C.

    2014-11-01

    The main problem of radiocarbon dating within permafrost is the uncertain reliability of the 14C dates. Syngenetic sediments contain allochthonous organic deposit that originated at a distance from its present position. Due to the very good preservation of organic materials in permafrost conditions and numerous re-burials of the fossils from ancient deposits into younger ones the dates could be both younger and older than the true age of dated material. The strategy for the most authentic radiocarbon date selection for dating of syncryogenic sediments is considered taking into account the fluvial origin of the syngenetic sediments. The re-deposition of organic material is discussed in terms of cyclic syncryogenic sedimentation and also the possible re-deposition of organic material in subaerial-subaqueous conditions. The advantages and the complications of dating organic micro-inclusions from ice wedges by the accelerator mass spectrometry (AMS) method are discussed applying to true age of dated material search. Radiocarbon dates of different organic materials from the same samples are compared. The younger age of the yedoma from cross-sections of Duvanny Yar in Kolyma River and Mamontova Khayata in the mouth of Lena River is substantiated due to the principle of the choice of the youngest 14C date from the set.

  3. Implications of a lightning-rich tundra biome for permafrost carbon and vegetation dynamics

    Science.gov (United States)

    Chen, Y.; Veraverbeke, S.; Randerson, J. T.

    2017-12-01

    Lightning is a major ignition source of wildfires in circumpolar boreal forests but rarely occurs in arctic tundra. While theoretical and empirical work suggests that climate change will increase lightning strikes in temperate regions, much less is known about future changes in lightning across terrestrial ecosystems at high northern latitudes. Here we analyzed the spatial and temporal patterns of lightning flash rate (FR) from the satellite observations and surface detection networks. Regression models between the observed FR from the Optical Transient Detector on the MicroLab-1 satellite (later renamed OV-1) and meteorological parameters, including surface temperature (T), convective available potential energy (CAPE), and convective precipitation (CP) from ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-interim reanalysis, were established and assessed. We found that FR had significant linear correlations with CAPE and CP, and a strong non-linear relationship with T. The statistical model based on T and CP can reproduce most of the spatial and temporal variability in FR in the circumpolar region. By using the regression model and meteorological predictions from 24 earth system models in the Coupled Model Intercomparison Project Phase 5 (CMIP5), we estimated the spatial distribution of FR by the end of the 21st century. Due to increases in surface temperature and convection, modeled FR shows substantial increase in northern biomes, including a 338% change in arctic tundra and a 185% change in regions with permafrost soil carbon reservoirs. These changes highlight a new mechanism by which permafrost carbon is vulnerable to the sustained impacts of climate warming. Increased fire in a warmer and lightning-rich future near the treeline has the potential to accelerate the northward migration of trees, which may further enhance warming and the abundance of lightning strikes.

  4. Sensitivity analysis of longitudinal cracking on asphalt pavement using MEPDG in permafrost region

    Directory of Open Access Journals (Sweden)

    Chen Zhang

    2015-02-01

    Full Text Available Longitudinal cracking is one of the most important distresses of asphalt pavement in permafrost regions. The sensitivity analysis of design parameters for asphalt pavement can be used to study the influence of every parameter on longitudinal cracking, which can help optimizing the design of the pavement structure. In this study, 20 test sections of Qinghai–Tibet Highway were selected to conduct the sensitivity analysis of longitudinal cracking on material parameter based on Mechanistic-Empirical Pavement Design Guide (MEPDG and single factorial sensitivity analysis method. Some computer aided engineering (CAE simulation techniques, such as the Latin hypercube sampling (LHS technique and the multiple regression analysis are used as auxiliary means. Finally, the sensitivity spectrum of material parameter on longitudinal cracking was established. The result shows the multiple regression analysis can be used to determine the remarkable influence factor more efficiently and to process the qualitative analysis when applying the MEPDG software in sensitivity analysis of longitudinal cracking in permafrost regions. The effect weights of the three parameters on longitudinal cracking in descending order are air void, effective binder content and PG grade. The influence of air void on top layer is bigger than that on middle layer and bottom layer. The influence of effective asphalt content on top layer is bigger than that on middle layer and bottom layer, and the influence of bottom layer is slightly bigger than middle layer. The accumulated value of longitudinal cracking on middle layer and bottom layer in the design life would begin to increase when the design temperature of PG grade increased.

  5. Characterizing vertical heterogeneity of permafrost soils in support of ABoVE radar retrievals

    Science.gov (United States)

    Tabatabaeenejad, A.; Chen, R. H.; Silva, A.; Schaefer, K. M.; Moghaddam, M.

    2017-12-01

    Permafrost-affected soils, including the top active layer and underlying permafrost, have unique seasonal variations in terms of soil temperature, soil moisture, and freeze/thaw-state profiles. The presence of a perennially frozen and impermeable substrate maintains the required temperature gradient for the descending thawing front, and causes meltwater to accumulate and form the saturated zone in the active layer. Radar backscattering measurements are sensitive to dielectric properties of subsurface soils, which are strongly correlated with unfrozen water content and soil texture/composition. To enable accurate radar retrievals, we need to properly characterize soil profile heterogeneity, which can be modeled with layered soil or depth-dependent functions. To this end, we first cross compare the measured radar backscatter and model-predicted radar backscatter using in-situ dielectric profile measurements as well as mathematical or hydrologic-based profile functions. Since radar signal's backscatter has limited penetration, to fully capture the true heterogeneity profile, we determine the optimal profile function by minimizing the error between predicted and measured radar backscatter signals as well as between in-situ and fitted profiles. The in-situ soil profile data (temperature, dielectric constant, unfrozen water content, organic/mineral soils) are collected from the Soil Moisture Sensing Controller And oPtimal Estimator (SoilSCAPE) sensor networks and from the Arctic-Boreal Vulnerability Experiment (ABoVE) field campaign in August 2017 (concurrent with the ABoVE August flights over Alaska North Slope) while the radar data are acquired by NASA's P-band AirMOSS and L-band UAVSAR as part of the ABoVE airborne campaign. The retrieval results using our new heterogeneity model will be compared with the results from retrievals that model soil as a layered medium. This analysis can advance the accuracy of retrieval of active layer properties using low-frequency SAR

  6. The Role of Arctic Soils in the Permafrost – Climate Feedback

    International Nuclear Information System (INIS)

    Richter, A.

    2016-01-01

    The total organic carbon pool in arctic and boreal permafrost soils has been estimated to be about 1,760 Petagram (10"1"5 g) C, more than twice today’s atmospheric C pool and about half of the global soil carbon. A significant proportion of this C pool may be vulnerable to climate warming through permafrost thawing and subsequent decomposition by microorganisms. Thus, it has been suggested that permafrost soils may become a future source of CO_2 and CH_4 to the atmosphere and lead to a strong positive feedback to global warming (up to + 0.5 °C until 2200). I will present results from several projects that aimed at understanding the mechanisms behind the permafrost-climate feedback, by identifying the major soil organic matter (SOM) stabilization mechanisms of permafrost SOM. I will address a range of different mechanisms by which SOM can be protected from decomposition, such as unfavourable temperature and moisture regimes, physical protection by formation of organo-mineral associations and chemical recalcitrance of SOM. I will focus, however, on energy and nutrient constraints of heterotrophic microbial communities and their role in SOM decomposition. I will then show that the physiology of the tiniest organisms on Earth will ultimately determine the vulnerability of the global permafrost carbon pool and thus the global permafrost-climate feedback. (author)

  7. The long-term fate of permafrost peatlands under rapid climate warming

    Science.gov (United States)

    Swindles, Graeme T.; Morris, Paul J.; Mullan, Donal; Watson, Elizabeth J.; Turner, T. Edward; Roland, Thomas P.; Amesbury, Matthew J.; Kokfelt, Ulla; Schoning, Kristian; Pratte, Steve; Gallego-Sala, Angela; Charman, Dan J.; Sanderson, Nicole; Garneau, Michelle; Carrivick, Jonathan L.; Woulds, Clare; Holden, Joseph; Parry, Lauren; Galloway, Jennifer M.

    2015-01-01

    Permafrost peatlands contain globally important amounts of soil organic carbon, owing to cold conditions which suppress anaerobic decomposition. However, climate warming and permafrost thaw threaten the stability of this carbon store. The ultimate fate of permafrost peatlands and their carbon stores is unclear because of complex feedbacks between peat accumulation, hydrology and vegetation. Field monitoring campaigns only span the last few decades and therefore provide an incomplete picture of permafrost peatland response to recent rapid warming. Here we use a high-resolution palaeoecological approach to understand the longer-term response of peatlands in contrasting states of permafrost degradation to recent rapid warming. At all sites we identify a drying trend until the late-twentieth century; however, two sites subsequently experienced a rapid shift to wetter conditions as permafrost thawed in response to climatic warming, culminating in collapse of the peat domes. Commonalities between study sites lead us to propose a five-phase model for permafrost peatland response to climatic warming. This model suggests a shared ecohydrological trajectory towards a common end point: inundated Arctic fen. Although carbon accumulation is rapid in such sites, saturated soil conditions are likely to cause elevated methane emissions that have implications for climate-feedback mechanisms. PMID:26647837

  8. Thermal state of permafrost in North America: A contribution to the international polar year

    Science.gov (United States)

    Smith, S.L.; Romanovsky, V.E.; Lewkowicz, A.G.; Burn, C.R.; Allard, M.; Clow, G.D.; Yoshikawa, K.; Throop, J.

    2010-01-01

    A snapshot of the thermal state of permafrost in northern North America during the International Polar Year (IPY) was developed using ground temperature data collected from 350 boreholes. More than half these were established during IPY to enhance the network in sparsely monitored regions. The measurement sites span a diverse range of ecoclimatic and geological conditions across the continent and are at various elevations within the Cordillera. The ground temperatures within the discontinuous permafrost zone are generally above -3°C, and range down to -15°C in the continuous zone. Ground temperature envelopes vary according to substrate, with shallow depths of zero annual amplitude for peat and mineral soils, and much greater depths for bedrock. New monitoring sites in the mountains of southern and central Yukon suggest that permafrost may be limited in extent. In concert with regional air temperatures, permafrost has generally been warming across North America for the past several decades, as indicated by measurements from the western Arctic since the 1970s and from parts of eastern Canada since the early 1990s. The rates of ground warming have been variable, but are generally greater north of the treeline. Latent heat effects in the southern discontinuous zone dominate the permafrost thermal regime close to 0°C and allow permafrost to persist under a warming climate. Consequently, the spatial diversity of permafrost thermal conditions is decreasing over time.

  9. Impacts of the active layer on runoff in an upland permafrost basin, northern Tibetan Plateau.

    Science.gov (United States)

    Gao, Tanguang; Zhang, Tingjun; Guo, Hong; Hu, Yuantao; Shang, Jianguo; Zhang, Yulan

    2018-01-01

    The paucity of studies on permafrost runoff generation processes, especially in mountain permafrost, constrains the understanding of permafrost hydrology and prediction of hydrological responses to permafrost degradation. This study investigated runoff generation processes, in addition to the contribution of summer thaw depth, soil temperature, soil moisture, and precipitation to streamflow in a small upland permafrost basin in the northern Tibetan Plateau. Results indicated that the thawing period and the duration of the zero-curtain were longer in permafrost of the northern Tibetan Plateau than in the Arctic. Limited snowmelt delayed the initiation of surface runoff in the peat permafrost in the study area. The runoff displayed intermittent generation, with the duration of most runoff events lasting less than 24 h. Precipitation without runoff generation was generally correlated with lower soil moisture conditions. Combined analysis suggested runoff generation in this region was controlled by soil temperature, thaw depth, precipitation frequency and amount, and antecedent soil moisture. This study serves as an important baseline to evaluate future environmental changes on the Tibetan Plateau.

  10. The transcriptional response of microbial communities in thawing Alaskan permafrost soils

    Directory of Open Access Journals (Sweden)

    M J L Coolen

    2015-03-01

    Full Text Available Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gases, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. Here, we performed a pilot study using ultrahigh throughput Illumina HiSeq sequencing of reverse transcribed messenger RNA to obtain a detailed overview of active metabolic pathways and responsible organisms in up to 70 cm deep permafrost soils at a moist acidic tundra location in Arctic Alaska. The transcriptional response of the permafrost microbial community was compared before and after eleven days of thaw. In general, the transcriptional profile under frozen conditions suggests a dominance of stress responses, survival strategies, and maintenance processes, whereas upon thaw a rapid enzymatic response to decomposing soil organic matter (SOM was observed. Bacteroidetes, Firmicutes, ascomycete fungi, and methanogens were responsible for largest transcriptional response upon thaw. Transcripts indicative of heterotrophic methanogenic pathways utilizing acetate, methanol, and methylamine were found predominantly in the permafrost table after thaw. Furthermore, transcripts involved in acetogenesis were expressed exclusively after thaw suggesting that acetogenic bacteria are a potential source of acetate for acetoclastic methanogenesis in freshly thawed permafrost. Metatranscriptomics is shown here to be a useful approach for inferring the activity of permafrost microbes that has potential to improve our understanding of permafrost SOM bioavailability and biogeochemical mechanisms contributing to greenhouse gas emissions as a result of permafrost thaw.

  11. Distribution of near-surface permafrost in Alaska: estimates of present and future conditions

    Science.gov (United States)

    Pastick, Neal J.; Jorgenson, M. Torre; Wylie, Bruce K.; Nield, Shawn J.; Johnson, Kristofer D.; Finley, Andrew O.

    2015-01-01

    High-latitude regions are experiencing rapid and extensive changes in ecosystem composition and function as the result of increases in average air temperature. Increasing air temperatures have led to widespread thawing and degradation of permafrost, which in turn has affected ecosystems, socioeconomics, and the carbon cycle of high latitudes. Here we overcome complex interactions among surface and subsurface conditions to map nearsurface permafrost through decision and regression tree approaches that statistically and spatially extend field observations using remotely sensed imagery, climatic data, and thematic maps of a wide range of surface and subsurface biophysical characteristics. The data fusion approach generated medium-resolution (30-m pixels) maps of near-surface (within 1 m) permafrost, active-layer thickness, and associated uncertainty estimates throughout mainland Alaska. Our calibrated models (overall test accuracy of ~85%) were used to quantify changes in permafrost distribution under varying future climate scenarios assuming no other changes in biophysical factors. Models indicate that near-surface permafrost underlies 38% of mainland Alaska and that near-surface permafrost will disappear on 16 to 24% of the landscape by the end of the 21st Century. Simulations suggest that near-surface permafrost degradation is more probable in central regions of Alaska than more northerly regions. Taken together, these results have obvious implications for potential remobilization of frozen soil carbon pools under warmer temperatures. Additionally, warmer and drier conditions may increase fire activity and severity, which may exacerbate rates of permafrost thaw and carbon remobilization relative to climate alone. The mapping of permafrost distribution across Alaska is important for land-use planning, environmental assessments, and a wide-array of geophysical studies.

  12. The transcriptional response of microbial communities in thawing Alaskan permafrost soils

    Science.gov (United States)

    Coolen, Marco J. L.; Orsi, William D.

    2015-01-01

    Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gasses, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. Here, we performed a pilot study using ultrahigh throughput Illumina HiSeq sequencing of reverse transcribed messenger RNA to obtain a detailed overview of active metabolic pathways and responsible organisms in up to 70 cm deep permafrost soils at a moist acidic tundra location in Arctic Alaska. The transcriptional response of the permafrost microbial community was compared before and after 11 days of thaw. In general, the transcriptional profile under frozen conditions suggests a dominance of stress responses, survival strategies, and maintenance processes, whereas upon thaw a rapid enzymatic response to decomposing soil organic matter (SOM) was observed. Bacteroidetes, Firmicutes, ascomycete fungi, and methanogens were responsible for largest transcriptional response upon thaw. Transcripts indicative of heterotrophic methanogenic pathways utilizing acetate, methanol, and methylamine were found predominantly in the permafrost table after thaw. Furthermore, transcripts involved in acetogenesis were expressed exclusively after thaw suggesting that acetogenic bacteria are a potential source of acetate for acetoclastic methanogenesis in freshly thawed permafrost. Metatranscriptomics is shown here to be a useful approach for inferring the activity of permafrost microbes that has potential to improve our understanding of permafrost SOM bioavailability and biogeochemical mechanisms contributing to greenhouse gas emissions as a result of permafrost thaw. PMID:25852660

  13. The permafrost carbon inventory on the Tibetan Plateau: a new evaluation using deep sediment cores.

    Science.gov (United States)

    Ding, Jinzhi; Li, Fei; Yang, Guibiao; Chen, Leiyi; Zhang, Beibei; Liu, Li; Fang, Kai; Qin, Shuqi; Chen, Yongliang; Peng, Yunfeng; Ji, Chengjun; He, Honglin; Smith, Pete; Yang, Yuanhe

    2016-08-01

    The permafrost organic carbon (OC) stock is of global significance because of its large pool size and the potential positive feedback to climate warming. However, due to the lack of systematic field observations and appropriate upscaling methodologies, substantial uncertainties exist in the permafrost OC budget, which limits our understanding of the fate of frozen carbon in a warming world. In particular, the lack of comprehensive estimates of OC stocks across alpine permafrost means that current knowledge on this issue remains incomplete. Here, we evaluated the pool size and spatial variations of permafrost OC stock to 3 m depth on the Tibetan Plateau by combining systematic measurements from a substantial number of pedons (i.e. 342 three-metre-deep cores and 177 50-cm-deep pits) with a machine learning technique (i.e. support vector machine, SVM). We also quantified uncertainties in permafrost carbon budget by conducting Monte Carlo simulations. Our results revealed that the combination of systematic measurements with the SVM model allowed spatially explicit estimates to be made. The OC density (OC amount per unit area, OCD) exhibited a decreasing trend from the south-eastern to the north-western plateau, with the exception that OCD in the swamp meadow was substantially higher than that in surrounding regions. Our results also demonstrated that Tibetan permafrost stored a large amount of OC in the top 3 m, with the median OC pool size being 15.31 Pg C (interquartile range: 13.03-17.77 Pg C). 44% of OC occurred in deep layers (i.e. 100-300 cm), close to the proportion observed across the northern circumpolar permafrost region. The large carbon pool size together with significant permafrost thawing suggests a risk of carbon emissions and positive climate feedback across the Tibetan alpine permafrost region. © 2016 John Wiley & Sons Ltd.

  14. Mapping surficial geology and assessment of permafrost conditions under the Iqaluit airport, Nunavut, Canada

    Science.gov (United States)

    Mathon-Dufour, V.; Allard, M.; Leblanc, A.; L'Hérault, E.; Oldenborger, G. A.; Sladen, W. E.

    2012-12-01

    in the natural terrain. Analysis of ground penetrating radar profiles indeed shows parabolic reflectors typical of ice wedges under the larger runway cracks. Temperature data acquired with five thermistor cables in the runway, in a taxiway, in the apron and in nearby natural terrain shows that the thickness of the active layer varies between 90 centimeters for sectors covered with vegetation and more than 2 meters below paved surfaces which means that the thaw depth has now reached down into the original natural terrain under the infrastructure, thus causing settlements due to melting ice wedges. Sink holes are mostly localised on the edges of the northern part of the runway. Processes responsible for these holes possibly are seepage of water into the base course and the subgrade, melting of bodies of ice or soil compaction problems. This established context of permafrost is now used for planning a detailed investigation program in preparation for the restoration of the airport and its adaptation to climate change. The program will include drilling, more geophysical surveys, thermal monitoring and numerical simulations.

  15. Spatial distribution and morphometry of permafrost-related landforms in the Central Pyrenees

    Science.gov (United States)

    Fernandes, Marcelo; Oliva, Marc; Lopes, Luís; Ruiz-Fernández, Jesus; Palma, Pedro; Pereira, Paulo

    2017-04-01

    Present and past permafrost distribution in the Pyrenees is still under discussion. As in other mid-latitude mountain regions, rock glaciers and protalus lobes are the min indicators of permafrost conditions. In this study, we examine the distribution of these landforms in the Boí valley, a formerly glaciated U-shaped valley ranging from 850 to 3000 m a.s.l. The valley encompasses a surface of 247 km2, mainly composed of granite and shales. The spatial distribution of rock glaciers and protalus lobes and their chronostratigraphic position within the valley allow a better understanding of the climatic and environmental conditions necessary for their development. Geomorphological mapping of these landforms was built using high resolution imagery provided by the Institut Cartogràfic i Geologic de Catalunya, complemented with Basemap ESRI images and Google Earth Pro, and subsequently improved with field observations. The map was generated in a GIS environment following the RCP 77 mapping system of the Centre National de la Recherche Scientifique (CNRS) (Joly, 1997). Several parameters of each landform have been measured (Table 1): area (ha), altitude (maximum, minimum, mean), length (L), width (W), aspect and slope. This information provides accurate characterization of the morphometric properties of these landforms as well as a detailed identification of their spatial distribution. Up to 121 permafrost-related landforms were identified in the Boí valley, including 84 rock glaciers and 37 protalus lobes. Most of the landforms (93% for rock glaciers and 95% for protalus lobes) are located inside the glacial cirques, while the rest is distributed in the valley bottom or slopes of the formerly glaciated valleys. The lowest elevation of both forms is situated at 2100 m a.s.l. Therefore, this altitude may be indicative of the lowest level recording permafrost conditions during the period in which these landforms formed. The maximum elevation of the landforms usually

  16. A national strategy for a long-term monitoring of permafrost and periglacial processes and their relationship to natural hazard prevention in Austria

    Science.gov (United States)

    Kellerer-Pirklbauer, Andreas; Bartsch, Annett; Gitschthaler, Christoph; Reisenhofer, Stefan; Weyss, Gernot; Riedl, Claudia; Avian, Michael

    2016-04-01

    of permafrost temperatures in western Austria. A central recommendation of the permAT-strategy is to increase the number of monitoring sites based on our analyses of the current situation and exchanges with different stakeholders. This should include temperature measurements in deep and shallow boreholes close to the surface, geophysical surveys and ground movement measurements (rock glaciers, instable rock faces). In addition to the terrestrial measurements a spatially continuous observation of surface movements with remote sensing methods is required. Demand is highest for the entire federal province of Tyrol, the district of Zell am See (province of Salzburg) and the south-eastern part of the province of Vorarlberg. In order to achieve a similar spatial coverage and technical set-up as in Switzerland a minimum investment of 1.5 Mio € is required taking advantages in synergies with e.g. existing automatic weather stations (e.g. from the Central Institute for Meteorology and Geodynamics), alpine huts and skiing infrastructure into account. Financial support could - similarly to Switzerland - come from a combination of partners from public institutions, economy and research institutes.

  17. Coupled thermo-geophysical inversion for high-latitude permafrost monitoring - assessment of the method and practical considerations

    Science.gov (United States)

    Tomaskovicova, Sonia; Paamand, Eskild; Ingeman-Nielsen, Thomas; Bauer-Gottwein, Peter

    2013-04-01

    The sedimentary settings of West Greenlandic towns with their fine-grained, often ice-rich marine deposits are of great concern in building and construction projects in Greenland, as they lose volume, strength and bearing capacity upon thaw. Since extensive permafrost thawing over large areas of inhabited Greenlandic coast has been predicted as a result of climate change, it is of great both technical and economical interest to assess the extent and thermal properties of such formations. Availability of methods able to determine the thermal parameters of permafrost and forecast its reaction to climate evolution is therefore crucial for sustainable infrastructure planning and development in the Arctic. We are developing a model of heat transport for permafrost able to assess the thermal properties of the ground based on calibration by surface geoelectrical measurements and ground surface temperature measurements. The advantages of modeling approach and use of exclusively surface measurements (in comparison with direct measurements on core samples) are smaller environmental impact, cheaper logistics, assessment of permafrost conditions over larger areas and possibility of forecasting of the fate of permafrost by application of climate forcing. In our approach, the heat model simulates temperature distribution in the ground based on ground surface temperature, specified proportions of the ground constituents and their estimated thermal parameters. The calculated temperatures in the specified model layers are governing the phase distribution between unfrozen water and ice. The changing proportion of unfrozen water content as function of temperature is the main parameter driving the evolution of electrical properties of the ground. We use a forward modeling scheme to calculate the apparent resistivity distribution of such a ground as if collected from a surface geoelectrical array. The calculated resistivity profile is compared to actual field measurements and a

  18. High bacterial diversity of biological soil crusts in water tracks over permafrost in the high arctic polar desert.

    Science.gov (United States)

    Steven, Blaire; Lionard, Marie; Kuske, Cheryl R; Vincent, Warwick F

    2013-01-01

    In this study we report the bacterial diversity of biological soil crusts (biocrusts) inhabiting polar desert soils at the northern land limit of the Arctic polar region (83° 05 N). Employing pyrosequencing of bacterial 16S rRNA genes this study demonstrated that these biocrusts harbor diverse bacterial communities, often as diverse as temperate latitude communities. The effect of wetting pulses on the composition of communities was also determined by collecting samples from soils outside and inside of permafrost water tracks, hill slope flow paths that drain permafrost-affected soils. The intermittent flow regime in the water tracks was correlated with altered relative abundance of phylum level taxonomic bins in the bacterial communities, but the alterations varied between individual sampling sites. Bacteria related to the Cyanobacteria and Acidobacteria demonstrated shifts in relative abundance based on their location either inside or outside of the water tracks. Among cyanobacterial sequences, the proportion of sequences belonging to the family Oscillatoriales consistently increased in relative abundance in the samples from inside the water tracks compared to those outside. Acidobacteria showed responses to wetting pulses in the water tracks, increasing in abundance at one site and decreasing at the other two sites. Subdivision 4 acidobacterial sequences tended to follow the trends in the total Acidobacteria relative abundance, suggesting these organisms were largely responsible for the changes observed in the Acidobacteria. Taken together, these data suggest that the bacterial communities of these high latitude polar biocrusts are diverse but do not show a consensus response to intermittent flow in water tracks over high Arctic permafrost.

  19. Subsurface flow pathway dynamics in the active layer of coupled permafrost-hydrogeological systems under seasonal and annual temperature variability.

    Science.gov (United States)

    Frampton, Andrew

    2017-04-01

    There is a need for improved understanding of the mechanisms controlling subsurface solute transport in the active layer in order to better understand permafrost-hydrological-carbon feedbacks, in particular with regards to how dissolved carbon is transported in coupled surface and subsurface terrestrial arctic water systems under climate change. Studying solute transport in arctic systems is also relevant in the context of anthropogenic pollution which may increase due to increased activity in cold region environments. In this contribution subsurface solute transport subject to ground surface warming causing permafrost thaw and active layer change is studied using a physically based model of coupled cryotic and hydrogeological flow processes combined with a particle tracking method. Changes in subsurface water flows and solute transport travel times are analysed for different modelled geological configurations during a 100-year warming period. Results show that for all simulated cases, the minimum and mean travel times increase non-linearly with warming irrespective of geological configuration and heterogeneity structure. The timing of the start of increase in travel time depends on heterogeneity structure, combined with the rate of permafrost degradation that also depends on material thermal and hydrogeological properties. These travel time changes are shown to depend on combined warming effects of increase in pathway length due to deepening of the active layer, reduced transport velocities due to a shift from horizontal saturated groundwater flow near the surface to vertical water percolation deeper into the subsurface, and pathway length increase and temporary immobilization caused by cryosuction-induced seasonal freeze cycles. The impact these change mechanisms have on solute and dissolved substance transport is further analysed by integrating pathway analysis with a Lagrangian approach, incorporating considerations for both dissolved organic and inorganic

  20. Ground thermal and geomechanical conditions in a permafrost-affected high-latitude rock avalanche site (Polvartinden, northern Norway

    Directory of Open Access Journals (Sweden)

    R. Frauenfelder

    2018-04-01

    Full Text Available On 26 June 2008, a rock avalanche detached in the northeast facing slope of Polvartinden, a high-alpine mountain in Signaldalen, northern Norway. Here, we report on the observed and modelled past and present near-surface temperature regime close to the failure zone, as well as on a subsequent simulation of the subsurface temperature regime, and on initial geomechanical mapping based on laser scanning. The volume of the rock avalanche was estimated to be approximately 500 000 m3. The depth to the actual failure surface was found to range from 40 m at the back of the failure zone to 0 m at its toe. Visible in situ ice was observed in the failure zone just after the rock avalanche. Between September 2009 and August 2013, ground surface temperatures were measured with miniature temperature data loggers at 14 different localities, close to the original failure zone along the northern ridge of Polvartinden and on the valley floor. The results from these measurements and from a basic three-dimensional heat conduction model suggest that the lower altitudinal limit of permafrost at present is at 600–650 m a.s.l., which corresponds to the upper limit of the failure zone. A coupling of our in situ data with regional climate data since 1958 suggests a general gradual warming and that the period with highest mean near surface temperatures on record ended four months before the Signaldalen rock avalanche detached. A comparison with a transient permafrost model run at 10 m depth, representative for areas where snow accumulates, strengthen these findings, which are also in congruence with measurements in nearby permafrost boreholes. It is likely that permafrost in and near the failure zone is presently subject to degradation. This degradation, in combination with the extreme warm year antecedent to the rock failure, is seen to have played an important role in the detaching of the Signaldalen rock avalanche.

  1. CFD analysis of onshore oil pipelines in permafrost

    Science.gov (United States)

    Nardecchia, Fabio; Gugliermetti, Luca; Gugliermetti, Franco

    2017-07-01

    Underground pipelines are built all over the world and the knowledge of their thermal interaction with the soil is crucial for their design. This paper studies the "thermal influenced zone" produced by a buried pipeline and the parameters that can influence its extension by 2D-steady state CFD simulations with the aim to improve the design of new pipelines in permafrost. In order to represent a real case, the study is referred to the Eastern Siberia-Pacific Ocean Oil Pipeline at the three stations of Mo'he, Jiagedaqi and Qiqi'har. Different burial depth sand diameters of the pipe are analyzed; the simulation results show that the effect of the oil pipeline diameter on the thermal field increases with the increase of the distance from the starting station.

  2. Minimum distribution of subsea ice-bearing permafrost on the US Beaufort Sea continental shelf

    Science.gov (United States)

    Brothers, Laura L.; Hart, Patrick E.; Ruppel, Carolyn D.

    2012-01-01

    Starting in Late Pleistocene time (~19 ka), sea level rise inundated coastal zones worldwide. On some parts of the present-day circum-Arctic continental shelf, this led to flooding and thawing of formerly subaerial permafrost and probable dissociation of associated gas hydrates. Relict permafrost has never been systematically mapped along the 700-km-long U.S. Beaufort Sea continental shelf and is often assumed to extend to ~120 m water depth, the approximate amount of sea level rise since the Late Pleistocene. Here, 5,000 km of multichannel seismic (MCS) data acquired between 1977 and 1992 were examined for high-velocity (>2.3 km s−1) refractions consistent with ice-bearing, coarse-grained sediments. Permafrost refractions were identified along sea ice-bearing permafrost, which does not extend seaward of 30 km offshore or beyond the 20 m isobath.

  3. Introduction to the special issue: permafrost and periglacial research from coasts to mountains

    Science.gov (United States)

    Schrott, Lothar; Humlum, Ole

    2017-09-01

    This special issue of Geomorphology includes eleven papers dealing with permafrost and periglacial research from coasts to mountains. The compilation represents a selection from 47 presentations (oral and posters) given at the 4th European Conference on Permafrost - IPA Regional Conference (EUCOP4, June 2014) in the session ;Periglacial Geomorphology;. Geomorphology as a leading journal for our discipline is particularly suitable to publish advances in permafrost and periglacial research with a focus on geomorphic processes. Since 1989 Geomorphology has published 121 special issues and two special issues are explicitly dedicated to permafrost and periglacial research, however, only with a focus on research in Antarctica. In this special issue we present papers from the Canadian Beaufort Sea, Alaska, Spitzbergen, central western Poland, the European Alps, the eastern Sudetes, the southern Carpathians, Nepal, and Antarctica.

  4. Permafrost and indigenous land use in the northern Urals: Komi and Nenets reindeer husbandry

    Science.gov (United States)

    Istomin, Kirill V.; Habeck, Joachim Otto

    2016-09-01

    Permafrost is an integral part of the environmental conditions that frame indigenous peoples' livelihoods in many parts of the circumpolar region. On the basis of their long-term ethnographic field researches, the authors describe the various ways in which permafrost dynamics influence the lives and economic activities of two groups of reindeer-herding nomads in North-Eastern Europe and Western Siberia: Komi and Nenets. Permafrost affects the herders directly, for the herders have to take into account the probability of thermokarst while choosing the campsite and performing certain herding procedures. It also affects the herders indirectly, through its influence on landscape and vegetation and thus on reindeer behavior. More rapid permafrost degradation will have a range of adverse effects on reindeer herding.

  5. Capturing temporal and spatial variability in the chemistry of shallow permafrost ponds

    Science.gov (United States)

    Morison, Matthew Q.; Macrae, Merrin L.; Petrone, Richard M.; Fishback, LeeAnn

    2017-12-01

    Across the circumpolar north, the fate of small freshwater ponds and lakes (mediated by processes within ponds. This work demonstrates the importance of understanding hydrologically driven chemodynamics in permafrost ponds on multiple scales (seasonal and event scale).

  6. Response of organic matter quality in permafrost soils to warming

    Science.gov (United States)

    Plaza, C.; Pegoraro, E.; Schuur, E.

    2016-12-01

    Global warming is predicted to thaw large quantities of the perennially frozen organic matter stored in northern permafrost soils. Upon thaw, this organic matter will be exposed to lateral export to water bodies and to microbial decomposition, which may exacerbate climate change by releasing significant amounts of greenhouse gases. To gain an insight into these processes, we investigated how the quality of permafrost soil organic matter responded to five years of warming. In particular, we sampled control and experimentally warmed soils in 2009 and 2013 from an experiment established in 2008 in a moist acidic tundra ecosystem in Healy, Alaska. We examined surface organic (0 to 15 cm), deep organic (15 to 35 cm), and mineral soil layers (35 to 55 cm) separately by means of stable isotope analysis (δ13C and δ15N) and solid-state 13C nuclear magnetic resonance. Compared to the control, the experimental warming did not affect the isotopic and molecular composition of soil organic matter across the depth profile. However, we did find significant changes with time. In particular, in the surface organic layer, δ13C decreased and alkyl/O-alkyl ratio increased from 2009 to 2013, which indicated variations in soil organic sources (e.g., changes in vegetation) and accelerated decomposition. In the deep organic layer, we found a slight increase in δ15N with time. In the mineral layer, δ13C values decreased slightly, whereas alkyl C/O-alkyl ratio increased, suggesting a preferential loss of relatively more degraded organic matter fractions probably by lateral transport by water flowing through the soil. Acknowledgements: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 654132. Web site: http://vulcan.comule.com

  7. Microbial Insights into Shifting Methane Production Potential in Thawing Permafrost

    Science.gov (United States)

    Crossen, K.; Wilson, R.; Raab, N.; Neumann, R.; Chanton, J.; Saleska, S. R.; Rich, V. I.

    2017-12-01

    Permafrost, which stores 50% of global soil carbon, is thawing rapidly due to climate change, and resident microbes are contributing to changing carbon gas emissions. Predictions of the fate of carbon in these regions is poorly constrained; however, improved, careful mapping of microbial community members influencing CO2 and CH4 emissions will help clarify the system response to continued change. In order to more fully understand connections between the microbial communities, major geochemical transformations, and CO2 and CH4 emissions, peat cores were collected from the active layers of three permafrost habitats spanning a thaw gradient (collapsed palsa, bog, and fen) at Stordalen Mire, Abisko, Sweden. Anaerobic incubations of shallow and deep subsamples from these sites were performed, with time-course characterization of the changes in microbial communities, peat geochemistry, and carbon gas production. The latter were profiled with 16S rRNA amplicon sequencing, and targeted metagenomes. The communities within each habitat and depth were statistically distinct, and changed significantly over the course of the incubations. Acidobacteria was consistently the dominant bacterial phylum in all three habitat types. With increased thaw, the relative abundance of Actinobacteria tended to decrease, while Chloroflexi and Bacteroidetes increased with thaw. The relative abundance of methanogens increased with thaw and with depth within each habitat. Over time in the incubations, the richness of the communities tended to decrease. Homoacetogenesis (CO2 + H2 -> CH3COOH) has been documented in other peatlands, and homoacetogens can influence CH4 production by interacting with methanogens, competing with hydrogenotrophs while providing substrate for acetoclasts. Modelling of microbial reaction networks suggests potential for highest homoacetogenesis rates in the collapsed palsa, which also contains the highest relative abundances of lineages taxonomically affiliated with known

  8. Species Composition at the Sub-Meter Level in Discontinuous Permafrost in Subarctic Sweden

    Science.gov (United States)

    Anderson, S. M.; Palace, M. W.; Layne, M.; Varner, R. K.; Crill, P. M.

    2013-12-01

    Northern latitudes are experiencing rapid warming. Wetlands underlain by permafrost are particularly vulnerable to warming which results in changes in vegetative cover. Specific species have been associated with greenhouse gas emissions therefore knowledge of species compositional shift allows for the systematic change and quantification of emissions and changes in such emissions. Species composition varies on the sub-meter scale based on topography and other microsite environmental parameters. This complexity and the need to scale vegetation to the landscape level proves vital in our estimation of carbon dioxide (CO2) and methane (CH4) emissions and dynamics. Stordalen Mire (68°21'N, 18°49'E) in Abisko and is located at the edge of discontinuous permafrost zone. This provides a unique opportunity to analyze multiple vegetation communities in a close proximity. To do this, we randomly selected 25 1x1 meter plots that were representative of five major cover types: Semi-wet, wet, hummock, tall graminoid, and tall shrub. We used a quadrat with 64 sub plots and measured areal percent cover for 24 species. We collected ground based remote sensing (RS) at each plot to determine species composition using an ADC-lite (near infrared, red, green) and GoPro (red, blue, green). We normalized each image based on a Teflon white chip placed in each image. Textural analysis was conducted on each image for entropy, angular second momentum, and lacunarity. A logistic regression was developed to examine vegetation cover types and remote sensing parameters. We used a multiple linear regression using forwards stepwise variable selection. We found statistical difference in species composition and diversity indices between vegetation cover types. In addition, we were able to build regression model to significantly estimate vegetation cover type as well as percent cover for specific key vegetative species. This ground-based remote sensing allows for quick quantification of vegetation

  9. Response of permafrost to projected climate change: Results from global offline model simulations with JSBACH

    Science.gov (United States)

    Blome, Tanja; Ekici, Altug; Beer, Christian; Hagemann, Stefan

    2014-05-01

    Permafrost or perennially frozen ground is an important part of the terrestrial cryosphere; roughly one quarter of Earth's land surface is underlain by permafrost. As it is a thermal phenomenon, its characteristics are highly dependent on climatic factors. The impact of the currently observed warming, which is projected to persist during the coming decades due to anthropogenic CO2 input, certainly has effects for the vast permafrost areas of the high northern latitudes. The quantification of these effects, however, is scientifically still an open question. This is partly due to the complexity of the system, where several feedbacks are interacting between land and atmosphere, sometimes counterbalancing each other. Moreover, until recently, many global circulation models (GCMs) lacked the sufficient representation of permafrost physics in their land surface schemes. In order to assess the response of permafrost to projected climate change for the 21st century, the land surface scheme of the Max-Planck-Institute for Meteorology, JSBACH, has recently been equipped with the important physical processes for permafrost studies, and was driven globally with bias corrected climate data, thereby spanning a period from 1850 until 2100. The applied land surface scheme JSBACH now considers the effects of freezing and thawing of soil water for both energy and water cycles, thermal properties depending on soil water and ice contents, and soil moisture movement being influenced by the presence of soil ice. To address the uncertainty range arising through different greenhouse gas concentrations as well as through different climate realisations when using various climate models, combinations of two Representative Concentration Pathways (RCPs) and two GCMs were used as driving data. In order to focus only on the climatic impact on permafrost, effects due to feedbacks between climate and permafrost (namely via carbon fluxes between land and atmosphere) are excluded in the experiments

  10. Human-Modified Permafrost Complexes in Urbanized Areas of the Russian North

    Science.gov (United States)

    Grebenets, V. I.; Streletskiy, D. A.

    2013-12-01

    Economic development in permafrost regions is accompanied by modification of natural geocryological conditions. Drastic landscape transformations in urbanized areas on permafrost are characterized by changes of heat and moisture exchange in permafrost - atmosphere system, and by engineering and technogenic influence upon the frozen ground, leading to alteration of its physical, thermal and mechanical properties. In northern cities this leads to overall increase of ground temperature relative to undisturbed areas and intensification of hazardous cryogenic processes in areas under engineering development, which together leads to reduction in stability of geotechnical environment. For example, deformations of structures in Norilsk district, Northern Siberia, in the last 15 years, became much more abundant than those revealed throughout the previous 50 years. About 250 large buildings in the local towns were deformed considerably due to deterioration of geocryological conditions, about 100 structures were functioning in emergency state, and almost 50 nine- and five-storey houses, built in the 1960-80s, have been recently disassembled. Increase in accident risk for various facilities (water and oil pipelines, industrial enterprises, etc.) enhances the technogenic pressure on permafrost, leading to the new milestone of changes in permafrost characteristics, i.e. to creation of 'another reality' of geocryological conditions. Social and natural factors dictate clustered spatial pattern of industrial development in permafrost regions. Cryogenic processes within the urban areas on permafrost are seldom similar with those under the natural conditions as intensity, duration and extent of the processes changes under technogenic impacts. Moreover, new cryogenic processes and phenomena may occur, which have not been typical for a given region. This makes mapping and characterization of these processes difficult task. Peculiar natural-technogenic geocryological complexes (NTGC

  11. Determining the terrain characteristics related to the surface expression of subsurface water pressurization in permafrost landscapes using susceptibility modelling

    Directory of Open Access Journals (Sweden)

    J. E. Holloway

    2017-06-01

    Full Text Available Warming of the Arctic in recent years has led to changes in the active layer and uppermost permafrost. In particular, thick active layer formation results in more frequent thaw of the ice-rich transient layer. This addition of moisture, as well as infiltration from late season precipitation, results in high pore-water pressures (PWPs at the base of the active layer and can potentially result in landscape degradation. To predict areas that have the potential for subsurface pressurization, we use susceptibility maps generated using a generalized additive model (GAM. As model response variables, we used active layer detachments (ALDs and mud ejections (MEs, both formed by high PWP conditions at the Cape Bounty Arctic Watershed Observatory, Melville Island, Canada. As explanatory variables, we used the terrain characteristics elevation, slope, distance to water, topographic position index (TPI, potential incoming solar radiation (PISR, distance to water, normalized difference vegetation index (NDVI; ME model only, geology, and topographic wetness index (TWI. ALDs and MEs were accurately modelled in terms of susceptibility to disturbance across the study area. The susceptibility models demonstrate that ALDs are most probable on hill slopes with gradual to steep slopes and relatively low PISR, whereas MEs are associated with higher elevation areas, lower slope angles, and areas relatively far from water. Based on these results, this method identifies areas that may be sensitive to high PWPs and helps improve our understanding of geomorphic sensitivity to permafrost degradation.

  12. Unraveling of permafrost hydrological variabilities on Central Qinghai-Tibet Plateau using stable isotopic technique.

    Science.gov (United States)

    Yang, Yuzhong; Wu, Qingbai; Hou, Yandong; Zhang, Zhongqiong; Zhan, Jing; Gao, Siru; Jin, Huijun

    2017-12-15

    Permafrost degradation on the Qinghai-Tibet Plateau (QTP) will substantially alter the surface runoff discharge and generation, which changes the recharge processes and influences the hydrological cycle on the QTP. Hydrological connections between different water bodies and the influence of thawing permafrost (ground ice) are not well understood on the QTP. This study applied water stable isotopic method to investigate the permafrost hydrological variabilities in Beiluhe Basin (BLB) on Central QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and near-surface ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost region. Results suggested that isotopic seasonalities in precipitation is evident, it is showing more positive values in summer seasons, and negative values in winter seasons. Stable isotopes of river flow are mainly distributed in the range of precipitation which is indicative of important replenishment from precipitation. δ 18 O, δD of thermokarst lakes are more positive than precipitation, indicating of basin-scale evaporation of lake water. Comparison of δ I values in different water bodies shows that hydrology of thermokarst lakes was related to thawing of permafrost (ground ice) and precipitation. Near-surface ground ice in BLB exhibits different isotopic characteristics, and generates a special δD-δ 18 O relationship (freezing line): δD=5.81δ 18 O-23.02, which reflects typical freezing of liquid water. From isotopic analysis, it is inferred that near-surface ground ice was mainly recharged by precipitation and active layer water. Stable isotopic and conceptual model is suggestive of striking hydrological connections between precipitation, river flow, thermokarst lake, and ground ice under degrading permafrost. This research provides fundamental comprehensions into the hydrological processes in permafrost regions on QTP, which should be considered

  13. Nitrogen availability increases in a tundra ecosystem during five years of experimental permafrost thaw.

    Science.gov (United States)

    Salmon, Verity G; Soucy, Patrick; Mauritz, Marguerite; Celis, Gerardo; Natali, Susan M; Mack, Michelle C; Schuur, Edward A G

    2016-05-01

    Perennially frozen soil in high latitude ecosystems (permafrost) currently stores 1330-1580 Pg of carbon (C). As these ecosystems warm, the thaw and decomposition of permafrost is expected to release large amounts of C to the atmosphere. Fortunately, losses from the permafrost C pool will be partially offset by increased plant productivity. The degree to which plants are able to sequester C, however, will be determined by changing nitrogen (N) availability in these thawing soil profiles. N availability currently limits plant productivity in tundra ecosystems but plant access to N is expected improve as decomposition increases in speed and extends to deeper soil horizons. To evaluate the relationship between permafrost thaw and N availability, we monitored N cycling during 5 years of experimentally induced permafrost thaw at the Carbon in Permafrost Experimental Heating Research (CiPEHR) project. Inorganic N availability increased significantly in response to deeper thaw and greater soil moisture induced by Soil warming. This treatment also prompted a 23% increase in aboveground biomass and a 49% increase in foliar N pools. The sedge Eriophorum vaginatum responded most strongly to warming: this species explained 91% of the change in aboveground biomass during the 5 year period. Air warming had little impact when applied alone, but when applied in combination with Soil warming, growing season soil inorganic N availability was significantly reduced. These results demonstrate that there is a strong positive relationship between the depth of permafrost thaw and N availability in tundra ecosystems but that this relationship can be diminished by interactions between increased thaw, warmer air temperatures, and higher levels of soil moisture. Within 5 years of permafrost thaw, plants actively incorporate newly available N into biomass but C storage in live vascular plant biomass is unlikely to be greater than losses from deep soil C pools. © 2015 John Wiley & Sons Ltd.

  14. New member of the hormone-sensitive lipase family from the permafrost microbial community.

    Science.gov (United States)

    Petrovskaya, Lada E; Novototskaya-Vlasova, Ksenia A; Gapizov, Sultan Sh; Spirina, Elena V; Durdenko, Ekaterina V; Rivkina, Elizaveta M

    2017-07-04

    Siberian permafrost is a unique environment inhabited with diverse groups of microorganisms. Among them, there are numerous producers of biotechnologically relevant enzymes including lipases and esterases. Recently, we have constructed a metagenomic library from a permafrost sample and identified in it several genes coding for potential lipolytic enzymes. In the current work, properties of the recombinant esterases obtained from this library are compared with the previously characterized lipase from Psychrobacter cryohalolentis and other representatives of the hormone-sensitive lipase family.

  15. Edaphic and microclimatic controls over permafrost response to fire in interior Alaska

    International Nuclear Information System (INIS)

    Nossov, Dana R; Kielland, Knut; Torre Jorgenson, M; Kanevskiy, Mikhail Z

    2013-01-01

    Discontinuous permafrost in the North American boreal forest is strongly influenced by the effects of ecological succession on the accumulation of surface organic matter, making permafrost vulnerable to degradation resulting from fire disturbance. To assess factors affecting permafrost degradation after wildfire, we compared vegetation composition and soil properties between recently burned and unburned sites across three soil landscapes (rocky uplands, silty uplands, and sandy lowlands) situated within the Yukon Flats and Yukon-Tanana Uplands in interior Alaska. Mean annual air temperatures at our study sites from 2011 to 2012 were relatively cold (−5.5 ° C) and favorable to permafrost formation. Burning of mature evergreen forests with thick moss covers caused replacement by colonizing species in severely burned areas and recovery of pre-fire understory vegetation in moderately burned areas. Surface organic layer thickness strongly affected thermal regimes and thaw depths. On average, fire caused a five-fold decrease in mean surface organic layer thickness, a doubling of water storage in the active layer, a doubling of thaw depth, an increase in soil temperature at the surface (−0.6 to +2.1 ° C) and at 1 m depth (−1.7 to +0.4 ° C), and a two-fold increase in net soil heat input. Degradation of the upper permafrost occurred at all burned sites, but differences in soil texture and moisture among soil landscapes allowed permafrost to persist beneath the active layer in the silty uplands, whereas a talik of unknown depth developed in the rocky uplands and a thin talik developed in the sandy lowlands. A changing climate and fire regime would undoubtedly influence permafrost in the boreal forest, but the patterns of degradation or stabilization would vary considerably across the discontinuous permafrost zone due to differences in microclimate, successional patterns, and soil characteristics. (letter)

  16. Frozen-Ground Cartoons: An international collaboration between artists and permafrost scientists

    OpenAIRE

    Fritz, Michael; Bouchard, Fréderic; Deshpande, Bethany; Malenfant-Lepage, Julie; Nieuwendam, Alexandre; Paquette, Michel; Rudy, Ashley; Siewert, Matthias; Veillete, Audrey; Weege, Stefanie; Harbor, Jonathan M.; Habeck, J. O.; Sjöberg, Ylva

    2018-01-01

    Communicating science about a phenomenon found under ground and defined by its thermal properties in an easy, funny, and engaging way, can be a challenge. Two years ago, a group of young researchers from Canada and Europe united to tackle this problem by combining arts and science to produce a series of outreach comic strips about permafrost (frozen ground). Because this concerns us all. As the climate warms, permafrost thaws and becomes unstable for houses, roads and airports. The thawi...

  17. Temporal Behavior of Lake Size-Distribution in a Thawing Permafrost Landscape in Northwestern Siberia

    Directory of Open Access Journals (Sweden)

    Johanna Mård Karlsson

    2014-01-01

    Full Text Available Arctic warming alters regional hydrological systems, as permafrost thaw increases active layer thickness and in turn alters the pathways of water flow through the landscape. Further, permafrost thaw may change the connectivity between deeper and shallower groundwater and surface water altering the terrestrial water balance and distribution. Thermokarst lakes and wetlands in the Arctic offer a window into such changes as these landscape elements depend on permafrost and are some of the most dynamic and widespread features in Arctic lowland regions. In this study we used Landsat remotely sensed imagery to investigate potential shifts in thermokarst lake size-distributions, which may be brought about by permafrost thaw, over three distinct time periods (1973, 1987–1988, and 2007–2009 in three hydrological basins in northwestern Siberia. Results revealed fluctuations in total area and number of lakes over time, with both appearing and disappearing lakes alongside stable lakes. On the whole basin scales, there is no indication of any sustained long-term change in thermokarst lake area or lake size abundance over time. This statistical temporal consistency indicates that spatially variable change effects on local permafrost conditions have driven the individual lake changes that have indeed occurred over time. The results highlight the importance of using multi-temporal remote sensing data that can reveal complex spatiotemporal variations distinguishing fluctuations from sustained change trends, for accurate interpretation of thermokarst lake changes and their possible drivers in periods of climate and permafrost change.

  18. Determinants of carbon release from the active layer and permafrost deposits on the Tibetan Plateau

    Science.gov (United States)

    Chen, Leiyi; Liang, Junyi; Qin, Shuqi; Liu, Li; Fang, Kai; Xu, Yunping; Ding, Jinzhi; Li, Fei; Luo, Yiqi; Yang, Yuanhe

    2016-01-01

    The sign and magnitude of permafrost carbon (C)-climate feedback are highly uncertain due to the limited understanding of the decomposability of thawing permafrost and relevant mechanistic controls over C release. Here, by combining aerobic incubation with biomarker analysis and a three-pool model, we reveal that C quality (represented by a higher amount of fast cycling C but a lower amount of recalcitrant C compounds) and normalized CO2–C release in permafrost deposits were similar or even higher than those in the active layer, demonstrating a high vulnerability of C in Tibetan upland permafrost. We also illustrate that C quality exerts the most control over CO2–C release from the active layer, whereas soil microbial abundance is more directly associated with CO2–C release after permafrost thaw. Taken together, our findings highlight the importance of incorporating microbial properties into Earth System Models when predicting permafrost C dynamics under a changing environment. PMID:27703168

  19. Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils

    Science.gov (United States)

    Schädel, Christina; Bader, Martin K.-F.; Schuur, Edward A.G.; Biasi, Christina; Bracho, Rosvel; Čapek, Petr; De Baets, Sarah; Diáková, Kateřina; Ernakovich, Jessica; Estop-Aragones, Cristian; Graham, David E.; Hartley, Iain P.; Iversen, Colleen M.; Kane, Evan S.; Knoblauch, Christian; Lupascu, Massimo; Martikainen, Pertti J.; Natali, Susan M.; Norby, Richard J.; O'Donnell, Jonathan A.; Roy Chowdhury, Taniya; Šantrůčková, Hana; Shaver, Gaius; Sloan, Victoria L.; Treat, Claire C.; Turetsky, Merritt R.; Waldrop, Mark P.; Wickland, Kimberly P.

    2016-01-01

    Increasing temperatures in northern high latitudes are causing permafrost to thaw, making large amounts of previously frozen organic matter vulnerable to microbial decomposition. Permafrost thaw also creates a fragmented landscape of drier and wetter soil conditions that determine the amount and form (carbon dioxide (CO2), or methane (CH4)) of carbon (C) released to the atmosphere. The rate and form of C release control the magnitude of the permafrost C feedback, so their relative contribution with a warming climate remains unclear. We quantified the effect of increasing temperature and changes from aerobic to anaerobic soil conditions using 25 soil incubation studies from the permafrost zone. Here we show, using two separate meta-analyses, that a 10 °C increase in incubation temperature increased C release by a factor of 2.0 (95% confidence interval (CI), 1.8 to 2.2). Under aerobic incubation conditions, soils released 3.4 (95% CI, 2.2 to 5.2) times more C than under anaerobic conditions. Even when accounting for the higher heat trapping capacity of CH4, soils released 2.3 (95% CI, 1.5 to 3.4) times more C under aerobic conditions. These results imply that permafrost ecosystems thawing under aerobic conditions and releasing CO2 will strengthen the permafrost C feedback more than waterlogged systems releasing CO2 and CH4 for a given amount of C.

  20. Microbial network, phylogenetic diversity and community membership in the active layer across a permafrost thaw gradient.

    Science.gov (United States)

    Mondav, Rhiannon; McCalley, Carmody K; Hodgkins, Suzanne B; Frolking, Steve; Saleska, Scott R; Rich, Virginia I; Chanton, Jeff P; Crill, Patrick M

    2017-08-01

    Biogenic production and release of methane (CH 4 ) from thawing permafrost has the potential to be a strong source of radiative forcing. We investigated changes in the active layer microbial community of three sites representative of distinct permafrost thaw stages at a palsa mire in northern Sweden. The palsa site (intact permafrost and low radiative forcing signature) had a phylogenetically clustered community dominated by Acidobacteria and Proteobacteria. The bog (thawing permafrost and low radiative forcing signature) had lower alpha diversity and midrange phylogenetic clustering, characteristic of ecosystem disturbance affecting habitat filtering. Hydrogenotrophic methanogens and Acidobacteria dominated the bog shifting from palsa-like to fen-like at the waterline. The fen (no underlying permafrost, high radiative forcing signature) had the highest alpha, beta and phylogenetic diversity, was dominated by Proteobacteria and Euryarchaeota and was significantly enriched in methanogens. The Mire microbial network was modular with module cores consisting of clusters of Acidobacteria, Euryarchaeota or Xanthomonodales. Loss of underlying permafrost with associated hydrological shifts correlated to changes in microbial composition, alpha, beta and phylogenetic diversity associated with a higher radiative forcing signature. These results support the complex role of microbial interactions in mediating carbon budget changes and climate feedback in response to climate forcing. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. Complete and Partial Photo-oxidation of Dissolved Organic Matter Draining Permafrost Soils.

    Science.gov (United States)

    Ward, Collin P; Cory, Rose M

    2016-04-05

    Photochemical degradation of dissolved organic matter (DOM) to carbon dioxide (CO2) and partially oxidized compounds is an important component of the carbon cycle in the Arctic. Thawing permafrost soils will change the chemical composition of DOM exported to arctic surface waters, but the molecular controls on DOM photodegradation remain poorly understood, making it difficult to predict how inputs of thawing permafrost DOM may alter its photodegradation. To address this knowledge gap, we quantified the susceptibility of DOM draining the shallow organic mat and the deeper permafrost layer of arctic soils to complete and partial photo-oxidation and investigated changes in the chemical composition of each DOM source following sunlight exposure. Permafrost and organic mat DOM had similar lability to photomineralization despite substantial differences in initial chemical composition. Concurrent losses of carboxyl moieties and shifts in chemical composition during photodegradation indicated that photodecarboxylation could account for 40-90% of DOM photomineralized to CO2. Permafrost DOM had a higher susceptibility to partial photo-oxidation compared to organic mat DOM, potentially due to a lower abundance of phenolic moieties with antioxidant properties. These results suggest that photodegradation will likely continue to be an important control on DOM fate in arctic freshwaters as the climate warms and permafrost soils thaw.

  2. Permafrost Favorability Index: Spatial Modeling in the French Alps Using a Rock Glacier Inventory

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    Marco Marcer

    2017-12-01

    Full Text Available In the present study we used the first rock glacier inventory for the entire French Alps to model spatial permafrost distribution in the region. Climatic and topographic data evaluated at the rock glacier locations were used as predictor variables in a Generalized Linear Model. Model performances are strong, suggesting that, in agreement with several previous studies, this methodology is able to model accurately rock glacier distribution. A methodology to estimate model uncertainties is proposed, revealing that the subjectivity in the interpretation of rock glacier activity and contours may substantially bias the model. The model highlights a North-South trend in the regional pattern of permafrost distribution which is attributed to the climatic influences of the Atlantic and Mediterranean climates. Further analysis suggest that lower amounts of precipitation in the early winter and a thinner snow cover, as typically found in the Mediterranean area, could contribute to the existence of permafrost at higher temperatures compared to the Northern Alps. A comparison with the Alpine Permafrost Index Map (APIM shows no major differences with our model, highlighting the very good predictive power of the APIM despite its tendency to slightly overestimate permafrost extension with respect to our database. The use of rock glaciers as indicators of permafrost existence despite their time response to climate change is discussed and an interpretation key is proposed in order to ensure the proper use of the model for research as well as for operational purposes.

  3. Ancient low-molecular-weight organic acids in permafrost fuel rapid carbon dioxide production upon thaw.

    Science.gov (United States)

    Drake, Travis W; Wickland, Kimberly P; Spencer, Robert G M; McKnight, Diane M; Striegl, Robert G

    2015-11-10

    Northern permafrost soils store a vast reservoir of carbon, nearly twice that of the present atmosphere. Current and projected climate warming threatens widespread thaw of these frozen, organic carbon (OC)-rich soils. Upon thaw, mobilized permafrost OC in dissolved and particulate forms can enter streams and rivers, which are important processors of OC and conduits for carbon dioxide (CO2) to the atmosphere. Here, we demonstrate that ancient dissolved organic carbon (DOC) leached from 35,800 y B.P. permafrost soils is rapidly mineralized to CO2. During 200-h experiments in a novel high-temporal-resolution bioreactor, DOC concentration decreased by an average of 53%, fueling a more than sevenfold increase in dissolved inorganic carbon (DIC) concentration. Eighty-seven percent of the DOC loss to microbial uptake was derived from the low-molecular-weight (LMW) organic acids acetate and butyrate. To our knowledge, our study is the first to directly quantify high CO2 production rates from permafrost-derived LMW DOC mineralization. The observed DOC loss rates are among the highest reported for permafrost carbon and demonstrate the potential importance of LMW DOC in driving the rapid metabolism of Pleistocene-age permafrost carbon upon thaw and the outgassing of CO2 to the atmosphere by soils and nearby inland waters.

  4. Ancient low–molecular-weight organic acids in permafrost fuel rapid carbon dioxide production upon thaw

    Science.gov (United States)

    Drake, Travis W.; Wickland, Kimberly P.; Spencer, Robert G. M.; McKnight, Diane M.; Striegl, Robert G.

    2015-01-01

    Northern permafrost soils store a vast reservoir of carbon, nearly twice that of the present atmosphere. Current and projected climate warming threatens widespread thaw of these frozen, organic carbon (OC)-rich soils. Upon thaw, mobilized permafrost OC in dissolved and particulate forms can enter streams and rivers, which are important processors of OC and conduits for carbon dioxide (CO2) to the atmosphere. Here, we demonstrate that ancient dissolved organic carbon (DOC) leached from 35,800 y B.P. permafrost soils is rapidly mineralized to CO2. During 200-h experiments in a novel high–temporal-resolution bioreactor, DOC concentration decreased by an average of 53%, fueling a more than sevenfold increase in dissolved inorganic carbon (DIC) concentration. Eighty-seven percent of the DOC loss to microbial uptake was derived from the low–molecular-weight (LMW) organic acids acetate and butyrate. To our knowledge, our study is the first to directly quantify high CO2 production rates from permafrost-derived LMW DOC mineralization. The observed DOC loss rates are among the highest reported for permafrost carbon and demonstrate the potential importance of LMW DOC in driving the rapid metabolism of Pleistocene-age permafrost carbon upon thaw and the outgassing of CO2 to the atmosphere by soils and nearby inland waters.

  5. Multi-omics of permafrost, active layer and thermokarst bog soil microbiomes.

    Science.gov (United States)

    Hultman, Jenni; Waldrop, Mark P; Mackelprang, Rachel; David, Maude M; McFarland, Jack; Blazewicz, Steven J; Harden, Jennifer; Turetsky, Merritt R; McGuire, A David; Shah, Manesh B; VerBerkmoes, Nathan C; Lee, Lang Ho; Mavrommatis, Kostas; Jansson, Janet K

    2015-05-14

    Over 20% of Earth's terrestrial surface is underlain by permafrost with vast stores of carbon that, once thawed, may represent the largest future transfer of carbon from the biosphere to the atmosphere. This process is largely dependent on microbial responses, but we know little about microbial activity in intact, let alone in thawing, permafrost. Molecular approaches have recently revealed the identities and functional gene composition of microorganisms in some permafrost soils and a rapid shift in functional gene composition during short-term thaw experiments. However, the fate of permafrost carbon depends on climatic, hydrological and microbial responses to thaw at decadal scales. Here we use the combination of several molecular 'omics' approaches to determine the phylogenetic composition of the microbial communities, including several draft genomes of novel species, their functional potential and activity in soils representing different states of thaw: intact permafrost, seasonally thawed active layer and thermokarst bog. The multi-omics strategy reveals a good correlation of process rates to omics data for dominant processes, such as methanogenesis in the bog, as well as novel survival strategies for potentially active microbes in permafrost.

  6. PeRL: a circum-Arctic Permafrost Region Pond and Lake database

    Science.gov (United States)

    Muster, Sina; Roth, Kurt; Langer, Moritz; Lange, Stephan; Cresto Aleina, Fabio; Bartsch, Annett; Morgenstern, Anne; Grosse, Guido; Jones, Benjamin; Sannel, A. Britta K.; Sjöberg, Ylva; Günther, Frank; Andresen, Christian; Veremeeva, Alexandra; Lindgren, Prajna R.; Bouchard, Frédéric; Lara, Mark J.; Fortier, Daniel; Charbonneau, Simon; Virtanen, Tarmo A.; Hugelius, Gustaf; Palmtag, Juri; Siewert, Matthias B.; Riley, William J.; Koven, Charles D.; Boike, Julia

    2017-06-01

    Ponds and lakes are abundant in Arctic permafrost lowlands. They play an important role in Arctic wetland ecosystems by regulating carbon, water, and energy fluxes and providing freshwater habitats. However, ponds, i.e., waterbodies with surface areas smaller than 1. 0 × 104 m2, have not been inventoried on global and regional scales. The Permafrost Region Pond and Lake (PeRL) database presents the results of a circum-Arctic effort to map ponds and lakes from modern (2002-2013) high-resolution aerial and satellite imagery with a resolution of 5 m or better. The database also includes historical imagery from 1948 to 1965 with a resolution of 6 m or better. PeRL includes 69 maps covering a wide range of environmental conditions from tundra to boreal regions and from continuous to discontinuous permafrost zones. Waterbody maps are linked to regional permafrost landscape maps which provide information on permafrost extent, ground ice volume, geology, and lithology. This paper describes waterbody classification and accuracy, and presents statistics of waterbody distribution for each site. Maps of permafrost landscapes in Alaska, Canada, and Russia are used to extrapolate waterbody statistics from the site level to regional landscape units. PeRL presents pond and lake estimates for a total area of 1. 4 × 106 km2 across the Arctic, about 17 % of the Arctic lowland ( pangaea.de/10.1594/PANGAEA.868349" target="_blank">https://doi.pangaea.de/10.1594/PANGAEA.868349.

  7. The potential significance of permafrost to the behaviour of a deep radioactive waste repository

    International Nuclear Information System (INIS)

    McEwen, T.; Marsily, G.de

    1991-02-01

    Permafrost is one of the scenarios that is being considered as part of the groundwater flow and transport modelling for the Project-90 assessment. It is included as one of the primary Features, Events and Processes (FEPs) which are being kept outside the Process System in the SKB/SKI scenario development project. There is a large amount of evidence that Sweden has suffered several cycles of permafrost development over the Quaternary, approximately the last 2My, and climatic predictions for the next hundred thousand years suggest that similar climatic cycling is likely to occur. The presence of permafrost could have important effects on the hydrogeological regime and could therefore be important in modifying the release and dispersion of radionuclides from a repository. The climatic conditions of permafrost would also influence radionuclide migration and accumulation in the biosphere and the associated radiation exposure of man. These biosphere aspects are not considered here but the implications for discharge into the biosphere are examined, including the abstraction of groundwater by man in permafrost regions. This report reviews the evidence relating to permafrost development and discusses the possible implications for the long-term safety of a deep repository. (78 refs.) (au)

  8. Circumpolar assessment of permafrost C quality and its vulnerability over time using long-term incubation data

    DEFF Research Database (Denmark)

    Schädel, Christina; Schuur, Edward A.G.; Bracho, Rosvel

    2014-01-01

    High-latitude ecosystems store approximately 1700 Pg of soil carbon (C), which is twice as much C as is currently contained in the atmosphere. Permafrost thaw and subsequent microbial decomposition of permafrost organic matter could add large amounts of C to the atmosphere, thereby influencing...... the global C cycle. The rates at which C is being released from the permafrost zone at different soil depths and across different physiographic regions are poorly understood but crucial in understanding future changes in permafrost C storage with climate change. We assessed the inherent decomposability of C...... from the permafrost zone by assembling a database of long-term (>1 year) aerobic soil incubations from 121 individual samples from 23 high-latitude ecosystems located across the northern circumpolar permafrost zone. Using a three-pool (i.e., fast, slow and passive) decomposition model, we estimated...

  9. The Thermal State of Permafrost in the Nordic Area during the International Polar Year 2007-2009

    DEFF Research Database (Denmark)

    Christiansen, H. H.; Etzelmuller, B.; Isaksen, K.

    2010-01-01

    This paper provides a snapshot of the permafrost thermal state in the Nordic area obtained during the International Polar Year (IPY) 2007-2009. Several intensive research campaigns were undertaken within a variety of projects in the Nordic countries to obtain this snapshot. We demonstrate...... for Scandinavia that both lowland permafrost in palsas and peat plateaus, and large areas of permafrost in the mountains are at temperatures close to 0 degrees C, which makes them sensitive to climatic changes. In Svalbard and northeast Greenland, and also in the highest parts of the mountains in the rest...... affect the permafrost thermal state in the Nordic area. Time series of active-layer thickness and permafrost temperature conditions in the Nordic area, which are generally only 10 years in length, show generally increasing active-layer depths and risings permafrost temperatures....

  10. Assessment of climate and land use change impacts on surface water runoff and connectivity in a continuous permafrost catchment on the Arctic Coastal Plain, Alaska

    Science.gov (United States)

    Gaedeke, A.; Arp, C. D.; Liljedahl, A. K.; Daanen, R. P.; Whitman, M. S.

    2016-12-01

    A changing climate is leading to rapid transformations of hydrological processes in low-gradient Arctic terrestrial ecosystems which are dominated by lakes and ponds, wetlands, polygonised tundra, and connecting stream and river networks. The aim of this study is to gain a deeper understanding of the impacts of climate and land use change on surface water availability and connectivity by utilizing the process-based, spatially distributed hydrological model WaSiM. Crea Creek Watershed (30 km2), which is located in the National Petroleum Reserve-Alaska (NPR-A) was chosen as study area because of its permafrost landforms (bedfast and floating ice lakes, high and low centered polygons), existing observational data (discharge, snow depth, and meteorological variables since 2009), and resource management issues related to permafrost degradation and aquatic habitat dynamics. Foremost of concern is oil development scheduled to begin starting in 2017 with the construction of a permanent road and drilling pad directly within the Crea Watershed. An interdisciplinary team consisting of scientists and regional stakeholders defined the following scenarios to be simulated using WaSiM: (1) industrial development (impact of water removal from lakes (winter) for ice road construction on downstream (summer) runoff), (2) permanent road construction to allow oil companies access to develop and extract petroleum, and (3) potential modes of climate change including warmer, snowier winters and prolonged drought during summers. Downscaled meteorological output from the Weather Research & Forecasting Model (WRF) will be used as the forcing for analysis of climate scenarios alone and for assessment of land-use responses under varying climate scenarios. Our results will provide regional stakeholders with information on the impacts of climate and land use change on surface water connectivity that affects aquatic habitat, as well as lake hydrologic interactions with permafrost. These finding

  11. Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 1. Minimum seaward extent defined from multichannel seismic reflection data

    Science.gov (United States)

    Brothers, Laura; Herman, Bruce M.; Hart, Patrick E.; Ruppel, Carolyn D.

    2016-01-01

    Subsea ice-bearing permafrost (IBPF) and associated gas hydrate in the Arctic have been subject to a warming climate and saline intrusion since the last transgression at the end of the Pleistocene. The consequent degradation of IBPF is potentially associated with significant degassing of dissociating gas hydrate deposits. Previous studies interpreted the distribution of subsea permafrost on the U.S. Beaufort continental shelf based on geographically sparse data sets and modeling of expected thermal history. The most cited work projects subsea permafrost to the shelf edge (∼100 m isobath). This study uses a compilation of stacking velocity analyses from ∼100,000 line-km of industry-collected multichannel seismic reflection data acquired over 57,000 km2 of the U.S. Beaufort shelf to delineate continuous subsea IBPF. Gridded average velocities of the uppermost 750 ms two-way travel time range from 1475 to 3110 m s−1. The monotonic, cross-shore pattern in velocity distribution suggests that the seaward extent of continuous IBPF is within 37 km of the modern shoreline at water depths < 25 m. These interpretations corroborate recent Beaufort seismic refraction studies and provide the best, margin-scale evidence that continuous subsea IBPF does not currently extend to the northern limits of the continental shelf.

  12. Modelling of permafrost freezing and melting and the impact of a climatic cycle on groundwater flow at the Meuse/Haute-Marne site

    International Nuclear Information System (INIS)

    Holmen, J.; Benabderrahmane, H.; Buoro, A.; Brulhet, J.

    2011-01-01

    A fully coupled three-dimensional groundwater flow and heat transport (convection-conduction) model has been developed, including permafrost. The model covers the entire Paris basin and is focused on the Meuse/Haute-Marne Sector area and the Bure investigation site. The model was calibrated on the basis of the present hydro-thermal situation. The studied time period corresponds to what is considered a typical climatic cycle of length 130,000 year. A build-up of a superficial glacial ice mass is not included in the model; it is assumed that accumulated snow will melt during the summer months. The temperature boundary condition on top of the model is specified as a time-varying surface temperature. The temperatures are derived from an estimate of the future climatic evolution. It is the changes with time of the prescribed temperatures along the topography that drives all changes in groundwater flow, temperature and permafrost inside the model. The simulations are transient, but the initial condition of the base case represents a steady state situation. The simulated time period, for reaching a steady state situation of groundwater flows and temperatures in the deep and highly permeable layers of the Dogger (in the Sector area) is considerable (in the range of 50,000. years), depending on perturbation studied (e.g. a change in surface temperature of 5 deg.) and convergence criteria. The simulated depth of the permafrost varies in space and time during the studied glacial periods. Within the area studied (the Sector area), the simulated permafrost reaches a maximum depth of approx. 110 m. This is a median depth taking into account the spatial distribution of the permafrost. The lowest simulated temperature in the lower parts of the Callovo-Oxfordian clay stone, in the immediate vicinity of the Bure investigation site (in the Sector area), is approx. 14.5 deg. C, which is approx. 7.5 deg. C lower than the initial temperature (22 deg. C). A full reversion back to the

  13. Relict Mountain Permafrost Area (Loess Plateau, China) Exhibits High Ecosystem Respiration Rates and Accelerating Rates in Response to Warming

    Science.gov (United States)

    Mu, Cuicui; Wu, Xiaodong; Zhao, Qian; Smoak, Joseph M.; Yang, Yulong; Hu, Lian; Zhong, Wen; Liu, Guimin; Xu, Haiyan; Zhang, Tingjun

    2017-10-01

    Relict permafrost regions are characterized by thin permafrost and relatively high temperatures. Understanding the ecosystem respiration rate (ERR) and its relationship with soil hydrothermal conditions in these areas can provide knowledge regarding the permafrost carbon cycle in a warming world. In this study, we examined a permafrost area, a boundary area, and a seasonally frozen ground area within a relict permafrost region on the east edge of the Qinghai-Tibetan Plateau, China. Measurements from July 2015 to September 2016 showed that the mean annual ecosystem CO2 emissions for the boundary area were greater than the permafrost area. The Q10 value of the ERRs in the seasonally frozen ground area was greater than the permafrost area, indicating that the carbon emissions in the nonpermafrost areas were more sensitive to warming. The 1 year open-top chamber (OTC) warming increased soil temperatures in both the permafrost and seasonally frozen ground areas throughout the year, and the warming increased the ERRs by 1.18 (0.99-1.38, with interquartile range) and 1.13 (0.75-1.54, with interquartile range) μmol CO2 m-2 s-1 in permafrost and seasonally frozen ground areas, respectively. The OTC warming increased annual ERRs by approximately 50% for both permafrost and seasonally frozen ground areas with half the increase occurring during the nongrowing seasons. These results suggest that the ERRs in relict permafrost are high in comparison with arctic regions, and the carbon balance in relict permafrost areas could be greatly changed by climate warming.

  14. Gas geochemistry studies at the gas hydrate occurrence in the permafrost environment of Mallik (NWT, Canada)

    Science.gov (United States)

    Wiersberg, T.; Erzinger, J.; Zimmer, M.; Schicks, J.; Dahms, E.; Mallik Working Group

    2003-04-01

    We present real-time mud gas monitoring data as well as results of noble gas and isotope investigations from the Mallik 2002 Production Research Well Program, an international research project on Gas Hydrates in the Northwest Territories of Canada. The program participants include 8 partners; The Geological Survey of Canada (GSC), The Japan National Oil Corporation (JNOC), GeoForschungsZentrum Potsdam (GFZ), United States Geological Survey (USGS), United States Department of the Energy (USDOE), India Ministry of Petroleum and Natural Gas (MOPNG)/Gas Authority of India (GAIL) and the Chevron-BP-Burlington joint venture group. Mud gas monitoring (extraction of gas dissolved in the drill mud followed by real-time analysis) revealed more or less complete gas depth profiles of Mallik 4L-38 and Mallik 5L-38 wells for N_2, O_2, Ar, He, CO_2, H_2, CH_4, C_2H_6, C_3H_8, C_4H10, and 222Rn; both wells are approx. 1150 m deep. Based on the molecular and and isotopic composition, hydrocarbons occurring at shallow depth (down to ˜400 m) are mostly of microbial origin. Below 400 m, the gas wetness parameter (CH_4/(C_2H_6 + C_3H_8)) and isotopes indicate mixing with thermogenic gas. Gas accumulation at the base of permafrost (˜650 m) as well as δ13C and helium isotopic data implies that the permafrost inhibits gas flux from below. Gas hydrate occurrence at Mallik is known in a depth between ˜890 m and 1100 m. The upper section of the hydrate bearing zone (890 m--920 m) consists predominantly of methane bearing gas hydrates. Between 920 m and 1050 m, concentration of C_2H_6, C_3H_8, and C_4H10 increases due to the occurrence of organic rich sediment layers. Below that interval, the gas composition is similar to the upper section of the hydrate zone. At the base of the hydrate bearing zone (˜1100 m), elevated helium and methane concentrations and their isotopic composition leads to the assumption that gas hydrates act as a barrier for gas migration from below. In mud gas

  15. Shifts of methanogenic communities in response to permafrost thaw results in rising methane emissions and soil property changes.

    Science.gov (United States)

    Wei, Shiping; Cui, Hongpeng; Zhu, Youhai; Lu, Zhenquan; Pang, Shouji; Zhang, Shuai; Dong, Hailiang; Su, Xin

    2018-05-01

    Permafrost thaw can bring negative consequences in terms of ecosystems, resulting in permafrost collapse, waterlogging, thermokarst lake development, and species composition changes. Little is known about how permafrost thaw influences microbial community shifts and their activities. Here, we show that the dominant archaeal community shifts from Methanomicrobiales to Methanosarcinales in response to the permafrost thaw, and the increase in methane emission is found to be associated with the methanogenic archaea, which rapidly bloom with nearly tenfold increase in total number. The mcrA gene clone libraries analyses indicate that Methanocellales/Rice Cluster I was predominant both in the original permafrost and in the thawed permafrost. However, only species belonging to Methanosarcinales showed higher transcriptional activities in the thawed permafrost, indicating a shift of methanogens from hydrogenotrophic to partly acetoclastic methane-generating metabolic processes. In addition, data also show the soil texture and features change as a result of microbial reproduction and activity induced by this permafrost thaw. Those data indicate that microbial ecology under warming permafrost has potential impacts on ecosystem and methane emissions.

  16. Wetland development, permafrost history and nutrient cycling inferred from late Holocene peat and lake sediment records in subarctic Sweden

    DEFF Research Database (Denmark)

    Kokfelt, U.; Reuss, N.; Struyf, E.

    2010-01-01

    to re-deposition of peat into one of the lakes after ca. 2,100 cal BP, and stimulated primary productivity in the other lake at ca. 1,900-1,800 cal BP. Carbonate precipitation appears to have been suppressed when acidic poor fen and bog (palsa) communities dominated the catchment mire, and permafrost...... insight into nutrient and permafrost dynamics in a subarctic wetland and imply that continued permafrost decay and related vegetation changes towards minerotrophy may increase carbon and nutrient storage of mire deposits and reduce nutrient fluxes in runoff. Rapid permafrost degradation may on the other...

  17. Permafrost distribution in peatlands of west-central Canada during the Holocene warm period 6000 years BP

    Energy Technology Data Exchange (ETDEWEB)

    Zoltai, S.C. [Canadian Forest Service, Edmonton, AB (Canada)

    1995-12-31

    The extent and timing of permafrost development in peatlands of west-central Canada are examined. The floristic composition of the permafrost peatlands was determined from macrofossil samples of cores drilled at 161 locations. Radiocarbon dating of substantial changes in the peat sequences and of basal peat deposition was used to provide chronological control. The reconstructed paleoenvironments show the presence or absence of permafrost at the time of peat formation. Permafrost distribution in peatlands is estimated during the warm period 6000 years BP. It is estimated that the mean annual temperature was approximately 5{degree}C warmer than at present. 42 refs., 3 figs., 4 tabs.

  18. Biomarker and carbon isotope constraints (δ13C, Δ14C) on sources and cycling of particulate organic matter discharged by large Siberian rivers draining permafrost areas

    International Nuclear Information System (INIS)

    Winterfeld, Maria

    2014-08-01

    consistent with inputs of OM from non-woody angiosperm sources mixed with organic matter derived from woody gymnosperm sources. A simple linear mixing model based on the lignin phenol distributions indicates organic matter in TSM samples from the delta and Buor Khaya Bay surface sediments contain comparable contributions from gymnosperm sources, which are primarily from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small area covered by tundra (∝12% of total catchment), the input of tundra-derived OM input is substantial and likely to increase in a warming Arctic. Radiocarbon compositions (Δ 14 C) of bulk OM in Lena River TSM samples varied from -55 to -391 permille, translating into 14 C ages of 395 to 3920 years BP. Using δ 13 C compositions to estimate the fraction of phytoplankton-derived OM and assuming that this material has a modern 14 C signature, we inferred the Δ 14 C compositions of terrigenous OM in TSM exported by the Lena River to range between -190 and -700 permille. Such variability in the ages of terrigenous OM (i.e. 1640 to 9720 14 C years BP) reflects the heterogeneous composition and residence time of OM in the Lena River catchment soils (Holocene to Pleistocene ages). Lignin phenol and Δ 14 C compositions of surface sediments from the adjacent Buor Khaya Bay suggest that terrestrial OM deposited there is older and more degraded than materials present in river particles and catchment soils. Stronger diagenetic alteration in Lena Delta TSM and marine sediments relative to soils may reflect degradation of more labile components during permafrost thawing and transport. Despite the high natural heterogeneity in catchment soils, the lignin biomarker compositions and radiocarbon ages of terrestrial OM exported by the Lena River reflect catchment characteristics such as vegetation and soil type. Climate warming related changes in the Lena River catchment may be detectable in changing lignin

  19. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    International Nuclear Information System (INIS)

    Cascoyne, M.

    2000-06-01

    Salt-rejection into the aqueous phase from permafrost growth ('aggradation') during the onset of cold-climate conditions in the Pleistocene period is a mechanism that could account for the presence of saline groundwaters in the Fennoscandian Shield. This report describes the results of a review of scientific literature on the subject of permafrost, to search for and evaluate information which may indicate whether this mechanism is feasible for sites such as Olkiluoto and Aespoe on the Baltic Sea coast. The geomorphological characteristics of permafrost (such as development of patterned ground, ice wedging, pingo growth) have been studied in detail in the literature and provide an understanding of the effects of pore water expulsion and saline water formation. Evidence of salt-rejection during permafrost aggradation is found in results of analyses of the chemical and isotopic compositions of water in pingos and open taliks published in North American, Chinese and Russian literature over the last fifty years. While most studies have concentrated on shallow permafrost in soils and sediments, deep-drilling by the oil and gas industry has shown that permafrost may extend both laterally and to considerable depth. For instance, permafrost on the north slope of Alaska is laterally continuous over an area of at least 1000 km 2 and is associated with fluids of salinities up to 130 g/L. Also, in northern Siberia, permafrost has been observed to depths of over 900 m. Saline waters are ubiquitous in coastal areas that are currently underlain by permafrost. However, it is not clear how much of the salinity has been produced by the freezing process and how much is simply due to leaching of saline soils and sediments by groundwaters and the presence of residual seawater in the sediments. Possible indicators of concentration by freezing include the presence of brines (i.e. waters of greater salinity than seawater), mineral precipitates (e.g. mirabilite) that are formed on freezing

  20. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    International Nuclear Information System (INIS)

    Gascoyne, M.

    2000-04-01

    Salt-rejection into the aqueous phase from permafrost growth during the onset of cold-climate conditions in the Pleistocene period is a mechanism that could account for the presence of saline groundwaters in the Fennoscandian Shield. This report describes the results of a review of scientific literature on the subject of permafrost, to search for and evaluate information which may indicate whether this mechanism is feasible for sites such as Olkiluoto and Aespoe on the Baltic Sea coast. The geomorphological characteristics of permafrost (such as development of patterned ground, ice wedging, pingo growth) have been studied in detail in the literature and provide an understanding of the effects of pore water expulsion and saline water formation. Evidence of salt-rejection during permafrost aggradation is found in results of analyses of the chemical and isotopic compositions of water in pingos and open taliks published in North American, Chinese and Russian literature over the last fifty years. While most studies have concentrated on shallow permafrost in soils and sediments, deep-drilling by the oil and gas industry has shown that permafrost may extend both laterally and to considerable depth. For instance, permafrost on the north slope of Alaska is laterally continuous over an area of at least 1000 km 2 and is associated with fluids of salinities up to 130 g/L. Also, in northern Siberia, permafrost has been observed to depths of over 900 m. Saline waters are ubiquitous in coastal areas that are currently underlain by permafrost. However, it is not clear how much of the salinity has been produced by the freezing process and how much is simply due to leaching of saline soils and sediments by ground- waters and the presence of residual seawater in the sediments. Possible indicators of concentration by freezing include the presence of brines (i.e.waters of greater salinity than seawater), mineral precipitates (e.g. mirabilite) that are formed on freezing of seawater

  1. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, M. [Gascoyne GeoProjects Inc., Pinawa (Canada)

    2000-04-01

    Salt-rejection into the aqueous phase from permafrost growth during the onset of cold-climate conditions in the Pleistocene period is a mechanism that could account for the presence of saline groundwaters in the Fennoscandian Shield. This report describes the results of a review of scientific literature on the subject of permafrost, to search for and evaluate information which may indicate whether this mechanism is feasible for sites such as Olkiluoto and Aespoe on the Baltic Sea coast. The geomorphological characteristics of permafrost (such as development of patterned ground, ice wedging, pingo growth) have been studied in detail in the literature and provide an understanding of the effects of pore water expulsion and saline water formation. Evidence of salt-rejection during permafrost aggradation is found in results of analyses of the chemical and isotopic compositions of water in pingos and open taliks published in North American, Chinese and Russian literature over the last fifty years. While most studies have concentrated on shallow permafrost in soils and sediments, deep-drilling by the oil and gas industry has shown that permafrost may extend both laterally and to considerable depth. For instance, permafrost on the north slope of Alaska is laterally continuous over an area of at least 1000 km{sup 2} and is associated with fluids of salinities up to 130 g/L. Also, in northern Siberia, permafrost has been observed to depths of over 900 m. Saline waters are ubiquitous in coastal areas that are currently underlain by permafrost. However, it is not clear how much of the salinity has been produced by the freezing process and how much is simply due to leaching of saline soils and sediments by ground- waters and the presence of residual seawater in the sediments. Possible indicators of concentration by freezing include the presence of brines (i.e.waters of greater salinity than seawater), mineral precipitates (e.g. mirabilite) that are formed on freezing of

  2. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Cascoyne, M. [Gascoyne GeoProjects Inc. (Canada)

    2000-06-01

    Salt-rejection into the aqueous phase from permafrost growth ('aggradation') during the onset of cold-climate conditions in the Pleistocene period is a mechanism that could account for the presence of saline groundwaters in the Fennoscandian Shield. This report describes the results of a review of scientific literature on the subject of permafrost, to search for and evaluate information which may indicate whether this mechanism is feasible for sites such as Olkiluoto and Aespoe on the Baltic Sea coast. The geomorphological characteristics of permafrost (such as development of patterned ground, ice wedging, pingo growth) have been studied in detail in the literature and provide an understanding of the effects of pore water expulsion and saline water formation. Evidence of salt-rejection during permafrost aggradation is found in results of analyses of the chemical and isotopic compositions of water in pingos and open taliks published in North American, Chinese and Russian literature over the last fifty years. While most studies have concentrated on shallow permafrost in soils and sediments, deep-drilling by the oil and gas industry has shown that permafrost may extend both laterally and to considerable depth. For instance, permafrost on the north slope of Alaska is laterally continuous over an area of at least 1000 km{sup 2} and is associated with fluids of salinities up to 130 g/L. Also, in northern Siberia, permafrost has been observed to depths of over 900 m. Saline waters are ubiquitous in coastal areas that are currently underlain by permafrost. However, it is not clear how much of the salinity has been produced by the freezing process and how much is simply due to leaching of saline soils and sediments by groundwaters and the presence of residual seawater in the sediments. Possible indicators of concentration by freezing include the presence of brines (i.e. waters of greater salinity than seawater), mineral precipitates (e.g. mirabilite) that are

  3. New insights into the ground thermal regime of talus slopes with permafrost below the timberline

    Science.gov (United States)

    Schwindt, Daniel; Kneisel, Christof

    2013-04-01

    In the central Alps permafrost can be expected above 2400 m a.s.l., at altitudes where mean annual air temperatures are below -1° C. However, isolated permafrost occurrences are present in north-exposed talus slopes, far below the timberline, where mean annual air temperatures are positive. Driving factors are assumed to be a low income of solar radiation, a thick organic layer with high insulation capacities as well as the thermally induced chimney effect (Wakonigg, 1996). Investigated are three talus slopes with permafrost in the Swiss Alps that differ with regard to elevation level, talus material, humus characteristics and vegetation composition as well as the mean annual air temperatures. Aim is to achieve a deeper understanding of the factors determining the site-specific thermal regime, as well as the spatially limited and temporally highly variable permafrost occurrences in vegetated talus slopes. Focus is not solely on the question of why permafrost exists at these sites, but also why permafrost does not exist in the immediate surroundings. To detect the temporal variability and spatial heterogeneity of the permafrost occurrences, electrical resistivity tomography monitoring, seismic refraction tomography monitoring, and quasi-3D ERT were applied. To determine the ground thermal regime, air-, ground surface-, and humus temperatures, as well as temperatures within vents of the chimneys were recorded. Furthermore, humus characteristics (thickness, -temperature and -moisture) were mapped in permafrost-affected slope areas and in the immediate surroundings. To test the correlation between solar radiation, permafrost distribution, and humus/vegetation composition, digital elevation models were used to calculate the income of solar radiation. The areal extent of the permafrost bodies coincide precisely with slope sections where the organic layer is thickest, a consistent moss cover is present, and where temperatures at the transition between humus layer and

  4. Effects of bryophyte and lichen cover on permafrost soil temperature at large scale

    Directory of Open Access Journals (Sweden)

    P. Porada

    2016-09-01

    Full Text Available Bryophyte and lichen cover on the forest floor at high latitudes exerts an insulating effect on the ground. In this way, the cover decreases mean annual soil temperature and can protect permafrost soil. Climate change, however, may change bryophyte and lichen cover, with effects on the permafrost state and related carbon balance. It is, therefore, crucial to predict how the bryophyte and lichen cover will react to environmental change at the global scale. To date, current global land surface models contain only empirical representations of the bryophyte and lichen cover, which makes it impractical to predict the future state and function of bryophytes and lichens. For this reason, we integrate a process-based model of bryophyte and lichen growth into the global land surface model JSBACH (Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg. The model simulates bryophyte and lichen cover on upland sites. Wetlands are not included. We take into account the dynamic nature of the thermal properties of the bryophyte and lichen cover and their relation to environmental factors. Subsequently, we compare simulations with and without bryophyte and lichen cover to quantify the insulating effect of the organisms on the soil. We find an average cooling effect of the bryophyte and lichen cover of 2.7 K on temperature in the topsoil for the region north of 50° N under the current climate. Locally, a cooling of up to 5.7 K may be reached. Moreover, we show that using a simple, empirical representation of the bryophyte and lichen cover without dynamic properties only results in an average cooling of around 0.5 K. This suggests that (a bryophytes and lichens have a significant impact on soil temperature in high-latitude ecosystems and (b a process-based description of their thermal properties is necessary for a realistic representation of the cooling effect. The advanced land surface scheme, including a dynamic bryophyte and lichen model, will

  5. Snowball Earth termination by destabilization of equatorial permafrost methane clathrate.

    Science.gov (United States)

    Kennedy, Martin; Mrofka, David; von der Borch, Chris

    2008-05-29

    The start of the Ediacaran period is defined by one of the most severe climate change events recorded in Earth history--the recovery from the Marinoan 'snowball' ice age, approximately 635 Myr ago (ref. 1). Marinoan glacial-marine deposits occur at equatorial palaeolatitudes, and are sharply overlain by a thin interval of carbonate that preserves marine carbon and sulphur isotopic excursions of about -5 and +15 parts per thousand, respectively; these deposits are thought to record widespread oceanic carbonate precipitation during postglacial sea level rise. This abrupt transition records a climate system in profound disequilibrium and contrasts sharply with the cyclical stratigraphic signal imparted by the balanced feedbacks modulating Phanerozoic deglaciation. Hypotheses accounting for the abruptness of deglaciation include ice albedo feedback, deep-ocean out-gassing during post-glacial oceanic overturn or methane hydrate destabilization. Here we report the broadest range of oxygen isotope values yet measured in marine sediments (-25 per thousand to +12 per thousand) in methane seeps in Marinoan deglacial sediments underlying the cap carbonate. This range of values is likely to be the result of mixing between ice-sheet-derived meteoric waters and clathrate-derived fluids during the flushing and destabilization of a clathrate field by glacial meltwater. The equatorial palaeolatitude implies a highly volatile shelf permafrost pool that is an order of magnitude larger than that of the present day. A pool of this size could have provided a massive biogeochemical feedback capable of triggering deglaciation and accounting for the global postglacial marine carbon and sulphur isotopic excursions, abrupt unidirectional warming, cap carbonate deposition, and a marine oxygen crisis. Our findings suggest that methane released from low-latitude permafrost clathrates therefore acted as a trigger and/or strong positive feedback for deglaciation and warming. Methane hydrate

  6. Assessing and Projecting Greenhouse Gas Release due to Abrupt Permafrost Degradation

    Science.gov (United States)

    Saito, K.; Ohno, H.; Yokohata, T.; Iwahana, G.; Machiya, H.

    2017-12-01

    Permafrost is a large reservoir of frozen soil organic carbon (SOC; about half of all the terrestrial storage). Therefore, its degradation (i.e., thawing) under global warming may lead to a substantial amount of additional greenhouse gas (GHG) release. However, understanding of the processes, geographical distribution of such hazards, and implementation of the relevant processes in the advanced climate models are insufficient yet so that variations in permafrost remains one of the large source of uncertainty in climatic and biogeochemical assessment and projections. Thermokarst, induced by melting of ground ice in ice-rich permafrost, leads to dynamic surface subsidence up to 60 m, which further affects local and regional societies and eco-systems in the Arctic. It can also accelerate a large-scale warming process through a positive feedback between released GHGs (especially methane), atmospheric warming and permafrost degradation. This three-year research project (2-1605, Environment Research and Technology Development Fund of the Ministry of the Environment, Japan) aims to assess and project the impacts of GHG release through dynamic permafrost degradation through in-situ and remote (e.g., satellite and airborn) observations, lab analysis of sampled ice and soil cores, and numerical modeling, by demonstrating the vulnerability distribution and relative impacts between large-scale degradation and such dynamic degradation. Our preliminary laboratory analysis of ice and soil cores sampled in 2016 at the Alaskan and Siberian sites largely underlain by ice-rich permafrost, shows that, although gas volumes trapped in unit mass are more or less homogenous among sites both for ice and soil cores, large variations are found in the methane concentration in the trapped gases, ranging from a few ppm (similar to that of the atmosphere) to hundreds of thousands ppm We will also present our numerical approach to evaluate relative impacts of GHGs released through dynamic

  7. Soil organic carbon pools and stocks in permafrost-affected soils on the tibetan plateau.

    Directory of Open Access Journals (Sweden)

    Corina Dörfer

    Full Text Available The Tibetan Plateau reacts particularly sensitively to possible effects of climate change. Approximately two thirds of the total area is affected by permafrost. To get a better understanding of the role of permafrost on soil organic carbon pools and stocks, investigations were carried out including both discontinuous (site Huashixia, HUA and continuous permafrost (site Wudaoliang, WUD. Three organic carbon fractions were isolated using density separation combined with ultrasonic dispersion: the light fractions (1.6 g cm(-3 of mineral associated organic matter (MOM. The fractions were analyzed for C, N, and their portion of organic C. FPOM contained an average SOC content of 252 g kg(-1. Higher SOC contents (320 g kg(-1 were found in OPOM while MOM had the lowest SOC contents (29 g kg(-1. Due to their lower density the easily decomposable fractions FPOM and OPOM contribute 27% (HUA and 22% (WUD to the total SOC stocks. In HUA mean SOC stocks (0-30 cm depth account for 10.4 kg m(-2, compared to 3.4 kg m(-2 in WUD. 53% of the SOC is stored in the upper 10 cm in WUD, in HUA only 39%. Highest POM values of 36% occurred in profiles with high soil moisture content. SOC stocks, soil moisture and active layer thickness correlated strongly in discontinuous permafrost while no correlation between SOC stocks and active layer thickness and only a weak relation between soil moisture and SOC stocks could be found in continuous permafrost. Consequently, permafrost-affected soils in discontinuous permafrost environments are susceptible to soil moisture changes due to alterations in quantity and seasonal distribution of precipitation, increasing temperature and therefore evaporation.

  8. Ice-Rich Yedoma Permafrost: A Synthesis of Circum-Arctic Distribution and Thickness

    Science.gov (United States)

    Strauss, J.; Fedorov, A. N.; Fortier, D.; Froese, D. G.; Fuchs, M.; Grosse, G.; Günther, F.; Harden, J. W.; Hugelius, G.; Kanevskiy, M. Z.; Kholodov, A. L.; Kunitsky, V.; Laboor, S.; Lapointe Elmrabti, L.; Rivkina, E.; Robinson, J. E.; Schirrmeister, L.; Shmelev, D.; Shur, Y.; Spektor, V.; Ulrich, M.; Veremeeva, A.; Walter Anthony, K. M.; Zimov, S. A.

    2015-12-01

    Vast portions of Arctic and sub-Arctic Siberia, Alaska and the Yukon Territory are covered by ice-rich silts that are penetrated by large ice wedges, resulting from syngenetic sedimentation and freezing. Accompanied by wedge-ice growth, the sedimentation process was driven by cold continental climatic and environmental conditions in unglaciated regions during the late Pleistocene, inducing the accumulation of the unique Yedoma permafrost deposits up to 50 meter thick. Because of fast incorporation of organic material into permafrost during formation, Yedoma deposits include low-decomposed organic matter. Moreover, ice-rich permafrost deposits like Yedoma are especially prone to degradation triggered by climate changes or human activity. When Yedoma deposits degrade, large amounts of sequestered organic carbon as well as other nutrients are released and become part of active biogeochemical cycling. This could be of global significance for the climate warming, as increased permafrost thaw is likely to cause a positive feedback loop. Therefore, a detailed assessment of the Yedoma deposit volume is of importance to estimate its potential future climate response. Moreover, as a step beyond the objectives of this synthesis study, our coverage (see figure for the Yedoma domain) and thickness estimation will provide critical data to refine the Yedoma permafrost organic carbon inventory, which is assumed to have freeze-locked between 83±12 and 129±30 gigatonnes (Gt) of organic carbon. Hence, we here synthesize data on the circum-Arctic and sub-Arctic distribution and thickness of Yedoma permafrost (see figure for the Yedoma domain) in the framework of an Action Group funded by the International Permafrost Association (IPA). The quantification of the Yedoma coverage is conducted by the digitization of geomorphological and Quaternary geological maps. Further data on Yedoma thickness is contributed from boreholes and exposures reported in the scientific literature.

  9. The Effects of Perchlorates on the Permafrost Methanogens: Implication for Autotrophic Life on Mars.

    Science.gov (United States)

    Shcherbakova, Viktoria; Oshurkova, Viktoria; Yoshimura, Yoshitaka

    2015-09-09

    The terrestrial permafrost represents a range of possible cryogenic extraterrestrial ecosystems on Earth-like planets without obvious surface ice, such as Mars. The autotrophic and chemolithotrophic psychrotolerant methanogens are more likely than aerobes to function as a model for life forms that may exist in frozen subsurface environments on Mars, which has no free oxygen, inaccessible organic matter, and extremely low amounts of unfrozen water. Our research on the genesis of methane, its content and distribution in permafrost horizons of different ages and origin demonstrated the presence of methane in permanently frozen fine-grained sediments. Earlier, we isolated and described four strains of methanogenic archaea of Methanobacterium and Methanosarcina genera from samples of Pliocene and Holocene permafrost from Eastern Siberia. In this paper we study the effect of sodium and magnesium perchlorates on growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. In this paper we study the effect of sodium and magnesium perchlorates on the growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. Furthermore, as shown in the studies strain M2(T) M. arcticum, probably can use perchlorate anion as an electron acceptor in anaerobic methane oxidation. Earth's subzero subsurface environments are the best approximation of environments on Mars, which is most likely to harbor methanogens; thus, a biochemical understanding of these pathways is expected to provide a basis for designing experiments to detect autotrophic methane-producing life forms on Mars.

  10. InSAR observation of seasonal ground surface deformation in permafrost area near Batagay, Siberia

    Science.gov (United States)

    Yanagiya, K.; Furuya, M.

    2017-12-01

    Thawing of permafrost can lead to ground deformation. Ground deformation has been studied as a serious problem in the Arctic Ocean coastal area such as Russia for a long time, because the deformation causes damage to architectures at these areas. However, there have been no quantitative observation data, and the spatial and temporal distributions have hardly been investigated. On the other hand, by the recently global warming influence, the importance of organic carbon stored in permafrost is pointed out. Although the release of methane gas is confirmed in some thermokarst lakes, it is very difficult to observe the permafrost in a wide area by field study. Instead, it is technically possible to monitor the subsidence and uplift of the ground over the permafrost area, which could potentially make a significant contribution to the monitoring thawing process of permafrost. In this study, we attempted to detect ground deformation signal in permafrost area by remote sensing using interferometric synthetic aperture radar (InSAR). Using the data of two SAR satellites ALOS and ALOS2 launched by JAXA, we observed recent ground deformation from 2007 to 2016. Particularly recent observations of ALOS2 from 2014 to 2016 discovered distant displacements towards the LOS direction in the northeast region from the town of Batagay,Siberia. The diameter of the displacements area covers about 7.7 km. In this study, we considered that this signal is likely to be due to permafrost thawing, we also investigated the seasonal characteristics and looked back ALOS data of this area. In addition, since the high latitude area, observation results include noise due to the ionosphere, so we tried to remove the noise.

  11. Nutrient Controls on Methane Emissions in a Permafrost Thaw Subarctic Peatland

    Science.gov (United States)

    Kashi, N. N.; Perryman, C. R.; Malhotra, A.; Marek, E. A.; Giesler, R.; Varner, R. K.

    2015-12-01

    Permafrost peatlands in northern latitudes are large reservoirs of sequestered carbon that are vulnerable to climate change. While peatlands account for a small fraction of total global land surfaces, their potential to release sequestered carbon in response to higher temperatures is of concern. Of particular relevance is the conversion of these carbon stores into methane (CH4), a strong greenhouse gas with a global warming potential 20 times greater than that of CO2 over a 100-year time frame. Here, we explore how key nutrients impact the consumption of CH4 at the Stordalen Mire in Abisko, Sweden, a discontinuous permafrost peatland with expanding thaw over the last century. Peatland CH4 emissions are highly spatially variable due to multiple emission pathways and strong dependence on several environmental factors. Among controls on CH4 emissions, such as temperature and water table depth, primary production of wetland vegetation is also a strong factor in the variability of CH4 emissions. Plant community shifts among permafrost thaw stages subsequently change nutrient cycling and availability, which in turn impacts primary production. Early stages of permafrost thaw are mosaicked with a variety of vascular plants and mosses. We analyzed potential enzymatic activities of chitinase, glucosidase, and phosphatase as proxies for organic nitrogen, carbon, and phosphorus cycling, respectively, in tandem with potential CH4 oxidation rates. In addition, stoichiometric ratios of carbon, nitrogen, and phosphorus concentrations are used to illustrate nutrient limitation controls on CH4 oxidation rates. While CH4 emissions are low throughout initial thaw stages, highest rates of potential CH4 oxidation. These permafrost thaw-induced CH4 oxidation rates are 5 and 11 times higher, in the surface and depth of the peat profile respectively, than subsequent aerobic permafrost thaw stages. As CH4 emissions are low in intact permafrost peatlands, these high rates of potential CH4

  12. The Effects of Perchlorates on the Permafrost Methanogens: Implication for Autotrophic Life on Mars

    Directory of Open Access Journals (Sweden)

    Viktoria Shcherbakova

    2015-09-01

    Full Text Available The terrestrial permafrost represents a range of possible cryogenic extraterrestrial ecosystems on Earth-like planets without obvious surface ice, such as Mars. The autotrophic and chemolithotrophic psychrotolerant methanogens are more likely than aerobes to function as a model for life forms that may exist in frozen subsurface environments on Mars, which has no free oxygen, inaccessible organic matter, and extremely low amounts of unfrozen water. Our research on the genesis of methane, its content and distribution in permafrost horizons of different ages and origin demonstrated the presence of methane in permanently frozen fine-grained sediments. Earlier, we isolated and described four strains of methanogenic archaea of Methanobacterium and Methanosarcina genera from samples of Pliocene and Holocene permafrost from Eastern Siberia. In this paper we study the effect of sodium and magnesium perchlorates on growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. In this paper we study the effect of sodium and magnesium perchlorates on the growth of permafrost and nonpermafrost methanogens, and present evidence that permafrost hydogenotrophic methanogens are more resistant to the chaotropic agent found in Martian soil. Furthermore, as shown in the studies strain M2T M. arcticum, probably can use perchlorate anion as an electron acceptor in anaerobic methane oxidation. Earth’s subzero subsurface environments are the best approximation of environments on Mars, which is most likely to harbor methanogens; thus, a biochemical understanding of these pathways is expected to provide a basis for designing experiments to detect autotrophic methane-producing life forms on Mars.

  13. Evolving hydrologic connectivity in discontinuous permafrost lowlands: what it means for lake systems

    Science.gov (United States)

    Walvoord, M. A.; Jepsen, S. M.; Rover, J.; Voss, C. I.; Briggs, M. A.

    2015-12-01

    Permafrost influence on the hydrologic connectivity of surface water bodies in high-latitude lowlands is complicated by subsurface heterogeneity and the propensity of the system to change over time. In general, permafrost limits the subsurface exchange of water, solute, and nutrients between lakes and rivers. It follows that permafrost thaw could enhance subsurface hydrologic connectivity among surface water bodies, but the impact of this process on lake distribution is not well known. Changes in the extent of lakes in interior Alaska have important ecological and societal impacts since lakes provide (1) critical habitat for migratory arctic shorebirds and waterfowl, fish, and wildlife, and (2) provisional, recreational, and cultural resources for local communities. We utilize electromagnetic imaging of the shallow subsurface and remote sensing of lake level dynamics in the Yukon Flats of interior Alaska, USA, together with water balance modeling, to gain insight into the influence of discontinuous permafrost on lowland lake systems. In the study region with relatively low precipitation, observations suggest that lakes that are hydrologically isolated during normal conditions are sustained by periodic river flooding events, including ice-jam floods that occur during river ice break-up. Climatically-influenced alterations in flooding frequency and intensity, as well as depth to permafrost, are quantitatively assessed in the context of lake maintenance. Scenario modeling is used to evaluate lake level evolution under plausible changing conditions. Model results demonstrate how permafrost degradation can reduce the dependence of typical lowland lakes on flooding events. Study results also suggest that river flooding may recharge a more spatially widespread zone of lakes and wetlands under future scenarios of permafrost table deepening and enhanced subsurface hydrologic connectivity.

  14. Permafrost degradation and associated ground settlement estimation under 2 °C global warming

    Science.gov (United States)

    Guo, Donglin; Wang, Huijun

    2017-10-01

    Global warming of 2 °C above preindustrial levels has been considered to be the threshold that should not be exceeded by the global mean temperature to avoid dangerous interference with the climate system. However, this global mean target has different implications for different regions owing to the globally nonuniform climate change characteristics. Permafrost is sensitive to climate change; moreover, it is widely distributed in high-latitude and high-altitude regions where the greatest warming is predicted. Permafrost is expected to be severely affected by even the 2 °C global warming, which, in turn, affects other systems such as water resources, ecosystems, and infrastructures. Using air and soil temperature data from ten coupled model intercomparison project phase five models combined with observations of frozen ground, we investigated the permafrost thaw and associated ground settlement under 2 °C global warming. Results show that the climate models produced an ensemble mean permafrost area of 14.01 × 106 km2, which compares reasonably with the area of 13.89 × 106 km2 (north of 45°N) in the observations. The models predict that the soil temperature at 6 m depth will increase by 2.34-2.67 °C on area average relative to 1990-2000, and the increase intensifies with increasing latitude. The active layer thickness will also increase by 0.42-0.45 m, but dissimilar to soil temperature, the increase weakens with increasing latitude due to the distinctly cooler permafrost at higher latitudes. The permafrost extent will obviously retreat north and decrease by 24-26% and the ground settlement owing to permafrost thaw is estimated at 3.8-15 cm on area average. Possible uncertainties in this study may be mostly attributed to the less accurate ground ice content data and coarse horizontal resolution of the models.

  15. The Antarctic permafrost as a testbed for REMS (Rover Environmental Monitoring Station-Mars Science Laboratory)

    Science.gov (United States)

    Esteban, B.; Ramos, M.; Sebastián, E.; Armiens, C.; Gómez-Elvira, J.; Cabos, W.; de Pablo, M. A.

    2009-04-01

    The present climatic characteristics of Mars favor the presence of extense permafrost areas in this lonely planet. Therefore environmental parameters that are included in Martian Rover missions are also used for monitoring thermal soil surface evolution in order to study the permafrost active layer thickness and the energy balance in the soil-atmosphere boundary limit layer. The REMS (Rover Environmental Monitoring Station) is an environmental station designed by the Centro de Astrobiología (CAB- Spain) with the collaboration of national and international partners (CRISA/EADS, UPC and FMI), which is part of the payload of the MSL (Mars Science Laboratory) NASA mission to Mars (http://mars.jpl.nasa.gov/msl/overview/). This mission is expected to be launched in the final months of 2009, and mainly consists of a Rover, with a complete set of scientific instruments; the Rover will carry the biggest, most advanced suite of instruments for scientific studies ever sent to the Martian surface. Five sensors compose the REMS instrument: ground (GT-REMS) and air temperatures, wind speed and direction, pressure, humidity and ultraviolet radiation (UV-REMS). A simplified setup of the REMS was deployed on Antarctica in the surroundings of the Spanish Antarctic Stations on Livingston and Deception Islands (Maritime Antarctica), where the permafrost distribution is well-known. The aim of the experiment was to check REMS's sensors response against hard environmental conditions and calibrates their measures with standard Antarctic devices. The experimental apparatuses included some standard meteorological and thermopiles sensors corresponding to the REMS. All the sensors are mounted in a 1.8 m mast and include a Pt100 air temperature sensor with shield solar protection on the mast top, a Kipp and Zonnen CNR1 net radiometer for measuring infrared (5-50 μm) and short wave solar (305-2800 nm) radiation at 1.5 m high, GT-REMS sensor and its amplification box at 0.7 m high and finally

  16. Explaining the dependence of climatic response of tree radial growth on permafrost

    Science.gov (United States)

    Bryukhanova, Marina; Benkova, Anna; von Arx, Georg; Fonti, Patrick; Simanko, Valentina; Kirdyanov, Alexander; Shashkin, Alexander

    2015-04-01

    In northern regions of Siberia it is infrequent to have long-term observations of the variability of soil features, phenological data, duration of the growing season, which can be used to infer the influence of the environment on tree growth and productivity. The best way to understand tree-growth and tree responses to environmental changes is to make use of mechanistic models, allowing to combine already available experiment/field data with other parameters based on biological principles of tree growth. The goal of our study is to estimate which tree species (deciduous, conifer deciduous or conifer evergreen) is more plastic under possible climate changes in permafrost zone. The studied object is located in the northern part of central Siberia, Russia (64°N, 100°E). The study plot was selected within a post-fire succession and representatives for 100 years old even aged mixed forest of Larix gmelinii (Rupr.) Rupr. and Betula pubescens Ehrh. with few exemplars of Spruce (Picea obovata Ledeb.). To understand physiological response of larch, birch and spruce trees to climatic changes the ecological-physiological process-based model of tree photosynthesis (Benkova and Shashkin 2003) was applied. Multiparametric tree-ring chronologies were analyzed and correlated with climatic parameters over the last 77 years. This work is supported by the Ministry of Education and Science of the Russian Federation (Grant from the President of RF for Young Scientists MK-1589.2014.4).

  17. Carbon and nitrogen pools in thermokarst-affected permafrost landscapes in Arctic Siberia

    Science.gov (United States)

    Fuchs, Matthias; Grosse, Guido; Strauss, Jens; Günther, Frank; Grigoriev, Mikhail; Maximov, Georgy M.; Hugelius, Gustaf

    2018-02-01

    Ice-rich yedoma-dominated landscapes store considerable amounts of organic carbon (C) and nitrogen (N) and are vulnerable to degradation under climate warming. We investigate the C and N pools in two thermokarst-affected yedoma landscapes - on Sobo-Sise Island and on Bykovsky Peninsula in the north of eastern Siberia. Soil cores up to 3 m depth were collected along geomorphic gradients and analysed for organic C and N contents. A high vertical sampling density in the profiles allowed the calculation of C and N stocks for short soil column intervals and enhanced understanding of within-core parameter variability. Profile-level C and N stocks were scaled to the landscape level based on landform classifications from 5 m resolution, multispectral RapidEye satellite imagery. Mean landscape C and N storage in the first metre of soil for Sobo-Sise Island is estimated to be 20.2 kg C m-2 and 1.8 kg N m-2 and for Bykovsky Peninsula 25.9 kg C m-2 and 2.2 kg N m-2. Radiocarbon dating demonstrates the Holocene age of thermokarst basin deposits but also suggests the presence of thick Holocene-age cover layers which can reach up to 2 m on top of intact yedoma landforms. Reconstructed sedimentation rates of 0.10-0.57 mm yr-1 suggest sustained mineral soil accumulation across all investigated landforms. Both yedoma and thermokarst landforms are characterized by limited accumulation of organic soil layers (peat). We further estimate that an active layer deepening of about 100 cm will increase organic C availability in a seasonally thawed state in the two study areas by ˜ 5.8 Tg (13.2 kg C m-2). Our study demonstrates the importance of increasing the number of C and N storage inventories in ice-rich yedoma and thermokarst environments in order to account for high variability of permafrost and thermokarst environments in pan-permafrost soil C and N pool estimates.

  18. Interactions between iron and organic matter may influence the fate of permafrost carbon in the Arctic

    Science.gov (United States)

    Cory, R. M.; Trusiak, A.; Ward, C.; Kling, G. W.; Tfaily, M.; Paša-Tolić, L.; Noel, V.; Bargar, J.

    2017-12-01

    The ongoing thawing of permafrost soils is the only environmental change that allows tremendous stores of organic carbon (C) to be converted into carbon dioxide (CO2) on decadal time scales, thus providing a positive and accelerating feedback to global warming. Evidence suggests that iron enhances abiotic reactions that convert dissolved organic matter (DOM) to CO2 in dark soils and in sunlit surface waters depending on its redox state and association with DOM (i.e., iron-DOM complexation). However, the complexation of iron in surface waters and soils remains too poorly understood to predict how iron influences the rates of oxidation of DOM to CO2. To address this knowledge gap, we characterized iron-DOM complexation in iron-rich soil and surface waters of the Arctic, in combination with measurements of DOM oxidation to CO2. These waters contain high concentrations of dissolved iron and DOM (up to 1 and 2 mM, respectively), and low concentrations of other potential ligands for iron such as sulfide, carbonate, chloride, or bromide. Ultra-high resolution mass spectrometry (FT-ICR MS) was used to identify ligands for iron within the DOM pool, and synchrotron based X-ray analysis (XAS and EXAFS) was used to assess iron's oxidation state, to detect iron complexation, and to constrain the chemical composition of the complexes. Across a natural gradient of dissolved iron and DOM concentrations, many potential ligands were identified within DOM that are expected to complex with iron (e.g., aromatic acids). EXAFS showed substantial complexation of reduced ferrous iron (Fe(II)) to DOM in arctic soil waters, on the basis of comparison to Fe(II)-DOM reference spectra. Identification of iron complexed to DOM in soil waters is consistent with strongly co-varying iron and DOM concentrations in arctic soil and surface waters, and supports our hypothesis that complexation of iron by DOM influences dark and light redox reactions that oxidize DOM to CO2. Understanding the molecular

  19. Content and distribution of trace metals in pristine permafrost environments of Northeastern Siberia, Russia

    Science.gov (United States)

    Antcibor, I.; Eschenbach, A.; Kutzbach, L.; Bolshiyanov, D.; Pfeiffer, E.-M.

    2012-04-01

    middle floodplain. Correlation analysis between element concentrations, grain-size distribution and carbon content revealed a direct dependence of the element distribution within all soil profiles on its mineralogical composition. Based on the obtained results we suggest that there are negligible atmospheric depositions caused by human activity on the investigation site. Therefore this data can provide a point of comparison against man-made influences on permafrost-affected landscapes and also on similar pristine areas in the Arctic region.

  20. Demequina lutea sp. nov., isolated from a high Arctic permafrost soil.

    Science.gov (United States)

    Finster, Kai Waldemar; Herbert, Rodney Andrew; Kjeldsen, Kasper Urup; Schumann, Peter; Lomstein, Bente Aagaard

    2009-04-01

    Two Gram-stain-positive, pigmented, non-motile, non-spore-forming, pleomorphic, rod-shaped bacteria (strains SV45(T) and SV47), isolated from a permafrost soil collected from the Adventdalen valley, Spitsbergen, northern Norway, have been characterized taxonomically using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the two permafrost isolates formed a distinct phyletic line within the suborder Micrococcineae of the order Actinomycetales. DNA-DNA hybridization analyses indicate that strains SV45(T) and SV47 are closely related (60-69 % relatedness) and belong to the same species, although they show slightly different colony pigmentation. The closest phylogenetic neighbour was Demequina aestuarii JC2054(T), with 96 % 16S rRNA gene sequence similarity. Optimum growth of SV45(T) and SV47 occurred aerobically in the absence of NaCl, but both isolates tolerated up to 2 % NaCl (w/v) in the growth medium. Growth under anaerobic conditions was slow and weak. The peptidoglycan of both isolates was of the A4beta type with l-ornithine as the diamino acid and serine as a component of the interpeptide bridge with either d-aspartate (SV45(T)) or d-glutamate (SV47) as the N-terminal amino acid. The major fatty acids present in both isolates were C(15 : 0) (3.2-8.6 %), iso-C(16 : 0) (5.0-8.9 %), anteiso-C(15 : 0) (59.4-61.5 %), anteiso-C(17 : 0) (4.1-8.8 %) and anteiso-C(15 : 1) (4.4-6.4 %). Isoprenoid quinones were present at exceptionally low levels in both isolates, and only demethylmenaquinone DMK-9(H(4)) could be identified with any degree of confidence. Phylogenetic analysis and differences in physiological and biochemical characteristics between the strains and Demequina aestuarii JC2054(T) indicate that these isolates belong to a novel species within the genus Demequina, for which the name Demequina lutea sp. nov. is proposed. The type strain is SV45(T) (=LMG 24795(T) =DSM 19970(T)).

  1. Permafrost warming and vegetation changes in continental Antarctica

    International Nuclear Information System (INIS)

    Guglielmin, Mauro; Dalle Fratte, Michele; Cannone, Nicoletta

    2014-01-01

    Continental Antarctica represents the last pristine environment on Earth and is one of the most suitable contexts to analyze the relations between climate, active layer and vegetation. In 2000 we started long-term monitoring of the climate, permafrost, active layer and vegetation in Victoria Land, continental Antarctica. Our data confirm the stability of mean annual and summer air temperature, of snow cover, and an increasing trend of summer incoming short wave radiation. The active layer thickness is increasing at a rate of 0.3 cm y −1 . The active layer is characterized by large annual and spatial differences. The latter are due to scarce vegetation, a patchy and very thin organic layer and large spatial differences in snow accumulation. The active layer thickening, probably due to the increase of incoming short wave radiation, produced a general decrease of the ground water content due to the better drainage of the ground. The resultant drying may be responsible for the decline of mosses in xeric sites, while it provided better conditions for mosses in hydric sites, following the species-specific water requirements. An increase of lichen vegetation was observed where the climate drying occurred. This evidence emphasizes that the Antarctic continent is experiencing changes that are in total contrast to the changes reported from maritime Antarctica. (paper)

  2. Susceptibility of Permafrost Soil Organic Carbon under Warming Climate

    Science.gov (United States)

    Yang, Z.; Wullschleger, S. D.; Liang, L.; Graham, D. E.; Gu, B.

    2015-12-01

    Degradation of soil organic carbon (SOC) that has been stored in permafrost is a key concern under warming climate because it could provide a positive feedback. Studies and conceptual models suggest that SOC degradation is largely controlled by the decomposability of SOC, but it is unclear exactly what portions of SOC are susceptible to rapid breakdown and what mechanisms may be involved in SOC degradation. Using a suite of analytical techniques, we examined the dynamic consumption and production of labile SOC compounds, including sugars, alcohols, and small molecular weight organic acids in incubation experiments (up to 240 days at either -2 or 8 °C) with a tundra soil under anoxic conditions, where SOC respiration and iron(III) reduction were monitored. We observe that sugars and alcohols are main components in SOC accounting for initial rapid release of CO2 and CH4 through anaerobic fermentation, whereas the fermentation products such as acetate and formate are subsequently utilized as primary substrates for methanogenesis. Iron(III) reduction is correlated to acetate production and methanogenesis, suggesting its important roles as an electron acceptor in tundra SOC respiration. These observations corroborate strongly with the glucose addition during incubation, in which rapid CO2 and CH4 production is observed concurrently with rapid production and consumption of organics such as acetate. Thus, the biogeochemical processes we document here are pertinent to understanding the accelerated SOC decomposition with temperature and could provide basis for model predicting feedbacks to climate warming in the Arctic.

  3. Effects of permafrost thaw on nitrogen availability and plant nitrogen acquisition in Interior Alaska

    Science.gov (United States)

    Finger, R.; Euskirchen, E. S.; Turetsky, M.

    2013-12-01

    The degradation of ice-rich permafrost, which covers a large portion of Interior Alaska, typically leads to thermokarst and increases in soil saturation. As a result, conifer peat plateaus degrade and are often replaced by wet collapse scar bogs. This state change results in profound changes in regional hydrology, biogeochemical cycling, and plant community composition. Preliminary data suggest that permafrost thaw can increase surface soil inorganic nitrogen (IN) concentrations but it is still unknown whether these changes in nutrient availability are short-lived (pulse releases) and whether or not they impact collapse scar vegetation composition or productivity, particularly as collapse scars undergo succession with time-after-thaw. Therefore we are currently examining changes in plant community composition, N availability and plant N acquisition along three thermokarst gradients in Interior Alaska. Each gradient is comprised of a forested permafrost peat plateau, adjacent ecotones experiencing active permafrost degradation (including a collapsing forest canopy and a saturated moat), and a collapse scar bog where permafrost has completely degraded. We predicted that IN concentrations would be highest along the active thaw margin, and lowest in the peat plateau. We also predicted that IN concentrations would be positively related to shifts in vegetation community composition, nutrient use efficiency (NUE) and tissue 15N concentrations. Preliminary results have shown that IN concentrations increase in newer collapse scar features as well as with thaw depth. Our data also show a shift from feather moss and ericaceous shrub-dominate understories in the permafrost plateau to Sphagnum and sedge dominated thaw ecotone and bog communities. Further successional development of the collapse scar bog results in the reintroduction of small evergreen and deciduous shrubs as the peat mat develops. Over time, collapse scar succession and peat accumulation appears to lead to

  4. Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

    International Nuclear Information System (INIS)

    Torre Jorgenson, M; Harden, Jennifer; Manies, Kristen; Kanevskiy, Mikhail; Shur, Yuri; O’Donnell, Jonathan; Wickland, Kim; Striegl, Robert; Ewing, Stephanie; Zhuang Qianlai; Koch, Josh

    2013-01-01

    The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to

  5. The role of deep nitrogen and dynamic rooting profiles on vegetation dynamics and productivity in response to permafrost thaw and climate change in Arctic tundra

    Science.gov (United States)

    Hewitt, R. E.; Helene, G.; Taylor, D. L.; McGuire, A. D.; Mack, M. C.

    2017-12-01

    The release of permafrost-derived nitrogen (N) has the potential to fertilize tundra vegetation, modulating plant competition, stimulating productivity, and offsetting carbon losses from thawing permafrost. Dynamic rooting, mycorrhizal interactions, and coupling of N availability and root N uptake have been identified as gaps in ecosystem models. As a first step towards understanding whether Arctic plants can access deep permafrost-derived N, we characterized rooting profiles and quantified acquisition of 15N tracer applied at the permafrost boundary by moist acidic tundra plants subjected to almost three decades of warming at Toolik Lake, Alaska. In the ambient control plots the vegetation biomass is distributed between five plant functional types (PFTs): sedges, evergreen and deciduous shrubs, mosses and in lower abundance, forbs. The warming treatment has resulted in the increase of deciduous shrub biomass and the loss of sedges, evergreen shrubs, and mosses. We harvested roots by depth increment down to the top of the permafrost. Roots were classified by size class and PFT. The average thaw depth in the warmed plots was 58.3 cm ± 6.4 S.E., close to 18 cm deeper than the average thaw depth in the ambient plots (40.8 cm ± 1.8 S.E.). Across treatments the deepest rooting species was Rubus chamaemorus (ambient 40.8 cm ± 1.8 S.E., warmed 50.3 cm ± 9.8 S.E.), a non-mycorrhizal forb, followed by Eriophorum vaginatum, a non-mycorrhizal sedge. Ectomycorrhizal deciduous and ericoid mycorrhizal evergreen shrubs were rooted at more shallow depths. Deeply rooted non-mycorrhizal species had the greatest uptake of 15N tracer within 24 hours across treatments. Tracer uptake was greatest for roots of E. vaginatum in ambient plots and R. chamaemorus in warmed plots. Root profiles were integrated into a process-based ecosystem model coupled with a dynamic vegetation model. Functions modeling dynamic rooting profile relative to thaw depth were implemented for each PFT. The

  6. Spatial variability and its main controlling factors of the permafrost soil-moisture on the northern-slope of Bayan Har Mountains in Qinghai-Tibet Plateau

    Science.gov (United States)

    Cao, W.; Sheng, Y.

    2017-12-01

    The soil moisture movement is an important carrier of material cycle and energy flow among the various geo-spheres in the cold regions. It is very critical to protect the alpine ecology and hydrologic cycle in Qinghai-Tibet Plateau. Especially, it becomes one of the key problems to reveal the spatial-temporal variability of soil moisture movement and its main influence factors in earth system science. Thus, this research takes the north slope of Bayan Har Mountains in Qinghai-Tibet Plateau as a case study. The present study firstly investigates the change of permafrost moisture in different slope positions and depths. Based on this investigation, this article attempts to investigate the spatial variability of permafrost moisture and identifies the key influence factors in different terrain conditions. The method of classification and regression tree (CART) is adopted to identify the main controlling factors influencing the soil moisture movement. And the relationships between soil moisture and environmental factors are revealed by the use of the method of canonical correspondence analysis (CCA). The results show that: 1) the change of the soil moisture on the permafrost slope is divided into 4 stages, including the freezing stability phase, the rapid thawing phase, the thawing stability phase and the fast freezing phase; 2) this greatly enhances the horizontal flow in the freezing period due to the terrain slope and the freezing-thawing process. Vertical migration is the mainly form of the soil moisture movement. It leads to that the soil-moisture content in the up-slope is higher than that in the down-slope. On the contrary, the soil-moisture content in the up-slope is lower than that in the down-slope during the melting period; 3) the main environmental factors which affect the slope-permafrost soil-moisture are elevation, soil texture, soil temperature and vegetation coverage. But there are differences in the impact factors of the soil moisture in different

  7. Groundwater storage changes in arctic permafrost watersheds from GRACE and in situ measurements

    International Nuclear Information System (INIS)

    Muskett, Reginald R; Romanovsky, Vladimir E

    2009-01-01

    The Arctic permafrost regions make up the largest area component of the cryosphere. Observations from the Gravity Recovery and Climate Experiment (GRACE) mission offer to provide a greater understanding of changes in water mass within permafrost regions. We investigate a GRACE monthly time series, snow water equivalent from the special scanning microwave imager (SSM/I), vegetation water content and soil moisture from the advanced microwave scanning radiometer for the Earth observation system (AMSR-E) and in situ discharge of the Lena, Yenisei, Ob', and Mackenzie watersheds. The GRACE water equivalent mass change responded to mass loading by snow accumulation in winter and mass unloading by runoff in spring-summer. Comparison of secular trends from GRACE to runoff suggests groundwater storage increased in the Lena and Yenisei watersheds, decreased in the Mackenzie watershed, and was unchanged in the Ob' watershed. We hypothesize that the groundwater storage changes are linked to the development of closed- and open-talik in the continuous permafrost zone and the decrease of permafrost lateral extent in the discontinuous permafrost zone of the watersheds.

  8. Selective Leaching of Dissolved Organic Matter From Alpine Permafrost Soils on the Qinghai-Tibetan Plateau

    Science.gov (United States)

    Wang, Yinghui; Xu, Yunping; Spencer, Robert G. M.; Zito, Phoebe; Kellerman, Anne; Podgorski, David; Xiao, Wenjie; Wei, Dandan; Rashid, Harunur; Yang, Yuanhe

    2018-03-01

    Ongoing global temperature rise has caused significant thaw and degradation of permafrost soils on the Qinghai-Tibetan Plateau (QTP). Leaching of organic matter from permafrost soils to aquatic systems is highly complex and difficult to reproduce in a laboratory setting. We collected samples from natural seeps of active and permafrost layers in an alpine swamp meadow on the QTP to shed light on the composition of mobilized dissolved organic matter (DOM) by combining optical measurements, ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry, radiocarbon (14C), and solid-state 13C nuclear magnetic resonance spectroscopy. Our results show that even though the active layer soils contain large amounts of proteins and carbohydrates, there is a selective release of aromatic components, whereas in the deep permafrost layer, carbohydrate and protein components are preferentially leached during the thawing process. Given these different chemical characteristics of mobilized DOM, we hypothesize that photomineralization contributes significantly to the loss of DOM that is leached from the seasonally thawed surface layer. However, with continued warming, biodegradation will become more important since biolabile materials such as protein and carbohydrate are preferentially released from deep-layer permafrost soils. This transition in DOM leachate source and associated chemical composition has ramifications for downstream fluvial networks on the QTP particularly in terms of processing of carbon and associated fluxes.

  9. Surface geophysical methods for characterising frozen ground in transitional permafrost landscapes

    Science.gov (United States)

    Briggs, Martin A.; Campbell, Seth; Nolan, Jay; Walvoord, Michelle Ann; Ntarlagiannis, Dimitrios; Day-Lewis, Frederick D.; Lane, John W.

    2017-01-01

    The distribution of shallow frozen ground is paramount to research in cold regions, and is subject to temporal and spatial changes influenced by climate, landscape disturbance and ecosystem succession. Remote sensing from airborne and satellite platforms is increasing our understanding of landscape-scale permafrost distribution, but typically lacks the resolution to characterise finer-scale processes and phenomena, which are better captured by integrated surface geophysical methods. Here, we demonstrate the use of electrical resistivity imaging (ERI), electromagnetic induction (EMI), ground penetrating radar (GPR) and infrared imaging over multiple summer field seasons around the highly dynamic Twelvemile Lake, Yukon Flats, central Alaska, USA. Twelvemile Lake has generally receded in the past 30 yr, allowing permafrost aggradation in the receded margins, resulting in a mosaic of transient frozen ground adjacent to thick, older permafrost outside the original lakebed. ERI and EMI best evaluated the thickness of shallow, thin permafrost aggradation, which was not clear from frost probing or GPR surveys. GPR most precisely estimated the depth of the active layer, which forward electrical resistivity modelling indicated to be a difficult target for electrical methods, but could be more tractable in time-lapse mode. Infrared imaging of freshly dug soil pit walls captured active-layer thermal gradients at unprecedented resolution, which may be useful in calibrating emerging numerical models. GPR and EMI were able to cover landscape scales (several kilometres) efficiently, and new analysis software showcased here yields calibrated EMI data that reveal the complicated distribution of shallow permafrost in a transitional landscape.

  10. Distribution of late Pleistocene ice-rich syngenetic permafrost of the Yedoma Suite in east and central Siberia, Russia

    Science.gov (United States)

    Grosse, Guido; Robinson, Joel E.; Bryant, Robin; Taylor, Maxwell D.; Harper, William; DeMasi, Amy; Kyker-Snowman, Emily; Veremeeva, Alexandra; Schirrmeister, Lutz; Harden, Jennifer

    2013-01-01

    This digital database is the product of collaboration between the U.S. Geological Survey, the Geophysical Institute at the University of Alaska, Fairbanks; the Los Altos Hills Foothill College GeoSpatial Technology Certificate Program; the Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany; and the Institute of Physical Chemical and Biological Problems in Soil Science of the Russian Academy of Sciences. The primary goal for creating this digital database is to enhance current estimates of soil organic carbon stored in deep permafrost, in particular the late Pleistocene syngenetic ice-rich permafrost deposits of the Yedoma Suite. Previous studies estimated that Yedoma deposits cover about 1 million square kilometers of a large region in central and eastern Siberia, but these estimates generally are based on maps with scales smaller than 1:10,000,000. Taking into account this large area, it was estimated that Yedoma may store as much as 500 petagrams of soil organic carbon, a large part of which is vulnerable to thaw and mobilization from thermokarst and erosion. To refine assessments of the spatial distribution of Yedoma deposits, we digitized 11 Russian Quaternary geologic maps. Our study focused on extracting geologic units interpreted by us as late Pleistocene ice-rich syngenetic Yedoma deposits based on lithology, ground ice conditions, stratigraphy, and geomorphological and spatial association. These Yedoma units then were merged into a single data layer across map tiles. The spatial database provides a useful update of the spatial distribution of this deposit for an approximately 2.32 million square kilometers land area in Siberia that will (1) serve as a core database for future refinements of Yedoma distribution in additional regions, and (2) provide a starting point to revise the size of deep but thaw-vulnerable permafrost carbon pools in the Arctic based on surface geology and the distribution of cryolithofacies types at high spatial

  11. Isolation of dissolved organic matter from permafrost soil and freshwater environments of the Kolyma River basin, east Siberia, for high resolution structural analysis

    Science.gov (United States)

    Dubinenkov, I. V.; Perminova, I. V.; Bulygina, E. B.; Holmes, R. M.; Davydov, S.; Mann, P. J.; Vonk, J.; Zimov, S. A.

    2010-12-01

    The Arctic and Subarctic ecosystems are known to be the most vulnerable with respect to climate change. Hence, research on carbon cycling in the Arctic region is very important for understanding the current climatic trends and their consequences. The Kolyma River watershed is one of the Arctic Ocean’s largest. It is dominated by continuous permafrost which is underlain with rich organic soils susceptible to increased fluvial transport. The thaw of permafrost enhanced due to global warming might provide additional large source of organic carbon to the Kolyma River and to the Arctic Ocean as a whole. For estimating the contribution of this source to the total pool of organic carbon, specific structural features of permafrost dissolved organic matter (DOM) as opposed to the waterborne DOM of the Kolyma River should be identified and monitored. The objective of this work was to isolate a representive set of the DOM samples from permafrost soil and freshwater environments of the Kolyma River basin suitable for further structural analysis using high resolution Fourier Transform Ion Cyclotron Resonance Mass Spectroscopy (FTICR-MS) and 1H NMR spectroscopy. The isolation protocol of DOM used in this study has been developed by Dittmar et al, 2008 for sampling marine DOM for NMR studies. It is based on the solid phase extraction of DOM from seawater using PPL Varian Bond Elute cartridges Those cartridges were shown to possess the highest efficiency in DOM isolation from marine water. Prior to discharge through the cartridge, a water sample was filtered through 0.45 μm filter for separation of particulate matter and acidified to pH 2 using HCl. About 50mg of DOM could be sequestered from aqueous phase using one cartridge. Sorption extent was monitored by measurements of DOC concentration and UV-vis spectra at the inlet and outlet of the cartridge. It was determined that from 60 to 65% of the total DOC could be extracted from the tested samples of freshwater. As a result

  12. LGM permafrost thickness and extent in the Northern Hemisphere derived from the earth system model iLOVECLIM

    NARCIS (Netherlands)

    Kitover, D.C.; van Balen, R.T.; Vandenberghe, J.F.; Roche, D.M.V.A.P.; Renssen, H.

    2016-01-01

    An estimate of permafrost extent and thickness in the northern hemisphere during the Last Glacial Maximum (LGM, ~ 21 ka) has been produced using the VU University Amsterdam Permafrost Snow (VAMPERS) model, forced by iLOVECLIM, an Earth System Model of Intermediate Complexity. We present model

  13. Changes in Hydrologic Conditions and Greenhouse Gas Emissions in Circumpolar Regions due to Climate Change Induced Permafrost Retreat

    Energy Technology Data Exchange (ETDEWEB)

    Whiticar, M. J. [School of Earth and Ocean Sciences, University of Victoria, Victoria (Canada); Bhatti, J.; Startsev, N. [Northern Forestry Centre, St Edmonton, AB (Canada)

    2013-07-15

    Thawing permafrost peatlands substantially influence Canadian northern ecosystems by changing the regional hydrology and mobilizing the vast carbon (C) reserves that results in increased greenhouse gas (GHGs) emissions to the atmosphere. With permafrost distribution controlled largely by topography and climate, our International polar y ear (IPY) study intensively monitored the local C cycling processes and GHG fluxes associated with different hydrologic and permafrost environments at 4 sites along a climatic gradient extending from the Isolated patches permafrost Zone (northern alberta), to the continuous permafrost Zone (Inuvik, NWT). Each site encompasses a local gradient from upland forest and p