WorldWideScience

Sample records for snow-covered atlas construction

  1. The value of snow cover

    Science.gov (United States)

    Sokratov, S. A.

    2009-04-01

    only and not even the main outcome from snow cover use. The value of snow cover for agriculture, water resources, industry and transportation is so naturally inside the activities that is not often quantified. However, any considerations of adaptation strategies for climate change with changing snow conditions need such quantification.

  2. MODIS Snow-Cover Products

    Science.gov (United States)

    Hall, Dorothy K.; Riggs, George A.; Salomonson, Vincent V.; DiGirolamo, Nicole E.; Bayr, Klaus J.; Houser, Paul R. (Technical Monitor)

    2002-01-01

    On December 18, 1999, the Terra satellite was launched with a complement of five instruments including the Moderate Resolution Imaging Spectroradiometer (MODIS). Many geophysical products are derived from MODIS data including global snow-cover products. MODIS snow and ice products have been available through the National Snow and Ice Data Center (NSIDC) Distributed Active Archive Center (DAAC) since September 13, 2000. MODIS snow-cover products represent potential improvement to or enhancement of the currently-available operational products mainly because the MODIS products are global and 500-m resolution, and have the capability to separate most snow and clouds. Also the snow-mapping algorithms are automated which means that a consistent data set may be generated for long-term climate studies that require snow-cover information. Extensive quality assurance (QA) information is stored with the products. The MODIS snow product suite begins with a 500-m resolution, 2330-km swath snow-cover map which is then gridded to an integerized sinusoidal grid to produce daily and 8-day composite tile products. The sequence proceeds to a climate-modeling grid (CMG) product at about 5.6-km spatial resolution, with both daily and 8-day composite products. Each pixel of the CMG contains fraction of snow cover from 40 - 100%. Measured errors of commission in the CMG are low, for example, on the continent of Australia in the spring, they vary from 0.02 - 0.10%. Near-term enhancements include daily snow albedo and fractional snow cover. A case study from March 6, 2000, involving MODIS data and field and aircraft measurements, is presented to show some early validation work.

  3. [Snow cover pollution monitoring in Ufa].

    Science.gov (United States)

    Daukaev, R A; Suleĭmanov, R A

    2008-01-01

    The paper presents the results of examining the snow cover polluted with heavy metals in the large industrial town of Ufa. The level of man-caused burden on the snow cover of the conventional parts of the town was estimated and compared upon exposure to a wide range of snow cover pollutants. The priority snow cover pollutants were identified among the test heavy metals.

  4. State of the Earth’s cryosphere at the beginning of the 21st century : glaciers, global snow cover, floating ice, and permafrost and periglacial environments: Chapter A in Satellite image atlas of glaciers of the world

    Science.gov (United States)

    Williams, Richard S.; Ferrigno, Jane G.; Williams, Richard S.; Ferrigno, Jane G.

    2012-01-01

    This chapter is the tenth in a series of 11 book-length chapters, collectively referred to as “this volume,” in the series U.S. Geological Survey Professional Paper 1386, Satellite Image Atlas of Glaciers of the World. In the other 10 chapters, each of which concerns a specific glacierized region of Earth, the authors used remotely sensed images, primarily from the Landsat 1, 2, and 3 series of spacecraft, in order to analyze that glacierized region and to monitor changes in its glaciers. Landsat images, acquired primarily during the period 1972 through 1981, were used by an international team of glaciologists and other scientists to study the various glacierized regions and (or) to discuss related glaciological topics. In each glacierized region, the present distribution of glaciers within its geographic area is compared, wherever possible, with historical information about their past areal extent. The atlas provides an accurate regional inventory of the areal extent of glacier ice on our planet during the 1970s as part of an expanding international scientific effort to measure global environmental change on the Earth’s surface. However, this chapter differs from the other 10 in its discussion of observed changes in all four elements of the Earth’s cryosphere (glaciers, snow cover, floating ice, and permafrost) in the context of documented changes in all components of the Earth System. Human impact on the planet at the beginning of the 21st century is pervasive. The focus of Chapter A is on changes in the cryosphere and the importance of long-term monitoring by a variety of sensors carried on Earth-orbiting satellites or by a ground-based network of observatories in the case of permafrost. The chapter consists of five parts. The first part provides an introduction to the Earth System, including the interrelationships of the geosphere (cryosphere, hydrosphere, lithosphere, and atmosphere), the biosphere, climate processes, biogeochemical cycles, and the

  5. Utilizing Multiple Datasets for Snow Cover Mapping

    Science.gov (United States)

    Tait, Andrew B.; Hall, Dorothy K.; Foster, James L.; Armstrong, Richard L.

    1999-01-01

    Snow-cover maps generated from surface data are based on direct measurements, however they are prone to interpolation errors where climate stations are sparsely distributed. Snow cover is clearly discernable using satellite-attained optical data because of the high albedo of snow, yet the surface is often obscured by cloud cover. Passive microwave (PM) data is unaffected by clouds, however, the snow-cover signature is significantly affected by melting snow and the microwaves may be transparent to thin snow (less than 3cm). Both optical and microwave sensors have problems discerning snow beneath forest canopies. This paper describes a method that combines ground and satellite data to produce a Multiple-Dataset Snow-Cover Product (MDSCP). Comparisons with current snow-cover products show that the MDSCP draws together the advantages of each of its component products while minimizing their potential errors. Improved estimates of the snow-covered area are derived through the addition of two snow-cover classes ("thin or patchy" and "high elevation" snow cover) and from the analysis of the climate station data within each class. The compatibility of this method for use with Moderate Resolution Imaging Spectroradiometer (MODIS) data, which will be available in 2000, is also discussed. With the assimilation of these data, the resolution of the MDSCP would be improved both spatially and temporally and the analysis would become completely automated.

  6. Central Asian Snow Cover from Hydrometeorological Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Central Asian Snow Cover from Hydrometeorological Surveys data are based on observations made by personnel for three river basins: Amu Darya, Sir Darya, and...

  7. Probabilistic liver atlas construction.

    Science.gov (United States)

    Dura, Esther; Domingo, Juan; Ayala, Guillermo; Marti-Bonmati, Luis; Goceri, E

    2017-01-13

    Anatomical atlases are 3D volumes or shapes representing an organ or structure of the human body. They contain either the prototypical shape of the object of interest together with other shapes representing its statistical variations (statistical atlas) or a probability map of belonging to the object (probabilistic atlas). Probabilistic atlases are mostly built with simple estimations only involving the data at each spatial location. A new method for probabilistic atlas construction that uses a generalized linear model is proposed. This method aims to improve the estimation of the probability to be covered by the liver. Furthermore, all methods to build an atlas involve previous coregistration of the sample of shapes available. The influence of the geometrical transformation adopted for registration in the quality of the final atlas has not been sufficiently investigated. The ability of an atlas to adapt to a new case is one of the most important quality criteria that should be taken into account. The presented experiments show that some methods for atlas construction are severely affected by the previous coregistration step. We show the good performance of the new approach. Furthermore, results suggest that extremely flexible registration methods are not always beneficial, since they can reduce the variability of the atlas and hence its ability to give sensible values of probability when used as an aid in segmentation of new cases.

  8. The seasonal cycle of snow cover, sea ice and surface albedo

    Science.gov (United States)

    Robock, A.

    1980-01-01

    The paper examines satellite data used to construct mean snow cover caps for the Northern Hemisphere. The zonally averaged snow cover from these maps is used to calculate the seasonal cycle of zonally averaged surface albedo. The effects of meltwater on the surface, solar zenith angle, and cloudiness are parameterized and included in the calculations of snow and ice albedo. The data allows a calculation of surface albedo for any land or ocean 10 deg latitude band as a function of surface temperature ice and snow cover; the correct determination of the ice boundary is more important than the snow boundary for accurately simulating the ice and snow albedo feedback.

  9. MODIS Snow Cover Recovery Using Variational Interpolation

    Science.gov (United States)

    Tran, H.; Nguyen, P.; Hsu, K. L.; Sorooshian, S.

    2017-12-01

    Cloud obscuration is one of the major problems that limit the usages of satellite images in general and in NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) global Snow-Covered Area (SCA) products in particular. Among the approaches to resolve the problem, the Variational Interpolation (VI) algorithm method, proposed by Xia et al., 2012, obtains cloud-free dynamic SCA images from MODIS. This method is automatic and robust. However, computational deficiency is a main drawback that degrades applying the method for larger scales (i.e., spatial and temporal scales). To overcome this difficulty, this study introduces an improved version of the original VI. The modified VI algorithm integrates the MINimum RESidual (MINRES) iteration (Paige and Saunders., 1975) to prevent the system from breaking up when applied to much broader scales. An experiment was done to demonstrate the crash-proof ability of the new algorithm in comparison with the original VI method, an ability that is obtained when maintaining the distribution of the weights set after solving the linear system. After that, the new VI algorithm was applied to the whole Contiguous United States (CONUS) over four winter months of 2016 and 2017, and validated using the snow station network (SNOTEL). The resulting cloud free images have high accuracy in capturing the dynamical changes of snow in contrast with the MODIS snow cover maps. Lastly, the algorithm was applied to create a Cloud free images dataset from March 10, 2000 to February 28, 2017, which is able to provide an overview of snow trends over CONUS for nearly two decades. ACKNOWLEDGMENTSWe would like to acknowledge NASA, NOAA Office of Hydrologic Development (OHD) National Weather Service (NWS), Cooperative Institute for Climate and Satellites (CICS), Army Research Office (ARO), ICIWaRM, and UNESCO for supporting this research.

  10. Consistent seasonal snow cover depth and duration variability over ...

    Indian Academy of Sciences (India)

    Decline in consistent seasonal snow cover depth, duration and changing snow cover build- up pattern over the WH in recent decades indicate that WH has undergone considerable climate change and winter weather patterns are changing in the WH. 1. Introduction. Mountainous regions around the globe are storehouses.

  11. Consistent seasonal snow cover depth and duration variability over ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 125; Issue 7. Consistent seasonal ... Consistent seasonal snow cover depth and duration, delay days and early melt days of consistent seasonal snow cover at 11 stations spread across different mountain ranges over the WH were analyzed. Mean, maximum and ...

  12. ISLSCP II Northern Hemisphere Monthly Snow Cover Extent

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This ISLSCP data set is derived from the National Snow and Ice Data Center (NSIDC) Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent...

  13. ISLSCP II Northern Hemisphere Monthly Snow Cover Extent

    Data.gov (United States)

    National Aeronautics and Space Administration — This ISLSCP data set is derived from the National Snow and Ice Data Center (NSIDC) Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent product which...

  14. [Characteristics of chemical pollution of snow cover in Aktobe areas].

    Science.gov (United States)

    Iskakov, A Zh

    2010-01-01

    The paper gives data on the nature of snow cover pollution in the urbanized areas in relation to the remoteness from the basic sources of ambient air pollution. The total snow content of carcinogens has been estimated.

  15. Monitoring Areal Snow Cover Using NASA Satellite Imagery

    Science.gov (United States)

    Harshburger, Brian J.; Blandford, Troy; Moore, Brandon

    2011-01-01

    The objective of this project is to develop products and tools to assist in the hydrologic modeling process, including tools to help prepare inputs for hydrologic models and improved methods for the visualization of streamflow forecasts. In addition, this project will facilitate the use of NASA satellite imagery (primarily snow cover imagery) by other federal and state agencies with operational streamflow forecasting responsibilities. A GIS software toolkit for monitoring areal snow cover extent and producing streamflow forecasts is being developed. This toolkit will be packaged as multiple extensions for ArcGIS 9.x and an opensource GIS software package. The toolkit will provide users with a means for ingesting NASA EOS satellite imagery (snow cover analysis), preparing hydrologic model inputs, and visualizing streamflow forecasts. Primary products include a software tool for predicting the presence of snow under clouds in satellite images; a software tool for producing gridded temperature and precipitation forecasts; and a suite of tools for visualizing hydrologic model forecasting results. The toolkit will be an expert system designed for operational users that need to generate accurate streamflow forecasts in a timely manner. The Remote Sensing of Snow Cover Toolbar will ingest snow cover imagery from multiple sources, including the MODIS Operational Snowcover Data and convert them to gridded datasets that can be readily used. Statistical techniques will then be applied to the gridded snow cover data to predict the presence of snow under cloud cover. The toolbar has the ability to ingest both binary and fractional snow cover data. Binary mapping techniques use a set of thresholds to determine whether a pixel contains snow or no snow. Fractional mapping techniques provide information regarding the percentage of each pixel that is covered with snow. After the imagery has been ingested, physiographic data is attached to each cell in the snow cover image. This data

  16. Distributed calibrating snow models using remotely sensed snow cover information

    Science.gov (United States)

    Li, H.

    2015-12-01

    Distributed calibrating snow models using remotely sensed snow cover information Hongyi Li1, Tao Che1, Xin Li1, Jian Wang11. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China For improving the simulation accuracy of snow model, remotely sensed snow cover data are used to calibrate spatial parameters of snow model. A physically based snow model is developed and snow parameters including snow surface roughness, new snow density and critical threshold temperature distinguishing snowfall from precipitation, are spatially calibrated in this study. The study region, Babaohe basin, located in northwestern China, have seasonal snow cover and with complex terrain. The results indicates that the spatially calibration of snow model parameters make the simulation results more reasonable, and the simulated snow accumulation days, plot-scale snow depth are more better than lumped calibration.

  17. ATLAS construction schedule

    CERN Multimedia

    Kotamaki, M

    The goal during the last few months has been to freeze and baseline as much as possible the schedules of various ATLAS systems and activities. The main motivations for the re-baselining of the schedules have been the new LHC schedule aiming at first collisions in early 2006 and the encountered delays in civil engineering as well as in the production of some of the detectors. The process was started by first preparing a new installation schedule that takes into account all the new external constraints and the new ATLAS staging scenario. The installation schedule version 3 was approved in the March EB and it provides the Ready For Installation (RFI) milestones for each system, i.e. the date when the system should be available for the start of the installation. TCn is now interacting with the systems aiming at a more realistic and resource loaded version 4 before the end of the year. Using the new RFI milestones as driving dates a new summary schedule has been prepared, or is under preparation, for each system....

  18. Deriving Snow Cover Metrics for Alaska from MODIS

    Directory of Open Access Journals (Sweden)

    Chuck Lindsay

    2015-09-01

    Full Text Available Moderate Resolution Imaging Spectroradiometer (MODIS daily snow cover products provide an opportunity for determining snow onset and melt dates across broad geographic regions; however, cloud cover and polar darkness are limiting factors at higher latitudes. This study presents snow onset and melt dates for Alaska, portions of western Canada and the Russian Far East derived from Terra MODIS snow cover daily 500 m grid data (MOD10A1 and evaluates our method for filling data gaps caused by clouds or polar darkness. Pixels classified as cloud or no data were reclassified by: spatial filtering using neighboring pixel values; temporal filtering using pixel values for days before/after cloud cover; and snow-cycle filtering based on a time series assessment of a pixel’s position within snow accumulation, cover or melt periods. During the 2012 snow year, these gap-filling methods reduced cloud pixels from 27.7% to 3.1%. A total of 12 metrics (e.g., date of first and last snow, date of persistent snow cover and periods of intermittence for each pixel were calculated by snow year. A comparison of MODIS-derived snow onset and melt dates with in situ observations from 244 weather stations generally showed an early bias in MODIS-derived dates and an effect of increasing cloudiness exacerbating bias. Our results show that mean regional duration of seasonal snow cover is 179–311 days/year and that snow cover is often intermittent, with 41% of the area experiencing ≥2 snow-covered periods during a snow season. Other regional-scale patterns in the timing of snow onset and melt are evident in the yearly 500 m gridded products publically available at http://static.gina.alaska.edu/NPS_products/MODIS_snow/.

  19. Relationships Between Canopy Openness, Snow Cover and Ground Temperature.

    Science.gov (United States)

    Mattson, L.

    2004-05-01

    Red pine stands, which have undergone varying degrees of thinning and site preparation, are examined with a view to identifying the relationships which exist between canopy openness, snow cover and ground temperature. More specifically, eight red pine stands, which have been intentionally harvested at varying densities within the National Petawawa Research Forest, have been heavily instrumented for detailed measurements of canopy openness, snow cover characteristics, above and subsurface temperature profiles as well as micro-meteorological conditions. Results allow for the specification of relationships between the effect of thinning and site preparation on the soils thermal regime which, in turn, impacts upon the natural regeneration of the pine.

  20. Dynamics of actual aggregation of petroleum products in snow cover

    Science.gov (United States)

    Begunova, L. A.; Kuznetsova, O. V.; Begunov, D. A.; Kuznetsova, A. N.

    2017-11-01

    The paper presents issues of snow cover pollution by petroleum products. Petroleum products content was determined using the fluorimetric method of analysis. The samples of snow were selected on the territory of Angarsk and Irkutsk cities. According to the obtained data, the content of petroleum products in the analyzed samples exceeds the background value up to 6 times. Analysis of the reference data for similar research confirms need for creation of an environmental monitoring centralized system to monitor atmospheric precipitation and, particularly, snow cover.

  1. ATLAS construction: A status report

    CERN Document Server

    Sfyrla, Anna

    2006-01-01

    ATLAS is a general purpose p-p collider detector being constructed for the CERN Large Hadron Collider (LHC). It is located in one of the two high luminosity bunch crossing points (peak luminosity of 1 0 3 4 c m - 2 s _ 1 ) of the LHC. It consists of 3 main sections. Located close to the beam axis, the tracking system employs pixel detectors, silicon microstrip modules and transition radiation straws, all within a 2 Tesla superconducting solenoid. The tracker is surrounded by the electromagnetic and hadronic calorimeters. In the outer part of the detector, 8 superconducting coils define an open toroidal magnetic field for muon detection. The construction status of the ATLAS detector towards being ready for the first collisions in 2007 will be presented, with particular emphasis on the construction and projected performance of the tracking system.

  2. Estimation of snow cover distribution in Beas basin, Indian Himalaya ...

    Indian Academy of Sciences (India)

    of snow cover in the study area are snow under vegetation, contaminated snow and patchy snow. To overcome these problems, ... using planetary reflectance), NIR band reflectance and forest/vegetation cover information. The satellite estimated ... exerts an influence on hydropower generation sys- tem, water management ...

  3. Effect of snow cover on soil frost penetration

    Science.gov (United States)

    Rožnovský, Jaroslav; Brzezina, Jáchym

    2017-12-01

    Snow cover occurrence affects wintering and lives of organisms because it has a significant effect on soil frost penetration. An analysis of the dependence of soil frost penetration and snow depth between November and March was performed using data from 12 automated climatological stations located in Southern Moravia, with a minimum period of measurement of 5 years since 2001, which belong to the Czech Hydrometeorological institute. The soil temperatures at 5 cm depth fluctuate much less in the presence of snow cover. In contrast, the effect of snow cover on the air temperature at 2 m height is only very small. During clear sky conditions and no snow cover, soil can warm up substantially and the soil temperature range can be even higher than the range of air temperature at 2 m height. The actual height of snow is also important - increased snow depth means lower soil temperature range. However, even just 1 cm snow depth substantially lowers the soil temperature range and it can therefore be clearly seen that snow acts as an insulator and has a major effect on soil frost penetration and soil temperature range.

  4. Estimation of snow cover distribution in Beas basin, Indian Himalaya ...

    Indian Academy of Sciences (India)

    areas of Himalaya, which is at high altitude,. Keywords. Snow cover monitoring; NDSI; AWiFS; reflectance; topographic corrections. J. Earth Syst. Sci. 118, No. 5, October 2009, pp. ... characteristics of snow and vegetation to reduce the errors caused ...... Thakur N and Manoj 2002a Effect of global warming on snow ablation ...

  5. Monitoring and evaluation of seasonal snow cover in Kashmir valley ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 118; Issue 6 ... Different geographical parameters of these regions were studied to evaluate the influence on snow cover and it was observed that altitude and position of region with respect to mountain range are the deciding factors for retaining the seasonal snow ...

  6. Modeling the Seasonality of Snow Cover in Naryn Oblast, Kyrgyzstan.

    Science.gov (United States)

    Tomaszewska, M. A.; Henebry, G. M.

    2016-12-01

    Vertical transhumance practiced by herders in the highlands of Kyrgyzstan is strongly affected by timing of snow melt in high-elevation summer pastures. To model snow cover seasonality, we explore a novel approach through the synergistic use of "frost degree-days" obtained from MODIS land surface temperature data and the normalized difference snow index (NDSI) derived from over 16 years of Landsat imagery (2000-2015). From the fitted parameter coefficients of a convex quadratic model linking NDSI to accumulated frost degree-days (AFDD), we calculated two key metrics—the Peak Height of the NDSI and the Thermal Time (in AFDD) to the Peak Height—to examine the interannual variation in the timing of snow cover onset, snow melt, and snow cover duration. We discuss the strengths and limitations of this modeling approach to snow cover seasonality as well as demonstrate how it complements the land surface phenology modeling for understanding climatic influences on the highland pastures of Naryn oblast in Central Kyrgyzstan.

  7. Monitoring and evaluation of seasonal snow cover in Kashmir valley ...

    Indian Academy of Sciences (India)

    in Kashmir valley using remote sensing, GIS and ancillary data. H S Negi∗, N K Thakur, Rajeev Kumar and Manoj Kumar. Snow and Avalanche Study Establishment, Him Parisar, Sector-37A, Chandigarh 160 036, India. ∗ e-mail: negi−hs@yahoo.com. Seasonal snow cover is a vital natural resource in the Himalaya.

  8. Estimation of snow cover distribution in Beas basin, Indian Himalaya ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 118; Issue 5 ... The satellite estimated snow or non-snow pixel information using proposed methodology was validated with the snow cover information collected at three observatory locations and it was found that the algorithm classify all the sample points correctly ...

  9. Validation of MODIS snow cover images over Austria

    Directory of Open Access Journals (Sweden)

    J. Parajka

    2006-01-01

    Full Text Available This study evaluates the Moderate Resolution Imaging Spectroradiometer (MODIS snow cover product over the territory of Austria. The aims are (a to analyse the spatial and temporal variability of the MODIS snow product classes, (b to examine the accuracy of the MODIS snow product against in situ snow depth data, and (c to identify the main factors that may influence the MODIS classification accuracy. We use daily MODIS grid maps (version 4 and daily snow depth measurements at 754 climate stations in the period from February 2000 to December 2005. The results indicate that, on average, clouds obscured 63% of Austria, which may significantly restrict the applicability of the MODIS snow cover images to hydrological modelling. On cloud-free days, however, the classification accuracy is very good with an average of 95%. There is no consistent relationship between the classification errors and dominant land cover type and local topographical variability but there are clear seasonal patterns to the errors. In December and January the errors are around 15% while in summer they are less than 1%. This seasonal pattern is related to the overall percentage of snow cover in Austria, although in spring, when there is a well developed snow pack, errors tend to be smaller than they are in early winter for the same overall percent snow cover. Overestimation and underestimation errors balance during most of the year which indicates little bias. In November and December, however, there appears to exist a tendency for overestimation. Part of the errors may be related to the temporal shift between the in situ snow depth measurements (07:00 a.m. and the MODIS acquisition time (early afternoon. The comparison of daily air temperature maps with MODIS snow cover images indicates that almost all MODIS overestimation errors are caused by the misclassification of cirrus clouds as snow.

  10. Satellite Snow-Cover Mapping: A Brief Review

    Science.gov (United States)

    Hall, Dorothy K.

    1995-01-01

    Satellite snow mapping has been accomplished since 1966, initially using data from the reflective part of the electromagnetic spectrum, and now also employing data from the microwave part of the spectrum. Visible and near-infrared sensors can provide excellent spatial resolution from space enabling detailed snow mapping. When digital elevation models are also used, snow mapping can provide realistic measurements of snow extent even in mountainous areas. Passive-microwave satellite data permit global snow cover to be mapped on a near-daily basis and estimates of snow depth to be made, but with relatively poor spatial resolution (approximately 25 km). Dense forest cover limits both techniques and optical remote sensing is limited further by cloudcover conditions. Satellite remote sensing of snow cover with imaging radars is still in the early stages of research, but shows promise at least for mapping wet or melting snow using C-band (5.3 GHz) synthetic aperture radar (SAR) data. Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) data beginning with the launch of the first EOS platform in 1998. Digital maps will be produced that will provide daily, and maximum weekly global snow, sea ice and lake ice cover at 1-km spatial resolution. Statistics will be generated on the extent and persistence of snow or ice cover in each pixel for each weekly map, cloudcover permitting. It will also be possible to generate snow- and ice-cover maps using MODIS data at 250- and 500-m resolution, and to study and map snow and ice characteristics such as albedo. been under development. Passive-microwave data offer the potential for determining not only snow cover, but snow water equivalent, depth and wetness under all sky conditions. A number of algorithms have been developed to utilize passive-microwave brightness temperatures to provide information on snow cover and water equivalent. The variability of vegetative Algorithms are being developed to map global snow

  11. Influence of snow-cover properties on avalanche dynamics

    Science.gov (United States)

    Steinkogler, W.; Sovilla, B.; Lehning, M.

    2012-04-01

    Snow avalanches with the potential of reaching traffic routes and settlements are a permanent winter threat for many mountain communities. Snow safety officers have to take the decision whether to close a road, a railway line or a ski slope. Those decisions are often very difficult as they demand the ability to interpret weather forecasts, to establish their implication for the stability and the structure of the snow cover and to evaluate the influence of the snow cover on avalanche run-out distances. In the operational programme 'Italy-Switzerland, project STRADA' we focus on the effects of snow cover on avalanche dynamics, and thus run-out distance, with the aim to provide a better understanding of this influence and to ultimately develop tools to support snow safety officers in their decision process. We selected five avalanches, measured at the Vallée de la Sionne field site, with similar initial mass and topography but different flow dynamics and run-out distances. Significant differences amongst the individual avalanches could be observed for front and internal velocities, impact pressures, flow regimes, deposition volumes and run-out distances. For each of these avalanches, the prevailing snow conditions at release were reconstructed using field data from local snowpits or were modeled with SNOWPACK. Combining flow dynamical data with snow cover properties shows that erodible snow depth, snow density and snow temperature in the snow pack along the avalanche track are among the decisive variables that appear to explain the observed differences. It is further discussed, how these influencing factors can be quantified and used for improved predictions of site and time specific avalanche hazard.

  12. Reconstructed North American, Eurasian, and Northern Hemisphere Snow Cover Extent, 1915-1997

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains time series of monthly snow cover extent (SCE) for North America, Eurasia, and the Northern Hemisphere from 1915 to 1997, based on snow cover...

  13. Northern Hemisphere EASE-Grid 2.0 Weekly Snow Cover and Sea Ice Extent

    Data.gov (United States)

    National Aeronautics and Space Administration — The Northern Hemisphere EASE-Grid 2.0 Weekly Snow Cover and Sea Ice Extent Version 4 product combine snow cover and sea ice extent at weekly intervals from 23...

  14. Characteristics of snow cover duration across the northeast United States of America

    Science.gov (United States)

    Leathers, Daniel J.; Luff, Barbara L.

    1997-11-01

    The presence or absence of a snow cover affects a myriad of environmental and societal systems through its modification of the surface radiation balance and its ultimate impact on near-surface air temperatures. Daily snow cover data were collected for a network of 91 stations covering the northeast USA from Maine, south through to West Virginia. The snow cover data along with ancillary temperature, snowfall and precipitation data were used to investigate the characteristics of snow cover duration in this region and the effects of the snow cover on boundary layer climate variables for the snow cover seasons 1948-1949 through to 1987-1988.Results indicate that snow cover duration is variable in both space and time. The duration of a snow cover of 2.5 cm or greater varies from greater than 100 days in northern New England to less than 20 days across areas of Delaware, Maryland and West Virginia. Temporally, snow cover duration for the region as a whole was very short from the late 1940s through to the mid-1950s. From the late 1950s to the end of the period snow cover duration has varied around a consistent mean value. No long-term trends in snow cover duration are apparent in the record for the northeast USA.Principal components analysis and clustering techniques were utilized to isolate spatially coherent regions in which snow cover duration has varied similarly over the period of record. This analysis resulted in the identification of four snow-cover-duration regions across the northeast USA: including (i) the West Virginia area, (ii) the mid-Atlantic from southern New England through to western Pennsylvania, (iii) western and central New York and (iv) northern New England. Snow cover duration is shown to be highly associated with snowfall and temperature but not strongly related to total liquid precipitation. The intra-annual variability of snow cover duration is also investigated for each region.

  15. Springtime warming and reduced snow cover from carbonaceous particles

    Directory of Open Access Journals (Sweden)

    M. G. Flanner

    2009-04-01

    Full Text Available Boreal spring climate is uniquely susceptible to solar warming mechanisms because it has expansive snow cover and receives relatively strong insolation. Carbonaceous particles can influence snow coverage by warming the atmosphere, reducing surface-incident solar energy (dimming, and reducing snow reflectance after deposition (darkening. We apply a range of models and observations to explore impacts of these processes on springtime climate, drawing several conclusions: 1 Nearly all atmospheric particles (those with visible-band single-scatter albedo less than 0.999, including all mixtures of black carbon (BC and organic matter (OM, increase net solar heating of the atmosphere-snow column. 2 Darkening caused by small concentrations of particles within snow exceeds the loss of absorbed energy from concurrent dimming, thus increasing solar heating of snowpack as well (positive net surface forcing. Over global snow, we estimate 6-fold greater surface forcing from darkening than dimming, caused by BC+OM. 3 Equilibrium climate experiments suggest that fossil fuel and biofuel emissions of BC+OM induce 95% as much springtime snow cover loss over Eurasia as anthropogenic carbon dioxide, a consequence of strong snow-albedo feedback and large BC+OM emissions from Asia. 4 Of 22 climate models contributing to the IPCC Fourth Assessment Report, 21 underpredict the rapid warming (0.64°C decade−1 observed over springtime Eurasia since 1979. Darkening from natural and anthropogenic sources of BC and mineral dust exerts 3-fold greater forcing on springtime snow over Eurasia (3.9 W m−2 than North America (1.2 W m−2. Inclusion of this forcing significantly improves simulated continental warming trends, but does not reconcile the low bias in rate of Eurasian spring snow cover decline exhibited by all models, likely because BC deposition trends are negative or near-neutral over much of Eurasia. Improved Eurasian

  16. Arctic moisture source for Eurasian snow cover variations in autumn

    Science.gov (United States)

    Wegmann, Martin; Orsolini, Yvan; Vázquez Dominguez, Marta; Gimeno Presa, Luis; Nieto, Raquel; Buligyna, Olga; Jaiser, Ralf; Handorf, Dörthe; Rinke, Anette; Dethloff, Klaus; Sterin, Alexander; Brönnimann, Stefan

    2015-04-01

    Global warming is enhanced at high northern latitudes where the Arctic surface air temperature has risen at twice the rate of the global average in recent decades - a feature called Arctic amplification. This recent Arctic warming signal likely results from several factors such as the albedo feedback due to a diminishing cryosphere, enhanced poleward atmospheric and oceanic transport, and change in humidity. The reduction in Arctic sea ice is without doubt substantial and a key factor. Arctic summer sea-ice extent has declined by more than 10% per decade since the start of the satellite era (e.g. Stroeve et al., 2012), culminating in a new record low in September 2012, with the long-term trend largely attributed to anthropogenic global warming. Eurasian snow cover changes have been suggested as a driver for changes in the Arctic Oscillation and might provide a link between sea ice decline in the Arctic during summer and atmospheric circulation in the following winter. However, the mechanism connecting snow cover in Eurasia to sea ice decline in autumn is still under debate. Our analysis focuses at sea ice decline in the Barents-Kara Sea region, which allows us to specify regions of interest for FLEXPART forward and backwards moisture trajectories. Based on Eularian and Lagrangian diagnostics from ERA-INTERIM, we can address the origin and cause of late autumn snow depth variations in a dense (snow observations from 820 land stations), unutilized observational datasets over the Commonwealth of Independent States. Open waters in the Barents and Kara Sea have been shown to increase the diabatic heating of the atmosphere, which amplifies baroclinic cyclones and might induce a remote atmospheric response by triggering stationary Rossby waves (Honda et al. 2009). In agreement with these studies, our results show enhanced storm activity originating at the Barents and Kara with disturbances entering the continent through a small sector from the Barents and Kara Seas

  17. Cloud removal methodology from MODIS snow cover product

    Directory of Open Access Journals (Sweden)

    A. Bárdossy

    2009-07-01

    Full Text Available The Moderate Resolution Imaging Spectroradiometer (MODIS employed by Terra and Aqua satellites provides spatially snow covered data with 500 m and daily temporal resolution. It delivers public domain data in raster format. The main disadvantage of the MODIS sensor is that it is unable to record observations under cloud covered regions. This is why this study focuses on estimating the pixel cover for cloud covered areas where no information is available. Our step to this product involves employing methodology based on six successive steps that estimate the pixel cover using different temporal and spatial information. The study was carried out for the Kokcha River basin located in northeastern part of Afghanistan. Snow coverage in catchments, like Kokcha, is very important where the melt-water from snow dominates the river discharge in vegetation period for irrigation purposes. Since no snow related observations were available from the region, the performance of the proposed methodology was tested using the cloud generated MODIS snow cover data as possible "ground truth" information. The results show successful performances arising from the methods applied, which resulted in all cloud coverage being removed. A validation was carried out for all subsequent steps, to be outlined below, where each step removes progressively more cloud coverage. Steps 2 to 5 (step 1 was not validated performed very well with an average accuracy of between 90–96%, when applied one after another for the selected valid days in this study. The sixth step was the least accurate at 78%, but it led to the removal of all remaining cloud cover.

  18. UAS applications in high alpine, snow-covered terrain

    Science.gov (United States)

    Bühler, Y.; Stoffel, A.; Ginzler, C.

    2017-12-01

    Access to snow-covered, alpine terrain is often difficult and dangerous. Hence parameters such as snow depth or snow avalanche release and deposition zones are hard to map in situ with adequate spatial and temporal resolution and with spatial continuous coverage. These parameters are currently operationally measured at automated weather stations and by observer networks. However such isolated point measurements are not able to capture the information spatial continuous and to describe the high spatial variability present in complex mountain topography. Unmanned Aerial Systems (UAS) have the potential to fill this gap by frequently covering selected high alpine areas with high spatial resolution down to ground resolutions of even few millimeters. At the WSL Institute for Snow and Avalanche Research SLF we test different photogrammetric UAS with visual and near infrared bands. During the last three years we were able to gather experience in more than 100 flight missions in extreme terrain. By processing the imagery applying state-of-the-art structure from motion (SfM) software, we were able to accurately document several avalanche events and to photogrammetrically map snow depth with accuracies from 1 to 20 cm (dependent on the flight height above ground) compare to manual snow probe measurements. This was even possible on homogenous snow surfaces with very little texture. A key issue in alpine terrain is flight planning. We need to cover regions at high elevations with large altitude differences (up to 1 km) with high wind speeds (up to 20 m/s) and cold temperatures (down to - 25°C). Only a few UAS are able to cope with these environmental conditions. We will give an overview on our applications of UAS in high alpine terrain that demonstrate the big potential of such systems to acquire frequent, accurate and high spatial resolution geodata in high alpine, snow covered terrain that could be essential to answer longstanding questions in avalanche and snow hydrology

  19. Variability in snow cover phenology in China from 1952 to 2010

    OpenAIRE

    C. Q. Ke; X. C. Li; H. Xie; X. Liu; C. Kou

    2015-01-01

    Daily snow observation data from 672 stations, particularly the 352 stations with over ten annual mean snow cover days (SCD), during 1952–2010 in China, are used in this study. We first examine spatiotemporal variations and trends of SCD, snow cover onset date (SCOD), and snow cover end date (SCED). We then investigate SCD relationships with number of days with temperature below 0 °C (TBZD), mean air temperature (MAT), and Arctic Oscillation (AO) index, the ...

  20. Snow Cover Monitoring Using MODIS Data in Liaoning Province, Northeastern China

    OpenAIRE

    Zhang; Yan; Lu

    2010-01-01

    This paper presents the results of snow cover monitoring studies in Liaoning Province, northeastern China, using MODIS data. Snow cover plays an important role in both the regional water balance and soil moisture properties during the early spring in northeastern China. In addition, heavy snowfalls commonly trigger hazards such as flooding, caused by rapid snow melt, or crop failure, resulting from fluctuations in soil temperature associated with changes in the snow cover. The latter is a fun...

  1. Snow cover - characteristics and trends for the meteorological mountain stations in Romania

    Science.gov (United States)

    Manea, A.; Ralita, I.; Dumitrescu, Al.; Boroneant, C.

    2009-04-01

    Snow cover represents an important climatological parameter for the specialized analysis because it can provide useful information regarding the climatological evolution of one region, taking into account the variability of the climate. The latest years brought milder winters for Romania. The number of days with snow cover and the depth of snow cover are very important factors for the mountain tourism and the winter sports. This paper presents the trends of the number of days with snow cover and the snow depth over the 1961-2007 period for 18 mountain meteorological stations in Romania. In this case, "mountain station" refers to a station located at an altitude higher than 1000 m.

  2. Influence of snow cover changes on surface radiation and heat balance based on the WRF model

    Science.gov (United States)

    Yu, Lingxue; Liu, Tingxiang; Bu, Kun; Yang, Jiuchun; Chang, Liping; Zhang, Shuwen

    2017-10-01

    The snow cover extent in mid-high latitude areas of the Northern Hemisphere has significantly declined corresponding to the global warming, especially since the 1970s. Snow-climate feedbacks play a critical role in regulating the global radiation balance and influencing surface heat flux exchange. However, the degree to which snow cover changes affect the radiation budget and energy balance on a regional scale and the difference between snow-climate and land use/cover change (LUCC)-climate feedbacks have been rarely studied. In this paper, we selected Heilongjiang Basin, where the snow cover has changed obviously, as our study area and used the WRF model to simulate the influences of snow cover changes on the surface radiation budget and heat balance. In the scenario simulation, the localized surface parameter data improved the accuracy by 10 % compared with the control group. The spatial and temporal analysis of the surface variables showed that the net surface radiation, sensible heat flux, Bowen ratio, temperature and percentage of snow cover were negatively correlated and that the ground heat flux and latent heat flux were positively correlated with the percentage of snow cover. The spatial analysis also showed that a significant relationship existed between the surface variables and land cover types, which was not obviously as that for snow cover changes. Finally, six typical study areas were selected to quantitatively analyse the influence of land cover types beneath the snow cover on heat absorption and transfer, which showed that when the land was snow covered, the conversion of forest to farmland can dramatically influence the net radiation and other surface variables, whereas the snow-free land showed significantly reduced influence. Furthermore, compared with typical land cover changes, e.g., the conversion of forest into farmland, the influence of snow cover changes on net radiation and sensible heat flux were 60 % higher than that of land cover changes

  3. Improving snow cover mapping in forests through the use of a canopy reflectance model

    International Nuclear Information System (INIS)

    Klein, A.G.; Hall, D.K.; Riggs, G.A.

    1998-01-01

    MODIS, the moderate resolution imaging spectro radiometer, will be launched in 1998 as part of the first earth observing system (EOS) platform. Global maps of land surface properties, including snow cover, will be created from MODIS imagery. The MODIS snow-cover mapping algorithm that will be used to produce daily maps of global snow cover extent at 500 m resolution is currently under development. With the exception of cloud cover, the largest limitation to producing a global daily snow cover product using MODIS is the presence of a forest canopy. A Landsat Thematic Mapper (TM) time-series of the southern Boreal Ecosystem–Atmosphere Study (BOREAS) study area in Prince Albert National Park, Saskatchewan, was used to evaluate the performance of the current MODIS snow-cover mapping algorithm in varying forest types. A snow reflectance model was used in conjunction with a canopy reflectance model (GeoSAIL) to model the reflectance of a snow-covered forest stand. Using these coupled models, the effects of varying forest type, canopy density, snow grain size and solar illumination geometry on the performance of the MODIS snow-cover mapping algorithm were investigated. Using both the TM images and the reflectance models, two changes to the current MODIS snow-cover mapping algorithm are proposed that will improve the algorithm's classification accuracy in forested areas. The improvements include using the normalized difference snow index and normalized difference vegetation index in combination to discriminate better between snow-covered and snow-free forests. A minimum albedo threshold of 10% in the visible wavelengths is also proposed. This will prevent dense forests with very low visible albedos from being classified incorrectly as snow. These two changes increase the amount of snow mapped in forests on snow-covered TM scenes, and decrease the area incorrectly identified as snow on non-snow-covered TM scenes. (author)

  4. Erosion potential of snow cover in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Hana Středová

    2012-01-01

    Full Text Available Amount of water derived from snow and melting rate can be collectively described as the erosion potential of water accumulated in the snow. The erosion potential of snow was calculated for thirty cold periods i.e. 1st November to 30th April (1980/1981 to 2009/2010 based on climatilogical data of fifty stations of Czech hydrometerological station from different climatic conditions according to Climatic region of Estimated Pedological Ecological Unit. Snow erosive potential statistically significantly depends on altitude (r = 0.726**, α = 0.01 and also on climatic region (r = 0.790**, α = 0.01. Mapping expression was based on average values of thirty-year period. Range of snow erosive potential in the map responces to quantile values, quintile values respectively (Q0.2, Q0.4, Q0.6, Q0.8. A map of erosion potential of snow cover for arable land deals with an assumption of arable land incidence. It was determined by excluding forests, built area, land with a slope of 12 ° and areas with an altitude of 700 m.

  5. Research on snow cover monitoring of Northeast China using Fengyun Geostationary Satellite

    Science.gov (United States)

    Wu, Tong; Gu, Lingjia; Ren, Ruizhi; Zhou, TIngting

    2017-09-01

    Snow cover information has great significance for monitoring and preventing snowstorms. With the development of satellite technology, geostationary satellites are playing more important roles in snow monitoring. Currently, cloud interference is a serious problem for obtaining accurate snow cover information. Therefore, the cloud pixels located in the MODIS snow products are usually replaced by cloud-free pixels around the day, which ignores snow cover dynamics. FengYun-2(FY-2) is the first generation of geostationary satellite in our country which complements the polar orbit satellite. The snow cover monitoring of Northeast China using FY-2G data in January and February 2016 is introduced in this paper. First of all, geometric and radiometric corrections are carried out for visible and infrared channels. Secondly, snow cover information is extracted according to its characteristics in different channels. Multi-threshold judgment methods for the different land types and similarity separation techniques are combined to discriminate snow and cloud. Furthermore, multi-temporal data is used to eliminate cloud effect. Finally, the experimental results are compared with the MOD10A1 and MYD10A1 (MODIS daily snow cover) product. The MODIS product can provide higher resolution of the snow cover information in cloudless conditions. Multi-temporal FY-2G data can get more accurate snow cover information in cloudy conditions, which is beneficial for monitoring snowstorms and climate changes.

  6. Removal of snow cover inhibits spring growth of Arctic ice algae through physiological and behavioral effects

    DEFF Research Database (Denmark)

    Lund-Hansen, L.C.; Hawes, Ian; Sorrell, Brian Keith

    2014-01-01

    The snow cover of Arctic sea ice has recently decreased, and climate models forecast that this will continue and even increase in future. We therefore tested the effect of snow cover on the optical properties of sea ice and the biomass, photobiology, and species composition of sea ice algae at Ka...

  7. Improving automated disturbance maps using snow-covered landsat time series stacks

    Science.gov (United States)

    Kirk M. Stueve; Ian W. Housman; Patrick L. Zimmerman; Mark D. Nelson; Jeremy Webb; Charles H. Perry; Robert A. Chastain; Dale D. Gormanson; Chengquan Huang; Sean P. Healey; Warren B. Cohen

    2012-01-01

    Snow-covered winter Landsat time series stacks are used to develop a nonforest mask to enhance automated disturbance maps produced by the Vegetation Change Tracker (VCT). This method exploits the enhanced spectral separability between forested and nonforested areas that occurs with sufficient snow cover. This method resulted in significant improvements in Vegetation...

  8. Chemical elements contamination of snow cover in region of coal production 'Karazhyra'

    International Nuclear Information System (INIS)

    Evlampieva, E.P.; Panin, M.S.

    2008-01-01

    Peculiarities of space distribution of chemical elements in hardphase and water-soluble falls of snow cover in region of coal deposit 'Karazhyra' are investigated. The maximal, minimal and background areas of elements accumulation in the snow of this region and distribution of their cumulative rates are determined. The main pollutants of snow cover unto background level are revealed.

  9. [Evaluation of pollution of an urban area by level of heavy metals in snow cover].

    Science.gov (United States)

    Stepanova, N V; Khamitova, R Ia; Petrova, R S

    2003-01-01

    The goal of this study was to systematize various methodological approaches to evaluating the contamination of the snow cover with heavy metals (HM) by using Kazan, an industrial city with diversified industry, as an example. The findings suggest that it is necessary to characterize the contamination of the snow cover by the actual entrance of an element per area unit of the snow cover for a definite period of time rather than by the concentration of TM in the volume unit of snow water (mg/l), which minimizes the uncertainties with spatial and temporary snow cover variations. The index of the maximum allowable entrance, which is of practical value, may be used to objectively calibrate the pollution of the snow cover, by estimating the amount of a coming element and its toxicity.

  10. No evidence of widespread decline of snow cover on the Tibetan Plateau over 2000-2015.

    Science.gov (United States)

    Wang, Xiaoyue; Wu, Chaoyang; Wang, Huanjiong; Gonsamo, Alemu; Liu, Zhengjia

    2017-11-07

    Understanding the changes in snow cover is essential for biological and hydrological processes in the Tibetan Plateau (TP) and its surrounding areas. However, the changes in snow cover phenology over the TP have not been well documented. Using Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow products and the Interactive Multi-sensor Snow and Ice Mapping System (IMS) data, we reported daily cloud-free snow cover product over the Tibetan Plateau (TP) for 2000-2015. Snow cover start (SCS), melt (SCM) and duration (SCD) dates were calculated for each hydrological year, and their spatial and temporal variations were analyzed with elevation variations. Our results show no widespread decline in snow cover over the past fifteen years and the trends of snow cover phenology over the TP has high spatial heterogeneity. Later SCS, earlier SCM, and thus decreased SCD mainly occurred in the areas with elevation below 3500 m a.s.l., while regions in central and southwestern edges of the TP showed advanced SCS, delayed SCM and consequently longer SCD. The roles of temperature and precipitation on snow cover penology varied in different elevation zones, and the impact of both temperature and precipitation strengthened as elevation increases.

  11. Spatiotemporal variability of snow cover and snow water equivalent in the last three decades over Eurasia

    Science.gov (United States)

    Zhang, Yinsheng; Ma, Ning

    2018-04-01

    Changes in the extent and amount of snow cover in Eurasia are of great interest because of their vital impacts on the global climate system and regional water resource management. This study investigated the spatial and temporal variability of the snow cover extent (SCE) and snow water equivalent (SWE) of the continental Eurasia using the Northern Hemisphere Equal-Area Scalable Earth Grid (EASE-Grid) Weekly SCE data for 1972-2006 and the Global Monthly EASE-Grid SWE data for 1979-2004. The results indicated that, in general, the spatial extent of snow cover significantly decreased during spring and summer, but varied little during autumn and winter over Eurasia in the study period. The date at which snow cover began to disappear in spring has significantly advanced, whereas the timing of snow cover onset in autumn did not vary significantly during 1972-2006. The snow cover persistence period declined significantly in the western Tibetan Plateau as well as partial area of Central Asia and northwestern Russia, but varied little in other parts of Eurasia. "Snow-free breaks" (SFBs) with intermittent snow cover in the cold season were principally observed in the Tibetan Plateau and Central Asia, causing a low sensitivity of snow cover persistence period to the timings of snow cover onset and disappearance over the areas with shallow snow. The averaged SFBs were 1-14 weeks during the study period and the maximum intermittence could even reach 25 weeks in certain years. At a seasonal scale, SWE usually peaked in February or March, but fell gradually since April across Eurasia. Both annual mean and annual maximum SWE decreased significantly during 1979-2004 in most parts of Eurasia except for eastern Siberia as well as northwestern and northeastern China. The possible cross-platform inconsistencies between two passive microwave radiometers may cause uncertainties in the detected trends of SWE here, suggesting an urgent need of producing a long-term, more homogeneous SWE

  12. Complex responses of spring alpine vegetation phenology to snow cover dynamics over the Tibetan Plateau, China.

    Science.gov (United States)

    Wang, Siyuan; Wang, Xiaoyue; Chen, Guangsheng; Yang, Qichun; Wang, Bin; Ma, Yuanxu; Shen, Ming

    2017-09-01

    Snow cover dynamics are considered to play a key role on spring phenological shifts in the high-latitude, so investigating responses of spring phenology to snow cover dynamics is becoming an increasingly important way to identify and predict global ecosystem dynamics. In this study, we quantified the temporal trends and spatial variations of spring phenology and snow cover across the Tibetan Plateau by calibrating and analyzing time series of the NOAA AVHRR-derived normalized difference vegetation index (NDVI) during 1983-2012. We also examined how snow cover dynamics affect the spatio-temporal pattern of spring alpine vegetation phenology over the plateau. Our results indicated that 52.21% of the plateau experienced a significant advancing trend in the beginning of vegetation growing season (BGS) and 34.30% exhibited a delaying trend. Accordingly, the snow cover duration days (SCD) and snow cover melt date (SCM) showed similar patterns with a decreasing trend in the west and an increasing trend in the southeast, but the start date of snow cover (SCS) showed an opposite pattern. Meanwhile, the spatial patterns of the BGS, SCD, SCS and SCM varied in accordance with the gradients of temperature, precipitation and topography across the plateau. The response relationship of spring phenology to snow cover dynamics varied within different climate, terrain and alpine plant community zones, and the spatio-temporal response patterns were primarily controlled by the long-term local heat-water conditions and topographic conditions. Moreover, temperature and precipitation played a profound impact on diverse responses of spring phenology to snow cover dynamics. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. MEaSUREs Northern Hemisphere Terrestrial Snow Cover Extent Daily 25km EASE-Grid 2.0 V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set offers users 25 km Northern Hemisphere snow cover extent represented by four different variables. Three of the snow cover variables are derived from...

  14. MODIS/Aqua Near Real Time (NRT) Snow Cover 5-Min L2 Swath 500m, Version 006

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS/Aqua Near Real Time (NRT) Snow Cover 5-Min L2 Swath 500m (MYD10_L2) data set contains snow cover and Quality Assessment (QA) data, latitudes and longitudes...

  15. Variability in snow cover phenology in China from 1952 to 2010

    OpenAIRE

    Ke, Chang-Qing; Li, Xiu-Cang; Xie, Hongjie; Ma, Dong-Hui; Liu, Xun; Kou, Cheng

    2016-01-01

    Daily snow observation data from 672 stations in China, particularly the 296 stations with over 10 mean snow cover days (SCDs) in a year during the period of 1952–2010, are used in this study. We first examine spatiotemporal variations and trends of SCDs, snow cover onset date (SCOD), and snow cover end date (SCED). We then investigate the relationships of SCDs with number of days with temperature below 0 °C (TBZD), mean air temperature (MAT), and Arctic Oscillation (AO) index....

  16. Prevalence of Pure Versus Mixed Snow Cover Pixels across Spatial Resolutions in Alpine Environments

    Directory of Open Access Journals (Sweden)

    David J. Selkowitz

    2014-12-01

    Full Text Available Remote sensing of snow-covered area (SCA can be binary (indicating the presence/absence of snow cover at each pixel or fractional (indicating the fraction of each pixel covered by snow. Fractional SCA mapping provides more information than binary SCA, but is more difficult to implement and may not be feasible with all types of remote sensing data. The utility of fractional SCA mapping relative to binary SCA mapping varies with the intended application as well as by spatial resolution, temporal resolution and period of interest, and climate. We quantified the frequency of occurrence of partially snow-covered (mixed pixels at spatial resolutions between 1 m and 500 m over five dates at two study areas in the western U.S., using 0.5 m binary SCA maps derived from high spatial resolution imagery aggregated to fractional SCA at coarser spatial resolutions. In addition, we used in situ monitoring to estimate the frequency of partially snow-covered conditions for the period September 2013–August 2014 at 10 60-m grid cell footprints at two study areas with continental snow climates. Results from the image analysis indicate that at 40 m, slightly above the nominal spatial resolution of Landsat, mixed pixels accounted for 25%–93% of total pixels, while at 500 m, the nominal spatial resolution of MODIS bands used for snow cover mapping, mixed pixels accounted for 67%–100% of total pixels. Mixed pixels occurred more commonly at the continental snow climate site than at the maritime snow climate site. The in situ data indicate that some snow cover was present between 186 and 303 days, and partial snow cover conditions occurred on 10%–98% of days with snow cover. Four sites remained partially snow-free throughout most of the winter and spring, while six sites were entirely snow covered throughout most or all of the winter and spring. Within 60 m grid cells, the late spring/summer transition from snow-covered to snow-free conditions lasted 17–56 days

  17. Laws of distribution of the snow cover on the greater Caucasus (Soviet Union)

    Science.gov (United States)

    Gurtovaya, Y. Y.; Sulakvelidze, G. K.; Yashina, A. V.

    1985-01-01

    The laws of the distribution of the snow cover on the mountains of the greater Caucasus are discussed. It is shown that an extremely unequal distribution of the snow cover is caused by the complex orography of this territory, the diversity of climatic conditions and by the difference in altitude. Regions of constant, variable and unstable snow cover are distinguished because of the clearly marked division into altitude layers, each of which is characterized by climatic differences in the nature of the snow accumulation.

  18. Global EASE-Grid 8-day Blended SSM/I and MODIS Snow Cover

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set comprises global, 8-day Snow-Covered Area (SCA) and Snow Water Equivalent (SWE) data from 2000 through 2008. Global SWE data are derived from the...

  19. Global EASE-Grid 8-day Blended SSM/I and MODIS Snow Cover, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set comprises global, 8-day Snow-Covered Area (SCA) and Snow Water Equivalent (SWE) data from 2000 through 2008. Global SWE data are derived from the...

  20. Nimbus-7 SMMR Derived Monthly Global Snow Cover and Snow Depth

    Data.gov (United States)

    National Aeronautics and Space Administration — The data set consists of monthly global snow cover and snow depth derived from Nimbus-7 SMMR data for 1978 through 1987. The SMMR data are interpolated for spatial...

  1. CLPX-Satellite: EO-1 Hyperion Surface Reflectance, Snow-Covered Area, and Grain Size

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of apparent surface reflectance, subpixel snow-covered area and grain size collected from the Hyperion hyperspectral imager. The Hyperion...

  2. Interannual changes in snow cover and its impact on ground surface temperatures in Livingston Island (Antarctica)

    Science.gov (United States)

    Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

    2015-04-01

    In permafrost areas the seasonal snow cover is an important factor on the ground thermal regime. Snow depth and timing are important in ground insulation from the atmosphere, creating different snow patterns and resulting in spatially variable ground temperatures. The aim of this work is to characterize the interactions between ground thermal regimes and snow cover and the influence on permafrost spatial distribution. The study area is the ice-free terrains of northwestern Hurd Peninsula in the vicinity of the Spanish Antarctic Station "Juan Carlos I" and Bulgarian Antarctic Station "St. Kliment Ohridski". Air and ground temperatures and snow thickness data where analysed from 4 sites along an altitudinal transect in Hurd Peninsula from 2007 to 2012: Nuevo Incinerador (25 m asl), Collado Ramos (110 m), Ohridski (140 m) and Reina Sofia Peak (275 m). The data covers 6 cold seasons showing different conditions: i) very cold with thin snow cover; ii) cold with a gradual increase of snow cover; iii) warm with thick snow cover. The data shows three types of periods regarding the ground surface thermal regime and the thickness of snow cover: a) thin snow cover and short-term fluctuation of ground temperatures; b) thick snow cover and stable ground temperatures; c) very thick snow cover and ground temperatures nearly constant at 0°C. a) Thin snow cover periods: Collado Ramos and Ohridski sites show frequent temperature variations, alternating between short-term fluctuations and stable ground temperatures. Nuevo Incinerador displays during most of the winter stable ground temperatures; b) Cold winters with a gradual increase of the snow cover: Nuevo Incinerador, Collado Ramos and Ohridski sites show similar behavior, with a long period of stable ground temperatures; c) Thick snow cover periods: Collado Ramos and Ohridski show long periods of stable ground, while Nuevo Incinerador shows temperatures close to 0°C since the beginning of the winter, due to early snow cover

  3. NOAA Climate Data Record (CDR) of Northern Hemisphere (NH) Snow Cover Extent (SCE), Version 1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This NOAA Climate Data Record (CDR) is a record for the Northern Hemisphere (NH) Snow Cover Extent (SCE) spanning from October 4, 1966 to present, updated monthly...

  4. Nimbus-7 SMMR Derived Monthly Global Snow Cover and Snow Depth, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The data set consists of monthly global snow cover and snow depth derived from Nimbus-7 SMMR data for 1978 through 1987. The SMMR data are interpolated for spatial...

  5. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Snow Cover Environmental Data Record (EDR) from NDE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of snow cover from the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument...

  6. Forcing the snow-cover model SNOWPACK with forecasted weather data

    Directory of Open Access Journals (Sweden)

    S. Bellaire

    2011-12-01

    Full Text Available Avalanche danger is often estimated based on snow cover stratigraphy and snow stability data. In Canada, single forecasting regions are very large (>50 000 km2 and snow cover data are often not available. To provide additional information on the snow cover and its seasonal evolution the Swiss snow cover model SNOWPACK was therefore coupled with a regional weather forecasting model GEM15. The output of GEM15 was compared to meteorological as well as snow cover data from Mt. Fidelity, British Columbia, Canada, for five winters between 2005 and 2010. Precipitation amounts are most difficult to predict for weather forecasting models. Therefore, we first assess the capability of the model chain to forecast new snow amounts and consequently snow depth. Forecasted precipitation amounts were generally over-estimated. The forecasted data were therefore filtered and used as input for the snow cover model. Comparison between the model output and manual observations showed that after pre-processing the input data the snow depth and new snow events were well modelled. In a case study two key factors of snow cover instability, i.e. surface hoar formation and crust formation were investigated at a single point. Over half of the relevant critical layers were reproduced. Overall, the model chain shows promising potential as a future forecasting tool for avalanche warning services in Canadian data sparse areas and could thus well be applied to similarly large regions elsewhere. However, a more detailed analysis of the simulated snow cover structure is still required.

  7. Spatial and Temporal Characteristics of Snow Cover in the Tizinafu Watershed of the Western Kunlun Mountains

    Directory of Open Access Journals (Sweden)

    Jiangfeng She

    2015-03-01

    Full Text Available The Tizinafu watershed has a complex mountainous terrain in the western Kunlun Mountains; little study has been done on the spatial and temporal characteristics of snow cover in the region. Daily snow cover data of 10 hydrological years (October 2002 to September 2012 in the watershed were generated by combining MODIS Terra (MOD10A1 and Aqua (MYD10A1 snow cover products and employing a nine-day temporal filter for cloud reduction. The accuracy and window size of the temporal filter were assessed using a simulation approach. Spatial and temporal characteristics of snow cover in the watershed were then analyzed. Our results showed that snow generally starts melting in March and reaches the minimum in early August in the watershed. Snow cover percentages (SCPs in all five elevation zones increase consistently with the rise of elevation. Slope doesn’t play a major role in snow cover distribution when it exceeds 10°. The largest SCP difference is between the south and the other aspects and occurs between mid-October and mid-November with decreasing SCP, indicating direct solar radiation may cause the reduction of snow cover. While both the mean snow cover durations (SCDs of the hydrological years and of the snowmelt seasons share a similar spatial pattern to the topography of the watershed, the coefficient of variation of the SCDs exhibits an opposite spatial distribution. There is a significant correlation between annual mean SCP and annual total stream flow, indicating that snowmelt is a major source of stream runoff that might be predictable with SCP.

  8. Partial least regression approach to forecast the East Asian winter monsoon using Eurasian snow cover and sea surface temperature

    Science.gov (United States)

    Yu, Lulu; Wu, Zhiwei; Zhang, Renhe; Yang, Xin

    2017-06-01

    Seasonal prediction of the East Asian (EA) winter monsoon (EAWM) is of great significance yet a challenging issue. In this study, three statistical seasonal prediction models for the EAWM are established using three leading modes of the Eurasian snow cover (ESC), the first leading mode of sea surface temperature (SST) and the four leading modes of the combination of the ESC and SST in preceding autumn, respectively. These leading modes are identified by the partial-least square (PLS) regression. The first PLS (PLS1) mode for the ESC features significantly anomalous snow cover in Siberia and Tibetan Plateau regions. The ESC second PLS (PLS2) mode corresponds to large areas of snow cover anomalies in the central Siberia, whereas the third PLS (PLS3) mode a meridional seesaw pattern of ESC. The SST PLS1 mode basically exhibits an El Niño-Southern Oscillation developing phase in equatorial eastern Pacific and significant SST anomalies in North Atlantic. A strong EAWM tends to emerge in a La Niña year concurrent with cold SST anomalies in the North Atlantic, and vice versa. After a 35-year training period (1967-2001), three PLS seasonal prediction models are constructed and the 11-year hindcast is performed for the period of 2002-2012, respectively. The PLS model based on combination of the autumn ESC and SST exhibits the best hindcast skill among the three models, its correlation coefficient between the observation and the hindcast reaching 0.86. This indicates that this physical-based PLS model may provide another practical tool for the EAWM. In addition, the relative contribution of the ESC and SST is also examined by assessing the hindcast skills of the other two PLS models constructed solely by the ESC or SST. Possible physical mechanisms are also discussed.

  9. ATLAS, Construction of a Giant

    CERN Multimedia

    McCubbin, Norman

    2004-01-01

    One of the most impressive aspects of modern particle physics in the scale of the equipment. The accelerators require the construction of underground tunnels many kilometers long containing evacuated pipes through which beams of particles travel at incredibly high energies. Even more spectacular are the gigantic complex assemblies that make up the experiments themselves

  10. Response of alpine vegetation growth dynamics to snow cover phenology on the Tibetan Plateau

    Science.gov (United States)

    Wang, X.; Wu, C.

    2017-12-01

    Alpine vegetation plays a crucial role in global energy cycles with snow cover, an essential component of alpine land cover showing high sensitivity to climate change. The Tibetan Plateau (TP) has a typical alpine vegetation ecosystem and is rich of snow resources. With global warming, the snow of the TP has undergone significant changes that will inevitably affect the growth of alpine vegetation, but observed evidence of such interaction is limited. In particular, a comprehensive understanding of the responses of alpine vegetation growth to snow cover variability is still not well characterized on TP region. To investigate this, we calculated three indicators, the start (SOS) and length (LOS) of growing season, and the maximum of normalized difference vegetation index (NDVImax) as proxies of vegetation growth dynamics from the Moderate Resolution Imaging Spectroradiometer (MODIS) data for 2000-2015. Snow cover duration (SCD) and melt (SCM) dates were also extracted during the same time frame from the combination of MODIS and the Interactive Multi-sensor Snow and Ice Mapping System (IMS) data. We found that the snow cover phenology had a strong control on alpine vegetation growth dynamics. Furthermore, the responses of SOS, LOS and NDVImax to snow cover phenology varied among plant functional types, eco-geographical zones, and temperature and precipitation gradients. The alpine steppes showed a much stronger negative correlation between SOS and SCD, and also a more evidently positive relationship between LOS and SCD than other types, indicating a longer SCD would lead to an earlier SOS and longer LOS. Most areas showed positive correlation between SOS and SCM, while a contrary response was also found in the warm but drier areas. Both SCD and SCM showed positive correlations with NDVImax, but the relationship became weaker with the increase of precipitation. Our findings provided strong evidences between vegetation growth and snow cover phenology, and changes in

  11. Satellite-observed snow cover variations over the Tibetan Plateau for the period 2001-2014

    Science.gov (United States)

    Long, D.; Chen, X.

    2016-12-01

    Snow is an integral component of the global climate system. Owing to its high albedo and thermal and water storage properties, snow has important linkages and feedbacks through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, and atmospheric circulation. As the "Roof of the World" and the "Third Pole" with the highest mountains in middle latitudes, the Tibetan Plateau (TP) is one of the most hot spots in climate change and hydrological studies, in which seasonal snow cover is a critical aspect. Unlike large-scale snow cover and regional-scale glaciers over other cryospheric regions, changes in snow cover over the TP has been largely unknown due mostly to the quality of observations. Based on improved MODIS daily snow cover products, this study aims to quantify the distribution and changes in snow cover over the TP for the period 2001 to 2014. Results show that the spatial distribution of changes in snow cover fraction (SCF) over the 14-year study period exhibited a general negative trend over the TP driven primarily by increasing land surface temperature (LST), except some areas of the upper Golden-Sanded River and upper Brahmaputra River basins. However, decreased LST and increased precipitation in the accumulation season (September to the following February) resulted in increased SCF in the accumulation season, coinciding with large-scale cold snaps and heavy snowfall events at middle latitudes. Detailed analyses of the intra-annual variability of SCF in the TP regions show an increase in SCF in the accumulation season but a decrease in SCF in the melting season (March to August), indicating that the intra-annual amplitude of SCF increased during the study period and more snow cover was released as snowmelt in the spring season.

  12. Multi-decadal evolution of ice/snow covers in the Mont-Blanc massif (France)

    Science.gov (United States)

    Guillet, Grégoire; Ravanel, Ludovic

    2017-04-01

    Dynamics and evolution of the major glaciers of the Mont-Blanc massif have been vastly studied since the XXth century. Ice/snow covers on steep rock faces as part of the cryosphere however remain poorly studied with only qualitative descriptions existing. The study of ice/snow covers is primordial to further understand permafrost degradation throughout the Mont-Blanc massif and to improve safety and prevention for mountain sports practitioners. This study focuses on quantifying the evolution of ice/snow covers surface during the past century using a specially developed monoplotting tool using Bayesian statistics and Markov Chain Monte Carlo algorithms. Combining digital elevation models and photographs covering a time-span of 110 years, we calculated the ice/snow cover surface for 3 study sites — North faces of the Tour Ronde (3792 m a.s.l.) and the Grandes Jorasses (4208 m a.s.l.) and Triangle du Tacul (3970 m a.s.l.) — and deduced the evolution of their area throughout the XXth century. First results are showing several increase/decrease periods. The first decrease in ice/snow cover surface occurs between the 1940's and the 1950's. It is followed by an increase up to the 1980's. Since then, ice/snow covers show a general decrease in surface which is faster since the 2010's. Furthermore, the gain/loss during the increase/decrease periods varies with the considered ice/snow cover, making it an interesting cryospheric entity of its own.

  13. Snow cover monitoring in the Kyrgyz Republic through MODIS time series (2000-2010)

    Science.gov (United States)

    Dedieu, J.-P.; Doutreleau, V.; Lessard-Fontaine, A.; Shalpykova, G.

    2012-04-01

    The Kyrgyz Republic is located at the convergence of two mountain systems (Tien Shan and Pamirs) in Central Asia. The region is of great interest all of Central Asia because of its consequent capital in water resources. Theses resources are of importance for electricity production (~15 TWH/year) and irrigation of agricultural land. Over 50% of the 52 km3 of Kyrgyz runoff water irrigates the Syr Darya River which flows over 2200 km from the confluence of Naryn and Kara Darya rivers to the Aral Sea. Around 40% of the Kyrgyz territory lies above 3000m; part of the water resource is cumulated as snow during large periods of the year. Snow cover is thus an important part of the Kyrgyz hydrological cycle. In this already water-stressed region, both climate change and irrigation expansion could trigger a greater scarcity of the resource in the future. One of the major impact could be a modification of the melting season period and the snow melt behavior. The use of passive optical remote sensing data could provide helpful complementary information for hydrological modeling of these effects, but currently, very few scientific publications concerning the Syr Darya headwaters in Kyrgyztan exist. Integrated in the EU-FP7 ACQWA Project (www.acqwa.ch), this study proposes 11 years of snow cover analysis using MODIS snow cover product data. The following parameters are retrieved from MODIS data: Snow Cover Area (SCA), Snow Fraction (FRA), snow cover duration and depletion maps. A Digital Elevation Model (DEM) from the NASA-SRTM database is used to better understand the topographic influence on snow melt behavior and a Land Use database (GlobCover 2009) for the environmental context of snow cover evolution. A statistical analysis of snow cover dynamics is performed on a 2000-2010 8-days temporal resolution dataset. Yearly mean snow cover is 40 ± 5 % and melting runs with 5%.8j-1 average velocity. We observe a greater variation of the inter-annual snow cover extent in winter

  14. Use of Sentinels to aid the global monitoring of snow cover

    Science.gov (United States)

    Pulliainen, Jouni; Salminen, Miia; Luojus, Kari; Metsämäki, Sari; Lemmetyinen, Juha; Takala, Matias; Cohen, Juval; Böttcher, Kristine

    2014-05-01

    Earth observation instruments onboard Sentinel satellites provide a unique opportunity for the monitoring and investigation of global snow processes. The issue of the possible decay of seasonal snow cover is highly relevant for climate research. In addition to water cycle, the extent and amount of snow affects to surface albedo, and indirectly to carbon cycling. The latter issue includes snow-induced changes in permafrost regions (active layer characteristics), as well as the effect of snow (melt) to vegetation growth and soil respiration. Recent advances in ESA DUE GlobSnow project have shown that by combining data from optical satellite sensors and passive microwave instruments advanced Climate Data Records (CDR) on seasonal snow cover can be produced, extending to time periods of over 30 years. The combined snow cover products provide information both on Snow Extent (SE) and Snow Water Equivalent (SWE) on a daily basis. The applicable instruments providing historical data for CDR generation include such microwave radiometers as SMMR, AMSR and SSMI/I, and such optical sensors as AVHRR, AATSR and VIIRS. Sentinel 3, especially its SLSTR instrument, is a prominent tool for expanding the snow CDR for forthcoming years. The developed global snow cover monitoring methodology, demonstrated and discussed here, derives the SWE information from passive microwave data (accompanied with in situ observations of snow depth at synoptic weather stations). The snow extent and fractional snow cover (FSC) on ground is derived from optical satellite data, in order to accurately map the continental line of seasonal snow cover, and to map regions of ephemeral snow cover. An advanced feature in the developed methodology is the provision of uncertainty information on snow cover characteristics associated with each individual satellite data footprint on ground and moment of time. In addition to assisting the generation and extension of the global snow cover CDR, Sentinel missions provide

  15. Modelling snow cover duration improves predictions of functional and taxonomic diversity for alpine plant communities.

    Science.gov (United States)

    Carlson, Bradley Z; Choler, Philippe; Renaud, Julien; Dedieu, Jean-Pierre; Thuiller, Wilfried

    2015-11-01

    Quantifying relationships between snow cover duration and plant community properties remains an important challenge in alpine ecology. This study develops a method to estimate spatial variation in energy availability in the context of a topographically complex, high-elevation watershed, which was used to test the explanatory power of environmental gradients both with and without snow cover in relation to taxonomic and functional plant diversity. Snow cover in the French Alps was mapped at 15-m resolution using Landsat imagery for five recent years, and a generalized additive model (GAM) was fitted for each year linking snow to time and topography. Predicted snow cover maps were combined with air temperature and solar radiation data at daily resolution, summed for each year and averaged across years. Equivalent growing season energy gradients were also estimated without accounting for snow cover duration. Relationships were tested between environmental gradients and diversity metrics measured for 100 plots, including species richness, community-weighted mean traits, functional diversity and hyperspectral estimates of canopy chlorophyll content. Accounting for snow cover in environmental variables consistently led to improved predictive power as well as more ecologically meaningful characterizations of plant diversity. Model parameters differed significantly when fitted with and without snow cover. Filtering solar radiation with snow as compared without led to an average gain in R(2) of 0·26 and reversed slope direction to more intuitive relationships for several diversity metrics. The results show that in alpine environments high-resolution data on snow cover duration are pivotal for capturing the spatial heterogeneity of both taxonomic and functional diversity. The use of climate variables without consideration of snow cover can lead to erroneous predictions of plant diversity. The results further indicate that studies seeking to predict the response of alpine

  16. MODIS Snow Cover Mapping Decision Tree Technique: Snow and Cloud Discrimination

    Science.gov (United States)

    Riggs, George A.; Hall, Dorothy K.

    2010-01-01

    Accurate mapping of snow cover continues to challenge cryospheric scientists and modelers. The Moderate-Resolution Imaging Spectroradiometer (MODIS) snow data products have been used since 2000 by many investigators to map and monitor snow cover extent for various applications. Users have reported on the utility of the products and also on problems encountered. Three problems or hindrances in the use of the MODIS snow data products that have been reported in the literature are: cloud obscuration, snow/cloud confusion, and snow omission errors in thin or sparse snow cover conditions. Implementation of the MODIS snow algorithm in a decision tree technique using surface reflectance input to mitigate those problems is being investigated. The objective of this work is to use a decision tree structure for the snow algorithm. This should alleviate snow/cloud confusion and omission errors and provide a snow map with classes that convey information on how snow was detected, e.g. snow under clear sky, snow tinder cloud, to enable users' flexibility in interpreting and deriving a snow map. Results of a snow cover decision tree algorithm are compared to the standard MODIS snow map and found to exhibit improved ability to alleviate snow/cloud confusion in some situations allowing up to about 5% increase in mapped snow cover extent, thus accuracy, in some scenes.

  17. Automated Webcam Monitoring of Fractional Snow Cover in Northern Boreal Conditions

    Directory of Open Access Journals (Sweden)

    Ali Nadir Arslan

    2017-07-01

    Full Text Available Fractional snow cover (FSC is an important parameter to estimate snow water equivalent (SWE and surface albedo important to climatic and hydrological applications. The presence of forest creates challenges to retrieve FSC accurately from satellite data, as forest canopy can block the sensor’s view of snow cover. In addition to the challenge related to presence of forest, in situ data of FSC—necessary for algorithm development and validation—are very limited. This paper investigates the estimation of FSC using digital imagery to overcome the obstacle caused by forest canopy, and the possibility to use this imagery in the validation of FSC derived from satellite data. FSC is calculated here using an algorithm based on defining a threshold value according to the histogram of an image, to classify a pixel as snow-covered or snow-free. Images from the MONIMET camera network, producing a continuous image series in Finland, are used in the analysis of FSC. The results obtained from automated image analysis of snow cover are compared with reference data estimated by visual inspection of same images. The results show the applicability and usefulness of digital imagery in the estimation of fractional snow cover in forested areas, with a Root Mean Squared Error (RMSE in the range of 0.1–0.3 (with the full range of 0–1.

  18. Global warming in the context of 2000 years of Australian alpine temperature and snow cover.

    Science.gov (United States)

    McGowan, Hamish; Callow, John Nikolaus; Soderholm, Joshua; McGrath, Gavan; Campbell, Micheline; Zhao, Jian-Xin

    2018-03-13

    Annual resolution reconstructions of alpine temperatures are rare, particularly for the Southern Hemisphere, while no snow cover reconstructions exist. These records are essential to place in context the impact of anthropogenic global warming against historical major natural climate events such as the Roman Warm Period (RWP), Medieval Climate Anomaly (MCA) and Little Ice Age (LIA). Here we show for a marginal alpine region of Australia using a carbon isotope speleothem reconstruction, warming over the past five decades has experienced equivalent magnitude of temperature change and snow cover decline to the RWP and MCA. The current rate of warming is unmatched for the past 2000 years and seasonal snow cover is at a minimum. On scales of several decades, mean maximum temperatures have undergone considerable change ≈ ± 0.8 °C highlighting local scale susceptibility to rapid temperature change, evidence of which is often masked in regional to hemisphere scale temperature reconstructions.

  19. Sensitivity of the French Alps snow cover to the variation of climatic variables

    Directory of Open Access Journals (Sweden)

    E. Martin

    Full Text Available In order to study the sensitivity of snow cover to changes in meteorological variables at a regional scale, a numerical snow model and an analysis system of the meteorological conditions adapted to relief were used. This approach has been successfully tested by comparing simulated and measured snow depth at 37 sites in the French Alps during a ten year data period. Then, the sensitivity of the snow cover to a variation in climatic conditions was tested by two different methods, which led to very similar results. To assess the impact of a particular "doubled CO2" scenario, coherent perturbations were introduced in the input data of the snow model. It was found that although the impact would be very pronounced, it would also be extremely differentiated, dependent on the internal state of the snow cover. The most sensitive areas are the elevations below 2400 m, especially in the southern part of the French Alps.

  20. Dynamics of snow cover characteristics exerting influence on stability of the Svalbard permafrost

    Directory of Open Access Journals (Sweden)

    N. I. Osokin

    2016-01-01

    Full Text Available Climate variations result in changes of the snow cover characteristics which have a certain influence upon thermal state and stability of permafrost. Analysis of data of meteorological station Barentsburg (Svalbard and our own observations has revealed small change in the snow cover thickness for the period 1984–2015. At the same time, duration of the snow cover presence has shortened by 8%. In recent years, more than 60% of the snow cover thickness was formed during the early third of the cold season which adversely affects a rate of the ground freezing. Durations of thaws increased from 12 to 22 days, and the rainfall amount decreased during the cold period from 60 to 120 mm. The largest increase in the thaw duration (by a factor of 7 and decrease of the rainfall amount (by a factor of 8 fall on January and February. Summing up of the thaw duration and the rainfall amount for the 5‑year periods demonstrated significant growth of both. It should be noted also that, according to data of the Barentsburg station and our ones, in a few last years, these parameters reached anomalously high values. Appearance of anomalous values of the snow cover thickness as well as of the dates of its onset became more frequent. For the last decade, recurrence of anomalous values of the snow cover thickness increased: one event for 2.4 years before 2000, and one occurrence of anomalous thickness for 1.4 years since 2001. The later onset of snow cover resulted in shortening of duration of its presence. Occurrence of anomalous duration of the snow cover presence was observed once for 4.3 years before 2001, and once for 3.3 years after 2000.

  1. Snow Cover Monitoring Using MODIS Data in Liaoning Province, Northeastern China

    Directory of Open Access Journals (Sweden)

    Yu Lu

    2010-03-01

    Full Text Available This paper presents the results of snow cover monitoring studies in Liaoning Province, northeastern China, using MODIS data. Snow cover plays an important role in both the regional water balance and soil moisture properties during the early spring in northeastern China. In addition, heavy snowfalls commonly trigger hazards such as flooding, caused by rapid snow melt, or crop failure, resulting from fluctuations in soil temperature associated with changes in the snow cover. The latter is a function of both regional, or global, climatic changes, as well as fluctuations in the albedo resulting from variations in the Snow Covered Area (SCA. These impacts are crucial to human activities, especially to those living in middle-latitude areas such as Liaoning Province. Thus, SCA monitoring is currently an important tool in studies of global climate change, particularly because satellite remote sensing data provide timely and efficient snow cover information for large areas. In this study, MODIS L1B data, MODIS Daily Snow Products (MOD10A1 and MODIS 8-day Snow Products (MOD10A2 were used to monitor the SCA of Liaoning Province over the winter months of November–April, 2006–2008. The effects of cloud masking and forest masking on the snow monitoring results were also assessed. The results show that the SCA percentage derived from MODIS L1B data is relatively consistent, but slightly higher than that obtained from MODIS Snow Products. In situ data from 25 snow stations were used to assess the accuracy of snow cover monitoring from the SCA compared to the results from MODIS Snow Products. The studies found that the SCA results were more reliable than MODIS Snow Products in the study area.

  2. Linkages between Snow Cover Seasonality, Terrain, and Land Surface Phenology in the Highland Pastures of Kyrgyzstan

    Science.gov (United States)

    Henebry, Geoffrey; Tomaszewska, Monika; Kelgenbaeva, Kamilya

    2017-04-01

    In the highlands of Kyrgyzstan, vertical transhumance is the foundation of montane agropastoralism. Terrain attributes, such as elevation, slope, and aspect, affect snow cover seasonality, which is a key influence on the timing of plant growth and forage availability. Our study areas include the highland pastures in Central Tien Shan mountains, specifically in the rayons of Naryn and At-Bashy in Naryn oblast, and Alay and Chong-Alay rayons in Osh oblast. To explore the linkages between snow cover seasonality and land surface phenology as modulated by terrain and variations in thermal time, we use 16 years (2001-2016) of Landsat surface reflectance data at 30 m resolution with MODIS land surface temperature and snow cover products at 1 km and 500 m resolution, respectively, and two digital elevation models, SRTM and ASTER GDEM. We model snow cover seasonality using frost degree-days and land surface phenology using growing degree-days as quadratic functions of thermal time: a convex quadratic (CxQ) model for land surface phenology and a concave quadratic (CvQ) model for snow cover seasonality. From the fitted parameter coefficients, we calculated phenometrics, including "peak height" and "thermal time to peak" for the CxQ models and "trough depth" and "thermal time to trough" for the CvQ models. We explore how these phenometrics change as a function of elevation and slope-aspect interactions and due to interannual variability. Further, we examine how snow cover duration and timing affects the subsequent peak height and thermal time to peak in wetter, drier, and normal years.

  3. Mapping snow cover using multi-source satellite data on big data platforms

    Science.gov (United States)

    Lhermitte, Stef

    2017-04-01

    Snowmelt is an important and dynamically changing water resource in mountainous regions around the world. In this framework, remote sensing data of snow cover data provides an essential input for hydrological models to model the water contribution from remote mountain areas and to understand how this water resource might alter as a result of climate change. Traditionally, however, many of these remote sensing products show a trade-off between spatial and temporal resolution (e.g., 16-day Landsat at 30m vs. daily MODIS at 500m resolution). With the advent of Sentinel-1 and 2 and the PROBA-V 100m products this trade-off can partially be tackled by having data that corresponds more closely to the spatial and temporal variations in snow cover typically observed over complex mountain areas. This study provides first a quantitative analysis of the trade-offs between the state-of-the-art snow cover mapping methodologies for Landsat, MODIS, PROBA-V, Sentinel-1 and 2 and applies them on big data platforms such as Google Earth Engine (GEE), RSS (ESA Research Service & Support) CloudToolbox, and the PROBA-V Mission Exploitation Platform (MEP). Second, it combines the different sensor data-cubes in one multi-sensor classification approach using newly developed spatio-temporal probability classifiers within the big data platform environments. Analysis of the spatio-temporal differences in derived snow cover areas from the different sensors reveals the importance of understanding the spatial and temporal scales at which variations occur. Moreover, it shows the importance of i) temporal resolution when monitoring highly dynamical properties such as snow cover and of ii) differences in satellite viewing angles over complex mountain areas. Finally, it highlights the potential and drawbacks of big data platforms for combining multi-source satellite data for monitoring dynamical processes such as snow cover.

  4. Investigation of snow cover dust pollution by contact and satellite observations

    Science.gov (United States)

    Raputa, Vladimir F.; Yaroslavtseva, Tatyana V.

    2015-11-01

    The problems of reconstructing the snow cover pollution fields from dusting, point, linear and area sources according to ground and satellite observations are considered. Using reconstruction models, the methods of the combined analysis of the characteristic images of snow cover pollution haloes in the vicinity of sources of dust and contact data observations have been developed. On the basis of the numerical data analysis of ground monitoring and satellite imagery, the stable quantitative regularities between the fields of dust fallouts and the intensity of a change of tones of gray in the radial directions relative to the main sources are identified.

  5. Describing macro-scale structure of the snow cover by a dynamic-stochastic model

    Directory of Open Access Journals (Sweden)

    A. N. Gelfan

    2015-01-01

    Full Text Available Possibilities to investigate the spatial structure of snow cover by means of dynamic-stochastic model are discussed in this article. Basin of the Cheboksary reservoir (area of 376 500 sq.km was used as an example. Results of numerical experiments show that our dynamic-stochastic model of the snow cover formation reproduces a snow field structure with adequate accuracy. The fractal dimensions of the modeled fields are in good correspondence with respective dimensions of fields obtained from data of the in situ observations.

  6. The role of surface energy fluxes in pan-Arctic snow cover changes

    International Nuclear Information System (INIS)

    Shi Xiaogang; Lettenmaier, Dennis P; Groisman, Pavel Ya; Dery, Stephen J

    2011-01-01

    We analyze snow cover extent (SCE) trends in the National Oceanic and Atmospheric Administration's (NOAA) northern hemisphere weekly satellite SCE data using the Mann-Kendall trend test and find that North American and Eurasian snow cover in the pan-Arctic have declined significantly in spring and summer over the period of satellite record beginning in the early 1970s. These trends are reproduced, both in trend direction and statistical significance, in reconstructions using the variable infiltration capacity (VIC) hydrological model. We find that spring and summer surface radiative and turbulent fluxes generated in VIC have strong correlations with satellite observations of SCE. We identify the role of surface energy fluxes and determine which is most responsible for the observed spring and summer SCE recession. We find that positive trends in surface net radiation (SNR) accompany most of the SCE trends, whereas modeled latent heat (LH) and sensible heat (SH) trends associated with warming on SCE mostly cancel each other, except for North America in spring, and to a lesser extent for Eurasia in summer. In spring over North America and summer in Eurasia, the SH contribution to the observed snow cover trends is substantial. The results indicate that ΔSNR is the primary energy source and ΔSH plays a secondary role in changes of SCE. Compared with ΔSNR and ΔSH, ΔLH has a minor influence on pan-Arctic snow cover changes.

  7. Estimation of the spatiotemporal dynamics of snow covered area by using cellular automata models

    Science.gov (United States)

    Pardo-Igúzquiza, Eulogio; Collados-Lara, Antonio-Juan; Pulido-Velazquez, David

    2017-07-01

    Given the need to consider the cryosphere in water resources management for mountainous regions, the purpose of this paper is to model the daily spatially distributed dynamics of snow covered area (SCA) by using calibrated cellular automata models. For the operational use of the calibrated model, the only data requirements are the altitude of each cell of the spatial discretization of the area of interest and precipitation and temperature indexes for the area of interest. For the calibration step, experimental snow covered area data are needed. Potential uses of the model are to estimate the snow covered area when satellite data are absent, or when they provide a temporal resolution different from the operational resolution, or when the satellite images are useless because they are covered by clouds or because there has been a sensor failure. Another interesting application is the simulation of SCA dynamics for the snow covered area under future climatic scenarios. The model is applied to the Sierra Nevada mountain range, in southern Spain, which is home to significant biodiversity, contains important water resources in its snowpack, and contains the most meridional ski resort in Europe.

  8. Modeling the influence of snow cover temperature and water content on wet-snow avalanche runout

    Science.gov (United States)

    Valero, Cesar Vera; Wever, Nander; Christen, Marc; Bartelt, Perry

    2018-03-01

    Snow avalanche motion is strongly dependent on the temperature and water content of the snow cover. In this paper we use a snow cover model, driven by measured meteorological data, to set the initial and boundary conditions for wet-snow avalanche calculations. The snow cover model provides estimates of snow height, density, temperature and liquid water content. This information is used to prescribe fracture heights and erosion heights for an avalanche dynamics model. We compare simulated runout distances with observed avalanche deposition fields using a contingency table analysis. Our analysis of the simulations reveals a large variability in predicted runout for tracks with flat terraces and gradual slope transitions to the runout zone. Reliable estimates of avalanche mass (height and density) in the release and erosion zones are identified to be more important than an exact specification of temperature and water content. For wet-snow avalanches, this implies that the layers where meltwater accumulates in the release zone must be identified accurately as this defines the height of the fracture slab and therefore the release mass. Advanced thermomechanical models appear to be better suited to simulate wet-snow avalanche inundation areas than existing guideline procedures if and only if accurate snow cover information is available.

  9. Surface energy balance of seasonal snow cover for snow-melt ...

    Indian Academy of Sciences (India)

    This study describes time series analysis of snow-melt, radiation data and energy balance for a seasonal snow cover at Dhundi field station of SASE, which lies in Pir Panjal range of the. N–W Himalaya, for a winter season from 13 January to 12 April 2005. The analysis shows that mean snow surface temperature remains ...

  10. Precipitation and snow cover in the Himalaya: from reanalysis to regional climate simulations

    Directory of Open Access Journals (Sweden)

    M. Ménégoz

    2013-10-01

    Full Text Available We applied a Regional Climate Model (RCM to simulate precipitation and snow cover over the Himalaya, between March 2000 and December 2002. Due to its higher resolution, our model simulates a more realistic spatial variability of wind and precipitation than those of the reanalysis of the European Centre of Medium range Weather Forecast (ECMWF used as lateral boundaries. In this region, we found very large discrepancies between the estimations of precipitation provided by reanalysis, rain gauges networks, satellite observations, and our RCM simulation. Our model clearly underestimates precipitation at the foothills of the Himalaya and in its eastern part. However, our simulation provides a first estimation of liquid and solid precipitation in high altitude areas, where satellite and rain gauge networks are not very reliable. During the two years of simulation, our model resembles the snow cover extent and duration quite accurately in these areas. Both snow accumulation and snow cover duration differ widely along the Himalaya: snowfall can occur during the whole year in western Himalaya, due to both summer monsoon and mid-latitude low pressure systems bringing moisture into this region. In Central Himalaya and on the Tibetan Plateau, a much more marked dry season occurs from October to March. Snow cover does not have a pronounced seasonal cycle in these regions, since it depends both on the quite variable duration of the monsoon and on the rare but possible occurrence of snowfall during the extra-monsoon period.

  11. Validation of the operational MSG-SEVIRI snow cover product over Austria

    Science.gov (United States)

    Surer, S.; Parajka, J.; Akyurek, Z.

    2014-02-01

    The objective of this study is to evaluate the mapping accuracy of the MSG-SEVIRI operational snow cover product over Austria. The SEVIRI instrument is aboard the geostationary Meteosat Second Generation (MSG) satellite. The snow cover product provides 32 images per day, with a relatively low spatial resolution of 5 km over Austria. The mapping accuracy is examined at 178 stations with daily snow depth observations and compared with the daily MODIS-combined (Terra + Aqua) snow cover product for the period April 2008-June 2012. The results show that the 15 min temporal sampling allows a significant reduction of clouds in the snow cover product. The mean annual cloud coverage is less than 30% in Austria, as compared to 52% for the combined MODIS product. The mapping accuracy for cloud-free days is 89% as compared to 94% for MODIS. The largest mapping errors are found in regions with large topographical variability. The errors are noticeably larger at stations with elevations that differ greatly from those of the mean MSG-SEVIRI pixel elevations. The median of mapping accuracy for stations with absolute elevation difference less than 50 m and more than 500 m is 98.9 and 78.2%, respectively. A comparison between the MSG-SEVIRI and MODIS products indicates an 83% overall agreement. The largest disagreements are found in Alpine valleys and flatland areas in the spring and winter months, respectively.

  12. River flow regime and snow cover of the Pamir Alay (Central Asia) in a changing climate

    NARCIS (Netherlands)

    Chevallier, P.; Pouyaud, B.; Mojaisky, M.; Bolgov, M.; Olsson, O.; Bauer, M.; Froebrich, J.

    2014-01-01

    The Vakhsh and Pyandj rivers, main tributaries of the Amu Darya River in the mountainous region of the Pamir Alay, play an important role in the water resources of the Aral Sea basin (Central Asia). In this region, the glaciers and snow cover significantly influence the water cycle and flow regime,

  13. Snow cover variability in a forest ecotone of the Oregon Cascades via MODIS Terra products

    Science.gov (United States)

    Tihomir Sabinov Kostadinov; Todd R. Lookingbill

    2015-01-01

    Snowcover pattern and persistence have important implications for planetary energy balance, climate sensitivity to forcings, and vegetation structure, function, and composition. Variability in snow cover within mountainous regions of the Pacific Northwest, USA is attributable to a combination of anthropogenic climate change and climate oscillations. However,...

  14. Snow Cover and Precipitation Impacts on Dry Season Streamflow in the Lower Mekong Basin

    Science.gov (United States)

    Cook, Benjamin I.; Bell, A. R.; Anchukaitis, K. J.; Buckley, B. M.

    2012-01-01

    Climate change impacts on dry season streamflow in the Mekong River are relatively understudied, despite the fact that water availability during this time is critically important for agricultural and ecological systems. Analyses of two gauging stations (Vientiane and Kratie) in the Lower Mekong Basin (LMB) show significant positive correlations between dry season (March through May, MAM) discharge and upper basin snow cover and local precipitation. Using snow cover, precipitation, and upstream discharge as predictors, we develop skillful regression models for MAM streamflow at Vientiane and Kratie, and force these models with output from a suite of general circulation model (GCM) experiments for the twentieth and twenty-first centuries. The GCM simulations predict divergent trends in snow cover (decreasing) and precipitation (increasing) over the twenty-first century, driving overall negligible long-term trends in dry season streamflow. Our study demonstrates how future changes in dry season streamflow in the LMB will depend on changes in snow cover and precipitation, factors that will need to be considered when assessing the full basin response to other climatic and non-climatic drivers.

  15. On a snow cover composition in the vicinity of the Verkhnekamsky Salt Deposit

    Directory of Open Access Journals (Sweden)

    S. M. Blinov

    2015-01-01

    Full Text Available The snow cover chemical composition was investigated on the territory of the Verkhnekamskiy potash-magnesium salt deposit in the zone of influence of atmospheric emissions of Berezniki Potash Mining Complex (Perm Region. The object of researches was the snow in this area. Features of specific pollutants contained in the emissions of these mine groups and their relationship with the air intake and following atmospheric deposition were examined. With regard for specific character of pollutants in the emissions, studies of melt water included determination of the following chemical components – SO42-, Cl-, NO3-, NO2-, НCO3-, Ca2+, Mg2+, Na+, K+, of the pH value as well as suspended solid substances, and total mineralization. An analysis of snow composition was performed on two sites from which one was the surrounding background territory, while another area was the urban territory of city Berezniki, i.e. area of operating mine group. To assess the results the indicator of specific stock macro component was used. Increased specific stock relative to the background snowpack is clearly indicative of components directly related to the extraction and processing of salts Cl-, Na+, K+. The revealed anomalies have a local character and, as a rule, do not extend beyond boundaries of sanitary protection zones of the enterprises. Maps of distribution of values of the specific reserves for the analyzed list of components in the melt water were constructed. Our results obtained for the Verkhnekamskiy Deposit area were compared with similar published data on the territories of cities in the zone influenced by motor roads, reserves, and coastal zones of the Russian Arctic seas.

  16. Space-time analysis of snow cover change in the Romanian Carpathians (2001-2016)

    Science.gov (United States)

    Micu, Dana; Cosmin Sandric, Ionut

    2017-04-01

    Snow cover is recognized as an essential climate variable, highly sensitive to the ongoing climate warming, which plays an important role in regulating mountain ecosystems. Evidence from the existing weather stations located above 800 m over the last 50 years points out that the climate of the Romanian Carpathians is visibly changing, showing an ongoing and consistent warming process. Quantifying and attributing the changes in snow cover on various spatial and temporal scales have a great environmental and socio-economic importance for this mountain region. The study is revealing the inter-seasonal changes in the timing and distribution of snow cover across the Romanian Carpathians, by combining gridded snow data (CARPATCLIM dataset, 1961-2010) and remote sensing data (2001-2016) in specific space-time assessment at regional scale. The geostatistical approach applied in this study, based on a GIS hotspot analysis, takes advantage of all the dimensions in the datasets, in order to understand the space-time trends in this climate variable at monthly time-scale. The MODIS AQUA and TERRA images available from 2001 to 2016 have been processed using ArcGIS for Desktop and Python programming language. All the images were masked out with the Carpathians boundary. Only the pixels with snow have been retained for analysis. The regional trends in snow cover distribution and timing have been analysed using Space-Time cube with ArcGIS for Desktop, according with Esri documentation using the Mann-Kendall trend test on every location with data as an independent bin time-series test. The study aimed also to assess the location of emerging hotspots of snow cover change in Carpathians. These hotspots have been calculated using Getis-Ord Gi* statistic for each bin using Hot Spot Analysis implemented in ArcGIS for Desktop. On regional scale, snow cover appear highly sensitive to the decreasing trends in air temperatures and land surface temperatures, combined with the decrease in

  17. Past and future of the Austrian snow cover - results from the CC-Snow project

    Science.gov (United States)

    Strasser, Ulrich; Marke, Thomas; Hanzer, Florian; Ragg, Hansjörg; Kleindienst, Hannes; Wilcke, Renate; Gobiet, Andreas

    2013-04-01

    This study has the goal to simulate the evolution of the Austrian snow cover from 1971 to 2050 by means of a coupled modelling scheme, and to estimate the effect of climate change on the evolution of the natural snow cover. The model outcomes are interepreted with focus on both the future natural snow conditions, and the effects on winter skiing tourism. Therefore the regional temperature-index snow model SNOWREG is applied, providing snow maps with a spatial resolution of 250 m. The model is trained by means of assimilating local measurements and observed natural snow cover patterns. Meteorological forcing consists of the output of four realizations of the ENSEMBLES project for the A1B emission scenario. The meteorological variables are downscaled and error corrected with a quantile based empirical-statistical method on a daily time basis. The control simulation is 1971-2000, and the scenario simulation 2021-2050. Spatial interpolation is performed on the basis of parameter-elevation relations. We compare the four different global/regional climate model combinations and their effect on the snow modelling, and we explain the patterns of the resulting snow cover by means of regional climatological characteristics. The provinces Tirol and Styria serve as test regions, being typical examples for the two climatic subregions of Austria. To support the interpretation of the simulation results we apply indicators which enable to define meaningful measures for the comparison of the different periods and regions. Results show that the mean duration of the snow cover will decrease by 15 to 30 days per winter season, mostly in elevations between 2000 and 2500 m. Above 3000 m the higher winter precipitation can compensate this effect, and mean snow cover duration may even slightly increase. We also investigate the local scale by application of the physically based mountain snow model AMUNDSEN. This model is capable of producing 50 m resolution output maps for indicators

  18. Changing Snow Cover and Stream Discharge in the Western United States - Wind River Range, Wyoming

    Science.gov (United States)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Barton, Jonathan S.; Riggs, George A.

    2011-01-01

    Earlier onset of springtime weather has been documented in the western United States over at least the last 50 years. Because the majority (>70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack has important implications for the management of water resources. We studied ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover products, 40 years of stream discharge and meteorological station data and 30 years of snow-water equivalent (SWE) SNOw Telemetry (SNOTEL) data in the Wind River Range (WRR), Wyoming. Results show increasing air temperatures for.the 40-year study period. Discharge from streams in WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades. Changes in streamflow may be related to increasing air temperatures which are probably contributing to a reduction in snow cover, although no trend of either increasingly lower streamflow or earlier snowmelt was observed within the decade of the 2000s. And SWE on 1 April does not show an expected downward trend from 1980 to 2009. The extent of snow cover derived from the lowest-elevation zone of the WRR study area is strongly correlated (r=0.91) with stream discharge on 1 May during the decade of the 2000s. The strong relationship between snow cover and streamflow indicates that MODIS snow-cover maps can be used to improve management of water resources in the drought-prone western U.S.

  19. Automated mapping of persistent ice and snow cover across the western U.S. with Landsat

    Science.gov (United States)

    Selkowitz, David J.; Forster, Richard R.

    2016-01-01

    We implemented an automated approach for mapping persistent ice and snow cover (PISC) across the conterminous western U.S. using all available Landsat TM and ETM+ scenes acquired during the late summer/early fall period between 2010 and 2014. Two separate validation approaches indicate this dataset provides a more accurate representation of glacial ice and perennial snow cover for the region than either the U.S. glacier database derived from US Geological Survey (USGS) Digital Raster Graphics (DRG) maps (based on aerial photography primarily from the 1960s–1980s) or the National Land Cover Database 2011 perennial ice and snow cover class. Our 2010–2014 Landsat-derived dataset indicates 28% less glacier and perennial snow cover than the USGS DRG dataset. There are larger differences between the datasets in some regions, such as the Rocky Mountains of Northwest Wyoming and Southwest Montana, where the Landsat dataset indicates 54% less PISC area. Analysis of Landsat scenes from 1987–1988 and 2008–2010 for three regions using a more conventional, semi-automated approach indicates substantial decreases in glaciers and perennial snow cover that correlate with differences between PISC mapped by the USGS DRG dataset and the automated Landsat-derived dataset. This suggests that most of the differences in PISC between the USGS DRG and the Landsat-derived dataset can be attributed to decreases in PISC, as opposed to differences between mapping techniques. While the dataset produced by the automated Landsat mapping approach is not designed to serve as a conventional glacier inventory that provides glacier outlines and attribute information, it allows for an updated estimate of PISC for the conterminous U.S. as well as for smaller regions. Additionally, the new dataset highlights areas where decreases in PISC have been most significant over the past 25–50 years.

  20. An analysis of snow cover changes in the Himalayan region using MODIS snow products and in-situ temperature data

    NARCIS (Netherlands)

    Maskey, S.; Uhlenbrook, S.; Ojha, S.

    2011-01-01

    Amidst growing concerns over the melting of the Himalayas’ snow and glaciers, we strive to answer some of the questions related to snow cover changes in the Himalayan region covering Nepal and its vicinity using Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover products from 2000 to

  1. MODIS/Terra Near Real Time (NRT) Snow Cover 5-Min L2 Swath 500m, Version 6

    Data.gov (United States)

    National Aeronautics and Space Administration — MODIS/Terra Near Real Time (NRT) Snow Cover 5-Min L2 Swath 500m (MOD10_L2) contains snow cover and quality assurance (QA) data, latitudes, and longitudes in HDF-EOS...

  2. Changing Arctic snow cover: A review of recent developments and assessment of future needs for observations, modelling, and impacts

    DEFF Research Database (Denmark)

    Bokhorst, Stef; Pedersen, Stine Højlund; Brucker, Ludovic

    2016-01-01

    Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover and snowpack conditions change through time pose challenges for measuring and prediction of snow. Plausible scenarios of how Arctic snow cover will respond to changing Arctic climate are important for i...

  3. Changing Arctic snow cover: A review of recent developments and assessment of future needs for observations, modelling, and impacts

    NARCIS (Netherlands)

    Bokhorst, Stef; Pedersen, Stine Højlund; Brucker, Ludovic; Anisimov, Oleg; Bjerke, Jarle W.; Brown, Ross D.; Ehrich, Dorothee; Essery, Richard L. H.; Heilig, Achim; Ingvander, Susanne; Johansson, Cecilia; Johansson, Margareta; Jónsdóttir, Ingibjörg Svala; Inga, Niila; Luojus, Kari; Macelloni, Giovanni; Mariash, Heather; Mclennan, Donald; Rosqvist, Gunhild Ninis; Sato, Atsushi; Savela, Hannele; Schneebeli, Martin; Sokolov, Aleksandr; Sokratov, Sergey A.; Terzago, Silvia; Vikhamar-schuler, Dagrun; Williamson, Scott; Qiu, Yubao; Callaghan, Terry V.

    2016-01-01

    Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover and snowpack conditions change through time pose challenges for measuring and prediction of snow. Plausible scenarios of how Arctic snow cover will respond to changing Arctic climate are important for

  4. Variability of snow line elevation, snow cover area and depletion in the main Slovak basins in winters 2001–2014

    Directory of Open Access Journals (Sweden)

    Krajčí Pavel

    2016-03-01

    Full Text Available Spatial and temporal variability of snow line (SL elevation, snow cover area (SCA and depletion (SCD in winters 2001–2014 is investigated in ten main Slovak river basins (the Western Carpathians. Daily satellite snow cover maps from MODIS Terra (MOD10A1, V005 and Aqua (MYD10A1, V005 with resolution 500 m are used.

  5. Construction, assembly and tests of the ATLAS electromagnetic barrel calorimeter

    CERN Document Server

    Aubert, B; Colas, Jacques; Delebecque, P; Di Ciaccio, L; El-Kacimi, M; Ghez, P; Girard, C; Gouanère, M; Goujdami, D; Jérémie, A; Jézéquel, S; Lafaye, R; Massol, N; Perrodo, P; Przysiezniak, H; Sauvage, G; Thion, J; Wingerter-Seez, I; Zitoun, R; Zolnierowski, Y; Alforque, R; Chen, H; Farrell, J; Gordon, H; Grandinetti, R; Hackenburg, R W; Hoffmann, A; Kierstead, J A; Köhler, J; Lanni, F; Lissauer, D; Ma, H; Makowiecki, D S; Müller, T; Norton, S; Radeka, V; Rahm, David Charles; Rehak, M; Rajagopalan, S; Rescia, S; Sexton, K; Sondericker, J; Stumer, I; Takai, H; Belymam, A; Benchekroun, D; Driouichi, C; Hoummada, A; Hakimi, M; Knee, Michael; Stroynowski, R; Wakeland, B; Datskov, V I; Drobin, V; Aleksa, Martin; Bremer, J; Carli, T; Chalifour, M; Chevalley, J L; Djama, F; Ema, L; Fabre, C; Fassnacht, P; Gianotti, F; Gonidec, A; Hansen, J B; Hervás, L; Hott, T; Lacaste, C; Marin, C P; Pailler, P; Pleskatch, A; Sauvagey, D; Vandoni, Giovanna; Vuillemin, V; Wilkens, H; Albrand, S; Belhorma, B; Collot, J; de Saintignon, P; Dzahini, D; Ferrari, A; Fulachier, J; Gallin-Martel, M L; Hostachy, J Y; Laborie, G; Ledroit-Guillon, F; Martin, P; Muraz, J F; Ohlsson-Malek, F; Saboumazrag, S; Viret, S; Othegraven, R; Zeitnitz, C; Banfi, D; Carminati, L; Cavalli, D; Citterio, M; Costa, G; Delmastro, M; Fanti, M; Mandelli, L; Mazzanti, M; Tartarelli, F; Augé, E; Baffioni, S; Bonis, J; Bonivento, W; Bourdarios, C; de La Taille, C; Fayard, L; Fournier, D; Guilhem, G; Imbert, P; Iconomidou-Fayard, L; Le Meur, G; Mencik, M; Noppe, J M; Parrour, G; Puzo, P; Rousseau, D; Schaffer, A C; Seguin-Moreau, N; Serin, L; Unal, G; Veillet, J J; Wicek, F; Zerwas, D; Astesan, F; Bertoli, W; Canton, B; Fleuret, F; Imbault, D; Lacour, D; Laforge, B; Schwemling, P; Abouelouafa, M; Ben-Mansour, A; Cherkaoui, R; El-Mouahhidi, Y; Ghazlane, H; Idrissi, A; Bazizi, K; England, D; Glebov, V; Haelen, T; Lobkowicz, F; Slattery, P F; Belorgey, J; Besson, N; Boonekamp, M; Durand, D; Ernwein, J; Mansoulié, B; Molinie, F; Meyer, J P; Perrin, P; Schwindling, J; Taguet, J P; Zaccone, Henri; Lund-Jensen, B; Rydström, S; Tayalati, Y; Botchev, B; Finocchiaro, G; Hoffman, J; McCarthy, R L; Rijssenbeek, M; Steffens, J; Zdrazil, M; Braun, H M

    2006-01-01

    The construction and assembly of the two half barrels of the ATLAS central electromagnetic calorimeter and their insertion into the barrel cryostat are described. The results of the qualification tests of the calorimeter before installation in the LHC ATLAS pit are given.

  6. Construction, assembly and tests of the ATLAS electromagnetic barrel calorimeter

    Science.gov (United States)

    Aubert, B.; Beaugiraud, B.; Colas, J.; Delebecque, P.; Di Ciaccio, L.; El Kacimi, M.; Ghez, P.; Girard, C.; Gouanère, M.; Goujdami, D.; Jeremie, A.; Jézéquel, S.; Lafaye, R.; Massol, N.; Perrodo, P.; Przysiezniak, H.; Sauvage, G.; Thion, J.; Wingerter-Seez, I.; Zitoun, R.; Zolnierowski, Y.; Alforque, R.; Chen, H.; Farrell, J.; Gordon, H.; Grandinetti, R.; Hackenburg, R.; Hoffmann, A.; Kierstead, J.; Koehler, J.; Lanni, F.; Lissauer, D.; Ma, H.; Makowiecki, D.; Muller, T.; Norton, S.; Radeka, V.; Rahm, D.; Rehak, M.; Rajagopalan, S.; Rescia, S.; Sexton, K.; Sondericker, J.; Stumer, I.; Takai, H.; Belymam, A.; Benchekroun, D.; Driouichi, C.; Hoummada, A.; Hakimi, M.; Knee, M.; Stroynowski, R.; Wakeland, B.; Datskov, V.; Drobin, V.; Aleksa, M.; Bremer, J.; Carli, T.; Chalifour, M.; Chevalley, J. L.; Djama, F.; Ema, L.; Fabre, C.; Fassnacht, P.; Gianotti, F.; Gonidec, A.; Hansen, J. B.; Hervas, L.; Hott, T.; Lacaste, C.; Marin, C. P.; Pailler, P.; Pleskatch, A.; Sauvage, D.; Vandoni, G.; Vuillemin, V.; Wilkens, H.; Albrand, S.; Belhorma, B.; Collot, J.; de Saintignon, P.; Dzahini, D.; Ferrari, A.; Fulachier, J.; Gallin-Martel, M. L.; Hostachy, J. Y.; Laborie, G.; Ledroit-Guillon, F.; Martin, P.; Muraz, J. F.; Ohlsson-Malek, F.; Saboumazrag, S.; Viret, S.; Othegraven, R.; Zeitnitz, C.; Banfi, D.; Carminati, L.; Cavalli, D.; Citterio, M.; Costa, G.; Delmastro, M.; Fanti, M.; Mandelli, L.; Mazzanti, M.; Tartarelli, F.; Augé, E.; Baffioni, S.; Bonis, J.; Bonivento, W.; Bourdarios, C.; De la Taille, C.; Fayard, L.; Fournier, D.; Guilhem, G.; Imbert, P.; Iconomidou-Fayard, L.; Le Meur, G.; Mencik, M.; Noppe, J.-M.; Parrour, G.; Puzo, P.; Rousseau, D.; Schaffer, A.-C.; Seguin-Moreau, N.; Serin, L.; Unal, G.; Veillet, J.-J.; Wicek, F.; Zerwas, D.; Astesan, F.; Bertoli, W.; Canton, B.; Fleuret, F.; Imbault, D.; Lacour, D.; Laforge, B.; Schwemling, Ph.; Abouelouafa, E. M.; Ben Mansour, A.; Cherkaoui, R.; El Mouahhidi, Y.; Ghazlane, H.; Idrissi, A.; Bazizi, K.; England, D.; Glebov, V.; Haelen, T.; Lobkowicz, F.; Slattery, P.; Belorgey, J.; Besson, N.; Boonekamp, M.; Durand, D.; Ernwein, J.; Mansoulié, B.; Molinié, F.; Meyer, J. P.; Perrin, P.; Schwindling, J.; Taguet, J. P.; Zaccone, H.; Lund-Jensen, B.; Rydström, S.; Tayalati, Y.; Botchev, B.; Finocchiaro, G.; Hoffman, J.; McCarthy, R. L.; Rijssenbeek, M.; Steffens, J.; Zdrazil, M.; Braun, H. M.

    2006-03-01

    The construction and assembly of the two half barrels of the ATLAS central electromagnetic calorimeter and their insertion into the barrel cryostat are described. The results of the qualification tests of the calorimeter before installation in the LHC ATLAS pit are given.

  7. The stepwise discriminant algorithm for snow cover mapping based on FY-3/MERSI data

    Science.gov (United States)

    Han, Tao; Wang, Dawei; Jiang, Youyan; Wang, Xiaowei

    2013-10-01

    Medium Resolution Spectral Imager (MERSI) on board China's new generation polar orbit meteorological satellite FY- 3A provides a new data source for snow monitoring in large area. As a case study, the typical snow cover of Qilian Mountains in northwest China was selected in this paper to develop the algorithm to map snow cover using FY- 3A/MERSI. By analyzing the spectral response characteristics of snow and other surface elements, as well as each channel image quality on FY-3A/MERSI, the widely used Normalized Difference Snow Index (NDSI) was defined to be computed from channel 2 and channel 7 for this satellite data. Basing on NDSI, a tree-structure prototype version of snow identification model was proposed, including five newly-built multi-spectral indexes to remove those pixels such as forest, cloud shadow, water, lake ice, sand (salty land), or cloud that are usually confused with snow step by step, especially, a snow/cloud discrimination index was proposed to eliminate cloud, apart from use of cloud mask product in advance. Furthermore, land cover land use (LULC) image has been adopted as auxiliary dataset to adjust the corresponding LULC NDSI threshold constraints for snow final determination and optimization. This model is composed as the core of FY-3A/MERSI snow cover mapping flowchart, to produce daily snow map at 250m spatial resolution, and statistics can be generated on the extent and persistence of snow cover in each pixel for time series maps. Preliminary validation activities of our snow identification model have been undertaken. Comparisons of the 104 FY- 3A/MERSI snow cover maps in 2010-2011 snow season with snow depth records from 16 meteorological stations in Qilian Mountains region, the sunny snow cover had an absolute accuracy of 92.8%. Results of the comparison with the snow cover identified from 6 Terra/MODIS scenes showed that they had consistent pixels about 85%. When the two satellite resultant snow cover maps compared with the 6

  8. Snow Cover, Snowmelt Timing and Stream Power in the Wind River Range, Wyoming

    Science.gov (United States)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Riggs, George A.

    2011-01-01

    Earlier onset of springtime weather, including earlier snowmelt, has been documented in the western United States over at least the last 50 years. Because the majority (is greater than 70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack (and shrinking glaciers) has important implications for the management of streamflow. The amount of water in a snowpack influences stream discharge which can also influence erosion and sediment transport by changing stream power, or the rate at which a stream can do work, such as move sediment and erode the stream bed. The focus of this work is the Wind River Range (WRR) in west-central Wyoming. Ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover, cloud-gap-filled (CGF) map products and 30 years of discharge and meteorological station data are studied. Streamflow data from streams in WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades, though no trend of either lower streamflow or earlier snowmelt was observed within the decade of the 2000s. Results show a statistically-significant trend at the 95% confidence level (or higher) of increasing weekly maximum air temperature (for three out of the five meteorological stations studied) in the decade of the 1970s, and also for the 40-year study period as a whole. The extent of snow-cover (percent of basin covered) derived from the lowest elevation zone (2500-3000 m) of the WRR, using MODIS CGF snow-cover maps, is strongly correlated with maximum monthly discharge on 30 April, where Spearman's Rank correlation, rs,=0.89 for the decade of the 2000s. We also investigated stream power for Bull Lake Creek above Bull Lake; and found a trend (significant at the 90% confidence level) toward reduced stream power from 1970 to 2009. Observed changes in streamflow and stream power may be related to increasing weekly maximum air temperature

  9. Assessment of Consistencies and Uncertainties between the NASA MODIS and VIIRS Snow-Cover Maps

    Science.gov (United States)

    Hall, D. K.; Riggs, G. A., Jr.; DiGirolamo, N. E.; Roman, M. O.

    2017-12-01

    Snow cover has great climatic and economic importance in part due to its high albedo and low thermal conductivity and large areal extent in the Northern Hemisphere winter, and its role as a freshwater source for about one-sixth of the world's population. The Rutgers University Global Snow Lab's 50-year climate-data record (CDR) of Northern Hemisphere snow cover is invaluable for climate studies, but, at 25-km resolution, the spatial resolution is too coarse to provide accurate snow information at the basin scale. Since 2000, global snow-cover maps have been produced from the MODerate-resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites at 500-m resolution, and from the Suomi-National Polar Program (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) since 2011 at 375-m resolution. Development of a moderate-resolution (375 - 500 m) earth system data record (ESDR) that utilizes both MODIS and VIIRS snow maps is underway. There is a 6-year overlap between the data records. In late 2017 the second in a series of VIIRS sensors will be launched on the Joint Polar Satellite System-1 (JPSS-1), with the JPSS-2 satellite scheduled for launch in 2021, providing the potential to extend NASA's snow-cover ESDR for decades into the future and to create a CDR. Therefore it is important to investigate the continuity between the MODIS and VIIRS NASA snow-cover data products and evaluate whether there are any inconsistencies and biases that would affect their value as CDR. Time series of daily normalized-difference snow index (NDSI) Terra and Aqua MODIS Collection 6 (C6) and NASA VIIRS Collection 1 (C1) snow-cover tile maps (MOD10A1 and VNP10A1) are studied for North America to identify NDSI differences and possible biases between the datasets. Developing a CDR using the MODIS and VIIRS records is challenging. Though the instruments and orbits are similar, differences in bands, viewing geometry, spatial resolution, and cloud- and snow-mapping algorithms

  10. Tree-Ring Widths and Snow Cover Depth in High Tauern

    Science.gov (United States)

    Falarz, Malgorzata

    2017-12-01

    The aim of the study is to examine the correlation of Norway spruce tree-ring widths and the snow cover depth in the High Tauern mountains. The average standardized tree-ring widths indices for Nowary spruce posted by Bednarz and Niedzwiedz (2006) were taken into account. Increment cores were collected from 39 Norway spruces growing in the High Tauern near the upper limit of the forest at altitude of 1700-1800 m, 3 km from the meteorological station at Sonnblick. Moreover, the maximum of snow cover depth in Sonnblick (3105 m a.s.l.) for each winter season in the period from 1938/39 to 1994/95 (57 winter seasons) was taken into account. The main results of the research are as follows: (1) tree-ring widths in a given year does not reveal statistically significant dependency on the maximum snow cover depth observed in the winter season, which ended this year; (2) however, the tested relationship is statistically significant in the case of correlating of the tree-ring widths in a given year with a maximum snow cover depth in a season of previous year. The correlation coefficient for the entire period of the study is not very high (r=0.27) but shows a statistical significance at the 0.05 level; (3) the described relationship is not stable over time. 30-year moving correlations showed no significant dependencies till 1942 and after 1982 (probably due to the so-called divergence phenomenon). However, during the period of 1943-1981 the values of correlation coefficient for moving 30-year periods are statistically significant and range from 0.37 to 0.45; (4) the correlation coefficient between real and calibrated (on the base of the regression equation) values of maximum snow cover depth is statistically significant for calibration period and not significant for verification one; (5) due to a quite short period of statistically significant correlations and not very strict dependencies, the reconstruction of snow cover on Sonnblick for the period before regular measurements

  11. Snow cover dynamics and water balance in complex high alpine terrain

    Science.gov (United States)

    Warscher, Michael; Kraller, Gabriele; Kunstmann, Harald; Strasser, Ulrich; Franz, Helmut

    2010-05-01

    The water balance in high alpine regions in its full complexity is so far insufficiently understood. High altitudinal gradients, a strong variability of meteorological variables in time and space, complex hydrogeological situations, unquantified lateral snow transport processes and heterogenous snow cover dynamics result in high uncertainties in the quantification of the water balance. To achieve interpretable modeling results we have complemented the deterministic hydrological model WaSiM-ETH with the high-alpine specific snow model AMUNDSEN. The integration of the new snow module was done to improve the modeling of water fluxes influenced by the dynamics of the snow cover, which greatly affect the water cycle in high alpine regions. To enhance the reproduction of snow deposition and ablation processes, the new approach calculates the energy balance of the snow cover considering the terrain-dependent radiation fluxes, the interaction between tree canopy and snow cover as well as lateral snow transport processes. The test site for our study is the Berchtesgaden National Park which is characterized by an extreme topography with mountain ranges covering an altitude from 607 to 2713 m.a.s.l. About one quarter of the investigated catchment area, which comprises 433 km² in total, is terrain steeper than 35°. Due to water soluble limestone being predominant in the region, a high number of subsurface water pathways (karst) exist. The results of several tracer experiments and extensive data of spring observations provide additional information to meet the challenge of modeling the unknown subsurface pathways and the complex groundwater system of the region. The validation of the new snow module is based on a dense network of meteorological stations which have been adapted to measure physical properties of the snow cover like snow water equivalent and liquid water content. We will present first results which show that the integration of the new snow module generates a

  12. Design, Development and Testing of Web Services for Multi-Sensor Snow Cover Mapping

    Science.gov (United States)

    Kadlec, Jiri

    This dissertation presents the design, development and validation of new data integration methods for mapping the extent of snow cover based on open access ground station measurements, remote sensing images, volunteer observer snow reports, and cross country ski track recordings from location-enabled mobile devices. The first step of the data integration procedure includes data discovery, data retrieval, and data quality control of snow observations at ground stations. The WaterML R package developed in this work enables hydrologists to retrieve and analyze data from multiple organizations that are listed in the Consortium of Universities for the Advancement of Hydrologic Sciences Inc (CUAHSI) Water Data Center catalog directly within the R statistical software environment. Using the WaterML R package is demonstrated by running an energy balance snowpack model in R with data inputs from CUAHSI, and by automating uploads of real time sensor observations to CUAHSI HydroServer. The second step of the procedure requires efficient access to multi-temporal remote sensing snow images. The Snow Inspector web application developed in this research enables the users to retrieve a time series of fractional snow cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) for any point on Earth. The time series retrieval method is based on automated data extraction from tile images provided by a Web Map Tile Service (WMTS). The average required time for retrieving 100 days of data using this technique is 5.4 seconds, which is significantly faster than other methods that require the download of large satellite image files. The presented data extraction technique and space-time visualization user interface can be used as a model for working with other multi-temporal hydrologic or climate data WMTS services. The third, final step of the data integration procedure is generating continuous daily snow cover maps. A custom inverse distance weighting method has been developed

  13. Microwave retrievals of terrestrial precipitation over snow-covered surfaces: A lesson from the GPM satellite

    Science.gov (United States)

    Ebtehaj, A. M.; Kummerow, C. D.

    2017-06-01

    Satellites are playing an ever-increasing role in estimating precipitation over remote areas. Improving satellite retrievals of precipitation requires increased understanding of its passive microwave signatures over different land surfaces. Snow-covered surfaces are notoriously difficult to interpret because they exhibit both emission from the land below and scattering from the ice crystals. Using data from the Global Precipitation Measurement (GPM) satellite, we demonstrate that microwave brightness temperatures of rain and snowfall transition from a scattering to an emission regime from summer to winter, due to expansion of less emissive snow cover. Evidence suggests that the combination of low- (10-19 GHz) and high-frequency (89-166 GHz) channels provides the maximum amount of information for snowfall detection. The results demonstrate that, using a multifrequency matching method, the probability of snowfall detection can even be higher than rainfall—chiefly because of the information content of the low-frequency channels that respond to the (near) surface temperature.

  14. Cadmium content in snow cover on the Pavlodar territory of the Republic of Kazakhstan

    International Nuclear Information System (INIS)

    Azhaev, G.S.; Panin, M.S.

    2008-01-01

    In the present report results of Cadmium concentration determination in aqueous and solid phases of snow cover on the Pavlodar territory of the Republic of Kazakhstan are presented. Cadmium content was tested with atomic absorption method on spectrophotometer of Perkin Elmer Company, model 403 with thermal-electric analyser HGA-74 and deuterium background corrector. Average concentration of cadmium in solid phase of snow goes up to 3.2 mg/kg, in aqueous phase - 2.1 mkg/dm 3 . That is respectively 22.9 and 13.1 times higher than background level. The cadmium concentration level in aqueous and solid phases of snow cover on the different areas of Pavlodar city is unequal. That indicates the specific character of different manufacturing enterprises, their anthropogenic impact on the environment and purification efficiency of emissions

  15. [Monitoring of the chemical composition of snow cover pollution in the Moscow region].

    Science.gov (United States)

    Ermakov, A A; Karpova, E A; Malysheva, A G; Mikhaylova, R I; Ryzhova, I N

    2014-01-01

    Monitoring of snow cover pollution as an indicator of ambient air pollution in 20 districts in the Moscow region during 2009-2013 was performed. The identification with a quantitative assessment of a wide array of organic compounds and the control of the main physical and chemical and inorganic indices of snow water pollution were carried out. More than 60 organic substances for most of which there are no the hygienic standards were established. The assessment of pollution levels of basic inorganic indices was given by means of the comparing them with the average values in the snow cover in the European territory of Russia and natural content in areas not been exposed to human impact.

  16. Impacts of changing climate and snow cover on the flow regime of Jhelum River, Western Himalayas

    KAUST Repository

    Azmat, Muhammad

    2016-11-17

    This study examines the change in climate variables and snow cover dynamics and their impact on the hydrological regime of the Jhelum River basin in Western Himalayas. This study utilized daily streamflow records from Mangla dam, spanning a time period of 19 years (1995–2013), along with precipitation and temperature data over 52 years (1961–2013) from 12 different climate stations in the catchment. Additionally, moderate-resolution imaging spectroradiometer (MODIS) remote sensing product MOD10A2 was utilized to analyze the change in snow cover dynamics during 2000–2013. The Pearson and Kendall rank correlation tests were used to scrutinize snow cover trends and correlation between temperature, precipitation, snow cover area (SCA) and streamflows records. Basin-wide trend analysis showed a slightly increasing tendency in temperature (τ = 0.098) and precipitation (τ = 0.094), during the years 1961–2013. The changes in streamflow indicated a positive (r > 0.12) relationship with respect to temperature but variable trends (r = −0.45–0.41) with respect to precipitation during both the winter and monsoon seasons. This indicates that temperature has a significant impact on the hydrological regime of the basin. MODIS data-based investigations suggested an expansion in SCA during 2000–2013. The changes in SCA of high-altitude zones (>2000 m a.s.l.) depicted a stronger positive correlation with climate variables and streamflow compared with those obtained for low-altitude regions (<2000 m a.s.l.). Overall, these results signify that high-altitude areas contribute to the streamflow largely in the form of snow- and glacier-melt during the early summer season. The streamflow is then further augmented by monsoon rainfall in the low-elevation regions during late summer.

  17. Black carbon and mineral dust in snow cover on the Tibetan Plateau

    Science.gov (United States)

    Zhang, Yulan; Kang, Shichang; Sprenger, Michael; Cong, Zhiyuan; Gao, Tanguang; Li, Chaoliu; Tao, Shu; Li, Xiaofei; Zhong, Xinyue; Xu, Min; Meng, Wenjun; Neupane, Bigyan; Qin, Xiang; Sillanpää, Mika

    2018-02-01

    Snow cover plays a key role for sustaining ecology and society in mountainous regions. Light-absorbing particulates (including black carbon, organic carbon, and mineral dust) deposited on snow can reduce surface albedo and contribute to the near-worldwide melting of snow and ice. This study focused on understanding the role of black carbon and other water-insoluble light-absorbing particulates in the snow cover of the Tibetan Plateau (TP). The results found that the black carbon, organic carbon, and dust concentrations in snow cover generally ranged from 202 to 17 468 ng g-1, 491 to 13 880 ng g-1, and 22 to 846 µg g-1, respectively, with higher concentrations in the central to northern areas of the TP. Back trajectory analysis suggested that the northern TP was influenced mainly by air masses from Central Asia with some Eurasian influence, and air masses in the central and Himalayan region originated mainly from Central and South Asia. The relative biomass-burning-sourced black carbon contributions decreased from ˜ 50 % in the southern TP to ˜ 30 % in the northern TP. The relative contribution of black carbon and dust to snow albedo reduction reached approximately 37 and 15 %, respectively. The effect of black carbon and dust reduced the snow cover duration by 3.1 ± 0.1 to 4.4 ± 0.2 days. Meanwhile, the black carbon and dust had important implications for snowmelt water loss over the TP. The findings indicate that the impacts of black carbon and mineral dust need to be properly accounted for in future regional climate projections, particularly in the high-altitude cryosphere.

  18. Changes of snow cover, temperature, and radiative heat balance over the Northern Hemisphere

    Science.gov (United States)

    Groisman, Pavel YA.; Karl, Thomas R.; Knight, Richard W.; Stenchikov, Georgiy L.

    1994-01-01

    Contemporary large-scale changes in satellite-derived snow cover were examined over the Northern Hemisphere extratropical land (NEL) areas. These areas encompass 55% of the land in the Northern Hemisphere. Snow cover (S) transient regions, the 'centers of action' relative to interannual variations of snow cover, were identified for the years 1972-1992. During these years a global retreat in snow cover extent (SE) occurred in the second half of the hydrologic year (April-September). Mean annual SE has decreased by 10% (2.3 x 10(exp 6) sq km). Negative trends account for one-third to one-half of the interannual continental variance of SE. The historical influence of S on the planetary albedo and outgoing longwave radiation (OLR) is investigated. The mean annual response of the S feedback on the radiative balance (RB) is negative and suggests a largescale heat redistribution. During autumn and early winter (up to January), however, the feedback of S on the planetary RB may be positive. Only by February does the cooling effect of S (due to albedo increase) dominate the planetary warming due to reduced OLR over the S. Despite a wintertime maximum in SE, the feedback in spring has the greatest magnitude. The global retreat of spring SE should lead to a positive feedback on temperature. Based on observed records of S, changes in RB are calculated that parallel an observed increase of spring temperature during the past 20 years. The results provide a partial explanation of the significant increase in spring surface air temperature observed over the land areas of the Northern Hemisphere during the past century. The mean SE in years with an El Nino and La Nina were also evaluated. El Nino events are generally accompanied by increased SE over the NEL during the first half of the hydrological year. In the second half of the hydrologic year (spring and summer), the El Nino events are accompanied by a global retreat of SE.

  19. Snow cover as a source of technogenic pollution of surface water during the snow melting period

    OpenAIRE

    Labuzova Olga; Noskova Tatyana; Lysenko Maria; Ovcharenko Elena; Papina Tatyana

    2016-01-01

    The study of pollutants in melt water of snow cover and snow disposal sites in the city of Barnaul showed that during the snow melting period the surface water is not subjected to significant technogenic impact according to a number of studied indices. The oils content is an exception: it can exceed MAC more than 20 times in river- water due to the melting of city disposal sites. Environmental damage due to an oils input into water resources during the snow melting period...

  20. Combining MOD10A1 and MYD10A1 Images For Snow Cover Area Monitoring

    Science.gov (United States)

    Tekeli, A. E.

    2008-12-01

    MOD10A1 and MYD10A1 daily snow cover maps at 500 m resolution are available from MODIS sensors on Terra and Aqua satellites. Aqua obtains the image of same region approximately three hours after Terra over Turkey region. MODIS is an optic sensor and cloud cover degrades the usability of derived snow cover maps. Moreover, spectral similarity between clouds and snow complicates their separability in visible imagery. Fortunately, dynamic behavior of clouds enables their discrimination from snow stationary on the surface. Combined use of MOD10A1 and MYD10A1 images mostly reduces the cloud cover present in one image alone and provides better representation of surface snow cover. Comparison of merged images with in situ data indicated higher hit ratios. The individual comparison of MOD10A1 and MYD10A1 images with ground data each yielded 31% hit ratio whereas, the merged images provided 38%. One-day shifts in comparisons increased hit ratios to 52 % and 46% whereas and two-day shifts gave 77 % and 79 % for MOD10A1 and MYD10A1 respectively. Merged maps yielded 54% and 83% for one and two day shifts. The improvement provided by the merging technique is found to be 7% for the present day, 7 % for one- day and 5% for two-day shifts for the whole season. Monthly decomposition resulted 25% improvement as the maximum. The snow cover product obtained by merging Terra and Aqua satellites provided higher hit ratios, as expected.

  1. Dust pollution of snow cover in the industrial areas of Tomsk city (Western Siberia, Russia)

    Science.gov (United States)

    Talovskaya, A. V.; Filimonenko, E. A.; Osipova, N. A.; Yazikov, E. G.; Nadeina, L. V.

    2016-03-01

    This article describes the results of long-term monitoring (2007-2014) of snow cover pollution in the territory of Tomsk city. Snow samples were collected in the territory of Tomsk. Determination of dust load level was carried out by comparing with the background and reference values. It has been determined that the north-east and central parts of Tomsk are the most contaminated areas, where brickworks, coal and gas-fired thermal power plant are located. The analysis of long-term dynamics showed a dust load decrease in the vicinity of coal and gas-fired thermal power plant due to upgrading of the existing dust collecting systems. During the monitoring period the high dust load in the vicinity of brickworks did not change. The lowest value of the dust load on snow cover was detected in the vicinity of the petrochemical plant and concrete product plants. The near and far zones of dust load on snow cover were determined with the reference to the location of the studied plants.

  2. Fractional Snow Cover Mapping by Artificial Neural Networks and Support Vector Machines

    Science.gov (United States)

    Çiftçi, B. B.; Kuter, S.; Akyürek, Z.; Weber, G.-W.

    2017-11-01

    Snow is an important land cover whose distribution over space and time plays a significant role in various environmental processes. Hence, snow cover mapping with high accuracy is necessary to have a real understanding for present and future climate, water cycle, and ecological changes. This study aims to investigate and compare the design and use of artificial neural networks (ANNs) and support vector machines (SVMs) algorithms for fractional snow cover (FSC) mapping from satellite data. ANN and SVM models with different model building settings are trained by using Moderate Resolution Imaging Spectroradiometer surface reflectance values of bands 1-7, normalized difference snow index and normalized difference vegetation index as predictor variables. Reference FSC maps are generated from higher spatial resolution Landsat ETM+ binary snow cover maps. Results on the independent test data set indicate that the developed ANN model with hyperbolic tangent transfer function in the output layer and the SVM model with radial basis function kernel produce high FSC mapping accuracies with the corresponding values of R = 0.93 and R = 0.92, respectively.

  3. Snow cover dynamics and hydrological regime of the Hunza River basin, Karakoram Range, Northern Pakistan

    Directory of Open Access Journals (Sweden)

    A. A. Tahir

    2011-07-01

    Full Text Available A major proportion of flow in the Indus River is contributed by its snow- and glacier-fed river catchments situated in the Himalaya, Karakoram and Hindukush ranges. It is therefore essential to understand the cryosphere dynamics in this area for water resource management. The MODIS MOD10A2 remote-sensing database of snow cover products from March 2000 to December 2009 was selected to analyse the snow cover changes in the Hunza River basin (the snow- and glacier-fed sub-catchment of the Indus River. A database of daily flows for the Hunza River at Dainyor Bridge over a period of 40 yr and climate data (precipitation and temperature for 10 yr from three meteorological stations within the catchment was made available to investigate the hydrological regime in the area. Analysis of remotely sensed cryosphere (snow and ice cover data during the last decade (2000–2009 suggest a rather slight expansion of cryosphere in the area in contrast to most of the regions in the world where glaciers are melting rapidly. This increase in snow cover may be the result of an increase in winter precipitation caused by westerly circulation. The impact of global warming is not effective because a large part of the basin area lies under high altitudes where the temperature remains negative throughout most of the year.

  4. Variability in snow cover phenology in China from 1952 to 2010

    Science.gov (United States)

    Ke, Chang-Qing; Li, Xiu-Cang; Xie, Hongjie; Ma, Dong-Hui; Liu, Xun; Kou, Cheng

    2016-02-01

    Daily snow observation data from 672 stations in China, particularly the 296 stations with over 10 mean snow cover days (SCDs) in a year during the period of 1952-2010, are used in this study. We first examine spatiotemporal variations and trends of SCDs, snow cover onset date (SCOD), and snow cover end date (SCED). We then investigate the relationships of SCDs with number of days with temperature below 0 °C (TBZD), mean air temperature (MAT), and Arctic Oscillation (AO) index. The results indicate that years with a positive anomaly of SCDs for the entire country include 1955, 1957, 1964, and 2010, and years with a negative anomaly of SCDs include 1953, 1965, 1999, 2002, and 2009. The reduced TBZD and increased MAT are the main reasons for the overall late SCOD and early SCED since 1952. This explains why only 12 % of the stations show significant shortening of SCDs, while 75 % of the stations show no significant change in the SCDs trends. Our analyses indicate that the distribution pattern and trends of SCDs in China are very complex and are not controlled by any single climate variable examined (i.e. TBZD, MAT, or AO), but a combination of multiple variables. It is found that the AO has the maximum impact on the shortening trends of SCDs in the Shandong peninsula, Changbai Mountains, Xiaoxingganling, and north Xinjiang, while the combined TBZD and MAT have the maximum impact on the shortening trends of SCDs in the Loess Plateau, Tibetan Plateau, and Northeast Plain.

  5. Snow Cover and Vegetation-Induced Decrease in Global Albedo From 2002 to 2016

    Science.gov (United States)

    Li, Qiuping; Ma, Mingguo; Wu, Xiaodan; Yang, Hong

    2018-01-01

    Land surface albedo is an essential parameter in regional and global climate models, and it is markedly influenced by land cover change. Variations in the albedo can affect the surface radiation budget and further impact the global climate. In this study, the interannual variation of albedo from 2002 to 2016 was estimated on the global scale using Moderate Resolution Imaging Spectroradiometer (MODIS) datasets. The presence and causes of the albedo changes for each specific region were also explored. From 2002 to 2016, the MODIS-based albedo decreased globally, snow cover declined by 0.970 (percent per pixel), while the seasonally integrated normalized difference vegetation index increased by 0.175. Some obvious increases in the albedo were detected in Central Asia, northeastern China, parts of the boreal forest in Canada, and the temperate steppe in North America. In contrast, noticeable decreases in the albedo were found in the Siberian tundra, Europe, southeastern Australia, and northeastern regions of North America. In the Northern Hemisphere, the greening trend at high latitudes made more contribution to the decline in the albedo. However, the dramatic fluctuation of snow-cover at midlatitudes predominated in the change of albedo. Our analysis can help to understand the roles that vegetation and snow cover play in the variation of albedo on global and regional scales.

  6. Preliminary analysis of measured sound propagation over various seasonal snow covers

    Science.gov (United States)

    Albert, Donald G.

    1990-01-01

    Measurements of acoustic pulse propagation in the 5 to 500-Hz frequency band were conducted under various snow cover conditions during the 1989 to 1990 winter in New Hampshire. The objective was to determine the effect of snow cover thickness and other snow properties on the absorption of acoustic pulses. Blank pistol shots were used as the source of the acoustic waves, and geophones and microphones in an 80 m-long linear array served as receivers. Snow thicknesses ranged from 0.05 to 0.35 m, and densities varied from 100 to 350 kg m(sup -3) during the 10 separate measurement days. Preliminary analysis indicates that the peak pulse amplitude decayed in proportion to approx. gamma (sup -1.7) for most conditions and that the acoustic-to-seismic ratios varied from about 4 to 15 x 10(exp -6) m s(sup -1) Pa(sup -1). Theoretical waveforms were calculated for propagation in a homogeneous atmosphere using Attenborough's model of ground impedance. An automatic fitting procedure for the normalized experimental and theoretical waveforms was used to determine the effective flow resistivity of the snow covers, and gave values of 10 to 35 kN s m(sup -4), in agreement with earlier results.

  7. Threshold temperatures mediate the impact of reduced snow cover on overwintering freeze-tolerant caterpillars

    Science.gov (United States)

    Marshall, Katie E.; Sinclair, Brent J.

    2012-01-01

    Decreases in snow cover due to climate change could alter the energetics and physiology of ectothermic animals that overwinter beneath snow, yet how snow cover interacts with physiological thresholds is unknown. We applied numerical simulation of overwintering metabolic rates coupled with field validation to determine the importance of snow cover and freezing to the overwintering lipid consumption of the freeze-tolerant Arctiid caterpillar Pyrrharctia isabella. Caterpillars that overwintered above the snow experienced mean temperatures 1.3°C lower than those below snow and consumed 18.36 mg less lipid of a total 68.97-mg reserve. Simulations showed that linear temperature effects on metabolic rate accounted for only 30% of the difference in lipid consumption. When metabolic suppression by freezing was included, 93% of the difference between animals that overwintered above and below snow was explained. Our results were robust to differences in temperature sensitivity of metabolic rate, changes in freezing point, and the magnitude of metabolic suppression by freezing. The majority of the energy savings was caused by the non-continuous reduction in metabolic rate due to freezing, the first example of the importance of temperature thresholds in the lipid use of overwintering insects.

  8. Changes in snow cover over China in the 21st century as simulated by a high resolution regional climate model

    International Nuclear Information System (INIS)

    Shi Ying; Gao Xuejie; Wu Jia; Giorgi, Filippo

    2011-01-01

    On the basis of the climate change simulations conducted using a high resolution regional climate model, the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model, RegCM3, at 25 km grid spacing, future changes in snow cover over China are analyzed. The simulations are carried out for the period of 1951–2100 following the IPCC SRES A1B emission scenario. The results suggest good performances of the model in simulating the number of snow cover days and the snow cover depth, as well as the starting and ending dates of snow cover to the present day (1981–2000). Their spatial distributions and amounts show fair consistency between the simulation and observation, although with some discrepancies. In general, decreases in the number of snow cover days and the snow cover depth, together with postponed snow starting dates and advanced snow ending dates, are simulated for the future, except in some places where the opposite appears. The most dramatic changes are found over the Tibetan Plateau among the three major snow cover areas of Northeast, Northwest and the Tibetan Plateau in China.

  9. Establishing a normative atlas of the human lung: computing the average transformation and atlas construction.

    Science.gov (United States)

    Li, Baojun; Christensen, Gary E; Hoffman, Eric A; McLennan, Geoffrey; Reinhardt, Joseph M

    2012-11-01

    To establish the range of normal for quantitative computed tomography (CT)-based measures of lung structure and function, we seek to develop methods for matching pulmonary structures across individuals and establishing a normative human lung atlas. In our previous work, we have presented a three-dimensional (3D) image registration method suitable for pulmonary atlas construction based on CT datasets. The method has been applied to a population of normative lungs in multiple experiments and, in each instance, has resulted in significant reductions in registration errors. This study is a continuation to our previous work by presenting a method for synthesizing a computerized human lung atlas from previously registered and matched 3D pulmonary CT datasets from a population of normative subjects. Our method consists of defining the origin of the atlas coordinate system; defining the nomenclature and labels for anatomical structures within the atlas system; computing the average transformation based on the displacement fields to register individual subject to the common template subject; constructing the atlas by deforming the template with the average transformation; and calculating shape variations within the population. The feasibility of pulmonary atlas construction was evaluated using CT datasets from 20 normal volunteers. Substantial reductions in shape variability were demonstrated. In addition, the constructed atlas depends only slightly on a specific subject being selected as the template. These results indicate the framework is a robust and valid method for pulmonary atlas construction based on CT scans. The atlas consists of a grayscale CT dataset of the template, a labeled mask dataset of the template (ie, lungs, lobes, and lobar fissures are labeled with different gray levels), a data set representing the population's average shape, datasets representing the population's shape variations (ie, the magnitude of standard deviation), a data structure to contain

  10. Alpine snow cover in a changing climate: a regional climate model perspective

    Science.gov (United States)

    Steger, Christian; Kotlarski, Sven; Jonas, Tobias; Schär, Christoph

    2013-08-01

    An analysis is presented of an ensemble of regional climate model (RCM) experiments from the ENSEMBLES project in terms of mean winter snow water equivalent (SWE), the seasonal evolution of snow cover, and the duration of the continuous snow cover season in the European Alps. Two sets of simulations are considered, one driven by GCMs assuming the SRES A1B greenhouse gas scenario for the period 1951-2099, and the other by the ERA-40 reanalysis for the recent past. The simulated SWE for Switzerland for the winters 1971-2000 is validated against an observational data set derived from daily snow depth measurements. Model validation shows that the RCMs are capable of simulating the general spatial and seasonal variability of Alpine snow cover, but generally underestimate snow at elevations below 1,000 m and overestimate snow above 1,500 m. Model biases in snow cover can partly be related to biases in the atmospheric forcing. The analysis of climate projections for the twenty first century reveals high inter-model agreement on the following points: The strongest relative reduction in winter mean SWE is found below 1,500 m, amounting to 40-80 % by mid century relative to 1971-2000 and depending upon the model considered. At these elevations, mean winter temperatures are close to the melting point. At higher elevations the decrease of mean winter SWE is less pronounced but still a robust feature. For instance, at elevations of 2,000-2,500 m, SWE reductions amount to 10-60 % by mid century and to 30-80 % by the end of the century. The duration of the continuous snow cover season shows an asymmetric reduction with strongest shortening in springtime when ablation is the dominant factor for changes in SWE. We also find a substantial ensemble-mean reduction of snow reliability relevant to winter tourism at elevations below about 1,800 m by mid century, and at elevations below about 2,000 m by the end of the century.

  11. Changing snow cover in tundra ecosystems tips the Arctic carbon balance

    Science.gov (United States)

    Zona, D.; Hufkens, K.; Gioli, B.; Kalhori, A. A. M.; Oechel, W. C.

    2014-12-01

    The Arctic environment has witnessed important changes due to global warming, resulting in increased surface air temperatures and rain events which both exacerbate snow cover deterioration (Semmens et al, 2013; Rennert et al, 2009; White et al, 2007; Min et al, 2008; Sharp et al, 2013; Schaeffer et al, 2013). Snow cover duration is declining by almost 20% per decade, a far higher rate than model estimates (Derksen and Brown, 2012). Concomitant with increasing temperatures and decreasing snow cover duration, the length of the arctic growing season is reported to have increased by 1.1 - 4.9 days per decade since 1951 (Menzel et al, 2006), and, plant productivity and CO2 uptake from arctic vegetation are strongly influenced by changes in growing season length (Myneni et al., 1997; Schaefer et al., 2005; Euskirchen et al., 2006). Based on more than a decade of eddy flux measurements in Arctic tundra ecosystems across the North slope of Alaska, and remotely sensed snow cover data, we show that earlier snow melt in the spring increase C uptake while an extended snow free period in autumn is associated with a higher C loss. Here we present the impacts of changes in snow cover dynamics between spring and autumn in arctic tundra ecosystems on the carbon dynamics and net C balance of the Alaskan Arctic. ReferencesDerksen, C., Brown R. (2012) Geophys. Res. Lett., doi:10.1029/2012GL053387 Euskirchen, E.S., et al. (2006) Glob. Change Biol., 12, 731-750. Menzel, A., et al. 2006. Glob. Change Biol., 12, 1969-1976. Min SK, Zhang X, Zweirs F (2008) Science 320: 518-520. Rennert K J, Roe G, Putkonen J and Bitz C M (2009) J. Clim. 22 2302-15. Schaefer, K., Denning A.S., Leonard O. (2005) Global Biogeochem. Cycles, 19, GB3017. Schaeffer, S. M., Sharp, E., Schimel, J. P. & Welker, J. M. (2013). Soil- plant N processes in a High Arctic ecosystem, NW Greenland are altered by long-term experimental warming and higher rainfall. Glob. Change Biol., 11, 3529-39. doi: 10.1111/gcb.12318

  12. Timing and Statistics of Autumn and Spring Annual Snow Cover for the Northern Hemisphere, 1972 to 2000

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Snow and Ice Data Center hosts a time-series data set comprising annual snow cover data for the Northern Hemisphere (covering land primarily over 45...

  13. CLPX-Satellite: EO-1 Hyperion Surface Reflectance, Snow-Covered Area, and Grain Size, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of apparent surface reflectance, subpixel snow-covered area, and grain size collected from the Hyperion hyperspectral imager. The Hyperion...

  14. A GIS Software Toolkit for Monitoring Areal Snow Cover and Producing Daily Hydrologic Forecasts using NASA Satellite Imagery, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aniuk Consulting, LLC, proposes to create a GIS software toolkit for monitoring areal snow cover extent and producing streamflow forecasts. This toolkit will be...

  15. Timing and Statistics of Autumn and Spring Annual Snow Cover for the Northern Hemisphere, 1972 to 2000, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set comprises a time series of annual snow cover data for the Northern Hemisphere (covering land primarily above 45 degrees North) from 1972 to 2000. Data...

  16. The effects of additional black carbon on Arctic sea ice surface albedo: variation with sea ice type and snow cover

    OpenAIRE

    A. A. Marks; M. D. King

    2013-01-01

    Black carbon in sea ice will decrease sea ice surface albedo through increased absorption of incident solar radiation, exacerbating sea ice melting. Previous literature has reported different albedo responses to additions of black carbon in sea ice and has not considered how a snow cover may mitigate the effect of black carbon in sea ice. Sea ice is predominately snow covered. Visible light absorption and light scattering coefficients are calculated for a typical first year and multi-y...

  17. Hydrological Modelling and data assimilation of Satellite Snow Cover Area using a Land Surface Model, VIC

    Science.gov (United States)

    Naha, Shaini; Thakur, Praveen K.; Aggarwal, S. P.

    2016-06-01

    The snow cover plays an important role in Himalayan region as it contributes a useful amount to the river discharge. So, besides estimating rainfall runoff, proper assessment of snowmelt runoff for efficient management and water resources planning is also required. A Land Surface Model, VIC (Variable Infiltration Capacity) is used at a high resolution grid size of 1 km. Beas river basin up to Thalot in North West Himalayas (NWH) have been selected as the study area. At first model setup is done and VIC has been run in its energy balance mode. The fluxes obtained from VIC has been routed to simulate the discharge for the time period of (2003-2006). Data Assimilation is done for the year 2006 and the techniques of Data Assimilation considered in this study are Direct Insertion (D.I) and Ensemble Kalman Filter (EnKF) that uses observations of snow covered area (SCA) to update hydrologic model states. The meteorological forcings were taken from 0.5 deg. resolution VIC global forcing data from 1979-2006 with daily maximum temperature, minimum temperature from Climate Research unit (CRU), rainfall from daily variability of NCEP and wind speed from NCEP-NCAR analysis as main inputs and Indian Meteorological Department (IMD) data of 0.25 °. NBSSLUP soil map and land use land cover map of ISRO-GBP project for year 2014 were used for generating the soil parameters and vegetation parameters respectively. The threshold temperature i.e. the minimum rain temperature is -0.5°C and maximum snow temperature is about +0.5°C at which VIC can generate snow fluxes. Hydrological simulations were done using both NCEP and IMD based meteorological Forcing datasets, but very few snow fluxes were obtained using IMD data met forcing, whereas NCEP based met forcing has given significantly better snow fluxes throughout the simulation years as the temperature resolution as given by IMD data is 0.5°C and rainfall resolution of 0.25°C. The simulated discharge has been validated using observed

  18. Assimilation of MODIS Snow Cover Fraction Observations into the NASA Catchment Land Surface Model

    Directory of Open Access Journals (Sweden)

    Ally M. Toure

    2018-02-01

    Full Text Available The NASA Catchment land surface model (CLSM is the land model component used for the Modern-Era Retrospective Analysis for Research and Applications (MERRA. Here, the CLSM versions of MERRA and MERRA-Land are evaluated using snow cover fraction (SCF observations from the Moderate Resolution Imaging Spectroradiometer (MODIS. Moreover, a computationally-efficient empirical scheme is designed to improve CLSM estimates of SCF, snow depth, and snow water equivalent (SWE through the assimilation of MODIS SCF observations. Results show that data assimilation (DA improved SCF estimates compared to the open-loop model without assimilation (OL, especially in areas with ephemeral snow cover and mountainous regions. A comparison of the SCF estimates from DA against snow cover estimates from the NOAA Interactive Multisensor Snow and Ice Mapping System showed an improvement in the probability of detection of up to 28% and a reduction in false alarms by up to 6% (relative to OL. A comparison of the model snow depth estimates against Canadian Meteorological Centre analyses showed that DA successfully improved the model seasonal bias from −0.017 m for OL to −0.007 m for DA, although there was no significant change in root-mean-square differences (RMSD (0.095 m for OL, 0.093 m for DA. The time-average of the spatial correlation coefficient also improved from 0.61 for OL to 0.63 for DA. A comparison against in situ SWE measurements also showed improvements from assimilation. The correlation increased from 0.44 for OL to 0.49 for DA, the bias improved from −0.111 m for OL to −0.100 m for DA, and the RMSD decreased from 0.186 m for OL to 0.180 m for DA.

  19. Southern Hemisphere origins for interannual variations of Tibetan Plateau snow cover in boreal summer

    Science.gov (United States)

    Wu, Z.

    2017-12-01

    The climate response to the Tibetan Plateau (TP) snow cover (TPSC) has been receiving extensive concern. However, relatively few studies have devoted to revealing the potential factors that can contribute to the TPSC variability on the interannual time scale. Especially during the boreal summer, snow cover can persist over the TP at high elevations, which exerts profound influences on the local and remote climate change. The present study finds that May Southern Hemisphere (SH) annular mode (SAM), the dominating mode of atmospheric circulation variability in the SH extratropics, exhibits a significant positive relationship with the boreal summer TPSC interannual variability. Observational analysis and numerical experiments manifest that the signal of May SAM can be "prolonged" by a meridional Indian Ocean tripole (IOT) sea surface temperature anomaly (SSTA) via atmosphere-ocean interaction. The IOT SSTA pattern persists into the following summer and excites anomalous local-scale zonal vertical circulation. Subsequently, a positive (or negative) tropical dipole rainfall (TDR) mode is induced with deficient (or sufficient) precipitation in tropical western Indian Ocean and sufficient (or deficient) precipitation in eastern Indian Ocean-Maritime continent. Rossby wave source diagnosis reveals that the wave energies, generated by the latent heat release of the TDR mode, propagate northward into western TP. As a response, abnormal cyclonic circulation and upward movement are triggered and prevail over western TP, providing favorable dynamical conditions for more TPSC, and vice versa. Hence, the IOT SSTA plays an "ocean bridge" role and the TDR mode acts as an "atmosphere bridge" role in the process of May SAM impacting the following summer TPSC variability. The results of our work may provide new insight about the cross-equatorial propagation of the SAM influence. Keywords Southern Hemisphere annular mode; Tibetan Plateau snow cover; Rossby wave source

  20. Aerotechnogenic Monitoring of Urban Environment on Snow Cover Pollution (on the Example of Voronezh City

    Directory of Open Access Journals (Sweden)

    Prozhorina Tatyana Ivanovna

    2014-09-01

    Full Text Available Snow cover is characterized by high sorption ability and represents an informative object in the process of identifying the technogenic pollution of urban environment. The article contains the results of the research on the chemical composition of the snow which fell in Voronezh in the winter period of 2013–2014. The coefficients of chemical elements concentration were calculated to provide objective characteristics of snow cover pollution. The authors analyze the connection between the presence of pollutants in snow and the level of technogenic impact. The obtained ranges of anomaly coefficients among anions reflect the composition of technogenic emissions. The mineralization of snow water reliably characterizes the intensity of anthropogenic impact on the urban environment, and the value of mineralization snow samples ranges from 62,6 (background to 183,9 mg/l. Maximum values of mineralization (more than 150 mg/l are typical for samples taken in transport area. High values of salinity (more than 120 mg/l are observed in snow samples taken in the industrial area, which confirms the high “technogenic pressure” on the urban environment in zones of industrial and transport potential of the city. The investigated functional areas can be arranged in the following series by descending level of contamination: transport area > industrial zone > residential and recreational areas > background territory. The study of the chemical composition of snow cover in the various functional areas of Voronezh allows to conclude that the pH level, mineralization and the content of suspended solids in snow waters characterize the intensity of anthropogenic pressure on the urban environment, and the composition of melt waters indicates the nature of its pollution.

  1. Dust pollution of snow cover in the industrial areas of Tomsk city (Western Siberia, Russia)

    OpenAIRE

    Talovskaya, Anna Valerievna; Filimonenko, Ekaterina Anatolievna; Osipova, Nina Aleksandrovna; Yazikov, Yegor (Egor) Grigoryevich; Nadeina, Louise Vasilievna

    2016-01-01

    This article describes the results of long-term monitoring (2007-2014) of snow cover pollution in the territory of Tomsk city. Snow samples were collected in the territory of Tomsk. Determination of dust load level was carried out by comparing with the background and reference values. It has been determined that the north-east and central parts of Tomsk are the most contaminated areas, where brickworks, coal and gas-fired thermal power plant are located. The analysis of long-term dynamics sho...

  2. Assessment of the economic risk for the ski resorts of changes in snow cover duration

    Directory of Open Access Journals (Sweden)

    S. A. Sokratov

    2014-01-01

    Full Text Available Winter tourism that is intensively developed in the Russian Federation in recent years strongly depends on the snow availability and properties in the region. Climate changes exert significant influence on the functioning of mountain ski resorts, especially if they are located in areas with relatively high air temperatures in winter season. At the present time, a snowy cluster of mountain ski resorts is intensively progressing in vicinity of Krasnaya Polyana. This region in the West Caucasus (Russia is characterized by relatively warm climate conditions. The snow cover thickness (of 1% insurance in area of the Aibga mountain range may reach 8.1 m. But the snow cover thickness is not the only characteristic of the mountain skiing attractiveness. According to the Swiss standards a mountain ski resort can be considered reliable if during seven seasons of ten ones the snow cover with minimal thickness of 30–50 cm exists for a time not shorter than 100 days during a period from 1st December till 15th April.According to the forecast, during future decades the calculated amount of solid precipitation should reduce by 25–30% in mountain regions on the south macro-slope of the Great Caucasus. As the calculations show, by 2041–2050 the maximal decade thickness of snow cover will decrease by 29–35% while a number of days with snow – by 35–40%. If this is the case, artificial snow will be needed in addition to the natural one. But, under warm climate conditions using of plants for artificial snow production will require a certain perfecting of the nowadays technologies, and very likely, with use of chemicals. That is why a shadowing of existing mountain ski routes by means of the tree planting along them could be ecologically more promising. As for the mountain ski resorts of the West Caucasus, we should mention a possible weakening of the avalanche activity as a potential positive effect of the climate warming predicted by models.

  3. An Automated Approach for Mapping Persistent Ice and Snow Cover over High Latitude Regions

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    David J. Selkowitz

    2015-12-01

    Full Text Available We developed an automated approach for mapping persistent ice and snow cover (glaciers and perennial snowfields from Landsat TM and ETM+ data across a variety of topography, glacier types, and climatic conditions at high latitudes (above ~65°N. Our approach exploits all available Landsat scenes acquired during the late summer (1 August–15 September over a multi-year period and employs an automated cloud masking algorithm optimized for snow and ice covered mountainous environments. Pixels from individual Landsat scenes were classified as snow/ice covered or snow/ice free based on the Normalized Difference Snow Index (NDSI, and pixels consistently identified as snow/ice covered over a five-year period were classified as persistent ice and snow cover. The same NDSI and ratio of snow/ice-covered days to total days thresholds applied consistently across eight study regions resulted in persistent ice and snow cover maps that agreed closely in most areas with glacier area mapped for the Randolph Glacier Inventory (RGI, with a mean accuracy (agreement with the RGI of 0.96, a mean precision (user’s accuracy of the snow/ice cover class of 0.92, a mean recall (producer’s accuracy of the snow/ice cover class of 0.86, and a mean F-score (a measure that considers both precision and recall of 0.88. We also compared results from our approach to glacier area mapped from high spatial resolution imagery at four study regions and found similar results. Accuracy was lowest in regions with substantial areas of debris-covered glacier ice, suggesting that manual editing would still be required in these regions to achieve reasonable results. The similarity of our results to those from the RGI as well as glacier area mapped from high spatial resolution imagery suggests it should be possible to apply this approach across large regions to produce updated 30-m resolution maps of persistent ice and snow cover. In the short term, automated PISC maps can be used to

  4. Subpixel Snow Cover Mapping from MODIS Data by Nonparametric Regression Splines

    Science.gov (United States)

    Akyurek, Z.; Kuter, S.; Weber, G. W.

    2016-12-01

    Spatial extent of snow cover is often considered as one of the key parameters in climatological, hydrological and ecological modeling due to its energy storage, high reflectance in the visible and NIR regions of the electromagnetic spectrum, significant heat capacity and insulating properties. A significant challenge in snow mapping by remote sensing (RS) is the trade-off between the temporal and spatial resolution of satellite imageries. In order to tackle this issue, machine learning-based subpixel snow mapping methods, like Artificial Neural Networks (ANNs), from low or moderate resolution images have been proposed. Multivariate Adaptive Regression Splines (MARS) is a nonparametric regression tool that can build flexible models for high dimensional and complex nonlinear data. Although MARS is not often employed in RS, it has various successful implementations such as estimation of vertical total electron content in ionosphere, atmospheric correction and classification of satellite images. This study is the first attempt in RS to evaluate the applicability of MARS for subpixel snow cover mapping from MODIS data. Total 16 MODIS-Landsat ETM+ image pairs taken over European Alps between March 2000 and April 2003 were used in the study. MODIS top-of-atmospheric reflectance, NDSI, NDVI and land cover classes were used as predictor variables. Cloud-covered, cloud shadow, water and bad-quality pixels were excluded from further analysis by a spatial mask. MARS models were trained and validated by using reference fractional snow cover (FSC) maps generated from higher spatial resolution Landsat ETM+ binary snow cover maps. A multilayer feed-forward ANN with one hidden layer trained with backpropagation was also developed. The mutual comparison of obtained MARS and ANN models was accomplished on independent test areas. The MARS model performed better than the ANN model with an average RMSE of 0.1288 over the independent test areas; whereas the average RMSE of the ANN model

  5. An automated approach for mapping persistent ice and snow cover over high latitude regions

    Science.gov (United States)

    Selkowitz, David J.; Forster, Richard R.

    2016-01-01

    We developed an automated approach for mapping persistent ice and snow cover (glaciers and perennial snowfields) from Landsat TM and ETM+ data across a variety of topography, glacier types, and climatic conditions at high latitudes (above ~65°N). Our approach exploits all available Landsat scenes acquired during the late summer (1 August–15 September) over a multi-year period and employs an automated cloud masking algorithm optimized for snow and ice covered mountainous environments. Pixels from individual Landsat scenes were classified as snow/ice covered or snow/ice free based on the Normalized Difference Snow Index (NDSI), and pixels consistently identified as snow/ice covered over a five-year period were classified as persistent ice and snow cover. The same NDSI and ratio of snow/ice-covered days to total days thresholds applied consistently across eight study regions resulted in persistent ice and snow cover maps that agreed closely in most areas with glacier area mapped for the Randolph Glacier Inventory (RGI), with a mean accuracy (agreement with the RGI) of 0.96, a mean precision (user’s accuracy of the snow/ice cover class) of 0.92, a mean recall (producer’s accuracy of the snow/ice cover class) of 0.86, and a mean F-score (a measure that considers both precision and recall) of 0.88. We also compared results from our approach to glacier area mapped from high spatial resolution imagery at four study regions and found similar results. Accuracy was lowest in regions with substantial areas of debris-covered glacier ice, suggesting that manual editing would still be required in these regions to achieve reasonable results. The similarity of our results to those from the RGI as well as glacier area mapped from high spatial resolution imagery suggests it should be possible to apply this approach across large regions to produce updated 30-m resolution maps of persistent ice and snow cover. In the short term, automated PISC maps can be used to rapidly

  6. Snow cover as a source of technogenic pollution of surface water during the snow melting period

    Directory of Open Access Journals (Sweden)

    Labuzova Olga

    2016-10-01

    Full Text Available The study of pollutants in melt water of snow cover and snow disposal sites in the city of Barnaul showed that during the snow melting period the surface water is not subjected to significant technogenic impact according to a number of studied indices. The oils content is an exception: it can exceed MAC more than 20 times in river- water due to the melting of city disposal sites. Environmental damage due to an oils input into water resources during the snow melting period can be more than 300000 thousand rubles.

  7. Construction and Application of Human Neonatal DTI Atlases

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    Rajiv eDeshpande

    2015-10-01

    Full Text Available Atlas-based analysis is one of many analytical methods and is used to investigate typical as well as abnormal neurodevelopment. It has been widely applied to the adult and pediatric populations. Successful applications of atlas-based analysis (ABA in those cohorts have motivated the creation of a neonatal atlas and parcellation map. The purpose of this review is to discuss the various neonatal diffusion tensor imaging (DTI atlases that are available for use in ABA, examine how such atlases are constructed, review their applications, and observe future directions in DTI. Neonatal DTI atlases are created from a template, which can be study-specific or standardized, and merged with the corresponding parcellation map. Study-specific templates can retain higher image registration accuracy, but are usually not applicable across different studies. However, standardized templates can be used to make comparisons among various studies, but may not accurately reflect the anatomies of the study population. Methods such as volume-based template estimation are being developed to overcome these limitations. The applications for ABA, including atlas-based image quantification and atlas-based connectivity analysis, vary from quantifying neurodevelopmental progress to analyzing population differences in groups of neonates. ABA can also be applied to detect pathology related to prematurity at birth or exposure to toxic substances. Future directions for this method include research designed to increase the accuracy of the image parcellation. Methods such as multi-atlas label fusion and multi-modal analysis applied to neonatal DTI currently comprise an active field of research. Moreover, ABA can be used in high-throughput analysis to efficiently process medical images and to assess longitudinal brain changes. Nevertheless, the overarching goal of neonatal ABA is application to the clinical setting, to assist with diagnoses, monitor disease progression, and outcome

  8. Overview of NASA's MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS) snow-cover Earth System Data Records

    Science.gov (United States)

    Riggs, George A.; Hall, Dorothy K.; Román, Miguel O.

    2017-10-01

    Knowledge of the distribution, extent, duration and timing of snowmelt is critical for characterizing the Earth's climate system and its changes. As a result, snow cover is one of the Global Climate Observing System (GCOS) essential climate variables (ECVs). Consistent, long-term datasets of snow cover are needed to study interannual variability and snow climatology. The NASA snow-cover datasets generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua spacecraft and the Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) are NASA Earth System Data Records (ESDR). The objective of the snow-cover detection algorithms is to optimize the accuracy of mapping snow-cover extent (SCE) and to minimize snow-cover detection errors of omission and commission using automated, globally applied algorithms to produce SCE data products. Advancements in snow-cover mapping have been made with each of the four major reprocessings of the MODIS data record, which extends from 2000 to the present. MODIS Collection 6 (C6; https://nsidc.org/data/modis/data_summaries) and VIIRS Collection 1 (C1; https://doi.org/10.5067/VIIRS/VNP10.001) represent the state-of-the-art global snow-cover mapping algorithms and products for NASA Earth science. There were many revisions made in the C6 algorithms which improved snow-cover detection accuracy and information content of the data products. These improvements have also been incorporated into the NASA VIIRS snow-cover algorithms for C1. Both information content and usability were improved by including the Normalized Snow Difference Index (NDSI) and a quality assurance (QA) data array of algorithm processing flags in the data product, along with the SCE map. The increased data content allows flexibility in using the datasets for specific regions and end-user applications. Though there are important differences between the MODIS and VIIRS instruments (e.g., the VIIRS 375

  9. Overview of NASA's MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS snow-cover Earth System Data Records

    Directory of Open Access Journals (Sweden)

    G. A. Riggs

    2017-10-01

    Full Text Available Knowledge of the distribution, extent, duration and timing of snowmelt is critical for characterizing the Earth's climate system and its changes. As a result, snow cover is one of the Global Climate Observing System (GCOS essential climate variables (ECVs. Consistent, long-term datasets of snow cover are needed to study interannual variability and snow climatology. The NASA snow-cover datasets generated from the Moderate Resolution Imaging Spectroradiometer (MODIS on the Terra and Aqua spacecraft and the Suomi National Polar-orbiting Partnership (S-NPP Visible Infrared Imaging Radiometer Suite (VIIRS are NASA Earth System Data Records (ESDR. The objective of the snow-cover detection algorithms is to optimize the accuracy of mapping snow-cover extent (SCE and to minimize snow-cover detection errors of omission and commission using automated, globally applied algorithms to produce SCE data products. Advancements in snow-cover mapping have been made with each of the four major reprocessings of the MODIS data record, which extends from 2000 to the present. MODIS Collection 6 (C6; https://nsidc.org/data/modis/data_summaries and VIIRS Collection 1 (C1; https://doi.org/10.5067/VIIRS/VNP10.001 represent the state-of-the-art global snow-cover mapping algorithms and products for NASA Earth science. There were many revisions made in the C6 algorithms which improved snow-cover detection accuracy and information content of the data products. These improvements have also been incorporated into the NASA VIIRS snow-cover algorithms for C1. Both information content and usability were improved by including the Normalized Snow Difference Index (NDSI and a quality assurance (QA data array of algorithm processing flags in the data product, along with the SCE map. The increased data content allows flexibility in using the datasets for specific regions and end-user applications. Though there are important differences between the MODIS and VIIRS instruments (e

  10. Evaluation of snow cover and snow depth on the Qinghai–Tibetan Plateau derived from passive microwave remote sensing

    Directory of Open Access Journals (Sweden)

    L. Dai

    2017-08-01

    Full Text Available Snow cover on the Qinghai–Tibetan Plateau (QTP plays a significant role in the global climate system and is an important water resource for rivers in the high-elevation region of Asia. At present, passive microwave (PMW remote sensing data are the only efficient way to monitor temporal and spatial variations in snow depth at large scale. However, existing snow depth products show the largest uncertainties across the QTP. In this study, MODIS fractional snow cover product, point, line and intense sampling data are synthesized to evaluate the accuracy of snow cover and snow depth derived from PMW remote sensing data and to analyze the possible causes of uncertainties. The results show that the accuracy of snow cover extents varies spatially and depends on the fraction of snow cover. Based on the assumption that grids with MODIS snow cover fraction > 10 % are regarded as snow cover, the overall accuracy in snow cover is 66.7 %, overestimation error is 56.1 %, underestimation error is 21.1 %, commission error is 27.6 % and omission error is 47.4 %. The commission and overestimation errors of snow cover primarily occur in the northwest and southeast areas with low ground temperature. Omission error primarily occurs in cold desert areas with shallow snow, and underestimation error mainly occurs in glacier and lake areas. With the increase of snow cover fraction, the overestimation error decreases and the omission error increases. A comparison between snow depths measured in field experiments, measured at meteorological stations and estimated across the QTP shows that agreement between observation and retrieval improves with an increasing number of observation points in a PMW grid. The misclassification and errors between observed and retrieved snow depth are associated with the relatively coarse resolution of PMW remote sensing, ground temperature, snow characteristics and topography. To accurately understand the variation in snow

  11. Overview of NASA's MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS) snow-cover Earth System Data Records

    Science.gov (United States)

    Riggs, George A.; Hall, Dorothy K.; Roman, Miguel O.

    2017-01-01

    Knowledge of the distribution, extent, duration and timing of snowmelt is critical for characterizing the Earth's climate system and its changes. As a result, snow cover is one of the Global Climate Observing System (GCOS) essential climate variables (ECVs). Consistent, long-term datasets of snow cover are needed to study interannual variability and snow climatology. The NASA snow-cover datasets generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua spacecraft and the Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) are NASA Earth System Data Records (ESDR). The objective of the snow-cover detection algorithms is to optimize the accuracy of mapping snow-cover extent (SCE) and to minimize snow-cover detection errors of omission and commission using automated, globally applied algorithms to produce SCE data products. Advancements in snow-cover mapping have been made with each of the four major reprocessings of the MODIS data record, which extends from 2000 to the present. MODIS Collection 6 (C6) and VIIRS Collection 1 (C1) represent the state-of-the-art global snow cover mapping algorithms and products for NASA Earth science. There were many revisions made in the C6 algorithms which improved snow-cover detection accuracy and information content of the data products. These improvements have also been incorporated into the NASA VIIRS snow cover algorithms for C1. Both information content and usability were improved by including the Normalized Snow Difference Index (NDSI) and a quality assurance (QA) data array of algorithm processing flags in the data product, along with the SCE map.The increased data content allows flexibility in using the datasets for specific regions and end-user applications.Though there are important differences between the MODIS and VIIRS instruments (e.g., the VIIRS 375m native resolution compared to MODIS 500 m), the snow detection algorithms and data

  12. Enhancement of snow cover change detection with sparse representation and dictionary learning

    Science.gov (United States)

    Varade, D.; Dikshit, O.

    2014-11-01

    Sparse representation and decoding is often used for denoising images and compression of images with respect to inherent features. In this paper, we adopt a methodology incorporating sparse representation of a snow cover change map using the K-SVD trained dictionary and sparse decoding to enhance the change map. The pixels often falsely characterized as "changes" are eliminated using this approach. The preliminary change map was generated using differenced NDSI or S3 maps in case of Resourcesat-2 and Landsat 8 OLI imagery respectively. These maps are extracted into patches for compressed sensing using Discrete Cosine Transform (DCT) to generate an initial dictionary which is trained by the K-SVD approach. The trained dictionary is used for sparse coding of the change map using the Orthogonal Matching Pursuit (OMP) algorithm. The reconstructed change map incorporates a greater degree of smoothing and represents the features (snow cover changes) with better accuracy. The enhanced change map is segmented using kmeans to discriminate between the changed and non-changed pixels. The segmented enhanced change map is compared, firstly with the difference of Support Vector Machine (SVM) classified NDSI maps and secondly with a reference data generated as a mask by visual interpretation of the two input images. The methodology is evaluated using multi-spectral datasets from Resourcesat-2 and Landsat-8. The k-hat statistic is computed to determine the accuracy of the proposed approach.

  13. Global Snow-Cover Evolution from Twenty Years of Satellite Passive Microwave Data

    Science.gov (United States)

    Mognard, N.M.; Kouraev, A.V.; Josberger, E.G.

    2003-01-01

    Starting in 1979 with the SMMR (Scanning Multichannel Microwave Radiometer) instrument onboard the satellite NIMBUS-7 and continuing since 1987 with the SSMI (Special Sensor Microwave Imager) instrument on board the DMSP (Defence Meteorological Satellite Program) series, more then twenty years of satellite passive microwave data are now available. This dataset has been processed to analyse the evolution of the global snow cover. This work is part of the AICSEX project from the 5th Framework Programme of the European Community. The spatio-temporal evolution of the satellite-derived yearly snow maximum extent and the timing of the spring snow melt were estimated and analysed over the Northern Hemisphere. Significant differences between the evolution of the yearly maximum snow extent in Eurasia and in North America were found. A positive correlation between the maximum yearly snow cover extent and the ENSO index was obtained. High interannual spatio-temporal variability characterises the timing of snow melt in the spring. Twenty-year trends in the timing of spring snow melt have been computed and compared with spring air temperature trends for the same period and the same area. In most parts of Eurasia and in the central and western parts of North America the tendency has been for earlier snow melt. In northeastern Canada, a large area of positive trends, where snow melt timing starts later than in the early 1980s, corresponds to a region of positive trends of spring air temperature observed over the same period.

  14. Improved identification of clouds and ice/snow covered surfaces in SCIAMACHY observations

    Directory of Open Access Journals (Sweden)

    J. M. Krijger

    2011-10-01

    Full Text Available In the ultra-violet, visible and near infra-red wavelength range the presence of clouds can strongly affect the satellite-based passive remote sensing observation of constituents in the troposphere, because clouds effectively shield the lower part of the atmosphere. Therefore, cloud detection algorithms are of crucial importance in satellite remote sensing. However, the detection of clouds over snow/ice surfaces is particularly difficult in the visible wavelengths as both clouds an snow/ice are both white and highly reflective. The SCIAMACHY Polarisation Measurement Devices (PMD Identification of Clouds and Ice/snow method (SPICI uses the SCIAMACHY measurements in the wavelength range between 450 nm and 1.6 μm to make a distinction between clouds and ice/snow covered surfaces, specifically developed to identify cloud-free SCIAMACHY observations. For this purpose the on-board SCIAMACHY PMDs are used because they provide higher spatial resolution compared to the main spectrometer measurements. In this paper we expand on the original SPICI algorithm (Krijger et al., 2005a to also adequately detect clouds over snow-covered forests which is inherently difficult because of the similar spectral characteristics. Furthermore the SCIAMACHY measurements suffer from degradation with time. This must be corrected for adequate performance of SPICI over the full SCIAMACHY time range. Such a correction is described here. Finally the performance of the new SPICI algorithm is compared with various other datasets, such as from FRESCO, MICROS and AATSR, focusing on the algorithm improvements.

  15. Modeling of surface dust concentration in snow cover at industrial area using neural networks and kriging

    Science.gov (United States)

    Sergeev, A. P.; Tarasov, D. A.; Buevich, A. G.; Shichkin, A. V.; Tyagunov, A. G.; Medvedev, A. N.

    2017-06-01

    Modeling of spatial distribution of pollutants in the urbanized territories is difficult, especially if there are multiple emission sources. When monitoring such territories, it is often impossible to arrange the necessary detailed sampling. Because of this, the usual methods of analysis and forecasting based on geostatistics are often less effective. Approaches based on artificial neural networks (ANNs) demonstrate the best results under these circumstances. This study compares two models based on ANNs, which are multilayer perceptron (MLP) and generalized regression neural networks (GRNNs) with the base geostatistical method - kriging. Models of the spatial dust distribution in the snow cover around the existing copper quarry and in the area of emissions of a nickel factory were created. To assess the effectiveness of the models three indices were used: the mean absolute error (MAE), the root-mean-square error (RMSE), and the relative root-mean-square error (RRMSE). Taking into account all indices the model of GRNN proved to be the most accurate which included coordinates of the sampling points and the distance to the likely emission source as input parameters for the modeling. Maps of spatial dust distribution in the snow cover were created in the study area. It has been shown that the models based on ANNs were more accurate than the kriging, particularly in the context of a limited data set.

  16. Cartographic modelling of aerotechnogenic pollution in snow cover in the landscapes of the Kola Peninsula.

    Science.gov (United States)

    Ratkin, N E; Asming, V E; Koshkin, V V

    2001-01-01

    The goal of this work was to develop computational techniques for sulphates, nickel and copper accumulation in the snow in the local pollution zone. The main task was to reveal the peculiarities of formation and pollution of snow cover on the region with complex cross-relief. A digital cartographic model of aerotechnogenic pollution of snow cover in the landscapes of the local zone has been developed, based on five-year experimental data. Data regarding annual emissions from the industrial complex, information about distribution of wind and the sum of precipitation from meteostation "Nikel" for the winter period, allowed the model to ensure: * material presentation in the form of maps of water capacity and accumulation of sulphates, nickel and copper in the snow over any winter period in retrospective; * calculation of water capacity and accumulation of pollutants for watersheds and other natural-territorial complexes; * solution of the opposite problem about the determination of the emissions of sulphates, nickel and copper from the enterprise by measuring snow pollution in datum points. The model can be used in other northern regions of the Russian Federation with similar physical-geographical and climatic conditions. The relationships between the sum of precipitation and water capacity in the landscapes of the same type and also the relationships between pollution content in snow and relief, pollution content in snow and distance from the source of emissions, were used as the basis for the model.

  17. Constructing a WISE High Resolution Galaxy Atlas

    Science.gov (United States)

    Jarrett, T. H.; Masci, F.; Tsai, C. W.; Petty, S.; Cluver, M.; Assef, Roberto J.; Benford, D.; Blain, A.; Bridge, C.; Donoso, E.; hide

    2012-01-01

    After eight months of continuous observations, the Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at 3.4 micron, 4.6 micron, 12 micron, and 22 micron. We have begun a dedicated WISE High Resolution Galaxy Atlas project to fully characterize large, nearby galaxies and produce a legacy image atlas and source catalog. Here we summarize the deconvolution techniques used to significantly improve the spatial resolution of WISE imaging, specifically designed to study the internal anatomy of nearby galaxies. As a case study, we present results for the galaxy NGC 1566, comparing the WISE enhanced-resolution image processing to that of Spitzer, Galaxy Evolution Explorer, and ground-based imaging. This is the first paper in a two-part series; results for a larger sample of nearby galaxies are presented in the second paper.

  18. Simulations of a Cold-Air Pool in Utah's Salt Lake Valley: Sensitivity to Land Use and Snow Cover

    Science.gov (United States)

    Foster, Christopher S.; Crosman, Erik T.; Horel, John D.

    2017-02-01

    Obtaining realistic land-surface states for initial and boundary conditions is important for the numerical weather prediction of many atmospheric phenomena. Here we investigate model sensitivity to land use and snow cover for a persistent wintertime cold-air pool in northern Utah during 1-8 January 2011. A Weather Research and Forecast model simulation using the 1993 United States Geological Survey land-use and North American Mesoscale model reanalysis snow-cover datasets is compared to an improved configuration using the modified 2011 National Land Cover Database and a more realistic representation of snow cover. The improved surface specification results in an increase (decrease) in urban land cover (Great Salt Lake surface area), and changes to the snow-cover initialization, depth, extent, and albedo. The results obtained from the model simulations are compared to observations collected during the Persistent Cold-Air Pool Study. The changes in land use and snow cover and the resulting impacts on the surface albedo and surface heat fluxes contributed to near-surface air temperature increases of 1-2°C in urban areas and decreases of 2-4°C in areas surrounding the Great Salt Lake. Although wind speeds in the boundary layer were overestimated in both simulations, shallow thermally-driven and terrain-forced flows were generally lessened in intensity and breadth in response to the decreased areal extent of the Great Salt Lake and increases in the urban footprint.

  19. Assessment of dynamic probabilistic methods for mapping snow cover in Québec Canada

    Science.gov (United States)

    De Seve, D.; Perreault, L.; Vachon, F.; Guay, F.; choquette, Y.

    2012-04-01

    Hydro-Quebec is the leader in electricity production in North America and uses hydraulic resources to generate 97% of its overall production where snow represents 30% of its annual energy reserve. Information on snow cover extent (SC) and snow water equivalent (SWE) is crucial for hydrological forecasting, particularly in Nordic regions where a majority of total precipitations falls as snow. Accurate estimation of the spatial distribution of snow cover variables is required to measure the extent of this resource but snow surveys are expensive due to inaccessibility factors and to the large extent nature of the Quebec geography. Consequently, the follow-up of snowmelt is particularly challenging for operational forecasting resulting in the need to develop a new approach to assist forecasters. For improved understanding of the dynamics of snow melting over watersheds and to generate optimized power production, Hydro-Québec's Research Institute (IREQ) has developed expertise in in-situ, remote sensing monitoring and statistical treatment of such data. The main goal of this Hydro-Quebec project is to develop an automatic and dynamic snow mapping system providing a daily snow map by merging remote sensing (AVHRR and SSMI) and in situ data. This paper focuses on the work accomplished on passive microwave SSM/I data to follow up snow cover. In our problematic, it is highly useful to classify snow, more specifically during the snowmelt period. The challenge is to be able to discriminate ground from wet snow as it will react as a black body, therefore, adding noise to global brightness temperature. Two dynamic snow classifiers were developed and tested. For this purpose, channels at 19 and 37 GHz in vertical polarization have been used to feed each model. SWE values from gamma ray in situ stations (GMON) and data snow depth from ultrasonic sensor (SR50) were used to validate the output models. The first algorithm is based on a standard K-mean clustering approach, combined

  20. Estimation of snow line elevation changes from MODIS snow cover data

    Science.gov (United States)

    Parajka, Juraj; Bezak, Nejc; Burkhart, John; Holko, Ladislav; Hundecha, Yeshewa; Krajči, Pavel; Mangini, Walter; Molnar, Peter; Sensoy, Aynur; Riboust, Phillippe; Rizzi, Jonathan; Thirel, Guillaume; Arheimer, Berit

    2017-04-01

    This contribution evaluates changes in snowline elevation during snowmelt runoff events in selected basins from Austria, France, Norway, Slovakia, Slovenia, Sweden, Switzerland and Turkey. The main objectives are to investigate the spatial and temporal differences in regional snowline elevation (RSLE) across Europe and to discuss the factors which control its change. The analysis is performed in two steps. In the first, the regional snowline elevation is processed from daily MODIS snow cover data (MOD10A1) by using the methodology of Krajčí et al., (2014). In the second step, the changes in RSLE are analysed for selected flood events in the period 2000-2015. The snowmelt runoff events are extracted from Catalogue of identified flood peaks from GRDC dataset (FLOOD TYPE experiment) available at http://www.water-switch-on.eu/sip-webclient/byod/#/resource/12056. The results will be discussed in terms of: (a) availability and potential of MODIS snow cover data for identifying RSLE changes during snowmelt runoff events, (b) spatial and temporal patterns of RSLE changes across Europe and (c) factor controlling the RSLE change. The analysis is performed as an experiment in Virtual Water Science Laboratory of SWITCH-ON Project (http://www.water-switch-on.eu/). All data, tools and results of the analysis will be open and accessible through the Spatial Information Platform of the Project (http://www.water-switch-on.eu/sip-webclient/byod/). We believe that such strategy will allow to improve and forward comparative research and cooperation between different partners in hydrology (Ceola et al., 2015). References Ceola, S., Arheimer, B., Baratti, E., Blöschl, G., Capell, R., Castellarin, A., Freer, J., Han, D., Hrachowitz, M., Hundecha, Y., Hutton, C., Lindström, G., Montanari, A., Nijzink, R., Parajka, J., Toth, E., Viglione, A., and Wagener, T.: Virtual laboratories: new opportunities for collaborative water science, Hydrol. Earth Syst. Sci., 19, 2101-2117, doi:10

  1. Isotope composition of winter precipitation and snow cover in the foothills of the Altai

    Directory of Open Access Journals (Sweden)

    N. S. Malygina

    2017-01-01

    Full Text Available Over the past three decades, several general circulation models of the atmosphere and ocean (atmospheric and oceanic general circulation models  – GCMs have been improved by modeling the hydrological cycle with the use of isotopologues (isotopes of water HDO and H2 18O. Input parameters for the GCM models taking into account changes in the isotope composition of atmospheric precipitation were, above all, the results obtained by the network GNIP – Global Network of Isotopes in Precipitation. At different times, on the vast territory of Russia there were only about 40 simultaneously functioning stations where the sampling of atmospheric precipitation was performed. In this study we present the results of the isotope composition of samples taken on the foothills of the Altai during two winter seasons of 2014/15 and 2015/16. Values of the isotope composition of precipitation changed in a wide range and their maximum fluctuations were 25, 202 and 18‰ for δ18О, dexc and δD, respectively. The weighted-mean values of δ18О and δD of the precipitation analyzed for the above two seasons were close to each other (−21.1 and −158.1‰ for the first season and −21.1 and −161.9‰ for the second one, while dexc values differed significantly. The comparison of the results of isotope analysis of the snow cover integral samples with the corresponding in the time interval the weighted-mean values of precipitation showed high consistency. However, despite the similarity of values of δ18О and δD, calculated for precipitation and snow cover, and the results, interpolated in IsoMAP (from data of the GNIP stations for 1960–2010, the dexc values were close to mean annual values of IsoMAP for only the second winter season. According to the trajectory analysis (the HYSPLIT model, the revealed differences between both, the seasons, and the long-term average values of IsoMAP, were associated with a change of main regions where the air masses

  2. Changing Arctic Snow Cover: A Review of Recent Developments and Assessment of Future Needs for Observations, Modelling, and Impacts

    Science.gov (United States)

    Bokhorst, Stef; Pedersen, Stine Hojlund; Brucker, Ludovic; Anisimov, Oleg; Bjerke, Jarle W.; Brown, Ross D.; Ehrich, Dorothee; Essery, Richard L. H.; Heilig, Achim; Ingvander, Susanne; hide

    2016-01-01

    Snow is a critically important and rapidly changing feature of the Arctic. However, snow-cover and snowpack conditions change through time pose challenges for measuring and prediction of snow. Plausible scenarios of how Arctic snow cover will respond to changing Arctic climate are important for impact assessments and adaptation strategies. Although much progress has been made in understanding and predicting snow-cover changes and their multiple consequences, many uncertainties remain. In this paper, we review advances in snow monitoring and modelling, and the impact of snow changes on ecosystems and society in Arctic regions. Interdisciplinary activities are required to resolve the current limitations on measuring and modelling snow characteristics through the cold season and at different spatial scales to assure human well-being, economic stability, and improve the ability to predict manage and adapt to natural hazards in the Arctic region.

  3. Snow cover and End of Summer Snowline statistics from a simple stochastic model

    Science.gov (United States)

    Petrelli, A.; Crouzy, B.; Perona, P.

    2012-04-01

    One essential parameter characterizing snow cover statistics is the End Of Summer Snowline (EOSS), which is also a good indicator of actual climatic trends in mountain regions. EOSS is usually modelled by means of spatially distributed physically based models, and typically require heavy parameterization. In this paper we validate the simple stochastic model proposed by Perona et al. (2007), by showing that the snow cover statistics and the position of EOSS can in principle be explained by only four essential (meteorological) parameters. Perona et al. (2007) proposed a model accounting for stochastic snow accumulation in the cold period, and deterministic melting dynamics in the warm period, and studied the statistical distribution of the snowdepth on the long term. By reworking the ensemble average of the steady state evolution equation we single out a relationship between the snowdepth statistics (including the position of EOSS) and the involved parameters. The validation of the established relationship is done using 50 years of field data from 73 Swiss stations located above 2000 m a.s.l. First an estimation of the meteorological parameters is made. Snow height data are used as a precipitation proxy, using temperature data to estimate SWE during the precipitation event. Thresholds are used both to separate accumulation from actual precipitation and wind transport phenomena, and to better assess summer melting rate, considered to be constant over the melting period according to the simplified model. First results show that data for most of the weather stations actually scales with the proposed relationship. This indicates that, on the long term, the effect of spatial and temporal noise masks most of the process detail so that minimalist models suffice to obtain reliable statistics. Future works will test the validity of this approach at different spatial scales, e.g., regional, continental and planetary. Reference: P. Perona, A. Porporato, and L. Ridolfi, "A

  4. IOD influence on the early winter tibetan plateau snow cover: diagnostic analyses and an AGCM simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Chaoxia; Tozuka, Tomoki; Yamagata, Toshio [The University of Tokyo, Department of Earth and Planetary Science, Graduate School of Science, Tokyo (Japan)

    2012-10-15

    Using diagnostic analyses and an AGCM simulation, the detailed mechanism of Indian Ocean Dipole (IOD) influence on the early winter Tibetan Plateau snow cover (EWTPSC) is clarified. In early winter of pure positive IOD years with no co-occurrence of El Nino, the anomalous dipole diabatic heating over the tropical Indian Ocean excites the baroclinic response in the tropics. Since both baroclinic and barotropic components of the basic zonal wind over the Arabian Peninsula increase dramatically in early winter due to the equatorward retreat of the westerly jet, the baroclinic mode excites the barotropic Rossby wave that propagates northeastward and induces a barotropic cyclonic anomaly north of India. This enables the moisture transport cyclonically from the northern Indian Ocean toward the Tibetan Plateau. The convergence of moisture over the plateau explains the positive influence of IOD on the EWTPSC. In contrast, the basic zonal wind over the Arabian Peninsula is weak in autumn. This is not favorable for excitation of the barotropic Rossby wave and teleconnection, even though the IOD-related diabatic heating anomaly in autumn similar to that in early winter exists. This result explains the insignificant (significant positive) partial correlation between IOD and the autumn (early winter) Tibetan Plateau snow cover after excluding the influence of ENSO. The sensitivity experiment forced by the IOD-related SST anomaly within the tropical Indian Ocean well reproduces the baroclinic response in the tropics, the teleconnection from the Arabian Peninsula, and the increased moisture supply to the Tibetan Plateau. Also, the seasonality of the atmospheric response to the IOD is simulated. (orig.)

  5. C-Band SAR Imagery for Snow-Cover Monitoring at Treeline, Churchill, Manitoba, Canada

    Directory of Open Access Journals (Sweden)

    Frédérique C. Pivot

    2012-07-01

    Full Text Available RADARSAT and ERS-2 data collected at multiple incidence angles are used to characterize the seasonal variations in the backscatter of snow-covered landscapes in the northern Hudson Bay Lowlands during the winters of 1997/98 and 1998/99. The study evaluates the usefulness of C-band SAR systems for retrieving the snow water equivalent under dry snow conditions in the forest–tundra ecotone. The backscatter values are compared against ground measurements at six sampling sites, which are taken to be representative of the land-cover types found in the region. The contribution of dry snow to the radar return is evident when frost penetrates the first 20 cm of soil. Only then does the backscatter respond positively to changes in snow water equivalent, at least in the open and forested areas near the coast, where 1-dB increases in backscatter for each approximate 5–10 mm of accumulated water equivalent are observed at 20–31° incidence angles. Further inland, the backscatter shows either no change or a negative change with snow accumulation, which suggests that the radar signal there is dominated by ground surface scattering (e.g., fen when not attenuated by vegetation (e.g., forested and transition. With high-frequency ground-penetrating radar, we demonstrate the presence of a 10–20-cm layer of black ice underneath the snow cover, which causes the reduced radar returns (−15 dB and less observed in the inland fen. A correlation between the backscattering and the snow water equivalent cannot be determined due to insufficient observations at similar incidence angles. To establish a relationship between the snow water equivalent and the backscatter, only images acquired with similar incidence angles should be used, and they must be corrected for both vegetation and ground effects.

  6. Capabilities of scatterometer for detection of diurnal thaw and refreeze of snow cover

    Science.gov (United States)

    Bartsch, A.; Naeimi, V.; Wagner, W.

    2009-04-01

    Microwave sensors with short wavelengths such as SeaWinds Quikscat (Ku-band) are sensitive to changes at snow surfaces due to thaw. Especially scatterometer can provide several measurements per day at high latitudes. Diurnal differences are investigated in a range of studies since they indicate exactly when snowmelt is taking place. Large changes in backscatter between morning and evening acquisitions are characteristic for the snowmelt period, when freezing takes place over night and thawing of the surface during the day. A change from volume to surface scattering occurs in case of melting. The actual number of dates of snow thaw is of most interest for glacier mass balance studies but the final disappearance of snow together with the length of spring thaw is required in regions with seasonal snow cover. When significant changes due to freeze/thaw cycling cease, closed snow cover also disappears. The exact day of year of beginning and end of freeze/thaw cycling can be clearly determined using QuikScat with consideration of long-term noise in order to exclude unnatural effects and changes in soil moisture and snow pack characteristics. SeaWinds Quikscat measurements are available since 1999. The first entire snowmelt period on the northern hemisphere is covered in 2000. A further scatteromter which provides the necessary observation intervals at high latitudes is the Metop ASCAT. It acquires data with %80 daily global coverage but at a longer wavelength (C-band) and different incidence angles since 2007. Comparison examples showing the capabilities of the two different sensors for the purpose of snowmelt detection are presented for high latitude regions and mountainous terrain at mid latitudes (Alps).

  7. EVALUATION OF THE URBAN DEVELOPMENT INFLUENCE ON POLLUTION OF SNOW COVER USING GEOINFORMATION AND STATISTICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    I. D. Korlyakov

    2017-01-01

    Full Text Available The influence of urban development parameters on the pollution of snow with heavy metals and metalloids (HMM has been assessed.The aim of the work is to assess the barrier functions of urban development by means of a joint analysis of data on the content of HMM in the snow cover and the parameters of the artificial relief. The residential area of the Ulan-Ude city was chosen as an object of the study, where 27 snow samples were selected. According to the data of the snow survey in 2014, the total content of HMM in the snow suspension was determined, the priority pollutants of the snow were received and the total indicator of immission at the sampling points was calculated. Data processing in the OpenStreetMap, 2GIS, ArcGis 10.0 and Statistica 7.0 software packages made it possible to determine the main parameters of the buildings near the sampling points. Correlation analysis has shown a significant influence of building parameters on the HMM immission in the snow cover. With an increase in the total and average building area, proximity of buildings to the sampling point, an increase in the immission of most or all HMMs has been observed. The height of houses is a secondary factor which positively affects the immission of Cu and Bi. The maximum correlation links are established in radii of 50, 100 and 150 m. The parameters of development affect the total precipitation of pollutants both in all cardinal directions, and in the south-western, northeast, southeast directions, which can be explained by the wind regime features during the winter season. 

  8. Impact of the snow cover scheme on snow distribution and energy budget modeling over the Tibetan Plateau

    Science.gov (United States)

    Xie, Zhipeng; Hu, Zeyong; Xie, Zhenghui; Jia, Binghao; Sun, Genhou; Du, Yizhen; Song, Haiqing

    2018-02-01

    This paper presents the impact of two snow cover schemes (NY07 and SL12) in the Community Land Model version 4.5 (CLM4.5) on the snow distribution and surface energy budget over the Tibetan Plateau. The simulated snow cover fraction (SCF), snow depth, and snow cover days were evaluated against in situ snow depth observations and a satellite-based snow cover product and snow depth dataset. The results show that the SL12 scheme, which considers snow accumulation and snowmelt processes separately, has a higher overall accuracy (81.8%) than the NY07 (75.8%). The newer scheme performs better in the prediction of overall accuracy compared with the NY07; however, SL12 yields a 15.1% underestimation rate while NY07 overestimated the SCF with a 15.2% overestimation rate. Both two schemes capture the distribution of the maximum snow depth well but show large positive biases in the average value through all periods (3.37, 3.15, and 1.48 cm for NY07; 3.91, 3.52, and 1.17 cm for SL12) and overestimate snow cover days compared with the satellite-based product and in situ observations. Higher altitudes show larger root-mean-square errors (RMSEs) in the simulations of snow depth and snow cover days during the snow-free period. Moreover, the surface energy flux estimations from the SL12 scheme are generally superior to the simulation from NY07 when evaluated against ground-based observations, in particular for net radiation and sensible heat flux. This study has great implications for further improvement of the subgrid-scale snow variations over the Tibetan Plateau.

  9. Missing (in-situ) snow cover data hampers climate change and runoff studies in the Greater Himalayas.

    Science.gov (United States)

    Rohrer, Mario; Salzmann, Nadine; Stoffel, Markus; Kulkarni, Anil V

    2013-12-01

    The Himalayas are presently holding the largest ice masses outside the polar regions and thus (temporarily) store important freshwater resources. In contrast to the contemplation of glaciers, the role of runoff from snow cover has received comparably little attention in the past, although (i) its contribution is thought to be at least equally or even more important than that of ice melt in many Himalayan catchments and (ii) climate change is expected to have widespread and significant consequences on snowmelt runoff. Here, we show that change assessment of snowmelt runoff and its timing is not as straightforward as often postulated, mainly as larger partial pressure of H2O, CO2, CH4, and other greenhouse gases might increase net long-wave input for snowmelt quite significantly in a future atmosphere. In addition, changes in the short-wave energy balance - such as the pollution of the snow cover through black carbon - or the sensible or latent heat contribution to snowmelt are likely to alter future snowmelt and runoff characteristics as well. For the assessment of snow cover extent and depletion, but also for its monitoring over the extremely large areas of the Himalayas, remote sensing has been used in the past and is likely to become even more important in the future. However, for the calibration and validation of remotely-sensed data, and even more so in light of possible changes in snow-cover energy balance, we strongly call for more in-situ measurements across the Himalayas, in particular for daily data on new snow and snow cover water equivalent, or the respective energy balance components. Moreover, data should be made accessible to the scientific community, so that the latter can more accurately estimate climate change impacts on Himalayan snow cover and possible consequences thereof on runoff. © 2013 Elsevier B.V. All rights reserved.

  10. Technique for radionuclide composition analysis of snow cover in the Chernobyl' NPP 30-km zone using fiber sorbents

    International Nuclear Information System (INIS)

    Kham'yanov, L.P.; Rau, D.F.; Amosov, M.M.; Strel'nikova, A.E.; Tereshchenko, V.I.; Veber, T.S.

    1989-01-01

    The high-sensitivity, simple and fast technique for analysis of large-dispersive and ionic components of snow cover radioactivity is suggested. It is based on separation of a sample by fractions, concentration of the dispersive fraction on mechanical filters and the dissolved one on ion-exchange sorbents and separated fraction spectrometry. The minimum measured contamination level is 3.7 Bq/dm 3 for each radionuclide analyzed. The conclusion is made that the technique suggested is the reliable method for radionuclide content analysis is snow cover samples of the Chernobyl' NPP zone. 1 tab

  11. The ATLAS Liquid Argon Calorimeter: Construction, Integration, Commissioning

    International Nuclear Information System (INIS)

    Aleksa, Martin

    2006-01-01

    The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two end caps with electromagnetic, hadronic and forward calorimeters. The liquid argon sampling technique, with an accordion geometry was chosen for the barrel electromagnetic calorimeter (EMB) and adapted to the end cap (EMEC). The hadronic end cap calorimeter (HEC) uses a copper-liquid argon sampling technique with flat plate geometry and is subdivided in depth in two wheels per end-cap. Finally, the forward calorimeter (FCAL) is composed of three modules employing cylindrical electrodes with thin liquid argon gaps.The construction of the full calorimeter system is complete since mid-2004. Production modules constructed in the home institutes were integrated into wheels at CERN in 2003-2004, and inserted into the three cryostats. They passed their first complete cold test before the lowering into the ATLAS cavern. Results of quality checks (e.g. electrical, mechanical, ...) performed on all the 190304 read-out channels after cool down will be reported. End 2004 the ATLAS barrel electromagnetic (EM) calorimeter was installed in the ATLAS cavern and since summer 2005 the front-end electronics are being connected and tested. Results of this first commissioning phase will be shown to demonstrate the high standards of quality control for our detectors

  12. The ATLAS Liquid Argon Calorimeter Construction, Integration, Commissioning

    CERN Document Server

    Aleksa, Martin

    2006-01-01

    The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two end caps with electromagnetic, hadronic and forward calorimeters. The liquid argon sampling technique, with an accordion geometry was chosen for the barrel electromagnetic calorimeter (EMB) and adapted to the end cap (EMEC). The hadronic end cap calorimeter (HEC) uses a copper-liquid argon sampling technique with flat plate geometry and is subdivided in depth in two wheels per end-cap. Finally, the forward calorimeter (FCAL) is composed of three modules employing cylindrical electrodes with thin liquid argon gaps. The construction of the full calorimeter system is complete since mid-2004. Production modules constructed in the home institutes were integrated into wheels at CERN in 2003-2004, and inserted into the three cryostats. They passed their first complete cold test before the lowering into the ATLAS cavern. Results of quality checks (e.g. electrical, mechanical, ...) performed on all the 190304 read...

  13. Boreal snow cover variations induced by aerosol emissions in the middle of the 21st century

    Science.gov (United States)

    Ménégoz, M.; Krinner, G.; Balkanski, Y.; Cozic, A.; Boucher, O.; Ciais, P.

    2012-11-01

    We used a coupled climate-chemistry model to quantify the impacts of aerosols on snow cover both for the present-day and for the middle of the 21st century. Black carbon (BC) deposition over continents induces a reduction in the Mean Number of Days With Snow at the Surface (MNDWS) that ranges from 0 to 10 days over large areas of Eurasia and Northern America for the present-day relative to the pre-industrial period. This is mainly due to BC deposition during the spring, a period of the year when the remaining of snow accumulated during the winter is exposed to both strong solar radiation and large amount of aerosol deposition induced themselves by a high level of transport of particles from polluted areas. North of 30° N, this deposition flux represents 222 Gg BC month-1 on average from April to June in our simulation. A large reduction in BC emissions is expected in the future in the Radiative Concentration Pathway (RCP) scenarios. Considering this scenario in our simulation leads to a decrease in the spring BC deposition down to 110 Gg month-1 in the 2050s in the RCP8.5 scenario. However, despite the reduction of the aerosol impact on snow, the MNDWS is strongly reduced by 2050, with a decrease ranging from 10 to 100 days from pre-industrial values over large parts of the Northern Hemisphere. This reduction is essentially due to temperature increase, which is quite strong in the RCP8.5 scenario in the absence of climate mitigation policies. Moreover, the projected sea-ice retreat in the next decades will open new routes for shipping in the Arctic. However, a large increase in shipping emissions in the Arctic by the mid 21st century does not lead to significant changes of BC deposition over snow-covered areas in our simulation. Therefore, the MNDWS is clearly not affected through snow darkening effects associated to these Arctic ship emissions. In an experiment without nudging toward atmospheric reanalyses, we simulated however some changes of the MNDWS

  14. Sensitivity Analysis of Snow Cover to Climate Change Scenarios and Their Impact on Plant Habitats in Alpine Terrain

    Energy Technology Data Exchange (ETDEWEB)

    Keller, F.; Goyette, S.; Beniston, M. [Department of Geosciences, Geography, Fribourg (Switzerland)

    2005-10-01

    In high altitude areas snow cover duration largely determines the length of the growing season of the vegetation. A sensitivity study of snow cover to various scenarios of temperature and precipitation has been conducted to assess how snow cover and vegetation may respond for a very localized area of the high Swiss Alps (2050-2500 m above sea level). A surface energy balance model has been upgraded to compute snow depth and duration, taking into account solar radiation geometry over complex topography. Plant habitat zones have been defined and 23 species, whose photoperiodic preferences were documented in an earlier study, were grouped into each zone. The sensitivity of snowmelt to a change in mean, minimum and maximum temperature alone and a change in mean temperature combined with a precipitation change of +10% in winter and -10% in summer is investigated. A seasonal increase in the mean temperature of 3 to 5 K reduces snow cover depth and duration by more than a month on average. Snow melts two months earlier in the rock habitat zone with the mean temperature scenario than under current climate conditions. This allows the species in this habitat to flower earlier in a warmer climate, but not all plants are able to adapt to such changes.

  15. Estimation of the condition of snow cover in Voronezh according to the chemical analysis of water from melted snow

    OpenAIRE

    Prozhorina Tatyana Ivanovna; Bespalova Elena Vladimirovna; Yakunina Nadezhda

    2014-01-01

    Snow cover possesses high sorption ability and represents informative object to identify technogenic pollution of an urban environment. In this article the investigation data of a chemical composition of snow fallen in Voronezh during the winter period of 2014 are given. Relationships between existence of pollutants in snow and the level of technogenic effect are analyzed.

  16. Missing (in-situ) snow cover data hampers climate change and runoff studies in the Greater Himalayas

    International Nuclear Information System (INIS)

    Rohrer, Mario; Salzmann, Nadine; Stoffel, Markus; Kulkarni, Anil V.

    2013-01-01

    The Himalayas are presently holding the largest ice masses outside the polar regions and thus (temporarily) store important freshwater resources. In contrast to the contemplation of glaciers, the role of runoff from snow cover has received comparably little attention in the past, although (i) its contribution is thought to be at least equally or even more important than that of ice melt in many Himalayan catchments and (ii) climate change is expected to have widespread and significant consequences on snowmelt runoff. Here, we show that change assessment of snowmelt runoff and its timing is not as straightforward as often postulated, mainly as larger partial pressure of H 2 O, CO 2 , CH 4 , and other greenhouse gases might increase net long-wave input for snowmelt quite significantly in a future atmosphere. In addition, changes in the short-wave energy balance – such as the pollution of the snow cover through black carbon – or the sensible or latent heat contribution to snowmelt are likely to alter future snowmelt and runoff characteristics as well. For the assessment of snow cover extent and depletion, but also for its monitoring over the extremely large areas of the Himalayas, remote sensing has been used in the past and is likely to become even more important in the future. However, for the calibration and validation of remotely-sensed data, and even more so in light of possible changes in snow-cover energy balance, we strongly call for more in-situ measurements across the Himalayas, in particular for daily data on new snow and snow cover water equivalent, or the respective energy balance components. Moreover, data should be made accessible to the scientific community, so that the latter can more accurately estimate climate change impacts on Himalayan snow cover and possible consequences thereof on runoff. - Highlights: • Remotely sensed snow-cover data need to be validated by in-situ measurements. • More in-situ snow measurement programs are needed along

  17. Improvement of Operational Streamflow Prediction with MODIS-derived Fractional Snow Covered Area Observations

    Science.gov (United States)

    Bender, S.; Burgess, A.; Goodale, C. E.; Mattmann, C. A.; Miller, W. P.; Painter, T. H.; Rittger, K. E.; Stokes, M.; Werner, K.

    2013-12-01

    Water managers in the western United States depend heavily on the timing and magnitude of snowmelt-driven runoff for municipal supply, irrigation, maintenance of environmental flows, and power generation. The Colorado Basin River Forecast Center (CBRFC) of the National Weather Service issues operational forecasts of snowmelt-driven streamflow for watersheds within the Colorado River Basin (CRB) and eastern Great Basin (EGB), across a wide variety of scales. Therefore, the CBRFC and its stakeholders consider snowpack observations to be highly valuable. Observations of fractional snow covered area (fSCA) from satellite-borne instrumentation can better inform both forecasters and water users with respect to subsequent snowmelt runoff, particularly when combined with observations from ground-based station networks and/or airborne platforms. As part of a multi-year collaborative effort, CBRFC has partnered with the Jet Propulsion Laboratory (JPL) under funding from NASA to incorporate observations of fSCA from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) into the operational CBRFC hydrologic forecasting and modeling process. In the first year of the collaboration, CBRFC and NASA/JPL integrated snow products into the forecasting and decision making processes of the CBRFC and showed preliminary improvement in operational streamflow forecasts. In late 2012, CBRFC and NASA/JPL began retrospective analysis of relationships between the MODIS Snow Covered Area and Grain size (MODSCAG) fSCA and streamflow patterns for several watersheds within the CRB and the EGB. During the 2013 snowmelt runoff season, CBRFC forecasters used MODIS-derived fSCA semi-quantitatively as a binary indicator of the presence or lack of snow. Indication of the presence or lack of snow by MODIS assisted CBRFC forecasters in determining the cause of divergence between modeled and recently observed streamflow. Several examples of improved forecasts from across the CRB and EGB, informed by

  18. Influence of snow cover distribution on soil temperature and nutrient dynamics in alpine pedoenvironments

    Directory of Open Access Journals (Sweden)

    Ermanno Zanini

    Full Text Available In Alpine sites snow is present on the ground from six to eight months per year in relation to elevation and exposure. Water is therefore immobilized into the solid state for the greater part of the winter season and released to the ground in a short period during spring snowmelt. In these areas, snow distribution exercises a fundamental role in influencing soil temperature and nutrient dynamics, in particular of nitrogen, with great consequences on plant nutrition. The dormant vegetation period, the low temperatures and the persistent snow cover suggest that soil biological activity is only concentrated during summer. As a matter of fact, soils covered with a consistent snow cover are isolated from the air temperature and can not freeze during winter. A snowpack of sufficient thickness, accumulated early in winter, insulates the ground from the surrounding atmosphere maintaining soil temperature closed to 0 °C during the whole winter season. The elevation of the snow line and the shorter permanence of snow on the ground, as a result of global warming (IPCC, 1996, 2001, might reduce the insulation effect of the snowpack, exposing soils of the mountain belt to lower temperatures and to a greater frequency of freeze/thaw cycles, which might alter organic matter dynamics and soil nutrient availability. Such thermal stresses may determine the lysis of microbial cells and the consequent increase of nitrogen and carbon mineralization by the survived microorganisms. Moreover, the freeze/thaw cycles can determine the exposure of exchange surfaces not available before, with release of organic matter of non-microbial origin, which may become available to surviving microorganisms for respiration. The reduced or absent microbial immobilization may cause the accumulation of remarkable amounts of inorganic nitrogen in soil, potentially leachable during spring snowmelt, when plants have not still started the growing season. Changes of snow distribution in

  19. Potential feedbacks between snow cover, soil moisture and surface energy fluxes in Southern Norway

    Science.gov (United States)

    Brox Nilsen, Irene; Tallaksen, Lena M.; Stordal, Frode

    2017-04-01

    At high latitudes, the snow season has become shorter during the past decades because snowmelt is highly sensitive to a warmer climate. Snowmelt influences the energy balance by changing the albedo and the partitioning between latent and sensible heat fluxes. It further influences the water balance by changing the runoff and soil moisture. In a previous study, we identified southern Norway as a region where significant temperature changes in summer could potentially be explained by land-atmosphere interactions. In this study we hypothesise that changes in snow cover would influence the summer surface fluxes in the succeeding weeks or months. The exceptionally warm summer of 2014 was chosen as a test bed. In Norway, evapotranspiration is not soil moisture limited, but energy limited, under normal conditions. During warm summers, however, such as in 2014, evapotranspiration can be restricted by the available soil moisture. Using the Weather Research and Forecasting (WRF) model we replace the initial ground conditions for 2014 with conditions representative of a snow-poor spring and a snow-rich spring. WRF was coupled to Noah-MP at 3 km horizontal resolution in the inner domain, and the simulations covered mid-May through September 2014. Boundary conditions used to force WRF were taken from the Era-Interim reanalysis. Snow, runoff, soil moisture and soil temperature observational data were provided by the Norwegian Water Resources and Energy Directorate for validation. The validation shows generally good agreement with observations. Preliminary results show that the reduced snowpack, hereafter "sim1" increased the air temperature by up to 5 K and the surface temperature by up to 10 K in areas affected by snow changes. The increased snowpack, hereafter "sim2", decreased the air and surface temperature by the same amount. These are weekly mean values for the first eight simulation weeks from mid May. Because of the higher net energy available ( 100 Wm-2) in sim 1, both

  20. Satellite Based Probabilistic Snow Cover Extent Mapping (SCE) at Hydro-Québec

    Science.gov (United States)

    Teasdale, Mylène; De Sève, Danielle; Angers, Jean-François; Perreault, Luc

    2016-04-01

    Over 40% of Canada's water resources are in Quebec and Hydro-Quebec has developed potential to become one of the largest producers of hydroelectricity in the world, with a total installed capacity of 36,643 MW. The Hydro-Québec fleet park includes 27 large reservoirs with a combined storage capacity of 176 TWh, and 668 dams and 98 controls. Thus, over 98% of all electricity used to supply the domestic market comes from water resources and the excess output is sold on the wholesale markets. In this perspective the efficient management of water resources is needed and it is based primarily on a good river flow estimation including appropriate hydrological data. Snow on ground is one of the significant variables representing 30% to 40% of its annual energy reserve. More specifically, information on snow cover extent (SCE) and snow water equivalent (SWE) is crucial for hydrological forecasting, particularly in northern regions since the snowmelt provides the water that fills the reservoirs and is subsequently used for hydropower generation. For several years Hydro Quebec's research institute ( IREQ) developed several algorithms to map SCE and SWE. So far all the methods were deterministic. However, given the need to maximize the efficient use of all resources while ensuring reliability, the electrical systems must now be managed taking into account all risks. Since snow cover estimation is based on limited spatial information, it is important to quantify and handle its uncertainty in the hydrological forecasting system. This paper presents the first results of a probabilistic algorithm for mapping SCE by combining Bayesian mixture of probability distributions and multiple logistic regression models applied to passive microwave data. This approach allows assigning for each grid point, probabilities to the set of the mutually exclusive discrete outcomes: "snow" and "no snow". Its performance was evaluated using the Brier score since it is particularly appropriate to

  1. Contribution of MODIS Derived Snow Cover Satellite Data into Artificial Neural Network for Streamflow Estimation

    Science.gov (United States)

    Uysal, Gokcen; Arda Sorman, Ali; Sensoy, Aynur

    2014-05-01

    Contribution of snowmelt and correspondingly snow observations are highly important in mountainous basins for modelers who deal with conceptual, physical or soft computing models in terms of effective water resources management. Long term archived continuous data are needed for appropriate training and testing of data driven approaches like artificial neural networks (ANN). Data is scarce at the upper elevations due to the difficulty of installing sufficient automated SNOTEL stations; thus in literatures many attempts are made on the rainfall dominated basins for streamflow estimation studies. On the other hand, optical satellites can easily detect snow because of its high reflectance property. MODIS (Moderate Resolution Imaging Spectroradiometer) satellite that has two platforms (Terra and Aqua) provides daily and 8-daily snow images for different time periods since 2000, therefore snow cover data (SCA) may be useful as an input layer for ANN applications. In this study, a multi-layer perceptron (MLP) model is trained and tested with precipitation, temperature, radiation, previous day discharges as well as MODIS daily SCA data. The weights and biases are optimized with fastest and robust Levenberg-Marquardt backpropagation algorithm. MODIS snow cover images are removed from cloud coverage using certain filtering techniques. The Upper Euphrates River Basin in eastern part of Turkey (10 250 km2) is selected as the application area since it is fed by snowmelt approximately 2/3 of total annual volume during spring and early summer. Several input models and ANN structures are investigated to see the effect of the contributions using 10 years of data (2001-2010) for training and validation. The accuracy of the streamflow estimations is checked with statistical criteria (coefficient of determination, Nash-Sutcliffe model efficiency, root mean square error, mean absolute error) and the results seem to improve when SCA data is introduced. Furthermore, a forecast study is

  2. Monitoring the spatio-temporal evolution of the snow cover in the eastern Alps from MODIS data

    Science.gov (United States)

    Cianfarra, P.; Salvini, F.; Valt, M.

    2009-04-01

    Estimating the snow cover extent in mountain ranges is important for a wide variety purposes including of scientific studies, environmental and meteo-climatic applications, as well as predicting water availability for energy resource and agriculture. Moreover, the monitoring of the spatio-temporal variation of the snow cover thickness, coupled with ground data from weather stations, allows to identify avalanche risk areas after heavy snowfall. The aim of this study is to test an automatic procedure to identify and map the snow coverage for different altitude interval in the eastern part of the Alpine range. There has been much progress since 1966 when the first operational snow mapping was done by NOAA with spaceborne sensors that provide daily, global observations to monitor the variability in space and time in the extent of snow cover. MODIS sensors offer increased improvements relative to the AVHRR that has been operational for many years on the NOAA Polar Operational Environmental Satellite System. In this context the MODIS provides observations at a nominal spatial resolution of 500 m versus the 1.1 km spatial resolution of the AVHRR and continuously available (spatially and temporally), spectral band observation that span the visible and short-wave infrared wavelengths, including those useful for recognize snow cover. The other advantage of using MODIS data is its availability and cost by the NASA's server. In this work we used MOD02 (L1B) data providing calibrated radiance values at the sensor (without atmospheric correction). Snow cover map production included the following steps: selection of the images with clear sky conditions, geometric correction and georeferencing to UTM zone 32 ,WSG 84 ellipsoid, to eliminate the distortion of and the typical bow-tie effect that produces the observed not alignment of the scan lines in the row image; spatial sub setting to produce an image covering an area of about 200 x 120 km; identification of the snow cover was

  3. Spatiotemporal analysis of snow cover variations at Mt. Kilimanjaro using multi-temporal Landsat images during 27 years

    Science.gov (United States)

    Park, Sung-Hwan; Lee, Moung-Jin; Jung, Hyung-Sup

    2016-06-01

    The Landsat TM and ETM+ images have been acquired for the long period from the 1980s until the present with the temporal resolution of a 16-day repeat cycle from the visible, near infrared (NIR), short wave infrared (SWIR) and thermal infrared (TIR) bands. The Landsat multi-temporal images have been successfully used to monitor variations of the Earth surface during 27 years. In this paper, we observe the variations of (1) the snow cover area, (2) the snowline height and (3) the land surface temperature (LST) lapse rate at Mt. Kilimanjaro using a total number of 15 Landsat-5 TM and Landsat-7 ETM+ images from June 1984-July 2011. Segmentation of normalized difference snow index (NDSI) images with a threshold of 0.6 is used to extract snow cover. Snowline altitude is then determined by combining the snow cover classification maps with a digital elevation model (DEM). And the LST lapse rate is also calculated from the TIR band in the forest area. The results from this study show that (1) the snow cover area largely decreases from 10.1 km2 to 2.3 km2 during about 27 years, which corresponds to a 77.2% reduction, (2) the snowline height rose from 4760 m to 5020 m by about 260 m, and (3) the LST lapse rate shifted from -5.2 °C/km to -2.7 °C/km. This study demonstrates that multi-temporal Landsat images can be successfully used for the spatiotemporal analysis of long-term snow cover changes.

  4. Trace element distribution in the snow cover from an urban area in central Poland.

    Science.gov (United States)

    Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

    2015-05-01

    This work presents the first results from winter field campaigns focusing on trace metals and metalloid chemistry in the snow cover from an urbanized region in central Poland. Samples were collected between January and March 2013 and trace element concentrations were determined using GF-AAS. A large inter-seasonal variability depending on anthropogenic emission, depositional processes, and meteorological conditions was observed. The highest concentration (in μg L(-1)) was reported for Pb (34.90), followed by Ni (31.37), Zn (31.00), Cu (13.71), Cr (2.36), As (1.58), and Cd (0.25). In addition, several major anthropogenic sources were identified based on principal component analysis (PCA), among which the most significant was the activity of industry and coal combustion for residential heating. It was stated that elevated concentrations of some trace metals in snow samples were associated with frequent occurrence of south and southeast advection of highly polluted air masses toward the sampling site, suggesting a large impact of regional urban/industrial pollution plumes.

  5. Long-term variability in Northern Hemisphere snow cover and associations with warmer winters

    Science.gov (United States)

    McCabe, Gregory J.; Wolock, David M.

    2010-01-01

    A monthly snow accumulation and melt model is used with gridded monthly temperature and precipitation data for the Northern Hemisphere to generate time series of March snow-covered area (SCA) for the period 1905 through 2002. The time series of estimated SCA for March is verified by comparison with previously published time series of SCA for the Northern Hemisphere. The time series of estimated Northern Hemisphere March SCA shows a substantial decrease since about 1970, and this decrease corresponds to an increase in mean winter Northern Hemisphere temperature. The increase in winter temperature has caused a decrease in the fraction of precipitation that occurs as snow and an increase in snowmelt for some parts of the Northern Hemisphere, particularly the mid-latitudes, thus reducing snow packs and March SCA. In addition, the increase in winter temperature and the decreases in SCA appear to be associated with a contraction of the circumpolar vortex and a poleward movement of storm tracks, resulting in decreased precipitation (and snow) in the low- to mid-latitudes and an increase in precipitation (and snow) in high latitudes. If Northern Hemisphere winter temperatures continue to warm as they have since the 1970s, then March SCA will likely continue to decrease.

  6. Detail-preserving construction of neonatal brain atlases in space-frequency domain.

    Science.gov (United States)

    Zhang, Yuyao; Shi, Feng; Yap, Pew-Thian; Shen, Dinggang

    2016-06-01

    Brain atlases are commonly utilized in neuroimaging studies. However, most brain atlases are fuzzy and lack structural details, especially in the cortical regions. This is mainly caused by the image averaging process involved in atlas construction, which often smoothes out high-frequency contents that capture fine anatomical details. Brain atlas construction for neonatal images is even more challenging due to insufficient spatial resolution and low tissue contrast. In this paper, we propose a novel framework for detail-preserving construction of population-representative atlases. Our approach combines spatial and frequency information to better preserve image details. This is achieved by performing atlas construction in the space-frequency domain given by wavelet transform. In particular, sparse patch-based atlas construction is performed in all frequency subbands, and the results are combined to give a final atlas. For enhancing anatomical details, tissue probability maps are also used to guide atlas construction. Experimental results show that our approach can produce atlases with greater structural details than existing atlases. Hum Brain Mapp 37:2133-2150, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  7. The construction of the ATLAS semi-conductor tracker

    International Nuclear Information System (INIS)

    Jones, Tim

    2006-01-01

    The ATLAS (A Toroidal LHC ApparatuS) experiment at the Large Hadron Collider (LHC) at CERN has been designed to explore physics at the TeV energy scale and will be commissioned in 2007. In the innermost region of the experiment is a charged particle tracker, the Inner Detector of which the Semiconductor Tracker (SCT) is a major component. The SCT comprises a central barrel section enclosed by two endcaps (A and C). The construction of the major components of the ATLAS Semi-conductor tracker (SCT) is now nearing completion. Following a brief description of the design of the SCT, the logistics and organisation of the construction phase of the project are discussed. Central to the delivery of a high quality detector is the testing of large numbers of modules both during assembly and after they are mounted on their final support structures. The results of these tests for endcap C are presented showing that the electrical performance of the 988 modules to be installed in ATLAS is compatible with the specifications required

  8. Energy feedbacks of northern high-latitude ecosystems to the climate system due to reduced snow cover during 20th century warming

    Science.gov (United States)

    Euskirchen, E.S.; McGuire, A.D.; Chapin, F.S.

    2007-01-01

    The warming associated with changes in snow cover in northern high-latitude terrestrial regions represents an important energy feedback to the climate system. Here, we simulate snow cover-climate feedbacks (i.e. changes in snow cover on atmospheric heating) across the Pan-arctic over two distinct warming periods during the 20th century, 1910-1940 and 1970-2000. We offer evidence that increases in snow cover-climate feedbacks during 1970-2000 were nearly three times larger than during 1910-1940 because the recent snow-cover change occurred in spring, when radiation load is highest, rather than in autumn. Based on linear regression analysis, we also detected a greater sensitivity of snow cover-climate feedbacks to temperature trends during the more recent time period. Pan-arctic vegetation types differed substantially in snow cover-climate feedbacks. Those with a high seasonal contrast in albedo, such as tundra, showed much larger changes in atmospheric heating than did those with a low seasonal contrast in albedo, such as forests, even if the changes in snow-cover duration were similar across the vegetation types. These changes in energy exchange warrant careful consideration in studies of climate change, particularly with respect to associated shifts in vegetation between forests, grasslands, and tundra. ?? 2007 Blackwell Publishing Ltd.

  9. Use of satellite-derived data for characterization of snow cover and simulation of snowmelt runoff through a distributed physically based model of runoff generation

    Directory of Open Access Journals (Sweden)

    L. S. Kuchment

    2010-02-01

    Full Text Available A technique of using satellite-derived data for constructing continuous snow characteristics fields for distributed snowmelt runoff simulation is presented. The satellite-derived data and the available ground-based meteorological measurements are incorporated in a physically based snowpack model. The snowpack model describes temporal changes of the snow depth, density and water equivalent (SWE, accounting for snow melt, sublimation, refreezing melt water and snow metamorphism processes with a special focus on forest cover effects. The remote sensing data used in the model consist of products include the daily maps of snow covered area (SCA and SWE derived from observations of MODIS and AMSR-E instruments onboard Terra and Aqua satellites as well as available maps of land surface temperature, surface albedo, land cover classes and tree cover fraction. The model was first calibrated against available ground-based snow measurements and then applied to calculate the spatial distribution of snow characteristics using satellite data and interpolated ground-based meteorological data. The satellite-derived SWE data were used for assigning initial conditions and the SCA data were used for control of snow cover simulation. The simulated spatial distributions of snow characteristics were incorporated in a distributed physically based model of runoff generation to calculate snowmelt runoff hydrographs. The presented technique was applied to a study area of approximately 200 000 km2 including the Vyatka River basin with catchment area of 124 000 km2. The correspondence of simulated and observed hydrographs in the Vyatka River are considered as an indicator of the accuracy of constructed fields of snow characteristics and as a measure of effectiveness of utilizing satellite-derived SWE data for runoff simulation.

  10. The ATLAS Insertable B-Layer: from construction to operation

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00218666; The ATLAS collaboration

    2016-01-01

    The ATLAS Insertable B-Layer (IBL) is the innermost layer of pixel detectors, and was installed in May 2014 at a radius of 3.3 cm from the beam axis, between the existing Pixel detector and a new smaller radius beam-pipe. The new detector, built to cope with high radiation and occupancy, is the first large scale application of 3D sensors and CMOS 130 nm technology. The IBL detector construction was completed within about two years (2012-2014), and the key features and challenges met during the IBL project are presented, as well as its commissioning and operational experience at the LHC

  11. Quantifying the impacts of snow on surface energy balance through assimilating snow cover fraction and snow depth

    Science.gov (United States)

    Meng, Chunlei

    2017-10-01

    Seasonal snow plays an important part in Earth's climate system. Snow cover regulates the land surface energy balance through altering the albedo of the land surface. To utilize the satellite-retrieved snow cover fraction (SCF) and snow depth (SD) data sufficiently and avoid inconsistency, this paper developed a very simple but robust quality control method to assimilate Fengyun satellite-retrieved SCF and SD simultaneously. The results show that the assimilation method which this paper implemented can not only utilize the satellite-retrieved SCF and SD data sufficiently but also avoid the inconsistency of them. Two experiments were designed and performed to quantify the impacts of snow on land surface energy balance using the integrated urban land model. With the increase of the SCF and SD, the net radiation decreased significantly during the day and increased a little at night; the sensible heat flux decreased significantly during the day; the evapotranspiration and ground heat flux decreased during the day too.

  12. Representation of vegetation effects on the snow-covered albedo in the Noah land surface model with multiple physics options

    OpenAIRE

    S. Park; S. K. Park

    2015-01-01

    Snow albedo plays a critical role in calculating the energy budget, but parameterization of the snow surface albedo is still under great uncertainty. It varies with snow grain size, snow cover thickness, snow age, forest shading factor and other variables. Snow albedo of forest is typically lower than that of short vegetation; thus snow albedo is dependent on the spatial distributions of characteristic land cover and on the canopy density and structure. In the No...

  13. Deriving Snow-Cover Depletion Curves for Different Spatial Scales from Remote Sensing and Snow Telemetry Data

    Science.gov (United States)

    Fassnacht, Steven R.; Sexstone, Graham A.; Kashipazha, Amir H.; Lopez-Moreno, Juan Ignacio; Jasinski, Michael F.; Kampf, Stephanie K.; Von Thaden, Benjamin C.

    2015-01-01

    During the melting of a snowpack, snow water equivalent (SWE) can be correlated to snow-covered area (SCA) once snow-free areas appear, which is when SCA begins to decrease below 100%. This amount of SWE is called the threshold SWE. Daily SWE data from snow telemetry stations were related to SCA derived from moderate-resolution imaging spectro radiometer images to produce snow-cover depletion curves. The snow depletion curves were created for an 80,000 sq km domain across southern Wyoming and northern Colorado encompassing 54 snow telemetry stations. Eight yearly snow depletion curves were compared, and it is shown that the slope of each is a function of the amount of snow received. Snow-cover depletion curves were also derived for all the individual stations, for which the threshold SWE could be estimated from peak SWE and the topography around each station. A stations peak SWE was much more important than the main topographic variables that included location, elevation, slope, and modelled clear sky solar radiation. The threshold SWE mostly illustrated inter-annual consistency.

  14. Snow cover dynamics in the Catalan Pyrenees range using remote sensing data from 2002 to 2008 period

    Science.gov (United States)

    Cea, C.; Cristóbal, J.; Pons, X.

    2009-04-01

    Snow cover dynamics in the Catalan Pyrenees range using remote sensing data from 2002 to 2008 period. C. Cea (1), J. Cristóbal (1), X. Pons (1, 2) (1) Department of Geography. Autonomous University of Barcelona. Cerdanyola del Vallès, 08193. Cristina.Cea@uab.cat, (2) Center for Ecological Research and Forestry Applications (CREAF) Cerdanyola del Vallès, 08193. Water resources and its management are essential in many alpine mountainous areas. Snow cover monitoring in the Mediterranean zone requires obtaining accurate snow cartography to estimate the volume of water derived from snow melting and species distribution modelling. Snow data is usually obtained by field campaigns, but to obtain a spatial and temporal cover of enough detail and quality it is necessary collect an important number of data. However, when a continuous surface is needed, Remote Sensing could provide better snow cover estimation due to its spatial and temporal resolution. The aim of this study is to map snow cover and analyse its spatial and temporal dynamics using medium and coarse remote sensing data at a regional scale over an heterogeneous area, the Catalan Pyrenees (NE of the Iberian Peninsula). The seasonal snow cover period is from October to June. In this period, regular snowfalls usually take place from December to April, although during the rest of the period, punctual but important episodes of snowfalls are frequent. To perform this analysis, a set of 96 Landsat images (36 Landsat-5 TM and 60 Landsat-7 ETM+) of path 197 and 198 and rows 31 and 32 from January 2002 to April 2007, and 90 Terra-MODIS images from October 2007 to July 2008, with a different percentage of cloudiness, have been chosen. The computation of the Landsat-5 TM and Landsat-7 ETM+ data used in snow cover mapping has been carried out by means of the following methodologies. Images have been geometrically corrected by means of techniques based on first order polynomials taking into account the effect of the relief

  15. The impact of organochlorines cycling in the cryosphere on global distributions and fate--2. Land ice and temporary snow cover.

    Science.gov (United States)

    Hofmann, Lorenz; Stemmler, Irene; Lammel, Gerhard

    2012-03-01

    Global fate and transport of γ-HCH and DDT was studied using a global multicompartment chemistry-transport model, MPI-MCTM, with and without inclusion of land ice (in Antarctica and Greenland) or snow cover (dynamic). MPI-MCTM is based on coupled ocean and atmosphere general circulation models. After a decade of simulation 4.2% γ-HCH and 2.3% DDT are stored in land ice and snow. Neglection of land ice and snow in modelling would underestimate the total environmental residence time, τ(ov), of γ-HCH and overestimate τ(ov) for DDT, both on the order of 1% and depending on actual compartmental distribution. Volatilisation of DDT from boreal, seasonally snow covered land is enhanced throughout the year, while volatilisation of γ-HCH is only enhanced during the snow-free season. Including land ice and snow cover in modelling matters in particular for the Arctic, where higher burdens are predicted to be stored. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Distribution and variability of total mercury in snow cover?a case study from a semi-urban site in Pozna?, Poland

    OpenAIRE

    Siudek, Patrycja

    2016-01-01

    In the present paper, the inter-seasonal Hg variability in snow cover was examined based on multivariate statistical analysis of chemical and meteorological data. Samples of freshly fallen snow cover were collected at the semi-urban site in Pozna? (central Poland), during 3-month field measurements in winter 2013. It was showed that concentrations of atmospherically deposited Hg were highly variable in snow cover, from 0.43 to 12.5?ng?L?1, with a mean value of 4.62?ng?L?1. The highest Hg conc...

  17. The ringed seal's last refuge and the importance of snow cover

    Science.gov (United States)

    Kelly, B. P.; Bitz, C. M.

    2010-12-01

    Ringed seals are strongly adapted to inhabiting seasonal ice cover throughout the Arctic Ocean, marginal seas, and some freshwater lakes. Their distribution has expanded and contracted with northern hemisphere ice cover and is expected to mirror declining ice cover in coming decades. Ringed seals require snow cover to provide shelter from extreme cold and from predators, and the southern extent of their range corresponds to the latitudes to which snow cover—sufficient to form and maintain subnivean lairs—extends. The lairs are especially critical to the survival of pups born and nursed under the snow in late March through May. Snow drifts 50 cm or deeper are necessary for lair occupation, and field measurements indicate that such drifting occurs only where average snow depths (on flat ice) exceed 20 cm. When snow depths are less, ringed seal pups freeze in their lairs and are vulnerable to predation by carnivores and birds. As the climate warms, winter precipitation is expected to increase in the Arctic Ocean, potentially favoring formation and occupation of lairs. At the same time, increasingly late ice formation is expected to decrease the overall accumulation of snow, an effect exacerbated by the high fraction of annual snow fall that occurs in autumn. Early snow melts also contribute to pup mortality and are likely to increase as the climate warms. We forecast April snow depths on Arctic sea ice through the year 2100 in seven runs of CCSM3. Despite predicted increases in winter precipitation in the Arctic, the model forecasted that the accumulation of snow on sea ice will decrease by almost 50% in this century. The timing of the onset of snow melt changes little in the projections, but the shallower snow pack will melt more quickly in the warmer climate. In almost all portions of the range, average snow depths are expected to be less than 20 cm and inadequate for successful rearing of ringed seal young by the end of the century and—in many locations

  18. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Snow Cover/Depth (SCD) Snow Fraction 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 Snow Cover/Depth Fraction (SCF) from the Visible Infrared Imaging Radiometer...

  19. NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Snow Cover/Depth (SCD) Binary Map 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 Binary Snow Cover (BSC) from the Visible Infrared Imaging Radiometer Suite...

  20. An Evaluation of High-Resolution Regional Climate Model Simulated Snow Cover Using Satellite Data (With Implications for the Simulated Snow-Albedo Feedback)

    Science.gov (United States)

    Minder, J. R.; Letcher, T.

    2015-12-01

    Snow cover often exhibits large spatial variability over mountainous regions where variations in elevation, aspect, vegetation, winds, and orographic precipitation all modulate snow cover. Under climate change, reductions in mountain snow cover are likely to substantially amplify regional warming via the snow-albedo feedback. To capture this important feedback it is crucial that regional climate models (RCMs) adequately simulate spatial and temporal variations in snow cover. Snow cover simulated by high-resolution RCMs over the central Rocky Mountains of the United States is evaluated. RCM simulations were conducted using the Weather Research and Forecasting (WRF) model on a 4 km horizontal grid forced by reanalysis boundary conditions over a seven-year time period. A pair of simulations is considered that differ in the domain size (regional vs. continental) and the land surface model (Noah vs. Noah-MP) employed. RCM output is compared with high-resolution gridded satellite analyses of surface albedo and fractional snow cover derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). Results reveal that both RCMs are generally successful at reproducing the observed seasonal cycle and interannual variability of snow extent over the high terrain of the Rockies. However, in simulations using the Noah land surface model (LSM), sub-grid scale fractional snow covered area of grid cells containing snow is systematically too high compared to observations, often exceeding observations by more than 0.2. This bias in fractional snow cover leads to a substantial positive bias in regional surface albedo. Simulations using the Noah-MP LSM produce more realistic variations in fractional snow cover and surface albedo, likely due to its more-realistic treatment of canopy effects. We quantify how differences in simulated snow cover affect the strength of the snow-albedo feedback under climate change. Both RCMs were used to conduct representative 7-year simulations of a

  1. Assimilation of snow cover and snow depth into a snow model to estimate snow water equivalent and snowmelt runoff in a Himalayan catchment

    Directory of Open Access Journals (Sweden)

    E. E. Stigter

    2017-07-01

    Full Text Available Snow is an important component of water storage in the Himalayas. Previous snowmelt studies in the Himalayas have predominantly relied on remotely sensed snow cover. However, snow cover data provide no direct information on the actual amount of water stored in a snowpack, i.e., the snow water equivalent (SWE. Therefore, in this study remotely sensed snow cover was combined with in situ observations and a modified version of the seNorge snow model to estimate (climate sensitivity of SWE and snowmelt runoff in the Langtang catchment in Nepal. Snow cover data from Landsat 8 and the MOD10A2 snow cover product were validated with in situ snow cover observations provided by surface temperature and snow depth measurements resulting in classification accuracies of 85.7 and 83.1 % respectively. Optimal model parameter values were obtained through data assimilation of MOD10A2 snow maps and snow depth measurements using an ensemble Kalman filter (EnKF. Independent validations of simulated snow depth and snow cover with observations show improvement after data assimilation compared to simulations without data assimilation. The approach of modeling snow depth in a Kalman filter framework allows for data-constrained estimation of snow depth rather than snow cover alone, and this has great potential for future studies in complex terrain, especially in the Himalayas. Climate sensitivity tests with the optimized snow model revealed that snowmelt runoff increases in winter and the early melt season (December to May and decreases during the late melt season (June to September as a result of the earlier onset of snowmelt due to increasing temperature. At high elevation a decrease in SWE due to higher air temperature is (partly compensated by an increase in precipitation, which emphasizes the need for accurate predictions on the changes in the spatial distribution of precipitation along with changes in temperature.

  2. Distribution and variability of total mercury in snow cover-a case study from a semi-urban site in Poznań, Poland.

    Science.gov (United States)

    Siudek, Patrycja

    2016-12-01

    In the present paper, the inter-seasonal Hg variability in snow cover was examined based on multivariate statistical analysis of chemical and meteorological data. Samples of freshly fallen snow cover were collected at the semi-urban site in Poznań (central Poland), during 3-month field measurements in winter 2013. It was showed that concentrations of atmospherically deposited Hg were highly variable in snow cover, from 0.43 to 12.5 ng L -1 , with a mean value of 4.62 ng L -1 . The highest Hg concentration in snow cover coincided with local intensification of fossil fuel burning, indicating large contribution from various anthropogenic sources such as commercial and domestic heating, power generation plants, and traffic-related pollution. Moreover, the variability of Hg in collected snow samples was associated with long-range transport of pollutants, nocturnal inversion layer, low boundary layer height, and relatively low air temperature. For three snow episodes, Hg concentration in snow cover was attributed to southerly advection, suggesting significant contribution from the highly polluted region of Poland (Upper Silesia) and major European industrial hotspots. However, the peak Hg concentration was measured in samples collected during predominant N to NE advection of polluted air masses and after a relatively longer period without precipitation. Such significant contribution to the higher Hg accumulation in snow cover was associated with intensive emission from anthropogenic sources (coal combustion) and atmospheric conditions in this area. These results suggest that further measurements are needed to determine how the Hg transformation paths in snow cover change in response to longer/shorter duration of snow cover occurrence and to determine the interactions between mercury and absorbing carbonaceous aerosols in the light of climate change.

  3. The impact of organochlorines cycling in the cryosphere on global distributions and fate – 2. Land ice and temporary snow cover

    International Nuclear Information System (INIS)

    Hofmann, Lorenz; Stemmler, Irene; Lammel, Gerhard

    2012-01-01

    Global fate and transport of γ-HCH and DDT was studied using a global multicompartment chemistry-transport model, MPI-MCTM, with and without inclusion of land ice (in Antarctica and Greenland) or snow cover (dynamic). MPI-MCTM is based on coupled ocean and atmosphere general circulation models. After a decade of simulation 4.2% γ-HCH and 2.3% DDT are stored in land ice and snow. Neglection of land ice and snow in modelling would underestimate the total environmental residence time, τ ov , of γ-HCH and overestimate τ ov for DDT, both on the order of 1% and depending on actual compartmental distribution. Volatilisation of DDT from boreal, seasonally snow covered land is enhanced throughout the year, while volatilisation of γ-HCH is only enhanced during the snow-free season. Including land ice and snow cover in modelling matters in particular for the Arctic, where higher burdens are predicted to be stored. - Highlights: ► Land ice and snow hosts 2–4% of the global environmental burden of γ-HCH and DDT. ► Inclusion of land ice and snow cover matters for global environmental residence time. ► Including of land ice and snow cover matters in particular for the Arctic. - The inclusion of cycling in temporary snow cover and land ice in the model is found relevant for predicted POPs multicompartmental distribution and fate in the Arctic and on the global scale.

  4. Performances of an expanding insect under elevated CO{sub 2} and snow cover in the Alps

    Energy Technology Data Exchange (ETDEWEB)

    Battisti, B.; Petrucco-Toffolo, E. [University of Padova, Legnaro (Italy). Dept. of Environmental Agronomy

    2008-09-30

    Variations of phenology and distribution have been recently highlighted in numerous insect species and attributed to climate change, particularly the increase of temperature and atmospheric carbon dioxide (CO{sub 2}). Both have been shown to have direct and indirect effects on insect species of various ecosystems, though the responses are often species-specific. The pine processionary moth, Thaumetopoea pityocampa (Lepidoptera, Notodontidae) is an important pest of conifers in the Mediterranean region, and has been recently shown to expand its altitudinal range in the Alps, including the mountain pine Pinus mugo as a novel host. We had the opportunity to transplant colonies of the pine processionary moth to a high elevation site well outside of the current range of the insect (Stillberg, Davos, Switzerland, 2180 m), where trees of the mountain pine have been grown for five years under ambient and elevated CO{sub 2} concentrations (ca. 570 ppm). The aim of the study was to evaluate the response of first instar larvae to extreme conditions of temperature and to an altered performance induced by the change of host metabolism under elevated CO{sub 2}. Larval mortality and relative growth rate did not differ between host trees grown in ambient or elevated CO{sub 2}. As extended snow cover may be an important mortality factor of larval colonies on the dwarf trees of mountain pine, we tested the survival of colonies transplanted at two extreme sites of Eastern Alps. The snow cover extended over more than one month proved to be an important mortality factor of larval colonies on mountain pine. We concluded that the first instar larvae of the pine processionary moth are not concerned by unusually low temperature and CO{sub 2} increase whereas they can be later strongly affected by snow accumulation. The decrease of snow cover observed in the last decades, however, may reduce such a risk.

  5. Hydrologic response to and recovery from differing silvicultural systems in a deciduous forest landscape with seasonal snow cover

    Science.gov (United States)

    Buttle, J. M.; Beall, F. D.; Webster, K. L.; Hazlett, P. W.; Creed, I. F.; Semkin, R. G.; Jeffries, D. S.

    2018-02-01

    Hydrological consequences of alternative harvesting strategies in deciduous forest landscapes with seasonal snow cover have received relatively little attention. Most forest harvesting experiments in landscapes with seasonal snow cover have focused on clearcutting in coniferous forests. Few have examined alternative strategies such as selection or shelterwood cutting in deciduous stands whose hydrologic responses to harvesting may differ from those of conifers. This study presents results from a 31-year examination of hydrological response to and recovery from alternative harvesting strategies in a deciduous forest landscape with seasonal snow cover in central Ontario, Canada. A quantitative means of assessing hydrologic recovery to harvesting is also developed. Clearcutting resulted in increased water year (WY) runoff. This was accompanied by increased runoff in all seasons, with greatest relative increases in Summer. Direct runoff and baseflow from treatment catchments generally increased following harvesting, although annual peak streamflow did not. Largest increases in WY runoff and seasonal runoff as well as direct runoff and baseflow generally occurred in the selection harvest catchment, likely as a result of interception of hillslope runoff by a forest access road and redirection to the stream channel. Hydrologic recovery appeared to begin towards the end of the experimental period for several streamflow metrics but was incomplete for all harvesting strategies 15 years after harvesting. Geochemical tracing indicated that harvesting enhanced the relative importance of surface and near-surface water pathways on catchment slopes for all treatments, with the clearcut catchment showing the most pronounced and prolonged response. Such insights into water partitioning between flow pathways may assist assessments of the ecological and biogeochemical consequences of forest disturbance.

  6. Prolongation of soil frost resulting from reduced snow cover increases nitrous oxide emissions from boreal forest soil

    Energy Technology Data Exchange (ETDEWEB)

    Maljanen, M.; Martikainen, P.J. (Univ. of Kuopio, Dept. of Environmental Science (Finland)); Alm, J.; Repo, T. (Finnish Forest Research Inst., Joensuu Research Centre (Finland))

    2010-07-01

    Emission rates of the greenhouse gas, nitrous oxide (N{sub 2}O), from northern upland forest soils are generally low. According to recent climate scenarios, the snow cover in the boreal region is predicted to decrease and which will result in lower soil temperatures. In this study, we investigated whether lower soil temperatures during winter can also trigger N{sub 2}O emissions from boreal forest soils with originally low N{sub 2}O emissions, as has earlier been shown for northern agricultural soils with higher N{sub 2}O emissions. We measured the N{sub 2}O emissions from a spruce forest in eastern Finland where the soil temperature was changed by manipulating snow-pack thickness and using insulating covers. The effects of the treatments on methane (CH{sub 4}) and carbon dioxide (CO{sub 2}) fluxes were also studied for comparative purposes. The results show that there can be an increase in N{sub 2}O emissions and CO{sub 2} production rate from boreal upland forest soils resulting from a thinner snow cover that causes a prolongation of soil frost. Reducing the snow pack thickness had only minor effects on the CH{sub 4} fluxes. (orig.)

  7. Spectral reflectance characteristics of different snow and snow-covered land surface objects and mixed spectrum fitting

    Science.gov (United States)

    Zhang, J.-H.; Zhou, Z.-M.; Wang, P.-J.; Yao, F.-M.; Yang, L.

    2011-01-01

    The field spectroradiometer was used to measure spectra of different snow and snow-covered land surface objects in Beijing area. The result showed that for a pure snow spectrum, the snow reflectance peaks appeared from visible to 800 nm band locations; there was an obvious absorption valley of snow spectrum near 1030 nm wavelength. Compared with fresh snow, the reflection peaks of the old snow and melting snow showed different degrees of decline in the ranges of 300~1300, 1700~1800 and 2200~2300 nm, the lowest was from the compacted snow and frozen ice. For the vegetation and snow mixed spectral characteristics, it was indicated that the spectral reflectance increased for the snow-covered land types(including pine leaf with snow and pine leaf on snow background), due to the influence of snow background in the range of 350~1300 nm. However, the spectrum reflectance of mixed pixel remained a vegetation spectral characteristic. In the end, based on the spectrum analysis of snow, vegetation, and mixed snow/vegetation pixels, the mixed spectral fitting equations were established, and the results showed that there was good correlation between spectral curves by simulation fitting and observed ones(correlation coefficient R2=0.9509).

  8. The strengthening relationship between Eurasian snow cover and December haze days in central North China after the mid-1990s

    Science.gov (United States)

    Yin, Zhicong; Wang, Huijun

    2018-04-01

    The haze pollution in December has become increasingly serious over recent decades and imposes damage on society, ecosystems, and human health. In addition to anthropogenic emissions, climate change and variability were conducive to haze in China. In this study, the relationship between the snow cover over eastern Europe and western Siberia (SCES) and the number of haze days in December in central North China was analyzed. This relationship significantly strengthened after the mid-1990s, which is attributed to the effective connections between the SCES and the Eurasian atmospheric circulations. During 1998-2016, the SCES significantly influenced the soil moisture and land surface radiation, and then the combined underlying drivers of enhanced soil moisture and radiative cooling moved the the East Asia jet stream northward and induced anomalous, anti-cyclonic circulation over central North China. Modulated by such atmospheric circulations, the local lower boundary layer, the decreased surface wind, and the more humid air were conducive to the worsening dispersion conditions and frequent haze occurrences. In contrast, from 1979 to 1997, the linkage between the SCES and soil moisture was negligible. Furthermore, the correlated radiative cooling was distributed narrowly and far from the key area of snow cover. The associated atmospheric circulations with the SCES were not significantly linked with the ventilation conditions over central North China. Consequently, the relationship between the SCES and the number of hazy days in central North China was insignificant before the mid-1990s but has strengthened and has become significant since then.

  9. The strengthening relationship between Eurasian snow cover and December haze days in central North China after the mid-1990s

    Directory of Open Access Journals (Sweden)

    Z. Yin

    2018-04-01

    Full Text Available The haze pollution in December has become increasingly serious over recent decades and imposes damage on society, ecosystems, and human health. In addition to anthropogenic emissions, climate change and variability were conducive to haze in China. In this study, the relationship between the snow cover over eastern Europe and western Siberia (SCES and the number of haze days in December in central North China was analyzed. This relationship significantly strengthened after the mid-1990s, which is attributed to the effective connections between the SCES and the Eurasian atmospheric circulations. During 1998–2016, the SCES significantly influenced the soil moisture and land surface radiation, and then the combined underlying drivers of enhanced soil moisture and radiative cooling moved the the East Asia jet stream northward and induced anomalous, anti-cyclonic circulation over central North China. Modulated by such atmospheric circulations, the local lower boundary layer, the decreased surface wind, and the more humid air were conducive to the worsening dispersion conditions and frequent haze occurrences. In contrast, from 1979 to 1997, the linkage between the SCES and soil moisture was negligible. Furthermore, the correlated radiative cooling was distributed narrowly and far from the key area of snow cover. The associated atmospheric circulations with the SCES were not significantly linked with the ventilation conditions over central North China. Consequently, the relationship between the SCES and the number of hazy days in central North China was insignificant before the mid-1990s but has strengthened and has become significant since then.

  10. Observed radiative cooling over the Tibetan Plateau for the past three decades driven by snow cover-induced surface albedo anomaly

    Science.gov (United States)

    Chen, Xiaona; Long, Di; Hong, Yang; Liang, Shunlin; Hou, Aizhong

    2017-06-01

    Seasonal snow cover on the Tibetan Plateau (TP) is a sensitive indicator of climate change. Unlike the decreasing snow cover extent and associated weakening of radiative cooling effects for the Northern Hemisphere during recent decades reported by previous studies, snow cover variability over the TP and its impact on the energy budget remain largely unknown. We defined the snow cover-induced radiative forcing (SnRF) as the instantaneous perturbation to Earth's shortwave radiation at the top of the atmosphere (TOA) induced by the presence of snow cover. Here using satellite observations and a radiative kernel approach, we found slightly enhanced SnRF, i.e., a radiative cooling effect on the TP during the past three decades (1982-2014). However, this cooling effect weakened during 2001-2014 because of reduced snow cover at a rate of -0.61% decade-1 and land surface albedo at a rate of -0.72% decade-1. Changes in snow cover fraction are highly correlated with anomalies in land surface albedo (as) over the TP both spatially and temporally. Moreover, the SnRF is closely related to the direct observation of TOA shortwave flux anomalies (R2 = 0.54, p = 0.004) over the TP during 2001-2014. Despite the insignificant interannual variability in SnRF, its intra-annual variability has intensified driven mostly by enhanced SnRF during the snow accumulation season but weakened SnRF during the melt season, indicating greater energy release during the transition between accumulation and melt seasons. This may pose a great challenge to snow meltwater use and flood prediction for transboundary rivers originating from the TP, such as the Brahmaputra River basin.

  11. Intensity and sulci landmark combined brain atlas construction for Chinese pediatric population.

    Science.gov (United States)

    Luo, Yishan; Shi, Lin; Weng, Jian; He, Hongjian; Chu, Winnie C W; Chen, Feiyan; Wang, Defeng

    2014-08-01

    Constructing an atlas from a population of brain images is of vital importance to medical image analysis. Especially in neuroscience study, creating a brain atlas is useful for intra- and inter-population comparison. Research on brain atlas construction has attracted great attention in recent years, but the research on pediatric population is still limited, mainly due to the limited availability and the relatively low quality of pediatric magnetic resonance brain images. This article is targeted at creating a high quality representative brain atlas for Chinese pediatric population. To achieve this goal, we have designed a set of preprocessing procedures to improve the image quality and developed an intensity and sulci landmark combined groupwise registration method to align the population of images for atlas construction. As demonstrated in experiments, the newly constructed atlas can better represent the size and shape of brains of Chinese pediatric population, and show better performance in Chinese pediatric brain image analysis compared with other standard atlases. Copyright © 2014 Wiley Periodicals, Inc.

  12. Snow Cover Variability in the Black Forest Region as an Example of a German Low Mountain Range under the Influence of Climate Change

    Science.gov (United States)

    Schoenbein, J.; Schneider, C.

    2003-04-01

    During the last decades high snow cover variability was observed in the German low mountain ranges. In addition, average snow cover periods have decreased at most localities. This process involves a strong economic impact on skiing resorts of low mountain ranges. Based on data sets from weather stations of the German meteorological service (Deutscher Wetterdienst (DWD)) which cover up to the last 60 years, the temporal development of the mean seasonal snow cover period in the low mountain ranges of Black Forest (south-west), Harz (north), and Bavarian Forest (south-east) of Germany was examined. Mean wintertime air temperature in the low mountain ranges is increasing more rapidly compared to the annual mean air temperature. Additionally the south west is the warmest region in Germany. Therefore, the snow cover of the Black Forest is much more susceptible to an increase in air temperature than in the other low mountain ranges in Germany. In the Black Forest region air temperatures near the melting point are observed even in January. Snow cover in the Bavarian Forest region with its much more continental climate is less affected by temperature variations but subject to variations in wintertime precipitation. Seasonal snow cover in the Harz region starts about two weeks earlier compared to Bavarian Forest and the Black Forest. The future snow cover development of Black Forest was examined using Intergovernmental Panel on Climate Change (IPCC) prognosis of future air temperature development and trend analysis within observed time series at low mountain range weather stations. The IPCC scenarios were adopted specifically with respect to region, season and altitude and afterwards compared to the observed trend. A transfer function describes the relation between seasonal air temperature change and snow cover duration. A mean reduction of snow cover duration until 2025 for each mountain range is approximated. For instance, the period of a snow cover with a minimum height

  13. Mechanical construction and installation of the ATLAS tile calorimeter

    Czech Academy of Sciences Publication Activity Database

    Abdallah, J.; Adragna, P.; Alexa, C.; Lokajíček, Miloš; Němeček, Stanislav; Přibyl, Lukáš

    2013-01-01

    Roč. 8, Nov (2013), 1-26 ISSN 1748-0221 Institutional support: RVO:68378271 Keywords : calorimeter * ATLAS * iron * scintillation counter * central region * CERN Lab * rapidity * ATLAS * CERN LHC Coll Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.526, year: 2013

  14. Using NASA Earth Observations to Assist the National Park Service in Assessing Snow Cover Distribution and Persistence Changes in the Sky Islands

    Science.gov (United States)

    Bayat, F.; Barrow, C., III; Gonsoroski, E.; Dutta, S.; Lynn, T.; Harville, K.; Spruce, J.

    2017-12-01

    Saguaro National Park in southeastern Arizona occupies one of several unique mountain ranges known collectively as the Sky Islands or the Madrean Archipelago. The Sky Islands are biodiversity hotspots and host different ecosystems, ranging from arid deserts to temperate forests. Snowmelt provides a source of water during the dry season for various flora and fauna inhabiting the region. Climate change and its effect on snow cover is of growing concern by resource managers in this location. Currently, the National Park Service (NPS) monitors water presence via stream gauges, but a synoptic record of snow presence does not exist due to the remote and rugged topography of the region. As a result, it is difficult to study how climate change has affected water resources in the Sky Islands and what effect this has on wildlife and vegetation. This project used NASA Earth observations (e.g., Landsat data) and GIS technology to help the NPS in understanding the role of snow cover in the Sky Islands. Historical snow cover maps were compiled using a combination of snow detection indices to provide spatio-temporal information on snow presence and phenology. With a more complete understanding of snow cover trends in the park, the NPS can further analyze snow cover impacts to improve future land management decisions.

  15. Some Characteristics of Dust Particles in Atmosphere of Kemerovo City According to Pollution Data of Snow Cover

    Science.gov (United States)

    Golokhvast, K. S.; Manakov, Yu A.; Bykov, A. A.; Chayka, V. V.; Nikiforov, P. A.; Rogulin, R. S.; Romanova, T. Yu; Karabtsov, A. A.; Semenikhin, V. A.

    2017-10-01

    The given paper presents the study results of solid particles contained in snow samples, taken on 10 sites in Kemerovo city in spring 2013. The sites were chosen in such a way as to prevent particles flow into the snow cover in other ways, except with atmospheric precipitation. Kuzbass Botanical Garden was chosen as the check point. In 7 out of 10 sampling sites on the territory of Kemerovo city the presence of particles that are particularly dangerous for human health was found. In one of the areas the particles of 200-400 nm size and with a specific surface area of 14,813.34 cm2/cm3 were detected in ecologically significant quantity (8%).

  16. Snow cover and extreme winter warming events control flower abundance of some, but not all species in high arctic Svalbard

    DEFF Research Database (Denmark)

    Semenchuk, Philipp R.; Elberling, Bo; Cooper, Elisabeth J.

    2013-01-01

    frequent extreme winter warming events. Flower production of many Arctic plants is dependent on melt out timing, since season length determines resource availability for flower preformation. We erected snow fences to increase snow depth and shorten growing season, and counted flowers of six species over 5......years, during which we experienced two extreme winter warming events. Most species were resistant to snow cover increase, but two species reduced flower abundance due to shortened growing seasons. Cassiope tetragona responded strongly with fewer flowers in deep snow regimes during years without extreme...... events, while Stellaria crassipes responded partly. Snow pack thickness determined whether winter warming events had an effect on flower abundance of some species. Warming events clearly reduced flower abundance in shallow but not in deep snow regimes of Cassiope tetragona, but only marginally for Dryas...

  17. Statistical adaptation of ALADIN RCM outputs over the French Alps – application to future climate and snow cover

    Directory of Open Access Journals (Sweden)

    M. Rousselot

    2012-07-01

    Full Text Available In this study, snowpack scenarios are modelled across the French Alps using dynamically downscaled variables from the ALADIN Regional Climate Model (RCM for the control period (1961–1990 and three emission scenarios (SRES B1, A1B and A2 for the mid- and late 21st century (2021–2050 and 2071–2100. These variables are statistically adapted to the different elevations, aspects and slopes of the Alpine massifs. For this purpose, we use a simple analogue criterion with ERA40 series as well as an existing detailed climatology of the French Alps (Durand et al., 2009a that provides complete meteorological fields from the SAFRAN analysis model. The resulting scenarios of precipitation, temperature, wind, cloudiness, longwave and shortwave radiation, and humidity are used to run the physical snow model CROCUS and simulate snowpack evolution over the massifs studied. The seasonal and regional characteristics of the simulated climate and snow cover changes are explored, as is the influence of the scenarios on these changes. Preliminary results suggest that the snow water equivalent (SWE of the snowpack will decrease dramatically in the next century, especially in the Southern and Extreme Southern parts of the Alps. This decrease seems to result primarily from a general warming throughout the year, and possibly a deficit of precipitation in the autumn. The magnitude of the snow cover decline follows a marked altitudinal gradient, with the highest altitudes being less exposed to climate change. Scenario A2, with its high concentrations of greenhouse gases, results in a SWE reduction roughly twice as large as in the low-emission scenario B1 by the end of the century. This study needs to be completed using simulations from other RCMs, since a multi-model approach is essential for uncertainty analysis.

  18. Snow cover setting-up dates in the north of Eurasia: relations and feedback to the macro-scale atmospheric circulation

    Directory of Open Access Journals (Sweden)

    V. V. Popova

    2014-01-01

    Full Text Available Variations of snow cover onset data in 1950–2008 based on daily snow depth data collected at first-order meteorological stations of the former USSR compiled at the Russia Institute of Hydrometeorological Information are analyzed in order to reveal climatic norms, relations with macro-scale atmospheric circulation and influence of snow cover anomalies on strengthening/weakening of westerly basing on observational data and results of simulation using model Planet Simulator, as well. Patterns of mean snow cover setting-up data and their correlation with temperature of the Northern Hemisphere extra-tropical land presented in Fig. 1 show that the most sensible changes observed in last decade are caused by temperature trend since 1990th. For the most portion of the studied territory variations of snow cover setting-up data may be explained by the circulation indices in the terms of Northern Hemisphere Teleconnection Patterns: Scand, EA–WR, WP and NAO (Fig. 2. Role of the Scand and EA–WR (see Fig. 2, а, в, г is recognized as the most significant.Changes of snow cover extent calculated on the base of snow cover onset data over the Russia territory, and its western and eastern parts as well, for the second decade of October (Fig. 3 demonstrate significant difference in variability between eastern and western regions. Eastern part of territory essentially differs by lower both year-to-year and long-term variations in the contrast to the western part, characterized by high variance including long-term tendencies: increase in 1950–70th and decrease in 1970–80 and during last six years. Nevertheless relations between snow cover anomalies and Arctic Oscillation (AO index appear to be significant exceptionally for the eastern part of the territory. In the same time negative linear correlation revealed between snow extent and AO index changes during 1950–2008 from statistically insignificant values (in 1950–70 and 1996–2008 to coefficient

  19. Boreal and temperate snow cover variations induced by black carbon emissions in the middle of the 21st century

    Science.gov (United States)

    Ménégoz, M.; Krinner, G.; Balkanski, Y.; Cozic, A.; Boucher, O.; Ciais, P.

    2013-03-01

    We used a coupled climate-chemistry model to quantify the impacts of aerosols on snow cover north of 30° N both for the present-day and for the middle of the 21st century. Black carbon (BC) deposition over continents induces a reduction in the mean number of days with snow at the surface (MNDWS) that ranges from 0 to 10 days over large areas of Eurasia and Northern America for the present-day relative to the pre-industrial period. This is mainly due to BC deposition during the spring, a period of the year when the remaining of snow accumulated during the winter is exposed to both strong solar radiation and a large amount of aerosol deposition induced themselves by a high level of transport of particles from polluted areas. North of 30° N, this deposition flux represents 222 Gg BC month-1 on average from April to June in our simulation. A large reduction in BC emissions is expected in the future in all of the Representative Concentration Pathway (RCP) scenarios. In particular, considering the RCP8.5 in our simulation leads to a decrease in the spring BC deposition down to 110 Gg month-1 in the 2050s. However, despite the reduction of the aerosol impact on snow, the MNDWS is strongly reduced by 2050, with a decrease ranging from 10 to 100 days from present-day values over large parts of the Northern Hemisphere. This reduction is essentially due to temperature increase, which is quite strong in the RCP8.5 scenario in the absence of climate mitigation policies. Moreover, the projected sea-ice retreat in the next decades will open new routes for shipping in the Arctic. However, a large increase in shipping emissions in the Arctic by the mid-21st century does not lead to significant changes of BC deposition over snow-covered areas in our simulation. Therefore, the MNDWS is clearly not affected through snow darkening effects associated with these Arctic ship emissions. In an experiment without nudging toward atmospheric reanalyses, we simulated however some changes of

  20. Snow cover detection and snow depth algorithms for the Global Change Observation Mission (GCOM) AMSR2 instrument using AMSR-E/AMSR2 measurements

    Science.gov (United States)

    Lee, Y. K.; Kongoli, C.; Key, J. R.

    2014-12-01

    Snow is one of the most dynamic hydrological variables on the Earth surface playing a key role in the global energy and water budget. The ability to detect global snow cover and measure snow depth in near all weather conditions has been demonstrated with satellite microwave measurements. The Advanced Microwave Scanning Radiometer 2 (AMSR2), launched on May 18, 2012 onboard SHIZUKU, is included in A-train group of satellites and will replace the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) instrument. The similarity of channels between AMSR-E and AMSR2 makes AMSR2 instrument a successor of AMSR-E instrument. This study will evaluate the suite of AMSR2 algorithms that are being developed for the operational retrieval of snow cover detection and snow depth using AMSR-E and AMSR2 data. AMSR-E data spans 10 years from June 2002 to September 2011; AMSR2 data spans 2 years from August 2012 to May 2014. The snow cover detection algorithm is based on the operational NOAA's heritage microwave algorithm with snow climatology tests and wet snow filtering as new enhancements. The SD algorithm is adopted from the current version of the operational NASA AMSR-E SWE algorithm. The 24- and 4-km IMS snow cover and in-situ SYNOP and COOP snow depth are used as references for the evaluation. More details about the reference data and evaluation results will be discussed.

  1. Ligninolytic Activity at 0 °C of Fungi on Oak Leaves Under Snow Cover in a Mixed Forest in Japan.

    Science.gov (United States)

    Miyamoto, Toshizumi; Koda, Keiichi; Kawaguchi, Arata; Uraki, Yasumitsu

    2017-08-01

    Despite the importance of litter decomposition under snow cover in boreal forests and tundra, very little is known regarding the characteristics and functions of litter-decomposing fungi adapted to the cold climate. We investigated the decomposition of oak leaves in a heavy snowfall forest region of Japan. The rate of litter weight loss reached 26.5% during the snow cover period for 7 months and accounted for 64.6% of the annual loss (41.1%). Although no statistically significant lignin loss was detected, decolourization portions of oak leaf litter, which was attributable to the activities of ligninolytic fungi, were observed during snow cover period. This suggests that fungi involved in litter decomposition can produce extracellular enzymes to degrade lignin that remain active at 0 °C. Fungi were isolated from oak leaves collected from the forest floor under the snow layer. One hundred and sixty-six strains were isolated and classified into 33 operational taxonomic units (OTUs) based on culture characteristics and nuclear rDNA internal transcribed spacer (ITS) region sequences. To test the ability to degrade lignin, the production of extracellular phenoloxidases by isolates was quantified at 0 °C. Ten OTUs (9 Ascomycota and 1 Basidiomycota) of fungi exhibited mycelial growth and ligninolytic activity. These results suggested that some litter-decomposing fungi that had the potential to degrade lignin at 0 °C significantly contribute to litter decomposition under snow cover.

  2. Evaluation of MODIS Albedo Product (MCD43A) over Grassland, Agriculture and Forest Surface Types During Dormant and Snow-Covered Periods

    Science.gov (United States)

    Wang, Zhousen; Schaaf, Crystal B.; Strahler, Alan H.; Chopping, Mark J.; Roman, Miguel O.; Shuai, Yanmin; Woodcock, Curtis E.; Hollinger, David Y.; Fitzjarrald, David R.

    2013-01-01

    This study assesses the Moderate-resolution Imaging Spectroradiometer (MODIS) BRDF/albedo 8 day standard product and products from the daily Direct Broadcast BRDF/albedo algorithm, and shows that these products agree well with ground-based albedo measurements during the more difficult periods of vegetation dormancy and snow cover. Cropland, grassland, deciduous and coniferous forests are considered. Using an integrated validation strategy, analyses of the representativeness of the surface heterogeneity under both dormant and snow-covered situations are performed to decide whether direct comparisons between ground measurements and 500-m satellite observations can be made or whether finer spatial resolution airborne or spaceborne data are required to scale the results at each location. Landsat Enhanced Thematic Mapper Plus (ETM +) data are used to generate finer scale representations of albedo at each location to fully link ground data with satellite data. In general, results indicate the root mean square errors (RMSEs) are less than 0.030 over spatially representative sites of agriculture/grassland during the dormant periods and less than 0.050 during the snow-covered periods for MCD43A albedo products. For forest, the RMSEs are less than 0.020 during the dormant period and 0.025 during the snow-covered periods. However, a daily retrieval strategy is necessary to capture ephemeral snow events or rapidly changing situations such as the spring snow melt.

  3. Evaluation of MODIS albedo product (MCD43A) over grassland, agriculture and forest surface types during dormant and snow-covered periods

    Science.gov (United States)

    Zhuosen Wang; Crystal B. Schaaf; Alan H. Strahler; Mark J. Chopping; Miguel O. Román; Yanmin Shuai; Curtis E. Woodcock; David Y. Hollinger; David R. Fitzjarrald

    2014-01-01

    This study assesses the Moderate-resolution Imaging Spectroradiometer (MODIS) BRDF/albedo 8 day standard product and products from the daily Direct Broadcast BRDF/albedo algorithm, and shows that these products agree well with ground-based albedo measurements during the more difficult periods of vegetation dormancy and snow cover. Cropland, grassland, deciduous and...

  4. Large-scale Desert Dust Deposition on the Himalayan Snow Cover: A Climatological Perspective from Satellite Observations

    Science.gov (United States)

    Gautam, R.; Hsu, N. C.; Lau, W. K.

    2013-12-01

    The Himalaya-Tibetan Plateau (HTP) has a profound influence on the Asian climate. The HTP are also among the largest snow/ice-covered regions on the Earth and provide major freshwater resource to the downstream densely-populated regions of Asia. Recent studies indicate climate warming over the HTP amplified by atmospheric heating and deposition of absorbing aerosols (e.g. dust and soot) over the HTP snowpack and glaciers. Recently, greater attention has focused on the effects of soot deposition on accelerated snowmelt and glacier retreat in the HTP, associated with increasing anthropogenic emissions in Asia. On the other hand, the role of transported dust affecting snow albedo/melt is not well understood over the HTP, in spite of the large annual cycle of mineral dust loading, particularly over the northern parts of south Asia during pre-monsoon season. This study addresses the large-scale effects of dust deposition on snow albedo in the elevated HTP from a satellite observational perspective. Dust aerosol transport, from southwest Asian arid regions, is observed in satellite imagery as darkening of the Himalayan snowpack. Additionally, multi-year spaceborne lidar observations, from CALIPSO, also show dust advected to elevated altitudes (~5km) over the Himalayan foothills, and episodically reaching the top of the western Himalaya. Spectral surface reflectance analysis of dust-laden snow cover (from MODIS) indicates enhanced absorption in the shorter visible wavelengths, yielding a significant gradient in the visible-nearIR reflectance spectrum. While soot in snow is difficult to distinguish from remote sensing, our spectral reflectance analysis of dust detection in the snowpack is consistent with theoretical simulations of snow darkening due to dust impurity. We find that the western HTP, in general, is influenced by enhanced dust deposition due to its proximity to major dust sources (and prevailing dust transport pathways), compared to the eastern HTP. Coinciding

  5. Ensemble-based assimilation of fractional snow-covered area satellite retrievals to estimate the snow distribution at Arctic sites

    Science.gov (United States)

    Aalstad, Kristoffer; Westermann, Sebastian; Vikhamar Schuler, Thomas; Boike, Julia; Bertino, Laurent

    2018-01-01

    With its high albedo, low thermal conductivity and large water storing capacity, snow strongly modulates the surface energy and water balance, which makes it a critical factor in mid- to high-latitude and mountain environments. However, estimating the snow water equivalent (SWE) is challenging in remote-sensing applications already at medium spatial resolutions of 1 km. We present an ensemble-based data assimilation framework that estimates the peak subgrid SWE distribution (SSD) at the 1 km scale by assimilating fractional snow-covered area (fSCA) satellite retrievals in a simple snow model forced by downscaled reanalysis data. The basic idea is to relate the timing of the snow cover depletion (accessible from satellite products) to the peak SSD. Peak subgrid SWE is assumed to be lognormally distributed, which can be translated to a modeled time series of fSCA through the snow model. Assimilation of satellite-derived fSCA facilitates the estimation of the peak SSD, while taking into account uncertainties in both the model and the assimilated data sets. As an extension to previous studies, our method makes use of the novel (to snow data assimilation) ensemble smoother with multiple data assimilation (ES-MDA) scheme combined with analytical Gaussian anamorphosis to assimilate time series of Moderate Resolution Imaging Spectroradiometer (MODIS) and Sentinel-2 fSCA retrievals. The scheme is applied to Arctic sites near Ny-Ålesund (79° N, Svalbard, Norway) where field measurements of fSCA and SWE distributions are available. The method is able to successfully recover accurate estimates of peak SSD on most of the occasions considered. Through the ES-MDA assimilation, the root-mean-square error (RMSE) for the fSCA, peak mean SWE and peak subgrid coefficient of variation is improved by around 75, 60 and 20 %, respectively, when compared to the prior, yielding RMSEs of 0.01, 0.09 m water equivalent (w.e.) and 0.13, respectively. The ES-MDA either outperforms or at least

  6. Ensemble-based assimilation of fractional snow-covered area satellite retrievals to estimate the snow distribution at Arctic sites

    Directory of Open Access Journals (Sweden)

    K. Aalstad

    2018-01-01

    Full Text Available With its high albedo, low thermal conductivity and large water storing capacity, snow strongly modulates the surface energy and water balance, which makes it a critical factor in mid- to high-latitude and mountain environments. However, estimating the snow water equivalent (SWE is challenging in remote-sensing applications already at medium spatial resolutions of 1 km. We present an ensemble-based data assimilation framework that estimates the peak subgrid SWE distribution (SSD at the 1 km scale by assimilating fractional snow-covered area (fSCA satellite retrievals in a simple snow model forced by downscaled reanalysis data. The basic idea is to relate the timing of the snow cover depletion (accessible from satellite products to the peak SSD. Peak subgrid SWE is assumed to be lognormally distributed, which can be translated to a modeled time series of fSCA through the snow model. Assimilation of satellite-derived fSCA facilitates the estimation of the peak SSD, while taking into account uncertainties in both the model and the assimilated data sets. As an extension to previous studies, our method makes use of the novel (to snow data assimilation ensemble smoother with multiple data assimilation (ES-MDA scheme combined with analytical Gaussian anamorphosis to assimilate time series of Moderate Resolution Imaging Spectroradiometer (MODIS and Sentinel-2 fSCA retrievals. The scheme is applied to Arctic sites near Ny-Ålesund (79° N, Svalbard, Norway where field measurements of fSCA and SWE distributions are available. The method is able to successfully recover accurate estimates of peak SSD on most of the occasions considered. Through the ES-MDA assimilation, the root-mean-square error (RMSE for the fSCA, peak mean SWE and peak subgrid coefficient of variation is improved by around 75, 60 and 20 %, respectively, when compared to the prior, yielding RMSEs of 0.01, 0.09 m water equivalent (w.e. and 0.13, respectively. The ES-MDA either

  7. The Atlas of Health and Working Conditions by Occupation. 2. A comparison with the "Atlas of Health and Working Conditions in the Construction Industry"

    NARCIS (Netherlands)

    Broersen, J. P.; Weel, A. N.; van Dijk, F. J.; Verbeek, J. H.; Bloemhoff, A.; Van Duivenbooden, J. C.

    1995-01-01

    The results of the general Atlas of Health and Working Conditions by Occupation were compared with the results of the Atlas of Health and Working Conditions in the Construction Industry. Both are based on questionnaire data from periodical occupational health surveys [POHSs]. The scores on most of

  8. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover.

  9. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover.

  10. Possible association of the western Tibetan Plateau snow cover with the decadal to interdecadal variations of northern China heatwave frequency

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhiwei [Nanjing University of Information Science and Technology, Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing (China); Chinese Academy of Sciences, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Beijing (China); Jiang, Zhihong; Zhong, Shanshan; Wang, Lijuan [Nanjing University of Information Science and Technology, Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing (China); Li, Jianping [Chinese Academy of Sciences, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Beijing (China)

    2012-11-15

    Northern China has been subject to increased heatwave frequency (HWF) in recent decades, which deteriorates the local droughts and desertification. More than half a billion people face drinking water shortages and worsening ecological environment. In this study, the variability in the western Tibetan Plateau snow cover (TPSC) is observed to have an intimate linkage with the first empirical orthogonal function mode of the summer HWF across China. This distinct leading mode is dominated by the decadal to inter-decadal variability and features a mono-sign pattern with the extreme value center prevailing over northern China and high pressure anomalies at mid- and upper troposphere over Mongolia and the adjacent regions. A simplified general circulation model is utilized to examine the possible physical mechanism. A reduced TPSC anomaly can induce a positive geopotential height anomaly at the mid- and upper troposphere and subsequently enhance the climatological high pressure ridge over Mongolia and the adjacent regions. The subsidence associated with the high pressure anomalies tends to suppress the local cloud formation, which increases the net radiation budget, heats the surface, and favors more heatwaves. On the other hand, the surface heating can excite high pressure anomalies at mid- and upper troposphere. The latter further strengthens the upper troposphere high pressure anomalies over Mongolia and the adjacent regions. Through such positive feedback effect, the TPSC is tied to the interdecadal variations of the northern China HWF. (orig.)

  11. Effects of an Ice Plate Formed by Inundation before the Continuous Snow Cover on Surface Soil Water after Disappearance of the Snow Cover at a Rotational Paddy in a Snowy Cold Region in the Period from Autumn of 2007 to Spring of 2008

    Science.gov (United States)

    Matsuda, Shuh; Mukai, Hiroyuki; Sato, Yoshikazu

    When melt water remains on the soil surface for a long time in rotational paddies in Hokkaido, a snowy cold region of Japan, machine work in the early spring is delayed, resulting in growth delay of crops and decrease in income. Ice plates can be made in paddies in Hokkaido by filling the paddies with water before the continuous snow cover, and melt water flows from the edges of the ice plate. It is expected that the surface soil water after disappearance of the snow cover can be reduced if melt water can flow to an underdrain through open channels along the levees in the paddy. In this study, the effects of an ice plate formed by inundation before the continuous snow cover on surface soil water after disappearance of the snow cover at a rotational paddy in the period from autumn of 2007 to spring of 2008 were examined. It was found that the volumetric water content in the ice plate area was lower than that in the conventional area after disappearance of the snow cover.

  12. Features of Duration and Borders of the Bedding of Snow Cover in the Conditions of Climatic Changes in the Territory of Northern Kazakhstan According to Land and Space Monitoring

    Science.gov (United States)

    Salnikov, Vitaliy; Turulina, Galina; Polyakova, Svetlana; Muratova, Nadiya; Kauazov, Azamat; Abugalieva, Aigul; Tazhibayeva, Tamara

    2014-05-01

    Precipitation and air temperature datasets from 34 meteorological stations were analyzed to reveal the regional climate changes at the territory in North Kazakhstan over the last 58 years (i.e., 1950-2008). Peculiarities and conditions of snow cover formation and melting have been analyzed at territory of Northern Kazakhstan using surface and space monitoring data. Methods of both the geo-informational processing of remote probing data and statistical processing of databases on snow cover, air temperature and precipitations have been used. Analysis of snow cover observations data for territory of Northern Kazakhstan has shown that the stable snow cover might be observed since the middle of November till the beginning of April. In a few last decades the tendency is observed for longevity decrease of snow cover bedding that appears to be on the background air temperature increase and insignificant increase of cold period precipitations due to the later bedding of the snow cover and its earlier destruction. Peculiarities of atmospheric circulation in Atlantic-Eurasian sector of Northern Semi sphere and their influence of formation of snow cover at territory of Northern Kazakhstan. The higher longevity of the snow cover bedding is defined by the predominance of E form circulation and lower longevity - by the predominance of W+C circulation form. Analysis conducted of the highest height of snow cover bedding has shown that for period of 1936-2012 in the most cases the statistically reliable decreasing trends are observed with the linear trend coefficients of 0,50 - 0,60 cm/year. The method is offered for determination of probable characteristics of the snow cover decade height. Using data of space monitoring are allocated the frontiers of snow cover bedding for the period of snow melting 1982-2008 and the snow cover melting maps are developed. The results further confirm the proposition that snow cover availability is an important and limiting factor in the generation

  13. SEGMENTATION OF SERIAL MRI OF TBI PATIENTS USING PERSONALIZED ATLAS CONSTRUCTION AND TOPOLOGICAL CHANGE ESTIMATION.

    Science.gov (United States)

    Wang, Bo; Prastawa, Marcel; Awate, Suyash P; Irimia, Andrei; Chambers, Micah C; Vespa, Paul M; van Horn, John D; Gerig, Guido

    2012-01-01

    Traumatic brain injury (TBI) due to falls, car accidents, and warfare affects millions of people annually. Determining personalized therapy and assessment of treatment efficacy can substantially benefit from longitudinal (4D) magnetic resonance imaging (MRI). In this paper, we propose a method for segmenting longitudinal brain MR images with TBI using personalized atlas construction. Longitudinal images with TBI typically present topological changes over time due to the effect of the impact force on tissue, skull, and blood vessels and the recovery process. We address this issue by defining a novel atlas construction scheme that explicitly models the effect of topological changes. Our method automatically estimates the probability of topological changes jointly with the personalized atlas. We demonstrate the effectiveness of this approach on MR images with TBI that also have been segmented by human raters, where our method that integrates 4D information yields improved validation measures compared to temporally independent segmentations.

  14. Variations in snow cover seasonality across the Kyrgyz Republic from 2000 to 2016 revealed through MODIS Terra and Aqua snow products

    Science.gov (United States)

    Tomaszewska, M. A.; Henebry, G. M.

    2017-12-01

    The vertical transhumance practiced by herders in the highlands of Kyrgyzstan is vulnerable to environmental change. Herd movements and pasture conditions are both affected by spatial and temporal variations in snow cover and the timing of snowmelt. Early growing season soil moisture conditions affect the phenology and growth of vegetation, especially in the high elevation pastures used for summer forage. To evaluate snow seasonality, we examined three snow cover variables—the first day of snow (FDoS), the last day of snow (LDoS), and the duration of snow cover (DoSC) over 17 years based on 8-day snow product from MODIS Terra and Aqua (MOD/MYD10A2) across the Kyrgyz Republic (KYR). To track the "snow season" efficiently in the presence of snow-capped peaks, we start each snow season at day of year (DOY) 169, approximately the summer solstice, and extend to DOY 168 of the following year. To track the interannual variation of these variables, we applied two nonparametric statistics: the Mann-Kendall trend test and the Theil-Sen linear trend estimator. Our preliminary results focusing on four rayons in two oblasts indicate both large swaths of positive and negative significant trends over the different regions of the country. Positive trends in FDoS, meaning later snow arrival, were detected in parts of central KYR. Negative trends in FDoS meaning earlier arrival were detected at lower elevations in southwestern KYR. Earlier snowmelt (negative trend in LDoS) in eastern KYR resulted in a shorter snow season (negative trend in DoSC); in contrast, later snowmelt in southwestern KYR (positive trend in LDoS) resulted in a longer period of snow cover (positive trend of DoSC). We extend the analysis to the entire country and explore the influence of terrain attribites (elevation, slope, and aspect) and MODIS IGBP land cover type (MCD12Q1) on trends in snow cover seasonality. Additionally, we ran the trend tests for the Terra and Aqua snow products separately to evaluate

  15. The bright side of snow cover effects on PV production - How to lower the seasonal mismatch between electricity supply and demand in a fully renewable Switzerland

    Science.gov (United States)

    Kahl, Annelen; Dujardin, Jérôme; Dupuis, Sonia; Lehning, Michael

    2017-04-01

    One of the major problems with solar PV in the context of a fully renewable electricity production at mid-latitudes is the trend of higher production in summer and lower production in winter. This trend is most often exactly opposite to demand patterns, causing a seasonal mismatch that requires extensive balancing power from other production sources or large storage capacities. Which possibilities do we have to bring PV production into closer correlation with demand? This question motivated our research and in response we investigated the effects of placing PV panels at different tilt angles in regions with extensive snow cover to increase winter production from ground reflected short wave radiation. The aim of this project is therefore to quantify the effect of varying snow cover duration (SCD) and of panel tilt angle on the annual total production and on production during winter months when electricity is most needed. We chose Switzerland as ideal test site, because it has a wide range of snow cover conditions and a high potential for renewable electricity production. But methods can be applied to other regions of comparable conditions for snow cover and irradiance. Our analysis can be separated into two steps: 1. A systematic, GIS and satellite-based analysis for all of Switzerland: We use time series of satellite-derived irradiance, and snow cover characteristics together with land surface cover types and elevation information to quantify the environmental conditions and to estimate potential production and ideal tilt angles. 2. A scenario-based analysis that contrasts the production patterns of different placement scenarios for PV panels in urban, rural and mountainous areas. We invoke a model of a fully renewable electricity system (including Switzerland's large hydropower system) at national level to compute the electricity import and storage capacity that will be required to balance the remaining mismatch between production and demand to further illuminate

  16. Construction of 4D high-definition cortical surface atlases of infants: Methods and applications.

    Science.gov (United States)

    Li, Gang; Wang, Li; Shi, Feng; Gilmore, John H; Lin, Weili; Shen, Dinggang

    2015-10-01

    In neuroimaging, cortical surface atlases play a fundamental role for spatial normalization, analysis, visualization, and comparison of results across individuals and different studies. However, existing cortical surface atlases created for adults are not suitable for infant brains during the first two postnatal years, which is the most dynamic period of postnatal structural and functional development of the highly-folded cerebral cortex. Therefore, spatiotemporal cortical surface atlases for infant brains are highly desired yet still lacking for accurate mapping of early dynamic brain development. To bridge this significant gap, leveraging our infant-dedicated computational pipeline for cortical surface-based analysis and the unique longitudinal infant MRI dataset acquired in our research center, in this paper, we construct the first spatiotemporal (4D) high-definition cortical surface atlases for the dynamic developing infant cortical structures at seven time points, including 1, 3, 6, 9, 12, 18, and 24 months of age, based on 202 serial MRI scans from 35 healthy infants. For this purpose, we develop a novel method to ensure the longitudinal consistency and unbiasedness to any specific subject and age in our 4D infant cortical surface atlases. Specifically, we first compute the within-subject mean cortical folding by unbiased groupwise registration of longitudinal cortical surfaces of each infant. Then we establish longitudinally-consistent and unbiased inter-subject cortical correspondences by groupwise registration of the geometric features of within-subject mean cortical folding across all infants. Our 4D surface atlases capture both longitudinally-consistent dynamic mean shape changes and the individual variability of cortical folding during early brain development. Experimental results on two independent infant MRI datasets show that using our 4D infant cortical surface atlases as templates leads to significantly improved accuracy for spatial normalization

  17. Temporal monitoring of the soil freeze-thaw cycles over snow-cover land by using off-ground GPR

    KAUST Repository

    Jadoon, Khan

    2013-07-01

    We performed off-ground ground-penetrating radar (GPR) measurements over a bare agricultural field to monitor the freeze-thaw cycles over snow-cover. The GPR system consisted of a vector network analyzer combined with an off-ground monostatic horn antenna, thereby setting up an ultra-wideband stepped-frequency continuous-wave radar. Measurements were performed during nine days and the surface of the bare soil was exposed to snow fall, evaporation and precipitation as the GPR antenna was mounted 110 cm above the ground. Soil surface dielectric permittivity was retrieved using an inversion of time-domain GPR data focused on the surface reflection. The GPR forward model used combines a full-waveform solution of Maxwell\\'s equations for three-dimensional wave propagation in planar layered media together with global reflection and transmission functions to account for the antenna and its interactions with the medium. Temperature and permittivity sensors were installed at six depths to monitor the soil dynamics in the top 8 cm depth. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and permittivity data and in particular freeze and thaw events were clearly visible. A good agreement of the trend was observed between the temperature, permittivity and GPR time-lapse data with respect to five freeze-thaw cycles. The GPR-derived permittivity was in good agreement with sensor observations. The proposed method appears to be promising for the real-time mapping and monitoring of the frozen layer at the field scale. © 2013 IEEE.

  18. Assessing the thermal dissipation sap flux density method for monitoring cold season water transport in seasonally snow-covered forests.

    Science.gov (United States)

    Chan, Allison M; Bowling, David R

    2017-07-01

    Productivity of conifers in seasonally snow-covered forests is high before and during snowmelt when environmental conditions are optimal for photosynthesis. Climate change is altering the timing of spring in many locations, and changes in the date of transition from winter dormancy can have large impacts on annual productivity. Sap flow methods provide a promising approach to monitor tree activity during the cold season and the winter-spring and fall-winter transitions. Although sap flow techniques have been widely used, cold season results are generally not reported. Here we examine the feasibility of using the Granier thermal dissipation (TD) sap flux density method to monitor transpiration and dormancy of evergreen conifers during the cold season. We conducted a laboratory experiment which demonstrated that the TD method reliably detects xylem water transport (when it occurs) both at near freezing temperature and at low flow rate, and that the sensors can withstand repeated freeze-thaw events. However, the dependence between sensor output and water transport rate in these experiments differed from the established TD relation. In field experiments, sensors installed in two Abies forests lasted through two winters and a summer with low failure. The baseline (no-flow) sensor output varied considerably with temperature during the cold season, and a new baseline algorithm was developed to accommodate this variation. The Abies forests differed in elevation (2070 and 2620 m), and there was a clear difference in timing of initiation and cessation of transpiration between them. We conclude that the TD method can be reliably used to examine water transport during cold periods with associated low flow conditions. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. A simple model for predicting soil temperature in snow-covered and seasonally frozen soil: model description and testing

    Directory of Open Access Journals (Sweden)

    K. Rankinen

    2004-01-01

    Full Text Available Microbial processes in soil are moisture, nutrient and temperature dependent and, consequently, accurate calculation of soil temperature is important for modelling nitrogen processes. Microbial activity in soil occurs even at sub-zero temperatures so that, in northern latitudes, a method to calculate soil temperature under snow cover and in frozen soils is required. This paper describes a new and simple model to calculate daily values for soil temperature at various depths in both frozen and unfrozen soils. The model requires four parameters: average soil thermal conductivity, specific heat capacity of soil, specific heat capacity due to freezing and thawing and an empirical snow parameter. Precipitation, air temperature and snow depth (measured or calculated are needed as input variables. The proposed model was applied to five sites in different parts of Finland representing different climates and soil types. Observed soil temperatures at depths of 20 and 50 cm (September 1981–August 1990 were used for model calibration. The calibrated model was then tested using observed soil temperatures from September 1990 to August 2001. R2-values of the calibration period varied between 0.87 and 0.96 at a depth of 20 cm and between 0.78 and 0.97 at 50 cm. R2-values of the testing period were between 0.87 and 0.94 at a depth of 20cm, and between 0.80 and 0.98 at 50cm. Thus, despite the simplifications made, the model was able to simulate soil temperature at these study sites. This simple model simulates soil temperature well in the uppermost soil layers where most of the nitrogen processes occur. The small number of parameters required means that the model is suitable for addition to catchment scale models. Keywords: soil temperature, snow model

  20. Evaluation of gridded snow water equivalent and satellite snow cover products for mountain basins in a hydrologic model

    Science.gov (United States)

    Dressler, K.A.; Leavesley, G.H.; Bales, R.C.; Fassnacht, S.R.

    2006-01-01

    The USGS precipitation-runoff modelling system (PRMS) hydrologic model was used to evaluate experimental, gridded, 1 km2 snow-covered area (SCA) and snow water equivalent (SWE) products for two headwater basins within the Rio Grande (i.e. upper Rio Grande River basin) and Salt River (i.e. Black River basin) drainages in the southwestern USA. The SCA product was the fraction of each 1 km2 pixel covered by snow and was derived from NOAA advanced very high-resolution radiometer imagery. The SWE product was developed by multiplying the SCA product by SWE estimates interpolated from National Resources Conservation Service snow telemetry point measurements for a 6 year period (1995-2000). Measured SCA and SWE estimates were consistently lower than values estimated from temperature and precipitation within PRMS. The greatest differences occurred in the relatively complex terrain of the Rio Grande basin, as opposed to the relatively homogeneous terrain of the Black River basin, where differences were small. Differences between modelled and measured snow were different for the accumulation period versus the ablation period and had an elevational trend. Assimilating the measured snowfields into a version of PRMS calibrated to achieve water balance without assimilation led to reduced performance in estimating streamflow for the Rio Grande and increased performance in estimating streamflow for the Black River basin. Correcting the measured SCA and SWE for canopy effects improved simulations by adding snow mostly in the mid-to-high elevations, where satellite estimates of SCA are lower than model estimates. Copyright ?? 2006 John Wiley & Sons, Ltd.

  1. Hg in snow cover and snowmelt waters in high-sulfide tailing regions (Ursk tailing dump site, Kemerovo region, Russia).

    Science.gov (United States)

    Gustaytis, M A; Myagkaya, I N; Chumbaev, A S

    2018-07-01

    Gold-bearing polymetallic Cu-Zn deposits of sulphur-pyrite ores were discovered in the Novo-Ursk region in the 1930s. The average content of mercury (Hg) was approximately 120 μg/g at the time. A comprehensive study of Hg distribution in waste of metal ore enrichment industry was carried out in the cold season on the tailing dump site and in adjacent areas. Mercury concentration in among snow particulate, dissolved and colloid fractions was determined. The maximal Hg content in particulate fraction from the waste tailing site ranged 230-573 μg/g. Such indices as the frequency of aerosol dust deposition events per units of time and area, enrichment factor and the total load allowed to establish that the territory of the tailing waste dump site had a snow cover highly contaminated with dust deposited at a rate of 247-480 mg/(m 2 ∙day). Adjacent areas could be considered as area with low Hg contamination rate with average deposition rate of 30 mg/(m 2 ∙day). The elemental composition of the aerosol dust depositions was determined as well, which allowed to reveal the extent of enrichment waste dispersion throughout adjacent areas. The amount of Hg entering environment with snowmelt water discharge was estimated. As a result of snowmelting, in 2014 the nearest to the dump site hydrographic network got Hg as 7.1 g with colloids and as 5880 g as particles. The results obtained allowed to assess the degree of Hg contamination of areas under the impact of metal enrichment industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Design, construction and quality control of resistive-Micromegas anode boards for the ATLAS experiment

    Science.gov (United States)

    Kuger, F.; Iengo, P.

    2018-02-01

    For the upcoming upgrade of the forward muon stations of the ATLAS detector, 1280m2 of Micromegas chambers have to be constructed. The industrialization of anode board production is an essential precondition. Design and construction methods of these boards have been optimized towards mass production. In parallel quality control procedures have been developed and established. The first set of large size Micromegas anode boards has finally been produced in industries and demonstrates the feasibility of the project on full-scale.

  3. Application of the MODIS “snow cover” product for identification of the snow cover pattern in Gis-Baikal region

    Directory of Open Access Journals (Sweden)

    E. A. Istomina

    2014-01-01

    Full Text Available Validation of remote sensing data MODIS «snow cover» in the period from September to May 2000/01, 2007/08, 2008/09 is realized on the base of weather stations data. Good repeatability of weather stations data and snow cover data is shown (more than 80% when snow depth is exceeds 2 cm. The minimum accuracy is in May and October for the variety of snowfall winters. Remote sensing data give possibility to extend the dot information of hydrometeorological stations network on the spatial snow distribution to the mountainous area of Predbajkalje where ground-based observations are absent. According to remote sensing earlier appearance and later melting of snow in mountain areas were identified. The plains and basins areas are characterized by later appearance and earlier melting of snow.

  4. [MONITORING OF THE CONTENT OF HEAVY METALS AND ELEMENTS IN THE SNOW COVER IN AGRICULTURAL SOILS AT THE TERRITORY OF THE MOSCOW REGION].

    Science.gov (United States)

    Ermakov, A A; Karpova, E A; Malysheva, A G; Mikhaylova, R I; Ryzhova, I N

    2015-01-01

    The monitoring of snow cover pollution by heavy metals and elements (zinc, copper, lead, cadmium, arsenic, nickel, chromium, strontium, manganese, fluorine, lithium) was performed in 20 districts of the Moscow region in 2009, 2012 and 2013. The assessment of the levels of contamination by heavy metals and elements was given by means of comparison of them with the average values in the snow cover near Moscow in the end of the last century and in some areas of the world, that no exposed to technological environmental impact. 7 districts of Moscow region were characterized by a high content of lead and cadmium in the snow water. It requires the control of water, soil and agricultural products pollution.

  5. Snow Precipitation and Snow Cover Climatic Variability for the Period 1971–2009 in the Southwestern Italian Alps: The 2008–2009 Snow Season Case Study

    Directory of Open Access Journals (Sweden)

    Simona Fratianni

    2010-10-01

    Full Text Available Snow cover greatly influences the climate in the Alpine region and is one of the most relevant parameters for the climate change analysis. Nevertheless, snow precipitation variability is a relatively underexplored field of research because of the lack of long-term, continuous and homogeneous time series. After a historical research aiming to recover continuous records, three high quality time series of snow precipitation and snow depth recorded in the southwestern Italian Alps were analyzed. The comparison between the climatological indices over the 30 years reference period 1971–2000 and the decade 2000–2009 outlined a general decrease in the amount of snow precipitation, and a shift in the seasonal distribution of the snow precipitation in the most recent period. In the analysis of the last decade snow seasons characteristics, the attention was focused on the heavy snowfalls that occurred in Piedmont during the 2008–2009 snow season: MODerate resolution Imager Spectroradiometer (MODIS snow cover products were used to evaluate snow cover extension at different times during the snow season, and the results were set in relation to the temperatures.

  6. ATLAS endcap liquid argon calorimeters. Description and construction of the cryostats

    International Nuclear Information System (INIS)

    Mace, Guy; Prat, Serge; Veillet, Jean-Jacques

    2006-05-01

    All forward calorimeters of the ATLAS detector use the same detection technique, energy loss in passive plates, followed by ionisation and charge detection in liquid argon. They are therefore all grouped in the same vessel which must basically support and keep in place the heavy plates and the detection electrodes and maintain liquid argon at cold and stable temperature. Taking into account all the constraints as detailed below, and the overall detector size, 5 meter diameter by 3 meter length this was quite a challenge. The design, construction and tests of these two cryostats, up to their delivery at CERN, are described in this document. These two cryostats are a joint 'in kind' contribution to the Atlas experiment of LAL (Orsay), Max Planck Institute (Muenchen) and Wuppertal University (Wuppertal) and have been designed and built under the responsibility of LAL (Orsay) with contributions of the technical groups of the above institutions and of ATLAS-CERN. (authors)

  7. ATLAS endcap liquid argon calorimeters. Description and construction of the cryostats

    Energy Technology Data Exchange (ETDEWEB)

    Mace, Guy; Prat, Serge; Veillet, Jean-Jacques [Laboratoire de l' Accelerateur Lineaire IN2P3-CNRS et Universite de Paris-Sud 11, BP 34, F-91898 Orsay Cedex (France)

    2006-05-15

    All forward calorimeters of the ATLAS detector use the same detection technique, energy loss in passive plates, followed by ionisation and charge detection in liquid argon. They are therefore all grouped in the same vessel which must basically support and keep in place the heavy plates and the detection electrodes and maintain liquid argon at cold and stable temperature. Taking into account all the constraints as detailed below, and the overall detector size, 5 meter diameter by 3 meter length this was quite a challenge. The design, construction and tests of these two cryostats, up to their delivery at CERN, are described in this document. These two cryostats are a joint 'in kind' contribution to the Atlas experiment of LAL (Orsay), Max Planck Institute (Muenchen) and Wuppertal University (Wuppertal) and have been designed and built under the responsibility of LAL (Orsay) with contributions of the technical groups of the above institutions and of ATLAS-CERN. (authors)

  8. Effect of summer throughfall exclusion, summer drought, and winter snow cover on methane fluxes in a temperate forest soil

    Science.gov (United States)

    Borken, W.; Davidson, E.A.; Savage, K.; Sundquist, E.T.; Steudler, P.

    2006-01-01

    Soil moisture strongly controls the uptake of atmospheric methane by limiting the diffusion of methane into the soil, resulting in a negative correlation between soil moisture and methane uptake rates under most non-drought conditions. However, little is known about the effect of water stress on methane uptake in temperate forests during severe droughts. We simulated extreme summer droughts by exclusion of 168 mm (2001) and 344 mm (2002) throughfall using three translucent roofs in a mixed deciduous forest at the Harvard Forest, Massachusetts, USA. The treatment significantly increased CH4 uptake during the first weeks of throughfall exclusion in 2001 and during most of the 2002 treatment period. Low summertime CH4 uptake rates were found only briefly in both control and exclusion plots during a natural late summer drought, when water contents below 0.15 g cm-3 may have caused water stress of methanotrophs in the A horizon. Because these soils are well drained, the exclusion treatment had little effect on A horizon water content between wetting events, and the effect of water stress was smaller and more brief than was the overall treatment effect on methane diffusion. Methane consumption rates were highest in the A horizon and showed a parabolic relationship between gravimetric water content and CH4 consumption, with maximum rate at 0.23 g H2O g-1 soil. On average, about 74% of atmospheric CH4 was consumed in the top 4-5 cm of the mineral soil. By contrast, little or no CH4 consumption occurred in the O horizon. Snow cover significantly reduced the uptake rate from December to March. Removal of snow enhanced CH4 uptake by about 700-1000%, resulting in uptake rates similar to those measured during the growing season. Soil temperatures had little effect on CH4 uptake as long as the mineral soil was not frozen, indicating strong substrate limitation of methanotrophs throughout the year. Our results suggest that the extension of snow periods may affect the annual rate

  9. Construction of a consistent high-definition spatio-temporal atlas of the developing brain using adaptive kernel regression.

    Science.gov (United States)

    Serag, Ahmed; Aljabar, Paul; Ball, Gareth; Counsell, Serena J; Boardman, James P; Rutherford, Mary A; Edwards, A David; Hajnal, Joseph V; Rueckert, Daniel

    2012-02-01

    Medical imaging has shown that, during early development, the brain undergoes more changes in size, shape and appearance than at any other time in life. A better understanding of brain development requires a spatio-temporal atlas that characterizes the dynamic changes during this period. In this paper we present an approach for constructing a 4D atlas of the developing brain, between 28 and 44 weeks post-menstrual age at time of scan, using T1 and T2 weighted MR images from 204 premature neonates. The method used for the creation of the average 4D atlas utilizes non-rigid registration between all pairs of images to eliminate bias in the atlas toward any of the original images. In addition, kernel regression is used to produce age-dependent anatomical templates. A novelty in our approach is the use of a time-varying kernel width, to overcome the variations in the distribution of subjects at different ages. This leads to an atlas that retains a consistent level of detail at every time-point. Comparisons between the resulting atlas and atlases constructed using affine and non-rigid registration are presented. The resulting 4D atlas has greater anatomic definition than currently available 4D atlases created using various affine and non-rigid registration approaches, an important factor in improving registrations between the atlas and individual subjects. Also, the resulting 4D atlas can serve as a good representative of the population of interest as it reflects both global and local changes. The atlas is publicly available at www.brain-development.org. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. ATLAS

    Data.gov (United States)

    Federal Laboratory Consortium — ATLAS is a particle physics experiment at the Large Hadron Collider at CERN, the European Organization for Nuclear Research. Scientists from Brookhaven have played...

  11. Construction of the ATLAS end cap electromagnetic calorimeter and study of its performances; Construction du bouchon du calorimetre electromagnetique d'ATLAS et etudes de ses performances

    Energy Technology Data Exchange (ETDEWEB)

    Barrillon, P

    2002-09-01

    ATLAS is one of the four experiments which will take place at the LHC, the CERN future protons collider. This accelerator, which should start in 2007, will allow to continue the studies carried out by its predecessors, as the standard model Higgs boson and new physics searches. The very high luminosity -10 fb{sup -1} during the first three functioning years, then 100 fb{sup -1}- and the 14 TeV in the frame center will ease these studies. The Centre de Physique des Particules de Marseille took part in the ATLAS collaboration, taking in charge half of the End-cap electromagnetic calorimeter modules construction. The description of this sub-detector and the construction steps, in particular the electrical tests which allow the stacking validation, are presented in this document. These tests results, obtained for the live first production modules, are analysed. The pre-series module (module 0) performances, obtained with beam tests performed at CERN in 1999, are also presented. The detector uniformity studies have allowed to perform important improvements on the calorimeter components. A 0.6% global constant term has been determined in the End-cap internal region (wheel). (author)

  12. Long-range transported dissolved organic matter, ions and black carbon deposited on Central Asian snow covered glaciers

    Science.gov (United States)

    Schmale, Julia; Kang, Shichang; Peltier, Richard

    2014-05-01

    Ninety percent of the Central Asian population depend on water precipitated in the mountains stored in glaciers and snow cover. Accelerated melting of the snow and ice can be induced by the deposition of airborne impurities such as mineral dust, black carbon and co-emitted species leading to significant reductions of the surface albedo. However, Central Asia is a relatively understudied region and data on the source regions, chemical and microphysical characteristics as well as modelling studies of long-range transported air pollution and dust to the Tien Shan mountains is very scarce. We studied the atmospheric aerosol deposited most likely between summer 2012 and summer 2013on three different glaciers in the Kyrgyz Republic. Samples were taken from four snow pits on the glaciers Abramov (2 pits, 39.59 °N, 71.56 °E, 4390 m elevation, 240 cm deep, and 39.62°N, 71.52 °E, 4275 m elevation, 125 cm deep), Ak-Shiirak (41.80 °N, 78.18 °E, 4325 m elevation, 75 cm deep) and Suek (41.78 °N, 77.75 °E, 4341 m elevation, 200 cm deep). The latter two glaciers are located roughly within 6 and 38 km of an operating gold mine. The snow was analyzed for black carbon, ions, metals and organic carbon. We here focus on the results of inorganic ion measurements and organic carbon speciation based on analysis with an Aerodyne high-resolution time-of-flight aerosol spectrometer (HR-ToF-AMS) and potential pollution sources that can be deduced from the chemical information as well as back trajectories. Average contributions of snow impurities measured by the HR-ToF-AMS were dominated by organic carbon. Relative concentrations of organic carbon, sulfate, nitrate and ammonium in snow were 86 %, 3 %, 9 % and 2 % respectively for Abramov, 92 %, 1 %, 5 % and 1 % for Suek, and 95 %, 1 %, 3 % and 1 % for Ak-Shiirak. Generally, impurities on Suek and Ak-Shiirak were three and five times higher than on Abramov. Mass concentrations of organic carbon were on average 6 times higher in samples

  13. Quantification of spatial temporal variability of snow cover and hydro-climatic variables based on multi-source remote sensing data in the Swat watershed, Hindukush Mountains, Pakistan

    Science.gov (United States)

    Anjum, Muhammad Naveed; Ding, Yongjian; Shangguan, Donghui; Liu, Junguo; Ahmad, Ijaz; Ijaz, Muhammad Wajid; Khan, Muhammad Imran

    2018-02-01

    The northern part of Hindukush Mountains has a perplexing environment due to the influence of adjacent mountains of Himalaya, Karakoram, and Tibetan Plateau. Although reliable evidences of climate change are available; however, a clear knowledge of snow cover dynamics in the context of climate change is missing for this region. In this study, we used various remotely sensed (TRMM precipitation product, while MODIS temperature and snow cover products) and gauge-based datasets to quantify the spatiotemporal variability of climatic variables and their turn effects over the snow cover area (SCA) and river discharge in the Swat watershed, northern Hindukush Mountains, Pakistan. The Mann-Kendall method and Sen's slope estimator were used to estimate the trends in SCA and hydro-climatic variables, at 5% significant level (P = 0.05). Results show that the winter and springs temperatures have increased (at the rate of 0.079 and 0.059 °C year-1, respectively), while decreasing in the summer and autumn (at the rate of 0.049 and 0.070 °C year-1, respectively). Basin-wide increasing tendency of precipitation was identified with a highest increasing rate of 3.563 mm year-1 in the spring season. A decreasing trend in the winter SCA (at the rate of -0.275% year-1) and increasing trends in other seasons were identified. An increasing tendency of river discharge on annual and seasonal scales was also witnessed. The seasonal variations in discharge showed significant positive and negative relationships with temperature and SCA, respectively. We conclude that the future variations in the temperature and SCA in the higher altitudes of the Swat watershed could substantially affect the seasonality of the river discharge. Moreover, it implies that the effect of ongoing global warming on the SCA in the snowmelt-dominated river basins needs to be considered for sustainable regional planning and management of water resources, hydropower production, and downstream irrigation scheduling.

  14. Using Gridded Snow Covered Area and Snow-Water Equivalence Spatial Data Sets to Improve Snow-Pack Depletion Simulation in a Continental Scale Hydrologic Model

    Science.gov (United States)

    Risley, J. C.; Tracey, J. A.; Markstrom, S. L.; Hay, L.

    2014-12-01

    Snow cover areal depletion curves were used in a continuous daily hydrologic model to simulate seasonal spring snowmelt during the period between maximum snowpack accumulation and total melt. The curves are defined as the ratio of snow-water equivalence (SWE) divided by the seasonal maximum snow-water equivalence (Ai) (Y axis) versus the percent snow cover area (SCA) (X axis). The slope of the curve can vary depending on local watershed conditions. Windy sparsely vegetated high elevation watersheds, for example, can have a steeper slope than lower elevation forested watersheds. To improve the accuracy of simulated runoff at ungaged watersheds, individual snow cover areal depletion curves were created for over 100,000 hydrologic response units (HRU) in the continental scale U.S. Geological Survey (USGS) National Hydrologic Model (NHM). NHM includes the same components of the USGS Precipitation-Runoff-Modeling System (PRMS), except it uses consistent land surface characterization and model parameterization across the U.S. continent. Weighted-mean daily time series of 1-kilometer gridded SWE, from Snow Data Assimilation System (SNODAS), and 500-meter gridded SCA, from Moderate Resolution Imaging Spectroradiometer (MODIS), for 2003-2014 were computed for each HRU using the USGS Geo Data Portal. Using a screening process, pairs of SWE/Ai and SCA from the snowmelt period of each year were selected. SCA values derived from imagery that did not have any cloud cover and were >0 and <100 percent were selected. Unrealistically low and high SCA values that were paired with high and low SWE/Ai ratios, respectively, were removed. Second order polynomial equations were then fit to the remaining pairs of SWE/Ai and SCA to create a unique curve for each HRU. Simulations comparing these new curves with an existing single default curve in NHM will be made to determine if there are significant improvements in runoff.

  15. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Khan Zaib Jadoon

    2015-09-01

    Full Text Available We tested an off-ground ground-penetrating radar (GPR system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  16. Toxic elements (As, Se, Cd, Hg, Pb) and their mineral and technogenic formations in the snow cover in the vicinity of the industrial enterprises of Tomsk

    International Nuclear Information System (INIS)

    Talovskaya, A V; Filimonenko, E A; Osipova, N A; Lyapina, E E; Azikov, E G Y

    2014-01-01

    Snow samples were collected in four industrial areas of Tomsk where brickworks, factories for the production of reinforced concrete structures, machine repair industries and local boilers, petrochemical plant and thermal power station are located. Study of insoluble fraction of aerosols in snow and melted snow water was performed to determine the contents of the emissions from these facilities. The insoluble fraction of aerosols in snow is aerosol particles deposited on snow cover. As, Se, Cd, Hg, Pb concentration was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Mineral modes of the elements were determined by scanning electron microscope. It was found the snow cover is mainly polluted by As, Se, Cd, Hg, Pb in the thermal power station impact area, by As – in the brickworks impact area, by Se – in the impact area of densely located factories for the production of reinforced concrete structures, machine repair industries and local boilers. The research results show that the mineral modes of As are associated with arsenopyrite, of Pb – with galena in the insoluble fraction of aerosols in snow

  17. Webcam network and image database for studies of phenological changes of vegetation and snow cover in Finland, image time series from 2014 to 2016

    Science.gov (United States)

    Peltoniemi, Mikko; Aurela, Mika; Böttcher, Kristin; Kolari, Pasi; Loehr, John; Karhu, Jouni; Linkosalmi, Maiju; Melih Tanis, Cemal; Tuovinen, Juha-Pekka; Nadir Arslan, Ali

    2018-01-01

    In recent years, monitoring of the status of ecosystems using low-cost web (IP) or time lapse cameras has received wide interest. With broad spatial coverage and high temporal resolution, networked cameras can provide information about snow cover and vegetation status, serve as ground truths to Earth observations and be useful for gap-filling of cloudy areas in Earth observation time series. Networked cameras can also play an important role in supplementing laborious phenological field surveys and citizen science projects, which also suffer from observer-dependent observation bias. We established a network of digital surveillance cameras for automated monitoring of phenological activity of vegetation and snow cover in the boreal ecosystems of Finland. Cameras were mounted at 14 sites, each site having 1-3 cameras. Here, we document the network, basic camera information and access to images in the permanent data repository (http://www.zenodo.org/communities/phenology_camera/). Individual DOI-referenced image time series consist of half-hourly images collected between 2014 and 2016 (https://doi.org/10.5281/zenodo.1066862). Additionally, we present an example of a colour index time series derived from images from two contrasting sites.

  18. Performance of complex snow cover descriptions in a distributed hydrological model system: A case study for the high Alpine terrain of the Berchtesgaden Alps.

    Science.gov (United States)

    Warscher, M; Strasser, U; Kraller, G; Marke, T; Franz, H; Kunstmann, H

    2013-05-01

    [1] Runoff generation in Alpine regions is typically affected by snow processes. Snow accumulation, storage, redistribution, and ablation control the availability of water. In this study, several robust parameterizations describing snow processes in Alpine environments were implemented in a fully distributed, physically based hydrological model. Snow cover development is simulated using different methods from a simple temperature index approach, followed by an energy balance scheme, to additionally accounting for gravitational and wind-driven lateral snow redistribution. Test site for the study is the Berchtesgaden National Park (Bavarian Alps, Germany) which is characterized by extreme topography and climate conditions. The performance of the model system in reproducing snow cover dynamics and resulting discharge generation is analyzed and validated via measurements of snow water equivalent and snow depth, satellite-based remote sensing data, and runoff gauge data. Model efficiency (the Nash-Sutcliffe coefficient) for simulated runoff increases from 0.57 to 0.68 in a high Alpine headwater catchment and from 0.62 to 0.64 in total with increasing snow model complexity. In particular, the results show that the introduction of the energy balance scheme reproduces daily fluctuations in the snowmelt rates that trace down to the channel stream. These daily cycles measured in snowmelt and resulting runoff rates could not be reproduced by using the temperature index approach. In addition, accounting for lateral snow transport changes the seasonal distribution of modeled snowmelt amounts, which leads to a higher accuracy in modeling runoff characteristics.

  19. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    KAUST Repository

    Jadoon, Khan

    2015-09-18

    We tested an off-ground ground-penetrating radar (GPR) system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  20. The ATLAS Liquid Argon Electromagnetic EndCap Calorimeter Construction and tests

    CERN Document Server

    Rodier, S; Del Peso, J

    2003-01-01

    This thesis has been carried out within the ATLAS collaboration. ATLAS is one of the two multipurpose experiments approved for data taking at the Large Hadron Collider (LHC) at CERN. The main goals of this experiment are, to find the Higgs boson, the missing piece in the otherwise so succesful Standard Model of Particle Physics, and to look for physics beyond the Standard Model up to a scale of 1TeV. For this purpose, electromagnetic (EM) calorimetry play a key role. The ATLAS Collaboration has chosen a Liquid Argon (LAr) option with lead as passive material. The liquid Argon Calorimeter is divided into two main subdetectors, the barrel and the end caps (EC). The design and construction of the LAr EM EC calorimeter is the responsability of the groups at Centre de Physique de Marseille (CPPM) and the Universidad Autonoma de Madrid (UAM)following the guideline developed by the research and development working, group 3 for LHC detectors (RD3). The sharing of responsabilities is such that CPPM provides spacers an...

  1. Construction and Test of Full-Size Micromegas Modules for the ATLAS New Small Wheel Upgrade

    Science.gov (United States)

    Bortfeldt, Jonathan

    2018-02-01

    In 2015 the first full size resistive-strip Micromegas modules for the ATLAS New Small Wheel upgrade will be realized. The goal is to provide precision muon tracking with spatial resolution below 100 μm on trapezoidal four-layer detector modules with areas between 2 and 3 m2. This poses stringent limits on the overall accuracy of the modules with respect to strip positioning and planarity. Each module is built as a quadruplet of four resistive strip Micromegas layers, constructed from stiff sandwich panels. An assembly procedure has been developed to build the panels and modules with the required mechanical precision of 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. The construction and quality assurance procedures ensure good module quality verified by checks done during the construction and the chamber assembly.

  2. Construction and Test of MDT Chambers for the ATLAS Muon Spectrometer

    CERN Document Server

    Bauer, F.; Dietl, H.; Kroha, H.; Lagouri, Th.; Manz, A.; Ostapchuk, A.; Richter, Robert; Schael, S.; Chouridou, S.; Deile, M.; Kortner, O.; Staude, A.; Stroehmer, R.; Trefzger, T.

    2001-01-01

    The Monitored Drift Tube (MDT) chambers for the muon spectrometer of the AT- LAS detector at the Large Hadron Collider (LHC) consist of 3-4 layers of pressurized drift tubes on either side of a space frame carrying an optical monitoring system to correct for deformations. The full-scale prototype of a large MDT chamber has been constructed with methods suitable for large-scale production. X-ray measurements at CERN showed a positioning accuracy of the sense wires in the chamber of better than the required 20 ?microns (rms). The performance of the chamber was studied in a muon beam at CERN. Chamber production for ATLAS now has started.

  3. Construction and test of a full-scale prototype of an ATLAS muon spectrometer tracking chamber

    International Nuclear Information System (INIS)

    Biscossa, A.; Cambiaghi, M.; Conta, C.; Ferrari, R.; Fraternali, M.; Freddi, A.; Iuvino, G.; Lanza, A.; Livan, M.; Negri, A.; Polesello, G.; Rimoldi, A.; Vercellati, F.; Vercesi, V.; Bagnaia, P.; Bini, C.; Capradossi, G.; Ciapetti, G.; Creti, P.; De Zorzi, G.; Iannone, M.; Lacava, F.; Mattei, A.; Nisati, L.; Oberson, P.; Pontecorvo, L.; Rosati, S.; Veneziano, S.; Zullo, A.; Daly, C.H.; Davisson, R.; Guldenmann, H.; Lubatti, H.J.; Zhao, T.

    1999-01-01

    We have built a full scale prototype of the precision tracking chambers (Monitored Drift Tubes, MDT) for the muon spectrometer of the Atlas Experiment at the LHC collider. This article describes in detail the procedures used in constructing the drift tubes and in assembling the chamber. It presents data showing that the required mechanical precision has been achieved as well as test beam results displaying the over all chamber performance. The article presents data demonstrating the derivation of the space-time relation of the drift tubes by the autocalibration procedure using real data from the tracks crossing the chamber. Autocalibration is the procedure which must be used during run time

  4. Relationship Between Satellite-Derived Snow Cover and Snowmelt-Runoff Timing and Stream Power in the Wind River Range, Wyoming

    Science.gov (United States)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Riggs, George A.

    2010-01-01

    Earlier onset of springtime weather including earlier snowmelt has been documented in the western United States over at least the last 50 years. Because the majority (>70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack (and shrinking glaciers) has important implications for streamflow management. The amount of water in a snowpack influences stream discharge which can also influence erosion and sediment transport by changing stream power, or the rate at which a stream can do work such as move sediment and erode the stream bed. The focus of this work is the Wind River Range (WRR) in west-central Wyoming. Ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover, cloud- gap-filled (CGF) map products and 30 years of discharge and meteorological station data are studied. Streamflow data from six streams in the WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades, though no trend of either lower streamflow or earlier snowmelt was observed using MODIS snow-cover maps within the decade of the 2000s. Results show a statistically-significant trend at the 95% confidence level (or higher) of increasing weekly maximum air temperature (for three out of the five meteorological stations studied) in the decade of the 1970s, and also for the 40-year study period. MODIS-derived snow cover (percent of basin covered) measured on 30 April explains over 89% of the variance in discharge for maximum monthly streamflow in the decade of the 2000s using Spearman rank correlation analysis. We also investigated stream power for Bull Lake Creek Above Bull Lake from 1970 to 2009; a statistically-significant end toward reduced stream power was found (significant at the 90% confidence level). Observed changes in streamflow and stream power may be related to increasing weekly maximum air temperature measured during the 40-year study period. The

  5. Financial evaluation of the integration of satellite technology for snow cover measurements at a hydroelectric plant. (Utilization of Radarsat I in the La Grande river basin, Quebec)

    International Nuclear Information System (INIS)

    Martin, D.; Bernier, M.; Sasseville, J.L.; Charbonneau, R.

    1999-01-01

    The emergence, on the markets, of new technologies evokes, for the potential users, a lot of questions concerning the implementation and operation costs associated with these technologies. Nevertheless, for a lot of users, costs should be considered with the benefits these technologies are able to generate. The benefit-cost analysis is a useful tool for a financial evaluation of the transferability of the technology. This method has been selected to evaluate the eventual implementation of remote sensing technologies for snow cover measurements in the La Grande river basin (Quebec, Canada). Indeed, a better assessment of the snow water equivalent leads to a better forecasting of the water inputs due to the snowmelt. Thus, the improvement of the snow cover monitoring has direct impact on hydroelectric reservoir management. The benefit-cost analysis was used to compare three acquisition modes of the satellite Radarsat 1 (ScanSAR, Wide and Standard). The costs considered for this project are: R and D costs and operations costs (the purchase of images and costs of ground truth measurements). We evaluated the raw benefits on the basis of reducing the standard deviation of predicted inflows. The results show that the ScanSAR mode is the primary remote sensing tool for the monitoring of the snow cover, on an operational basis. With this acquisition mode, the benefit-cost ratios range between 2.3:1 and 3.9:1, using a conservative 4% reduction of the standard deviation. Even if the reduction is only 3%, ScanSAR remains profitable. Due to the large number of images needed to cover all the territory, the Standard and Wide modes are penalized by the purchase and the processing costs of the data and with delays associated to the processing. Nevertheless, with these two modes, it could be possible to work with a partial coverage of the watershed, 75% being covered in 4 days in Wide mod. The estimated B/C ratios (1.5:1 and 2:1) confirm the advantages of this alternative

  6. Ground measurements of the hemispherical-directional reflectance of Arctic snow covered tundra for the validation of satellite remote sensing products

    Science.gov (United States)

    Ball, C. P.; Marks, A. A.; Green, P.; Mac Arthur, A.; Fox, N.; King, M. D.

    2013-12-01

    Surface albedo is the hemispherical and wavelength integrated reflectance over the visible, near infrared and shortwave infrared regions of the solar spectrum. The albedo of Arctic snow can be in excess of 0.8 and it is a critical component in the global radiation budget because it determines the proportion of solar radiation absorbed, and reflected, over a large part of the Earth's surface. We present here our first results of the angularly resolved surface reflectance of Arctic snow at high solar zenith angles (~80°) suitable for the validation of satellite remote sensing products. The hemispherical directional reflectance factor (HDRF) of Arctic snow covered tundra was measured using the GonioRAdiometric Spectrometer System (GRASS) during a three-week field campaign in Ny-Ålesund, Svalbard, in March/April 2013. The measurements provide one of few existing HDRF datasets at high solar zenith angles for wind-blown Arctic snow covered tundra (conditions typical of the Arctic region), and the first ground-based measure of HDRF at Ny-Ålesund. The HDRF was recorded under clear sky conditions with 10° intervals in view zenith, and 30° intervals in view azimuth, for several typical sites over a wavelength range of 400-1500 nm at 1 nm resolution. Satellite sensors such as MODIS, AVHRR and VIIRS offer a method to monitor the surface albedo with high spatial and temporal resolution. However, snow reflectance is anisotropic and is dependent on view and illumination angle and the wavelength of the incident light. Spaceborne sensors subtend a discrete angle to the target surface and measure radiance over a limited number of narrow spectral bands. Therefore, the derivation of the surface albedo requires accurate knowledge of the surfaces bidirectional reflectance as a function of wavelength. The ultimate accuracy to which satellite sensors are able to measure snow surface properties such as albedo is dependant on the accuracy of the BRDF model, which can only be assessed

  7. ATLAS

    CERN Multimedia

    Akhnazarov, V; Canepa, A; Bremer, J; Burckhart, H; Cattai, A; Voss, R; Hervas, L; Kaplon, J; Nessi, M; Werner, P; Ten kate, H; Tyrvainen, H; Vandelli, W; Krasznahorkay, A; Gray, H; Alvarez gonzalez, B; Eifert, T F; Rolando, G; Oide, H; Barak, L; Glatzer, J; Backhaus, M; Schaefer, D M; Maciejewski, J P; Milic, A; Jin, S; Von torne, E; Limbach, C; Medinnis, M J; Gregor, I; Levonian, S; Schmitt, S; Waananen, A; Monnier, E; Muanza, S G; Pralavorio, P; Talby, M; Tiouchichine, E; Tocut, V M; Rybkin, G; Wang, S; Lacour, D; Laforge, B; Ocariz, J H; Bertoli, W; Malaescu, B; Sbarra, C; Yamamoto, A; Sasaki, O; Koriki, T; Hara, K; Da silva gomes, A; Carvalho maneira, J; Marcalo da palma, A; Chekulaev, S; Tikhomirov, V; Snesarev, A; Buzykaev, A; Maslennikov, A; Peleganchuk, S; Sukharev, A; Kaplan, B E; Swiatlowski, M J; Nef, P D; Schnoor, U; Oakham, G F; Ueno, R; Orr, R S; Abouzeid, O; Haug, S; Peng, H; Kus, V; Vitek, M; Temming, K K; Dang, N P; Meier, K; Schultz-coulon, H; Geisler, M P; Sander, H; Schaefer, U; Ellinghaus, F; Rieke, S; Nussbaumer, A; Liu, Y; Richter, R; Kortner, S; Fernandez-bosman, M; Ullan comes, M; Espinal curull, J; Chiriotti alvarez, S; Caubet serrabou, M; Valladolid gallego, E; Kaci, M; Carrasco vela, N; Lancon, E C; Besson, N E; Gautard, V; Bracinik, J; Bartsch, V C; Potter, C J; Lester, C G; Moeller, V A; Rosten, J; Crooks, D; Mathieson, K; Houston, S C; Wright, M; Jones, T W; Harris, O B; Byatt, T J; Dobson, E; Hodgson, P; Hodgkinson, M C; Dris, M; Karakostas, K; Ntekas, K; Oren, D; Duchovni, E; Etzion, E; Oren, Y; Ferrer, L M; Testa, M; Doria, A; Merola, L; Sekhniaidze, G; Giordano, R; Ricciardi, S; Milazzo, A; Falciano, S; De pedis, D; Dionisi, C; Veneziano, S; Cardarelli, R; Verzegnassi, C; Soualah, R; Ochi, A; Ohshima, T; Kishiki, S; Linde, F L; Vreeswijk, M; Werneke, P; Muijs, A; Vankov, P H; Jansweijer, P P M; Dale, O; Lund, E; Bruckman de renstrom, P; Dabrowski, W; Adamek, J D; Wolters, H; Micu, L; Pantea, D; Tudorache, V; Mjoernmark, J; Klimek, P J; 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Sadrozinski, H; Lockman, W S; Martinez-mc kinney, G; Goussiou, A; Jones, A; Lie, K; Hasegawa, Y; Olcese, M; Gilewsky, V; Harrison, P F; Janus, M; Spangenberg, M; De, K; Ozturk, N; Pal, A K; Darmora, S; Bullock, D J; Oviawe, O; Derkaoui, J E; Rahal, G; Sircar, A; Frey, A S; Stolte, P; Rosien, N; Zoch, K; Li, L; Schouten, D W; Catinaccio, A; Ciapetti, M; Delruelle, N; Ellis, N; Farthouat, P; Hoecker, A; Klioutchnikova, T; Macina, D; Malyukov, S; Spiwoks, R D; Unal, G P; Vandoni, G; Petersen, B A; Pommes, K; Nairz, A M; Wengler, T; Mladenov, D; Solans sanchez, C A; Lantzsch, K; Schmieden, K; Jakobsen, S; Ritsch, E; Sciuccati, A; Alves dos santos, A M; Ouyang, Q; Zhou, M; Brock, I C; Janssen, J; Katzy, J; Anders, C F; Nilsson, B S; Bazan, A; Di ciaccio, L; Yildizkaya, T; Collot, J; Malek, F; Trocme, B S; Breugnon, P; Godiot, S; Adam bourdarios, C; Coulon, J; Duflot, L; Petroff, P G; Zerwas, D; Lieuvin, M; Calderini, G; Laporte, D; Ocariz, J; Gabrielli, A; Ohska, T K; Kurochkin, Y; Kantserov, V; Vasilyeva, L; Speransky, M; Smirnov, S; Antonov, A; Bulekov, O; Tikhonov, Y; Sargsyan, L; Vardanyan, G; Budick, B; Kocian, M L; Luitz, S; Young, C C; Grenier, P J; Kelsey, M; Black, J E; Kneringer, E; Jussel, P; Horton, A J; Beaudry, J; Chandra, A; Ereditato, A; Topfel, C M; Mathieu, R; Bucci, F; Muenstermann, D; White, R M; He, M; Urban, J; Straka, M; Vrba, V; Schumacher, M; Parzefall, U; Mahboubi, K; Sommer, P O; Koepke, L H; Bethke, S; Moser, H; Wiesmann, M; Walkowiak, W A; Fleck, I J; Martinez-perez, M; Sanchez sanchez, C A; Jorgensen roca, S; Accion garcia, E; Sainz ruiz, C A; Valls ferrer, J A; Amoros vicente, G; Vives torrescasana, R; Ouraou, A; Formica, A; Hassani, S; Watson, M F; Cottin buracchio, G F; Bussey, P J; Saxon, D; Ferrando, J E; Collins-tooth, C L; Hall, D C; Cuhadar donszelmann, T; Dawson, I; Duxfield, R; Argyropoulos, T; Brodet, E; Livneh, R; Shougaev, K; Reinherz, E I; Guttman, N; Beretta, M M; Vilucchi, E; Aloisio, A; Patricelli, S; Caprio, M; Cevenini, F; De vecchi, C; Livan, M; Rimoldi, A; Vercesi, V; Ayad, R; Mastroberardino, A; Ciapetti, G; Luminari, L; Rescigno, M; Santonico, R; Salamon, A; Del papa, C; Kurashige, H; Homma, Y; Tomoto, M; Horii, Y; Sugaya, Y; Hanagaki, K; Bobbink, G; Kluit, P M; Koffeman, E N; Van eijk, B; Lee, H; Eigen, G; Dorholt, O; Strandlie, A; Strzempek, P B; Dita, S; Stoicea, G; Chitan, A; Leven, S S; Moa, T; Brenner, R; Ekelof, T J C; Olshevskiy, A; Roumiantsev, V; Chlachidze, G; Zimine, N; Gusakov, Y; Grigalashvili, N; Mineev, M; Potrap, I; Barashkou, A; Shoukavy, D; Shaykhatdenov, B; Pikelner, A; Gladilin, L; Ammosov, V; Abramov, A; Arik, M; Sahinsoy, M; Uysal, Z; Azizi, K; Hotinli, S C; Zhou, S; Berger, E; Blair, R; Underwood, D G; Einsweiler, K; Garcia-sciveres, M A; Siegrist, J L; Kipnis, I; Dahl, O; Holland, S; Barbaro galtieri, A; Smith, P T; Parua, N; Franklin, M; Mercurio, K M; Tong, B; Pod, E; Cole, S G; Hopkins, W H; Guest, D H; Severini, H; Marsicano, J J; Abbott, B K; Wang, Q; Lissauer, D; Ma, H; Takai, H; Rajagopalan, S; Protopopescu, S D; Snyder, S S; Undrus, A; Popescu, R N; Begel, M A; Blocker, C A; Amelung, C; Mandic, I; Macek, B; Tucker, B H; Citterio, M; Troncon, C; Orestano, D; Taccini, C; Romeo, G L; Dova, M T; Taylor, G N; Gesualdi manhaes, A; Mcpherson, R A; Sobie, R; Taylor, R P; Dolezal, Z; Kodys, P; Slovak, R; Sopko, B; Vacek, V; Sanders, M P; Hertenberger, R; Meineck, C; Becks, K; Kind, P; Sandhoff, M; Cantero garcia, J; De la torre perez, H; Castillo gimenez, V; Ros, E; Hernandez jimenez, Y; Chadelas, R; Santoni, C; Washbrook, A J; O'brien, B J; Wynne, B M; Mehta, A; Vossebeld, J H; Landon, M; Teixeira dias castanheira, M; Cerrito, L; Keates, J R; Fassouliotis, D; Chardalas, M; Manousos, A; Grachev, V; Seliverstov, D; Sedykh, E; Cakir, O; Ciftci, R; Edson, W; Prell, S A; Rosati, M; Stroman, T; Jiang, H; Neal, H A; Li, X; Gan, K K; Smith, D S; Kruse, M C; Ko, B R; Leung fook cheong, A M; Cole, B; Angerami, A R; Greene, Z S; Kroll, J I; Van berg, R P; Forbush, D A; Lubatti, H; Raisher, J; Shupe, M A; Wolin, S; Oshita, H; Gaudio, G; Das, R; Konig, A C; Croft, V A; Harvey, A; Maaroufi, F; Melo, I; Greenwood jr, Z D; Shabalina, E; Mchedlidze, G; Drechsler, E; Rieger, J K; Blackston, M; Colombo, T

    2002-01-01

    % ATLAS \\\\ \\\\ ATLAS is a general-purpose experiment for recording proton-proton collisions at LHC. The ATLAS collaboration consists of 144 participating institutions (June 1998) with more than 1750~physicists and engineers (700 from non-Member States). The detector design has been optimized to cover the largest possible range of LHC physics: searches for Higgs bosons and alternative schemes for the spontaneous symmetry-breaking mechanism; searches for supersymmetric particles, new gauge bosons, leptoquarks, and quark and lepton compositeness indicating extensions to the Standard Model and new physics beyond it; studies of the origin of CP violation via high-precision measurements of CP-violating B-decays; high-precision measurements of the third quark family such as the top-quark mass and decay properties, rare decays of B-hadrons, spectroscopy of rare B-hadrons, and $ B ^0 _{s} $-mixing. \\\\ \\\\The ATLAS dectector, shown in the Figure includes an inner tracking detector inside a 2~T~solenoid providing an axial...

  8. Construction of the ATLAS end cap electromagnetic calorimeter and study of its performances

    International Nuclear Information System (INIS)

    Barrillon, P.

    2002-09-01

    ATLAS is one of the four experiments which will take place at the LHC, the CERN future protons collider. This accelerator, which should start in 2007, will allow to continue the studies carried out by its predecessors, as the standard model Higgs boson and new physics searches. The very high luminosity -10 fb -1 during the first three functioning years, then 100 fb -1 - and the 14 TeV in the frame center will ease these studies. The Centre de Physique des Particules de Marseille took part in the ATLAS collaboration, taking in charge half of the End-cap electromagnetic calorimeter modules construction. The description of this sub-detector and the construction steps, in particular the electrical tests which allow the stacking validation, are presented in this document. These tests results, obtained for the live first production modules, are analysed. The pre-series module (module 0) performances, obtained with beam tests performed at CERN in 1999, are also presented. The detector uniformity studies have allowed to perform important improvements on the calorimeter components. A 0.6% global constant term has been determined in the End-cap internal region (wheel). (author)

  9. Frozen soil and snow cover with respect to the hydrological land-surface behaviour; Gefrorener Boden und Schneebedeckung unter besonderer Beruecksichtigung des hydrologischen Verhaltens der Landoberflaeche

    Energy Technology Data Exchange (ETDEWEB)

    Warrach, K. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Atmosphaerenphysik

    2000-07-01

    Investigations of the water and energy cycle in the climate system using atmospheric circulation models require a proper representation of the land surface. The land-surface model SEWAB calculates the vertical exchange of water and energy between the atmosphere and the land-surface. This includes the calculation of runoff from the land-surface into the rivers and of the vertical heat and water fluxes within the soil. The inclusion of soil freezing and thawing and the accumulation and ablation of a snow cover in SEWAB is introduced. Additionally changes in the runoff calculation such as the inclusion of the TOPMODEL-approach to consider orographic effects are made. Applications carried out for various regions of North America show good agreement between model results and measurements. (orig.)

  10. The influence of snow cover on alpine floods reconstructed from the analysis of satellite images. The case of the Hasli-Aare river basin, Berner Oberland (1987-2012)

    Science.gov (United States)

    Cabrera-Medina, Paula; Schulte, Lothar; Carvalho, Filipe; Peña, Juan Carlos; García, Carles

    2016-04-01

    Regarding the hydrological hazards in the Hasli-Aare river over the last century, instrumental and documentary data show that flood frequency and magnitude increased since 1977. One of the main water inputs contributing to peak discharges is given by the thaw of the stored snow. Therefore, the knowledge of the evolution of snow cover is considered essential for the assessment of alpine floods. Snow cover studies can be made by different approaches such as the analysis of data provided by field work or by nivometeorological stations. However, these methods are usually expensive and do not present adequate spatial or temporal coverage data. For this reason, satellite images with different spatial and temporal resolution are an interesting complementary source for the understanding of the snow cover dynamics. The aim of the paper is to study the influence of snow cover variations during years of severe floods that occurred in the upper Aare basin from 1987 to 2012. Three satellite images have been selected for each of the 9 studied events: 1) maximum snow cover during winter, 2) the last image before the event and 3) the first image after the flood. Each image has been processed with the ArcGIS software applying a statistical method of supervised classification. This image processing allows the spatial quantification of the variation of the snow cover in the Aare headwater catchment. Because the melting of snow cover is related to the changes of weather situations before and during the flood episode, it is important to analyse also the nivometeorological data of stations located in the catchment (snow depth, temperature and precipitation). From these data we determined 4 types of flood, which can be classified according to their nivometeorological variables and synoptic situation (500 hPa geopotential and Sea Level Pressure) into two patterns. The first group of events can be associated to an Atlantic pattern recording decreasing temperatures, moderate to high

  11. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    Losel, Philipp Jonathan; The ATLAS collaboration

    2014-01-01

    Large area Micromegas detectors will be employed fo r the first time in high-energy physics experiments. A total surface of about 150 m$^2$ of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m$^2$ for a total active area of 1200 m$^2$. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resol ution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical prec ision of each plane of the assembled module must be as good as 30 $\\mu$m along the precision coordi nate and 80 $\\mu$m perpendicular to the chamber. The design and construction procedure of the microm egas modules will be presented, as well as the design for the assembly of modules onto the New Small Wheel. Emphasis wi...

  12. Design and Construction of Large Size Micromegas Chambers for the Upgrade of the ATLAS Muon Spectrometer

    CERN Document Server

    Lösel, Philipp; Müller, Ralph

    2015-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about $\\mathbf{150~m^2}$ of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each layer covers more than $\\mathbf{2~m^2}$ for a total active area of $\\mathbf{1200~m^2}$. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15$\\mathbf{\\%}$ transverse momentum resolution for $\\mathbf{1~TeV}$ muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as $\\mathbf{30~\\mu m}$ along the precision coordinate and $\\mathbf{80~\\mu m}$ perpendicular to the chamber. The design and construction procedure of the Micromegas modules will be presented, as well as the design for the assembly ...

  13. Winter stream temperature in the rain-on-snow zone of the Pacific Northwest: influences of hillslope runoff and transient snow cover

    Directory of Open Access Journals (Sweden)

    J. A. Leach

    2014-02-01

    Full Text Available Stream temperature dynamics during winter are less well studied than summer thermal regimes, but the winter season thermal regime can be critical for fish growth and development in coastal catchments. The winter thermal regimes of Pacific Northwest headwater streams, which provide vital winter habitat for salmonids and their food sources, may be particularly sensitive to changes in climate because they can remain ice-free throughout the year and are often located in rain-on-snow zones. This study examined winter stream temperature patterns and controls in small headwater catchments within the rain-on-snow zone at the Malcolm Knapp Research Forest, near Vancouver, British Columbia, Canada. Two hypotheses were addressed by this study: (1 winter stream temperatures are primarily controlled by advective fluxes associated with runoff processes and (2 stream temperatures should be depressed during rain-on-snow events, compared to rain-on-bare-ground events, due to the cooling effect of rain passing through the snowpack prior to infiltrating the soil or being delivered to the stream as saturation-excess overland flow. A reach-scale energy budget analysis of two winter seasons revealed that the advective energy input associated with hillslope runoff overwhelms vertical energy exchanges (net radiation, sensible and latent heat fluxes, bed heat conduction, and stream friction and hyporheic energy fluxes during rain and rain-on-snow events. Historical stream temperature data and modelled snowpack dynamics were used to explore the influence of transient snow cover on stream temperature over 13 winters. When snow was not present, daily stream temperature during winter rain events tended to increase with increasing air temperature. However, when snow was present, stream temperature was capped at about 5 °C, regardless of air temperature. The stream energy budget modelling and historical analysis support both of our hypotheses. A key implication is that

  14. Snow cover dynamics in Andean watersheds of Chile (32.0-39.5° S) during the years 2000-2016

    Science.gov (United States)

    Stehr, Alejandra; Aguayo, Mauricio

    2017-10-01

    Andean watersheds present important snowfall accumulation mainly during the winter, which melts during the spring and part of the summer. The effect of snowmelt on the water balance can be critical to sustain agriculture activities, hydropower generation, urban water supplies and wildlife. In Chile, 25 % of the territory between the region of Valparaiso and Araucanía comprises areas where snow precipitation occurs. As in many other difficult-to-access regions of the world, there is a lack of hydrological data of the Chilean Andes related to discharge, snow courses, and snow depths, which complicates the analysis of important hydrological processes (e.g. water availability). Remote sensing provides a promising opportunity to enhance the assessment and monitoring of the spatial and temporal variability of snow characteristics, such as the snow cover area (SCA) and snow cover dynamic (SCD). With regards to the foregoing questions, the objective of the study is to evaluate the spatiotemporal dynamics of the SCA at five watersheds (Aconcagua, Rapel, Maule, Biobío and Toltén) located in the Chilean Andes, between latitude 32.0 and 39.5° S, and to analyse its relationship with the precipitation regime/pattern and El Niño-Southern Oscillation (ENSO) events. Those watersheds were chosen because of their importance in terms of their number of inhabitants, and economic activities depending on water resources. The SCA area was obtained from MOD10A2 for the period 2000-2016, and the SCD was analysed through a number of statistical tests to explore observed trends. In order to verify the SCA for trend analysis, a validation of the MOD10A2 product was done, consisting of the comparison of snow presence predicted by MODIS with ground observations. Results indicate that there is an overall agreement of 81 to 98 % between SCA determined from ground observations and MOD10A2, showing that the MODIS snow product can be taken as a feasible remote sensing tool for SCA estimation in

  15. Design and Construction of Precision Tooling for Construction of Micromegas Detectors for the ATLAS Small Wheel Upgrade Project in Germany

    CERN Document Server

    Losel, Philipp Jonathan; The ATLAS collaboration; Schaile, Otto; Hertenberger, Ralf; Biebel, Otmar; Bortfeldt, Jonathan; Flierl, Bernhard Matthias

    2016-01-01

    Mechanical precision is a key-aspect of the high-rate capable Micromegas detectors for the upgrade of the Small Wheels of the ATLAS muon spectrometer. 32 SM2 quadruplets will be built by four German institutes with cathodes and strip-anodes made of stable honeycomb sandwiches. To achieve a single plane resolution below $100\\mu m$ the deviation from planarity of a single detector plane must not exceed $80\\mu m$ over the whole active area and the global position of the readout strips has to be within $30\\mu m$ for a single readout-plane of 3 PCB's, as well as between all four planes of a quadruplet. Precision tooling is used for the correct positioning of readout PCB's and readout sandwich planes. For quality control of the planarity of the sandwich planes a laser distance sensor combined with a coordinate measurement system has been developed. Deviation from planarity below 10 $\\mu$m can be easily resolved. We will present key features of the challenging construction procedure to achieve this high level of pre...

  16. On the Linkage between Springtime Eurasian Snow Cover Retreat due to the Global Warming and Changes in Summertime Atmospheric Circulation over Japan and East Asia

    Science.gov (United States)

    Nozawa, T.; Fujiwara, S.

    2017-12-01

    According to the 5th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5), snow cover extent (SCE) over the northern hemisphere is greatly decreasing in spring. This change is expected to affect atmospheric circulation change via land-atmosphere interactions. In this study, we investigated relationships between spring SCE anomaly over the Eurasia and changes in atmospheric circulations, mainly analyzing the Japanese 55-year Reanalysis (JRA-55). Differences in composites of zonal winds at upper and middle levels between large and small SCE years over Western Siberia in spring show that, around Japan and East Asia, jet stream in small SCE years is shifted southward in April and June. We also analyzed surface temperature and soil moisture and find that, in small SCE years, surface temperature in Western Siberia and Central Asia is increased and soil moisture reduced significantly in June. The air temperature in the middle and low level atmosphere also significantly increased and have wave-like pattern in May. These results suggest that there are some linkages between the springtime Eurasian SCE reduction and changes in summertime jet stream over Japan and East Asia through land-atmosphere interactions.

  17. Construction and Test of New Precision Drift-Tube Chambers for the ATLAS Muon Spectrometer

    CERN Document Server

    INSPIRE-00218480

    2017-02-11

    ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 ?micons have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new R...

  18. Design, construction, quality checks and test results of first resistive-Micromegas read-out boards for the ATLAS experiment

    CERN Document Server

    Iengo, Paolo; The ATLAS collaboration

    2015-01-01

    The development work carried out at CERN to push the Micromegas technology to a new frontier is now coming to an end. The construction of the first read-out boards for the upgrade of the ATLAS muon system will demonstrate in full-scale the feasibility of this ambitious project. The read-out boards, representing the heart of the detector, are manufactured in industries, making the Micromegas for ATLAS the first MPGD for a large experiment with a relevant part industrially produced. The boards are 50 cm wide and up to 220 cm long, carrying copper strips 315 μm wide with 415 μm pitch. Interconnected resistive strips, having the same pattern as the copper strips, provide spark protection. The boards are completed by the creation of cylindrical pillars 128 μm high, 280 μm in diameter and arranged in a triangular array 7 mm aside. The total number of boards to be produced for ATLAS is 2048 of 32 different types. We will review the main design parameters of the read-out boards for the ATLAS Micromegas, following...

  19. Construction and Test of Full-Size Micromegas Modules for the ATLAS New Small Wheel Upgrade

    CERN Document Server

    Bortfeldt, Jonathan; The ATLAS collaboration

    2015-01-01

    In 2015 the first full size resistive-strip Micromegas operational modules for the ATLAS New Small Wheel upgrade will be realized. The goal is to provide precision muon tracking with spatial resolution below 100$\\mu$m on trapezoidal four-layer detector modules with areas between 2 and 3m$^2$. This poses stringent limits on the overall accuracy of the modules with respect to strip positioning and planarity. The overall thickness of each modules is about 70mm and the total number of readout channels is on the order of $1.5\\cdot10^4$ per module. Each module is a quadruplet of four resistive strip Micromegas layers with 5mm drift gap. It is constructed from two readout panels with readout anodes on both sides and three drift panels, that carry the cathode structure. The panels are realized as sandwich structures of aluminum honeycomb, framed by aluminum bars and faced by printed circuit boards, carrying readout or cathode structures. The readout structure consists of strips with 0.43mm pitch and up to 2m length. ...

  20. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about 150 m{sup 2} of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m{sup 2} for a total active area of 1200 m{sup 2}. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS end-cap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. In the prototyping towards the final configuration two similar quadruplets with dimensions 1.2 x 0.5 m{sup 2} have been built with the same structure as foreseen for the NSW upgrade. It represents the first example of a Micromegas quadruplet ever built, realized using the resistive-strip technology and decoupling the amplification mesh from the readout structure. All readout planes are segmented into strips with a pitch of 400 μm for a total of 4096 strips. In two of the four planes the strips are inclined by 1.5 deg. and provide a measurement of the second coordinate. The design and construction procedure of the Micromegas modules will be presented, as well as the design for the assembly of modules onto the New Small Wheel. Emphasis will be given on the methods developed to achieve the challenging mechanical precision. Measurements of deformation on chamber prototypes as a function of thermal gradients, gas over-pressure and internal stress (mesh tension and module fixation on supports) will be also shown in comparison to simulation. These tests were essential in the development of the final design in order to minimize the

  1. Construction of patient specific atlases from locally most similar anatomical pieces

    Science.gov (United States)

    Ramus, Liliane; Commowick, Olivier; Malandain, Grégoire

    2010-01-01

    Radiotherapy planning requires accurate delineations of the critical structures. To avoid manual contouring, atlas-based segmentation can be used to get automatic delineations. However, the results strongly depend on the chosen atlas, especially for the head and neck region where the anatomical variability is high. To address this problem, atlases adapted to the patient’s anatomy may allow for a better registration, and already showed an improvement in segmentation accuracy. However, building such atlases requires the definition of a criterion to select among a database the images that are the most similar to the patient. Moreover, the inter-expert variability of manual contouring may be high, and therefore bias the segmentation if selecting only one image for each region. To tackle these issues, we present an original method to design a piecewise most similar atlas. Given a query image, we propose an efficient criterion to select for each anatomical region the K most similar images among a database by considering local volume variations possibly induced by the tumor. Then, we present a new approach to combine the K images selected for each region into a piecewise most similar template. Our results obtained with 105 CT images of the head and neck show that our method reduces the over-segmentation seen with an average atlas while being robust to inter-expert manual segmentation variability. PMID:20879395

  2. Indicative properties on snow cover based on the results of experimental studies in the winter 2011/12 in the central part of the East European Plain

    Directory of Open Access Journals (Sweden)

    L. M. Kitaev

    2013-01-01

    Full Text Available Local and regional differences in the snow formation were studied in different landscapes of the central part of the East European Plain – within reserves in the Moscow and Tver’ regions (south-north direction; the study period is the winter 2011/12. The observed increase of snow storage in 1.3–1.5 times in the direction south-north is connected, apparently. The difference in the five-day appearance of snow cover maximum is related to differences in regional winter air temperature. Throughout the snow depth and snow storage in spruce are smaller than in deciduous forest – in the ratio of 0.81 in south area and 0.93 in north area; in spruce the large part of solid precipitation is intercepted by the crowns pine trees. Snow stratigraphy at south areas has four layers, six layers at the north area are more variable in snow density and snow storage. Perhaps, gravitational conversion is more noticeable due to larger snow depth. Snow density and snow storage at the open areas are more heterogeneous than in the forest. This is due to sharp fluctuations in air temperature, wind transport and compaction of snow, evaporation from the snow surface. The stratigraphy of snow also reflects the history of winter changes of air temperature and snow accumulation. Common feature for reserves at south and north is the availability of layers with maximum snow storage in the middle of the snow thickness, which were formed during the air temperature drops to the lowest seasonal values in period with increase of snow depth to maximum. Formation of depth hoar in snow thickness are touched everywhere the bottom and middle layers, respectively, it was formed both before and during the period with minimal air temperature. Thus, the results of experimental studies confirm the significance of the differences of individual components of the landscape setting. Analytical conclusions are largely qualitative in nature due to the lack to date of initial information, and

  3. The effects of additional black carbon on the albedo of Arctic sea ice: variation with sea ice type and snow cover

    Directory of Open Access Journals (Sweden)

    A. A. Marks

    2013-07-01

    Full Text Available The response of the albedo of bare sea ice and snow-covered sea ice to the addition of black carbon is calculated. Visible light absorption and light-scattering cross-sections are derived for a typical first-year and multi-year sea ice with both "dry" and "wet" snow types. The cross-sections are derived using data from a 1970s field study that recorded both reflectivity and light penetration in Arctic sea ice and snow overlying sea ice. The variation of absorption cross-section over the visible wavelengths suggests black carbon is the dominating light-absorbing impurity. The response of first-year and multi-year sea ice albedo to increasing black carbon, from 1 to 1024 ng g−1, in a top 5 cm layer of a 155 cm-thick sea ice was calculated using a radiative-transfer model. The albedo of the first-year sea ice is more sensitive to additional loadings of black carbon than the multi-year sea ice. An addition of 8 ng g−1 of black carbon causes a decrease to 98.7% of the original albedo for first-year sea ice compared to a decrease to 99.7% for the albedo of multi-year sea ice, at a wavelength of 500 nm. The albedo of sea ice is surprisingly unresponsive to additional black carbon up to 100 ng g−1 . Snow layers on sea ice may mitigate the effects of black carbon in sea ice. Wet and dry snow layers of 0.5, 1, 2, 5 and 10 cm depth were added onto the sea ice surface. The albedo of the snow surface was calculated whilst the black carbon in the underlying sea ice was increased. A layer of snow 0.5 cm thick greatly diminishes the effect of black carbon in sea ice on the surface albedo. The albedo of a 2–5 cm snow layer (less than the e-folding depth of snow is still influenced by the underlying sea ice, but the effect of additional black carbon in the sea ice is masked.

  4. Use of time series of optical and SAR images in the estimation of snow cover for the optimization of water use in the Andes of Argentina and Chile

    Science.gov (United States)

    Salinas de Salmuni, Graciela; Cabezas Cartes, Ricardo; Menicocci, Felix

    2014-05-01

    This paper describes the progress in the bilateral cooperation project between academic and water resources management institutions from the Andes region of Argentina and Chile. The study zone is located in fragile ecosystems and mountain areas of the Andes (limit zone between the Province of San Juan, Argentina, and the IV Region of Coquimbo, Chile), with arid climate, where snow precipitates in the headwaters of watershed feed the rivers of the region by melting, which are the only source of water for human use, productive and energetic activities, as well as the native flora and fauna. CONAE, the Argentine Space Agency, participates in the Project through the provision of satellite data to the users and by this it contributes to ensuring the continuity of the results of the project. Also, it provides training in digital image processing. The project also includes the participation of water resource management institutions like Secretaria de Recursos Hidricos of Argentina and the Centro de Información de Recursos Naturales de Chile (CIREN), and of academic institution like the University of San Juan (Argentina) and University of La Serena (Chile). These institutions benefit from the incorporation of new methodologies advanced digital image processing and training of staff (researcher, lecturers, PhD Students and technical). Objectives: 1-Improve water distribution incorporating space technology for application in the prediction models of the stream flow. 2- Conduct an inventory of glaciers as well as studies in selected watersheds in the Andean region, aiming to know the water resource, its availability and potential risks to communities in the region. 3. Contribute to vulnerability studies in biodiversity Andean watersheds. Results: For estimation Snow cover Area, the MODIS images are appropriate due their high temporal resolution and allows for monitoring large areas (greater than 10 km) The proposed methodology (Use of snow index, NSDI) is appropriate for

  5. Development and construction of large size signal electrodes for the ATLAS electromagnetic calorimeter

    International Nuclear Information System (INIS)

    Aubert, B.; Ballansat, J.; Colas, J.

    2005-01-01

    We describe the electric circuits (electrodes) which polarize and read out the lead-liquid argon electromagnetic calorimeter for the ATLAS detector. The paper covers design and material choices of the circuits as well as their production in industry. We also show how the electrodes integrate into the calorimeter and conclude with results from groups of electrodes making up calorimeter modules

  6. Construction of the new silicon microstrips tracker for the Phase-II ATLAS detector

    CERN Document Server

    Liang, Zhijun; The ATLAS collaboration

    2018-01-01

    The inner detector of the present ATLAS detector has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the next-generation tracking detector proposed for the High Luminosity LHC (HL-LHC), the so-called ATLAS Phase-II Upgrade, the particle densities and radiation levels will be higher by as much as a factor of ten. The new detectors must be faster, they need to be more highly segmented, and covering more area. They also need to be more resistant to radiation, and they require much greater power delivery to the front-end systems. For those reasons, the inner tracker of the ATLAS detector must be redesigned and rebuilt completely. The design of the ATLAS Upgrade inner tracker (ITk) has already been defined. It consists of several layers of silicon particle detectors. The innermost layers will be composed of silicon pixel sensors, and the outer layers will consist of silicon microstrip sensors. This paper will focus on the latest research and development act...

  7. Unbiased group-wise image registration: applications in brain fiber tract atlas construction and functional connectivity analysis.

    Science.gov (United States)

    Geng, Xiujuan; Gu, Hong; Shin, Wanyong; Ross, Thomas J; Yang, Yihong

    2011-10-01

    We propose an unbiased implicit-reference group-wise (IRG) image registration method and demonstrate its applications in the construction of a brain white matter fiber tract atlas and the analysis of resting-state functional MRI (fMRI) connectivity. Most image registration techniques pair-wise align images to a selected reference image and group analyses are performed in the reference space, which may produce bias. The proposed method jointly estimates transformations, with an elastic deformation model, registering all images to an implicit reference corresponding to the group average. The unbiased registration is applied to build a fiber tract atlas by registering a group of diffusion tensor images. Compared to reference-based registration, the IRG registration improves the fiber track overlap within the group. After applying the method in the fMRI connectivity analysis, results suggest a general improvement in functional connectivity maps at a group level in terms of larger cluster size and higher average t-scores.

  8. Status of design and construction of the Transition Radiation Tracker (TRT) for the ATLAS experiment at the LHC

    Science.gov (United States)

    Akesson, T.; Anghinolfi, F.; Arik, E.; Baker, O. K.; Baron, S.; Benjamin, D.; Bertelsen, H.; Bondarenko, V.; Bytchkov, V.; Callahan, J.; Capeáns, M.; Cardiel-Sas, L.; Catinaccio, A.; Cetin, S. A.; Cwetanski, P.; Dam, M.; Danielsson, H.; Dittus, F.; Dolgoshein, B.; Dressnandt, N.; Driouichi, C.; Ebenstein, W. L.; Eerola, P.; Farthouat, P.; Fedin, O.; Froidevaux, D.; Gagnon, P.; Grichkevitch, Y.; Grigalashvili, N.; Hajduk, Z.; Hansen, P.; Kayumov, F.; Keener, P. T.; Kekelidze, G.; Khristatchev, A.; Konovalov, S.; Koudine, L.; Kovalenko, S.; Kowalski, T.; Kramarenko, V. A.; Krüger, K.; Laritchev, A.; Lichard, P.; Luehring, F.; Lundberg, B.; Maleev, V.; Markina, I.; McFarlane, K. W.; Mialkovski, V.; Mindur, B.; Mitsou, V. A.; Morozov, S.; Munar, A.; Muraviev, S.; Nadtochy, A.; Newcomer, F. M.; Ogren, H.; Oh, S. H.; Oleshko, S.; Olszowska, J.; Passmore, S.; Patritchev, S.; Peshekhonov, V.; Petti, R.; Price, M.; Rembser, C.; Rohne, O.; Romaniouk, A.; Rust, D. R.; Ryabov, Yu.; Ryjov, V.; Schegelsky, V.; Seliverstov, D.; Shin, T.; Shmeleva, A.; Smirnov, S.; Sosnovtsev, V.; Soutchkov, V.; Spiridenkov, E.; Szczygiel, R.; Tikhomirov, V.; van Berg, R.; Vassilakopoulos, V. I.; Vassilieva, L.; Wang, C.; Williams, H. H.; Zalite, A.

    2004-04-01

    The ATLAS Inner Detector consists of three sub-systems, the Pixel Detector at the innermost radius, the Semi-Conductor Tracker at intermediate radii, and the Transition Radiation Tracker (TRT) at the outermost radius in front of the electromagnetic calorimeter. The TRT provides a combination of continuous tracking with many projective measurements based on individual drift-tubes (or straws) and of electron identification based on radiator fibres or foils interleaved between the straws themselves. This paper describes the current status of design and construction of the various components of the TRT: the assembly of the barrel modules has recently been completed, that of the end-cap wheels is well underway, and the on-detector front-end electronics is in production. The detector modules and front-end electronics boards will be integrated together over the next year, the barrel and end-cap TRT parts will be assembled and tested with their SCT counterparts during 2005 and installation and commissioning in the ATLAS pit will take place at the end of 2005 and the beginning of 2006.

  9. Constructing fine-granularity functional brain network atlases via deep convolutional autoencoder.

    Science.gov (United States)

    Zhao, Yu; Dong, Qinglin; Chen, Hanbo; Iraji, Armin; Li, Yujie; Makkie, Milad; Kou, Zhifeng; Liu, Tianming

    2017-12-01

    State-of-the-art functional brain network reconstruction methods such as independent component analysis (ICA) or sparse coding of whole-brain fMRI data can effectively infer many thousands of volumetric brain network maps from a large number of human brains. However, due to the variability of individual brain networks and the large scale of such networks needed for statistically meaningful group-level analysis, it is still a challenging and open problem to derive group-wise common networks as network atlases. Inspired by the superior spatial pattern description ability of the deep convolutional neural networks (CNNs), a novel deep 3D convolutional autoencoder (CAE) network is designed here to extract spatial brain network features effectively, based on which an Apache Spark enabled computational framework is developed for fast clustering of larger number of network maps into fine-granularity atlases. To evaluate this framework, 10 resting state networks (RSNs) were manually labeled from the sparsely decomposed networks of Human Connectome Project (HCP) fMRI data and 5275 network training samples were obtained, in total. Then the deep CAE models are trained by these functional networks' spatial maps, and the learned features are used to refine the original 10 RSNs into 17 network atlases that possess fine-granularity functional network patterns. Interestingly, it turned out that some manually mislabeled outliers in training networks can be corrected by the deep CAE derived features. More importantly, fine granularities of networks can be identified and they reveal unique network patterns specific to different brain task states. By further applying this method to a dataset of mild traumatic brain injury study, it shows that the technique can effectively identify abnormal small networks in brain injury patients in comparison with controls. In general, our work presents a promising deep learning and big data analysis solution for modeling functional connectomes, with

  10. Construction and Performance of the ATLAS SCT Barrels and Cosmic Tests

    CERN Document Server

    Demirkoz, Bilge Melahat

    2007-01-01

    ATLAS is a multi-purpose detector for the LHC and will detect proton-proton collisions with center of mass energy of $14$TeV. Part of the central inner detector, the Semi-Conductor Tracker (SCT) barrels, were assembled and tested at Oxford University and later integrated at CERN with the TRT (Transition Radiation Tracker) barrel. The barrel SCT is composed of 4 layers of silicon strip modules with two sensor layers with $80 \\mu$m channel width. The design of the modules and the barrels has been optimized for low radiation length while maintaining mechanical stability, bringing services to the detector, and ensuring a cold and dry environment. The high granularity, high detector efficiency and low noise occupancy ($ < 5 \\times 10^{-4}$) of the SCT will enable ATLAS to have an efficient pattern recognition capability. Due to the binary nature of the SCT read-out, a stable read-out system and the calibration system is of critical importance. SctRodDaq is the online software framework for the calibration and a...

  11. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00380308; The ATLAS collaboration

    2016-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface area of about 150 m$^2$ of the forward regions (pseudo-rapidity coverage -- 1.3 $\\boldsymbol{< |\\eta| <}$ 2.7) of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m$^2$ for a total active area of 1200 m$^2$. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels (NSW), which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15\\% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic position resolution, the mechanical precision of each plane of the assembled module must be $\\boldsymbol{30{\\mu}m}$ along the precision coordinate and $\\boldsymbol{80{\\mu}m}$ perpendicular to the chamber. All readout planes are segmented into strips with a pitch of $\\bold...

  12. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    Jeanneau, Fabien; The ATLAS collaboration

    2015-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m2 for a total active area of 1200 m2. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. In the prototyping towards the final configuration two similar quadruplets with dimensions 1.2×0.5 m2 have been built with the same structure as foreseen for the NSW upgrade. It represents ...

  13. Design and Construction of Large Size Micromegas Chambers for the ATLAS Upgrade of the Muon Spectrometer

    CERN Document Server

    Jeanneau, Fabien; The ATLAS collaboration

    2015-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3 m2 for a total active area of 1200 m2. Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic resolution, the mechanical precision of each plane of the assembled module must be as good as 30 μm along the precision coordinate and 80 μm perpendicular to the chamber. All readout planes are segmented into strips with a pitch of 400 μm for a total of 4096 strips. In two of the four planes the strips are inclined by 1.5 ◦ and provide a measurement of the...

  14. Airborne gamma-radiation snow water-equivalent and soil-moisture measurements and satellite areal extent of snow-cover measurements. A user's guide. Version 3.0

    International Nuclear Information System (INIS)

    Carroll, T.; Allen, M.

    1988-01-01

    The National Remote Sensing Hydrology Program is managed by the Office of Hydrology and consists of the Airborne Snow Survey Section and the Satellite Hydrology Section. The Airborne Snow Survey Section makes airborne snow water-equivalent and soil-moisture measurements over large areas of the country subject to a severe and chronic snowmelt flooding threat. The User's Guide is intended primarily to provide field hydrologists with some background on the technical and administrative aspects of the National Remote Sensing Hydrology Program. The guide summarizes the techniques and procedures used to make and distribute real-time, operational airborne snow water-equivalent measurements and satellite areal extent of snow-cover measurements made over large areas of the country. The current airborne and satellite databases are summarized, and procedures to access the real-time observations through both AFOS and through a commercial, electronic bulletin board system are given in the appendices

  15. Seasonal and inter-annual variability of aerosol optical properties during 2005-2010 over Red Mountain Pass and Impact on the Snow Cover of the San Juan Mountains

    Science.gov (United States)

    Singh, R. P.; Gautam, R.; Painter, T. H.

    2011-12-01

    Growing body of evidence suggests the significant role of aerosol solar absorption in accelerated seasonal snowmelt in the cryosphere and elevated mountain regions via snow contamination and radiative warming processes. Characterization of aerosol optical properties over seasonal snow cover and snowpacks is therefore important towards the better understanding of aerosol radiative effects and associated impact on snow albedo. In this study, we present seasonal variations in column-integrated aerosol optical properties retrieved from AERONET sunphotometer measurements (2005-2010) at Red Mountain Pass (37.90° N, 107.72° W, 3368 msl) in the San Juan Mountains, in the vicinity of the North American Great Basin and Colorado Plateau deserts. The aerosol optical depth (AOD) measured at 500nm is generally low (pollutant transport. In addition, the possibility of the observed increased coarse-mode influence associated with mineral dust influx cannot be ruled out, due to westerly-airmass driven transport from arid/desert regions as suggested by backward trajectory simulations. A meteorological coupling is also found in the summer season between AOD and column water vapor retrieved from AERONET with co-occurring enhanced water vapor and AOD. Based on column measurements, it is difficult to ascertain the aerosol composition, however, the summer-time enhanced aerosol loading as presented here is consistent with the increased dust deposition in the San Juan mountain snow cover as reported in recent studies. In summary, this study is expected to better understand the seasonal and inter-annual aerosol column variations and is an attempt to provide an insight into the effects of aerosol solar absorption on accelerated seasonal snowmelt in the San Juan mountains.

  16. Construction of an end-cap module prototype for the ATLAS transition radiation tracker

    CERN Document Server

    Danielsson, H

    2000-01-01

    We have designed, built and tested an 8-plane module prototype for the end-cap of the ATLAS TRT (Transition Radiation Tracker). The overall mechanics as well as the detailed design of individual components are presented. The prototype contains over 6000 straw tubes with a diameter of 4 mm, filled with an active gas mixture of 70% Xe, 20% CF4 and 10% CO//2. Very tight requirements on radiation hardness (10 Mrad and 2 multiplied by l0**1**4 neutrons per cm**2) straw straightness (sagitta less than 300 m), wire positions and leak tightness put great demands upon design and assembly. In order to verify the design, the stability of the wire tension, straw straightness, high-voltage performance and total leak rate have been measured and the results are presented. Some examples of dedicated assembly tooling and testing procedures are also given. Finally, the results of the calculations and measurements of both mechanical behaviour and wire offset are presented. 6 Refs.

  17. Construction and Test of Full-Size Micromegas Modules for the ATLAS New Small Wheel Upgrade

    CERN Document Server

    Bortfeldt, Jonathan; The ATLAS collaboration

    2015-01-01

    In 2015 the first full size resistive-strip MicroMegas operational modules for the ATLAS New Small Wheel upgrade will be realized. The goal is to provide precision muon tracking with spatial resolution below 100 μm on trapezoidal detector areas between 2 and 3 m^2. The overall thickness of each detector modules is about 70 mm and the total number of read-out channels is of the order of 10^4. Each module consists of a quadruplet of four MicroMegas with 5 mm drift gaps intervaled with 2 read-out panels with anodes on both sides and 3 drift panels. The panels are realized as 11 mm thick stiffening sandwiches made of 10 mm thick honeycomb, 0.5 mm thick FR4 pcb material sheets as surfaces and aluminium frames. The active part of the read-out anodes consists of horizontal strips with 0.45 mm pitch. Two out of the four anode planes are built with stereo strips of identical pitch and stereo angles of ±1.5 degrees. A sequence of 128 μm height insulating pillars on the read-out planes allows the pretensioned microme...

  18. A CD with the wishes for the 21st century from thousands of readers of the science magazine "Newton", was buried at the Atlas construction site on 16.03.2000 (handling the CD: Giorgio Riviecco, Editor of "Newton")

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    A CD with the wishes for the 21st century from thousands of readers of the science magazine "Newton", was buried at the Atlas construction site on 16.03.2000 (handling the CD: Giorgio Riviecco, Editor of "Newton")

  19. Design and Construction of Precision Tooling for the Construction of Resistive Strip Micromegas Detectors for the ATLAS Small Wheel Upgrade Project

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00389964; The ATLAS collaboration

    2015-01-01

    Mechanical precision is a key-aspect of the $2~m^2$ high-rate capable Micromegas detectors for the upgrade of the Small Wheels of the ATLAS muon spectrometer. 32 SM2 quadruplets will be built by four German sites with cathodes and strip-anodes made of stable honeycomb sandwiches.\\\\ To achieve the required single plane resolution below $100\\mu m$ the deviation from planarity of a single detector plane must not exceed $80\\mu m$ in direction perpendicular to the precision coordinate. The global position of the readout strips has to be within $30\\mu m$ for a single readout-plane of three PCBs, as well as between all four planes of a quadruplet.\\\\ Precision tooling is used for the correct positioning of readout PCBs and readout sandwich planes. For quality control of the planarity of the sandwich planes a laser distance sensor combined with a coordinate measurement system has been developed. Deviation from planarity below 10 $\\mu$m can be easily resolved.\\\\ We will present key features of the challenging construct...

  20. Evaluation of polynomial image deformation for matching of 3D- abdominal MR-images using anatomical landmarks and for atlas construction

    CERN Document Server

    Kimiaei, S; Jonsson, E; Crafoord, J; Maguire, G Q

    1999-01-01

    The aim of this study is to compare and evaluate the potential usability of linear and non-linear (polynomial) 3D-warping for constructing an atlas by matching abdominal MR-images from a number of different individuals using manually picked anatomical landmarks. The significance of this study lies in the fact that it illustrates the potential to use polynomial matching at a local or organ level. This is a necessary requirement for constructing an atlas and for fine intra-patient image matching and fusion. Finally 3D-image warping using anatomical landmark for inter-patient intra-modality image co-registration and fusion was found to be a very powerful and robust method. Additionally it can be used for intra-patient inter- modality image matching.

  1. Signal formation processes in Micromegas detectors and quality control for large size detector construction for the ATLAS new small wheel

    International Nuclear Information System (INIS)

    Kuger, Fabian

    2017-01-01

    The Micromegas technology is one of the most successful modern gaseous detector concepts and widely utilized in nuclear and particle physics experiments. Twenty years of R and D rendered the technology sufficiently mature to be selected as precision tracking detector for the New Small Wheel (NSW) upgrade of the ATLAS Muon spectrometer. This will be the first large scale application of Micromegas in one of the major LHC experiments. However, many of the fundamental microscopic processes in these gaseous detectors are still not fully understood and studies on several detector aspects, like the micromesh geometry, have never been addressed systematically. The studies on signal formation in Micromegas, presented in the first part of this thesis, focuses on the microscopic signal electron loss mechanisms and the amplification processes in electron gas interaction. Based on a detailed model of detector parameter dependencies, these processes are scrutinized in an iterating comparison between experimental results, theory prediction of the macroscopic observables and process simulation on the microscopic level. Utilizing the specialized detectors developed in the scope of this thesis as well as refined simulation algorithms, an unprecedented level of accuracy in the description of the microscopic processes is reached, deepening the understanding of the fundamental process in gaseous detectors. The second part is dedicated to the challenges arising with the large scale Micromegas production for the ATLAS NSW. A selection of technological choices, partially influenced or determined by the herein presented studies, are discussed alongside a final report on two production related tasks addressing the detectors' core components: For the industrial production of resistive anode PCBs a detailed quality control (QC) and quality assurance (QA) scheme as well as the therefore required testing tools have been developed. In parallel the study on micromesh parameter optimization

  2. Design and construction of Micromegas detectors for the ATLAS Muon Spectrometer Upgrade

    CERN Document Server

    Sessa, Marco

    2016-01-01

    Thanks to significant technological improvements, developed during a intensive R&D; activity carried out in the last years, large-area Micromegas (MM) will be employed, for the first time, in the High Energy Physics field. Starting from 2019, they will cover a large surface of about 150m2 in the forward regions of the Muon Spectrometer. In this paper, the performances of MM chambers and, in particular, the spatial resolution and the efficiency, obtained using data from different test beam campaigns, will be described. Moreover, it will be shown the present status of the Micromegas chambers construction from the Italian INFN groups, focusing, especially, on the construction procedures and the methodologies developed to obtain the challenging required mechanical precision.

  3. SU-E-I-87: Automated Liver Segmentation Method for CBCT Dataset by Combining Sparse Shape Composition and Probabilistic Atlas Construction

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dengwang [Shandong Normal University, Jinan, Shandong Province (China); Liu, Li [Shandong Normal University, Jinan, Shandong (China); Chen, Jinhu; Li, Hongsheng [Shandong Cancer Hospital and Institute, Jinan, Shandong (China)

    2014-06-01

    Purpose: The aiming of this study was to extract liver structures for daily Cone beam CT (CBCT) images automatically. Methods: Datasets were collected from 50 intravenous contrast planning CT images, which were regarded as training dataset for probabilistic atlas and shape prior model construction. Firstly, probabilistic atlas and shape prior model based on sparse shape composition (SSC) were constructed by iterative deformable registration. Secondly, the artifacts and noise were removed from the daily CBCT image by an edge-preserving filtering using total variation with L1 norm (TV-L1). Furthermore, the initial liver region was obtained by registering the incoming CBCT image with the atlas utilizing edge-preserving deformable registration with multi-scale strategy, and then the initial liver region was converted to surface meshing which was registered with the shape model where the major variation of specific patient was modeled by sparse vectors. At the last stage, the shape and intensity information were incorporated into joint probabilistic model, and finally the liver structure was extracted by maximum a posteriori segmentation.Regarding the construction process, firstly the manually segmented contours were converted into meshes, and then arbitrary patient data was chosen as reference image to register with the rest of training datasets by deformable registration algorithm for constructing probabilistic atlas and prior shape model. To improve the efficiency of proposed method, the initial probabilistic atlas was used as reference image to register with other patient data for iterative construction for removing bias caused by arbitrary selection. Results: The experiment validated the accuracy of the segmentation results quantitatively by comparing with the manually ones. The volumetric overlap percentage between the automatically generated liver contours and the ground truth were on an average 88%–95% for CBCT images. Conclusion: The experiment demonstrated

  4. The construction and the quality assurance-quality control of the 112 MDT-Barrel Inner Small precision chambers of the ATLAS Muon Spectrometer

    International Nuclear Information System (INIS)

    Bachas, K.; Bouzakis, K.; Krepouri, A.; Liolios, A.; Petridou, Ch.; Sampsonidis, D.; Tsiafis, I.; Valderanis, Ch.; Wotschack, J.

    2007-01-01

    The construction of the 112 BIS monitored drift-tube chambers (MDT) for the ATLAS muon spectrometer is described, with emphasis on the quality assurance-quality control procedures. The required mechanical precision of 20μm on the location of the individual wires has been achieved and maintained during the five years of construction at University of Thessaloniki. A sample of 12% of the chambers, randomly selected over the entire production period, has been scanned at the X-ray tomograph facility at CERN. The agreement between the quality assurance-quality control measurements during the assembly and the X-ray tomograph results is also presented

  5. Towards Year-round Estimation of Terrestrial Water Storage over Snow-Covered Terrain via Multi-sensor Assimilation of GRACE/GRACE-FO and AMSR-E/AMSR-2.

    Science.gov (United States)

    Wang, J.; Xue, Y.; Forman, B. A.; Girotto, M.; Reichle, R. H.

    2017-12-01

    The Gravity and Recovery Climate Experiment (GRACE) has revolutionized large-scale remote sensing of the Earth's terrestrial hydrologic cycle and has provided an unprecedented observational constraint for global land surface models. However, the coarse-scale (in space and time), vertically-integrated measure of terrestrial water storage (TWS) limits GRACE's applicability to smaller scale hydrologic applications. In order to enhance model-based estimates of TWS while effectively adding resolution (in space and time) to the coarse-scale TWS retrievals, a multi-variate, multi-sensor data assimilation framework is presented here that simultaneously assimilates gravimetric retrievals of TWS in conjunction with passive microwave (PMW) brightness temperature (Tb) observations over snow-covered terrain. The framework uses the NASA Catchment Land Surface Model (Catchment) and an ensemble Kalman filter (EnKF). A synthetic assimilation experiment is presented for the Volga river basin in Russia. The skill of the output from the assimilation of synthetic observations is compared with that of model estimates generated without the benefit of assimilating the synthetic observations. It is shown that the EnKF framework improves modeled estimates of TWS, snow depth, and snow mass (a.k.a. snow water equivalent). The data assimilation routine produces a conditioned (updated) estimate that is more accurate and contains less uncertainty during both the snow accumulation phase of the snow season as well as during the snow ablation season.

  6. Brilliant Colours from a White Snow Cover

    Science.gov (United States)

    Vollmer, Michael; Shaw, Joseph A

    2013-01-01

    Surprisingly colourful views are possible from sparkling white snow. It is well known that similarly colourful features can exist in the sky whenever appropriate ice crystals are around. However, the transition of light reflection and refraction from ice crystals in the air to reflection and refraction from those in snow on the ground is not…

  7. ATLAS Point 1 Construction

    CERN Multimedia

    Inigo-Golfin, J

    After 3 years of work in point 1, a number of surface buildings have already been completed and handed over to CERN (the control, the gas and the cooling and ventilation buildings) and, probably more appealing to the public, 60,000 m3 of earth have already been excavated from underground. At present, the technical cavern USA15 and its access shaft are almost finished, leaving only the main cavern and the liaison galleries to be completed in the coming year and a half. The main cavern has been excavated down to the radiation limit and its walls and vault will presently be concreted (see below the picture of the section of the vault with the impressive shell of 1.2 m thickness). The excavation of the bench (27 vertical metres to go yet!) will proceed from August, when some additional civil engineering work in the LHC tunnel will be undertaken. Needless to say many different services are necessary around the detector, both for its installation and future operation for physics. To that end much of the heavy...

  8. The construction of the Insertable B-Layer and the $b$-tagging performance at high-\\pt of the ATLAS experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00362129; La Rosa, Alessandro; Ferrere, Didier

    Although the recent discovery of the Higgs boson by the LHC experiments represented a major success of the Standard Model theory, several questions need still to be answered. The search of new physics particles beyond the Standard Model will require the LHC to collect a large amount of data. To achieve this goal the LHC collider went through a long shutdown, increasing both the energy and the luminosity. In particular the increase of luminosity will require the ATLAS Inner Detector to operate in a more track-dense environment, which mainly affects the ATLAS Pixel Detector. In order to cope with the high pile-up expected with the increase of luminosity the Pixel detector was then upgraded during the long shutdown with the insertion of a fourth innermost layer, the Insertable B-Layer (IBL). This thesis focuses on the construction of the IBL. This includes the loading of silicon pixel detector modules on the support staves, the quality assurance of these instrumented staves and the commissioning after the integr...

  9. Construction and QA/QC of the Micromegas Pavia Readout Panels for the Muon Spectrometer Upgrade of the ATLAS New Small Wheel

    CERN Document Server

    Kourkoumeli-Charalampidi, Athina; The ATLAS collaboration

    2016-01-01

    In order to cope with the required precision tracking and trigger capabilities from Run III onwards in the ATLAS experiment, the innermost layer of the Muon Spectrometer endcap (Small Wheels) will be upgraded. The New Small Wheel (NSW) will be equipped with eight layers of MicroMegas (MM) detectors and eight layers of small-strip Thin Gap Chambers (sTGC), both arranged in two quadruplets. MM detectors of large size (up to 3 m$^2$) will be employed for the first time in HEP experiments. Four different types of MM quadruplets modules (SM1, SM2, LM1, LM2), built by different Institutes, will compose the NSW. The Italian INFN is responsible for the construction of the SM1 modules. The construction is shared among different INFN sites, Pavia being responsible for the readout panel construction. Due to the challenging mechanical specifications (with precisions of tens microns over meters), the construction procedure has been optimized to obtain the required strip alignment precision in the panel. A number of data q...

  10. Construction and Quality Assurance of Large Area Resistive Strip Micromegas for the Upgrade of the ATLAS Muon Spectrometer at LHC/CERN

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00389527; The ATLAS collaboration

    2017-01-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. To cope with increasing background rates, associated with the steadily increasing luminosity of LHC to 10 times design luminosity, the present detector technology in the current innermost stations of the muon endcap system of the ATLAS experiment (the Small Wheel), will be replaced in 2019 by resistive strip Micromegas and small strip TGC detectors. Both technologies will provide tracking and trigger information. In the ``New Small Wheel'' the Micromegas will be arranged in eight detection layers built of trapezoidally shaped quadruplets of four different sizes covering in total about 1200\\,m$^2$ of detection plane. In order to achieve 15\\,\\% transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction of each active plane, with an alignment of the readout strips at the level of 30\\,\\textmu m along the precision coordinate and 80\\,\\textmu m perpendicular...

  11. Simulation studies on the new small wheel shielding of the ATLAS experiment and design and construction of a test facility for gaseous detectors

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Stefan

    2016-04-27

    In this thesis two main projects are presented, both aiming at the overall goal of particle detector development. In the first part of the thesis detailed shielding studies are discussed, focused on the shielding section of the planned New Small Wheel as part of the ATLAS detector upgrade. Those studies supported the discussions within the upgrade community and decisions made on the final design of the New Small Wheel. The second part of the thesis covers the design, construction and functional demonstration of a test facility for gaseous detectors at the University of Wuerzburg. Additional studies on the trigger system of the facility are presented. Especially the precision and reliability of reference timing signals were investigated.

  12. Construction and QA/QC of the MicroMegas Pavia Readout Panels for the Muon Spectrometer Upgrade of the ATLAS Experiment

    CERN Document Server

    Kourkoumeli-Charalampidi, Athina; The ATLAS collaboration

    2016-01-01

    In order to cope with the required precision tracking and trigger capabilities during Run III in ATLAS experiment, the innermost layer of the Muon Spectrometer endcap (Small Wheels) will be upgraded. The New Small Wheel (NSW) will be equipped with eight layers of MicroMegas (MM) detectors and eight layers of small-strip Thin Gap Chambers (sTGC), both arranged in two quadruplets. MM detectors of large size (up to 2 $m^{2}$) will be employed for the first time in HEP experiments. Four different types of MM quadruplets modules (SM1, SM2, LM1, LM2), built by different Institutes, will compose the NSW. Italian INFN is responsible for the construction of the SM1 modules. The construction is shared among different INFN sites. In particular, readout panels are built in Pavia. Due to the challenging mechanical specifications (with precisions of tens microns over meters), the construction procedure has been optimized to obtain the required strip alignment precision in the panel. A number of data quality checks on both ...

  13. Signal Formation Processes in Micromegas Detectors and Quality Control for large size Detector Construction for the ATLAS New Small Wheel

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00387450; Rembser, Christoph

    2017-08-04

    The Micromegas technology is one of the most successful modern gaseous detector concepts and widely utilized in nuclear and particle physics experiments. Twenty years of R & D rendered the technology sufficiently mature to be selected as precision tracking detector for the New Small Wheel (NSW) upgrade of the ATLAS Muon spectrometer. This will be the first large scale application of Micromegas in one of the major LHC experiments. However, many of the fundamental microscopic processes in these gaseous detectors are still not fully understood and studies on several detector aspects, like the micromesh geometry, have never been addressed systematically. The studies on signal formation in Micromegas, presented in the first part of this thesis, focuses on the microscopic signal electron loss mechanisms and the amplification processes in electron gas interaction. Based on a detailed model of detector parameter dependencies, these processes are scrutinized in an iterating comparison between exper- imental result...

  14. ATLAS recognises its best suppliers

    CERN Multimedia

    2002-01-01

    The ATLAS Collaboration has recently rewarded two of its suppliers in the construction of very major detector components, fabricated in Japan. The ATLAS Supplier Award in recognition of excellent supplier performance has just been attributed to Kawasaki Heavy Industries, while Toshiba Corporation received the award two months ago at their headquarters in Japan.

  15. National Atlas of Arctic: structure and creation approaches

    Directory of Open Access Journals (Sweden)

    N. S. Kasimov

    2015-01-01

    Full Text Available On the instructions of President and Government of the Russian Federation, works for development of National Atlas of Arctic are started in the country. In this article the authors present their ideas from viewpoint of geographers who are well experienced in the field of cartographic works. A structure of future Atlas and lines of approaches to its development are proposed. The totality of experiences of preparation of other geographical atlases in both, the USSR and Russia, as well as the latest achievements of cartography, aerospace sources and GIS-technologies are recommended to be used. The National Atlas of Arctic is understood as a collection of knowledge of spatial-temporal information about geographical, ecological, economic, historical-ethnographic, cultural and social features of the Arctic. This cartographic model of the territory is designed for using in a wide range of scientific, managing, economic, defensive and social activities. A hard copy of the atlas is intended to be used as scientific-reference publication while its electronic version will make it possible to renovate its content and to improve it by means of actualization according to various directions of its practical use 16 sections proposed in a draft of the Atlas content are as follows: introductory, geological structure, relief, mineral resources, environment evolution, climate, land waters, seas, seashores, snow cover, glaciers, permafrost, soils, flora and fauna, state of the environment and the Nature protection, population, economics, and prospects for future. The popular-scientific edition of the Atlas is intended for use by wide circle of readers and also as a textbook for all levels of education. Presentation of material in the Atlas should combine a high scientific level and accessible language. In a popular form it will clarify traditions of careful treatment to the Nature and the nature-protective ethics of religious confessions of local people

  16. Construction and Quality Assurance of Large Area Resistive Strip Micromegas for the Upgrade of the ATLAS Muon Spectrometer

    CERN Document Server

    Losel, Philipp Jonathan; The ATLAS collaboration

    2017-01-01

    To cope with the increased background induced hit rate of up to ~15 kHz/cm$^2$ in the innermost stations of the muon endcap system of the ATLAS experiment after the high-luminosity upgrade of the LHC, the currently used precision detectors will be replaced by resistive strip Micromegas in 2019. In the "New Small Wheel" the Micromegas will be arranged in two times four detection layers built of trapezoidally shaped quadruplets of four different sizes.The Micromegas quadruplets will consist of 5 panels, 3 drift panels and 2 readout panels, made of aluminum honeycomb core sandwiched by printed circuit boards (PCBs). To achieve 15% transverse momentum resolution for 1 TeV muons and thus a spatial resolution in a single plane of about 100 $\\mu$m, each active plane has to have an accuracy of 80 $\\mu$m perpendicular to the plane and the alignment of the readout strips on the individual PCBs and particularly the alignment within a quadruplet must fulfill a challenging precision of 30 $\\mu$m. The required mechanical p...

  17. Construction

    Science.gov (United States)

    2002-01-01

    Harbor Deepening Project, Jacksonville, FL Palm Valley Bridge Project, Jacksonville, FL Rotary Club of San Juan, San Juan, PR Tren Urbano Subway...David. What is nanotechnology? What are its implications for construction?, Foresight/CRISP Workshop on Nanotechnology, Royal Society of Arts

  18. Evaluation of an assimilation scheme to estimate snow water equivalent in the High Atlas of Morocco.

    Science.gov (United States)

    Baba, W. M.; Baldo, E.; Gascoin, S.; Margulis, S. A.; Cortés, G.; Hanich, L.

    2017-12-01

    The snow melt from the Atlas mountains represents a crucial water resource for crop irrigation in Morocco. Due to the paucity of in situ measurements, and the high spatial variability of the snow cover in this semi-arid region, assimilation of snow cover area (SCA) from high resolution optical remote sensing into a snowpack energy-balance model is considered as a promising method to estimate the snow water equivalent (SWE) and snow melt at catchment scales. Here we present a preliminary evaluation of an uncalibrated particle batch smoother data assimilation scheme (Margulis et al., 2015, J. Hydrometeor., 16, 1752-1772) in the High-Atlas Rheraya pilot catchment (225 km2) over a snow season. This approach does not require in situ data since it is based on MERRA-2 reanalyses data and satellite fractional snow cover area data. We compared the output of this prior/posterior ensemble data assimilation system to output from the distributed snowpack evolution model SnowModel (Liston and Elder, 2006, J. Hydrometeor. 7, 1259-1276). SnowModel was forced with in situ meteorological data from five automatic weather stations (AWS) and some key parameters (precipitation correction factor and rain-snow phase transition parameters) were calibrated using a time series of 8-m resolution SCA maps from Formosat-2. The SnowModel simulation was validated using a continuous snow height record at one high elevation AWS. The results indicate that the open loop simulation was reasonably accurate (compared to SnowModel results) in spite of the coarse resolution of the MERRA-2 forcing. The assimilation of Formosat-2 SCA further improved the simulation in terms of the peak SWE and SWE evolution over the melt season. During the accumulation season, the differences between the modeled and estimated (posterior) SWE were more substantial. The differences appear to be due to some observed precipitation events not being captured in MERRA-2. Further investigation will determine whether additional

  19. View of the ATLAS cavern at SX15

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Photo 01: Coactivity in UX15: installation of the cranes and of the metallic structures. Photo 02: The ATLAS HO structure in UX15: a 12 storey metallic frame underground Photo 03: ATLAS giant structures under construction in UX15.

  20. ATLAS Facility Description Report

    International Nuclear Information System (INIS)

    Kang, Kyoung Ho; Moon, Sang Ki; Park, Hyun Sik; Cho, Seok; Choi, Ki Yong

    2009-04-01

    A thermal-hydraulic integral effect test facility, ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), has been constructed at KAERI (Korea Atomic Energy Research Institute). The ATLAS has the same two-loop features as the APR1400 and is designed according to the well-known scaling method suggested by Ishii and Kataoka to simulate the various test scenarios as realistically as possible. It is a half-height and 1/288-volume scaled test facility with respect to the APR1400. The fluid system of the ATLAS consists of a primary system, a secondary system, a safety injection system, a break simulating system, a containment simulating system, and auxiliary systems. The primary system includes a reactor vessel, two hot legs, four cold legs, a pressurizer, four reactor coolant pumps, and two steam generators. The secondary system of the ATLAS is simplified to be of a circulating loop-type. Most of the safety injection features of the APR1400 and the OPR1000 are incorporated into the safety injection system of the ATLAS. In the ATLAS test facility, about 1300 instrumentations are installed to precisely investigate the thermal-hydraulic behavior in simulation of the various test scenarios. This report describes the scaling methodology, the geometric data of the individual component, and the specification and the location of the instrumentations in detail

  1. Construction and quality assurance of large area resistive strip Micromegas for the upgrade of the ATLAS Muon Spectrometer at LHC/CERN

    Science.gov (United States)

    Lösel, P.

    2017-06-01

    Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. To cope with increasing background rates, associated with the steadily increasing luminosity of LHC to 10 times design luminosity, the present detector technology in the current innermost stations of the muon endcap system of the ATLAS experiment (the Small Wheel), will be replaced in 2019/2020 by resistive strip Micromegas and small strip TGC detectors. Both technologies will provide tracking and trigger information. In the "New Small Wheel" the Micromegas will be arranged in eight detection layers built of trapezoidally shaped quadruplets of four different sizes covering in total about 1200 m2 of detection plane. In order to achieve 15 % transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction of each active plane, with an alignment of the readout strips at the level of 30 μm RMS along the precision coordinate and 80 μm RMS perpendicular to the plane. Each individual Micromegas plane must achieve a spatial resolution better than 100 μm at background rates up to 15 kHz/cm2 while being operated in an inhomogeneous magnetic field (B <= 0.3 T). The required mechanical precision for the production of the components and their assembly, on such large area detectors, is a key point and must be controlled during construction and integration. Particularly the alignment of the readout strips within a quadruplet appears to be demanding. The readout strips are etched on PCB boards using photolithographic processes. Depending on the type of the module, 3 or 5 PCB boards need to be joined and precisely aligned to form a full readout plane. The precision in the alignment is reached either by use of precision mechanical holes or by optical masks, both referenced to the strip patterns. Assembly procedures have been developed to build the single panels with the required mechanical precision and to assemble them in a

  2. ATLAS recognises its best suppliers

    CERN Multimedia

    Jenni, P

    The ATLAS Collaboration has recently rewarded two of its suppliers in the construction of very major detector components, fabricated in Japan. The ATLAS Supplier Award in recognition of excellent supplier performance was attributed on 2nd September 2002 during a ceremony in Hall 180 to Kawasaki Heavy Industries, while Toshiba Corporation received the award two months before at their headquarters in Japan. The ATLAS experiment will become a reality thanks to a large international collaboration partnership. The industrial suppliers for the components all over the world play a major role in the construction of this gigantic jigsaw for the LHC. And sometimes they perform so well, that their work deserves specially to be recognised. This is the case for Kawasaki Heavy Industries and Toshiba Corporation, producers of the Liquid Argon Barrel Cryostat and of the Superconducting Central Solenoid, respectively. With these awards, the ATLAS Collaboration wants to congratulate Kawasaki and Toshiba for fulfilling the hi...

  3. Supporting ATLAS

    CERN Multimedia

    maximilien brice

    2003-01-01

    Eighteen feet made of stainless steel will support the barrel ATLAS detector in the cavern at Point 1. In total, the ATLAS feet system will carry approximately 6000 tons, and will give the same inclination to the detector as the LHC accelerator.

  4. Supporting ATLAS

    CERN Multimedia

    2003-01-01

    Eighteen feet made of stainless steel will support the barrel ATLAS detector in the cavern at Point 1. In total, the ATLAS feet system will carry approximately 6000 tons, and will give the same inclination to the detector as the LHC accelerator. The installation of the feet is scheduled to finish during January 2004 with an installation precision at the 1 mm level despite their height of 5.3 metres. The manufacture was carried out in Russia (Company Izhorskiye Zavody in St. Petersburg), as part of a Russian and JINR Dubna in-kind contribution to ATLAS. Involved in the installation is a team from IHEP-Protvino (Russia), the ATLAS technical co-ordination team at CERN, and the CERN survey team. In all, about 15 people are involved. After the feet are in place, the barrel toroid magnet and the barrel calorimeters will be installed. This will keep the ATLAS team busy for the entire year 2004.

  5. Construction and tests of the Atlas barrel pre sampler and study of the photon/pion rejection in the electromagnetic calorimeter; Realisation du pre-echantillonneur central d'ATLAS et etude de la separation {gamma}/{pi}{sup 0} dans le calorimetre electromagnetique

    Energy Technology Data Exchange (ETDEWEB)

    Saboumazrag, S

    2004-02-01

    ATLAS is one of the detectors which will equip the future proton-proton collider LHC at CERN. The main motivation for the ATLAS experiment is the quest for the Higgs boson. The observation of this particle would be an important step in the understanding of particle physics in the context of the standard model, with or without supersymmetry. This thesis aims to present the construction of the barrel pre-sampler which will equip the front face of the ATLAS electromagnetic calorimeter. The construction and tests of sectors were achieved at the Laboratory of Subatomic Physics and Cosmology of Grenoble. Two of these sectors were mounted on one module of the electromagnetic calorimeter and tested with electron, photon and muon beams at CERN. I participated in these tests and analysed the data. The results were compared to a Monte-Carlo simulation GEANT3. One of the difficulties lies in the necessity to discard photons coming from {pi}{sup 0} {yields} {gamma}{gamma} events because they can be mistaken for photons released in gamma channels of Higgs boson decay. In the mass range spreading from 95 MeV to 150 MeV, H{sup 0} {yields} {gamma}{gamma} is the most adequate process to detect the Higgs boson. A study of the discard parameter {gamma}/{pi}{sup 0} has been performed. For a photon detection efficiency of 90%, the average discard parameter has been assessed to be 2.5 which is slightly lower than the value given by the simulation.

  6. Two new wheels for ATLAS

    CERN Multimedia

    2002-01-01

    Juergen Zimmer (Max Planck Institute), Roy Langstaff (TRIUMF/Victoria) and Sergej Kakurin (JINR), in front of one of the completed wheels of the ATLAS Hadronic End Cap Calorimeter. A decade of careful preparation and construction by groups in three continents is nearing completion with the assembly of two of the four 4 m diameter wheels required for the ATLAS Hadronic End Cap Calorimeter. The first two wheels have successfully passed all their mechanical and electrical tests, and have been rotated on schedule into the vertical position required in the experiment. 'This is an important milestone in the completion of the ATLAS End Cap Calorimetry' explains Chris Oram, who heads the Hadronic End Cap Calorimeter group. Like most experiments at particle colliders, ATLAS consists of several layers of detectors in the form of a 'barrel' and two 'end caps'. The Hadronic Calorimeter layer, which measures the energies of particles such as protons and pions, uses two techniques. The barrel part (Tile Calorimeter) cons...

  7. Mongolian Atlas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Climatic atlas dated 1985, in Mongolian, with introductory material also in Russian and English. One hundred eight pages in single page PDFs.

  8. A novel approach of fMRI-guided tractography analysis within a group: construction of an fMRI-guided tractographic atlas.

    Science.gov (United States)

    Preti, Maria Giulia; Makris, Nikos; Laganà, Maria Marcella; Papadimitriou, George; Baglio, Francesca; Griffanti, Ludovica; Nemni, Raffaello; Cecconi, Pietro; Westin, Carl-Fredrik; Baselli, Giuseppe

    2012-01-01

    Diffusion Tensor Imaging (DTI) tractography and functional Magnetic Resonance Imaging (fMRI) investigate two complementary aspects of brain networks: white matter (WM) anatomical connectivity and gray matter (GM) function. However, integration standards have yet to be defined; namely, individual fMRI-driven tractography is usually applied and only few studies address group analysis. This work proposes an efficient method of fMRI-driven tractography at group level through the creation of a tractographic atlas starting from the GM areas activated by a verbal fluency task in 11 healthy subjects. The individual tracts were registered to the MNI space. Selection ROIs derived by GM masking and dilation of group activated areas were applied to obtain the fMRI-driven subsets within tracts. An atlas of the tracts recruited among the population was obtained by selecting for each subject the fMRI-guided tracts passing through the high probability voxels (the voxels recruited by the 90% of the subjects) and merging them together. The reliability of this approach was assessed by comparing it with the probabilistic atlas previously introduced in literature. The introduced method allowed to successfully reconstruct activated tracts, which comprehended corpus callosum, left cingulum and arcuate, a small portion of the right arcuate, both cortico-spinal tracts and inferior fronto-occipital fasciculi. Moreover, it proved to give results concordant with the previously introduced probabilistic approach, allowing in addition to reconstruct 3D trajectories of the activated fibers, which appear particularly helpful in the detection of WM connections.

  9. Construction of an in vivo human spinal cord atlas based on high-resolution MR images at cervical and thoracic levels: preliminary results.

    Science.gov (United States)

    Taso, Manuel; Le Troter, Arnaud; Sdika, Michaël; Ranjeva, Jean-Philippe; Guye, Maxime; Bernard, Monique; Callot, Virginie

    2014-06-01

    Our goal was to build a probabilistic atlas and anatomical template of the human cervical and thoracic spinal cord (SC) that could be used for segmentation algorithm improvement, parametric group studies, and enrichment of biomechanical modelling. High-resolution axial T2*-weighted images were acquired at 3T on 15 healthy volunteers using a multi-echo-gradient-echo sequence (1 slice per vertebral level from C1 to L2). After manual segmentation, linear and affine co-registrations were performed providing either inter-individual morphometric variability maps, or substructure probabilistic maps [CSF, white and grey matter (WM/GM)] and anatomical SC template. The larger inter-individual morphometric variations were observed at the thoraco-lumbar levels and in the posterior GM. Mean SC diameters were in agreement with the literature and higher than post-mortem measurements. A representative SC MR template was generated and values up to 90 and 100% were observed on GM and WM-probability maps. This work provides a probabilistic SC atlas and a template that could offer great potentialities for parametrical MRI analysis (DTI/MTR/fMRI) and group studies, similar to what has already been performed using a brain atlas. It also offers great perspective for biomechanical models usually based on post-mortem or generic data. Further work will consider integration into an automated SC segmentation pipeline.

  10. Snowmelt and sublimation: field experiments and modelling in the High Atlas Mountains of Morocco

    Directory of Open Access Journals (Sweden)

    O. Schulz

    2004-01-01

    Full Text Available Snow in the High Atlas Mountains is a major source for freshwater renewal and for water availability in the semi-arid lowlands of south-eastern Morocco. Snowfall- and snow-ablation monitoring and modelling is important for estimating potential water delivery from the mountain water towers to the forelands. This study is part of GLOWA-IMPETUS, an integrated management project dealing with scarce water resources in West Africa. The Ameskar study area is located to the south of the High Atlas Mountains, in their rain shadow. As a part of the M’Goun river basin within the upper Drâa valley, the study area is characterised by high radiation inputs, low atmospheric humidity and long periods with sub-zero temperatures. Its altitude ranges between 2000 m and 4000 m, with dominant north- and south-facing slopes. Snowfall occurs mainly from November to April but even summit regions can become repeatedly devoid of snow cover. Snow cover maps for the M’Goun basin (1240 km2 are derived from calculations of NDSI (Normalized Difference Snow Index from MODIS satellite images and snow depth is monitored at four automatic weather stations between 2000–4000 m. Snowfall events are infrequent at lower altitudes. The presence of snow penitentes at altitudes above 3000 m indicates that snow sublimation is an important component of snow ablation. Snow ablation was modelled with the UEB Utah Energy Balance Model (Tarboton and Luce, 1996. This single layer, physically-based, point energy and mass balance model is driven by meteorological variables recorded at the automatic weather stations at Tounza (2960 m and Tichki (3260 m. Data from snow pillows at Tounza and Tichki are used to validate the model’s physical performance in terms of energy and water balances for a sequence of two snowfall events in the winter of 2003/4. First UEB modelling results show good overall performance and timing of snowmelt and sublimation compared to field investigations. Up to 44

  11. New observations indicate the possible presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

    Science.gov (United States)

    Vieira, Gonçalo; Mora, Carla; Faleh, Ali

    2017-07-01

    Relict and present-day periglacial features have been reported in the literature for the upper reaches of the High Atlas mountains, which is the highest range in North Africa (Djebel Toubkal - 4167 m a.s.l.). A lobate feature in the Irhzer Ikhibi south at 3800 m a.s.l. has been previously interpreted as an active rock glacier, but no measurements of ground or air temperatures are known to exist for the area. In order to assess the possible presence of permafrost, we analyse data from June 2015 to June 2016 from two air temperature measurement sites at 2370 and 3210 m a.s.l. and from four ground surface temperature (GST) sites at 3220, 3815, 3980 and 4160 m a.s.l. to characterize conditions along an altitudinal gradient along the Oued Ihghyghaye valley to the summit of the Djebel Toubkal. GSTs were collected at 1 h intervals, and the presence of snow cover at the monitoring sites was validated using Landsat 8 and Sentinel-2 imagery. Two field visits allowed for logger installation and collection and for assessing the geomorphological features in the area. The results show that snow plays a major role on the thermal regime of the shallow ground, inducing important spatial variability. The lowest site at 3220 m had a thermal regime characterized by frequent freeze-thaw cycles during the cold season but with few days of snow. When snow settled, the ground surface remained isothermal at 0 °C , indicating the absence of permafrost. The highest sites at 3980 and 4160 m a.s.l. showed very frequent freeze-thaw cycles and a small influence of the snow cover on GST, reflecting the lack of snow accumulation due to the wind-exposed settings on a ridge and on the summit plateau. The site located at 3815 m in the Irhzer Ikhibi south valley had a cold, stable thermal regime with GST varying from -4.5 to -6 °C from December to March, under a continuous snow cover. The site's location in a concave setting favours wind-driven snow accumulation and lower incoming solar radiation due

  12. Central Asian Snow Cover from Hydrometeorological Surveys, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides observations of end of month snow depth, snow density, and snow water equivalent from three river basins in Central Asia: Amu Darya, Sir...

  13. Analysis of the Lake Superior Watershed Seasonal Snow Cover

    National Research Council Canada - National Science Library

    Daly, Steven F; Baldwin, Timothy B; Weyrick, Patricia

    2007-01-01

    Daily estimates of the snow water equivalent (SWE) distribution for the period from 1 December through 30 April for each winter season from 1979 80 through 2002 03 were calculated for the entire Lake Superior watershed...

  14. Numerical study of fracture arrest on snow cover

    Directory of Open Access Journals (Sweden)

    B. Frigo

    2010-10-01

    Full Text Available Under the hypothesis of a perfectly brittle phenomenon, avalanche triggering can be investigated numerically by means of Linear Elastic Fracture Mechanics (LEFM. Since, however, the real phenomenon is intrinsically dynamical, another aspect to investigate is represented by dynamic fracture propagation. In this paper, we model dynamic crack propagation into a dry snow slab and we investigate the possibility to arrest the crack propagation through the presence of weak zones distributed along the extension of the snow slope. Assuming that the weak layer is almost collapsed, we simulate the efficiency of artificial voids in the slab to arrest fracture propagation, into the framework of Dynamical Fracture Mechanics. We put forward here a new philosophy for the use of artificial discontinuities (void into the snowpack able to perform as crack arresters distributed along the snow slope area: the target is to split a large avalanche slab into smaller slabs, causing small avalanches to propagate with less catastrophic effects.

  15. Western Italian Alps Monthly Snowfall and Snow Cover Duration

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of snow observations for 18 stations in the western Italian Alps. Two types of data are included: monthly snowfall amounts and monthly snow...

  16. Snow and Water: Imaging Spectroscopy for coasts and snow cover

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal addresses the NASA Earth Science focus areas of Carbon Cycle & Ecosystems, and Water & Energy Cycle. We will develop and demonstrate a scalable...

  17. Consistent seasonal snow cover depth and duration variability over ...

    Indian Academy of Sciences (India)

    of biodiversity, global ecosystem and global hydro- logical cycle (Robinson ... climate change impacts assessment, water resources ...... Brown R D and Braaten R O 1998 Spatial and temporal vari- ability of Canadian monthly snow depths; Atmos. Ocean. 36 37–54. Cayan D R 1996 Interannual climate variability and snow.

  18. Snow cover as an indicator of cumulative land pollution

    Directory of Open Access Journals (Sweden)

    V. R. Alekseev

    2013-01-01

    Full Text Available A reliable technique has been devised for a simultaneous total and serial retrospective assessment of the ever increasing pollution of lands from aerospace images and from benchmark ground-based observations which permit calculations of the negative human impact on the environment for the particular regions, river drainage basins, states, and for the planet Earth as a whole. Use is made of the glacio-indication approach to the study of polluted territories around cities and transport routes that has come to be known as the «ProcUsmethod». An assessment of the land pollution across the globe was made for 221 administrative entities. Calculations were done for 193 states and 41 trust territories. The total area of polluted lands on the continents was estimated at 13 606 thousand km2 (10% of the Earth’s land surface. The heaviest pollution corresponds to West Europe (44.5% of its area, Micronesia (33.3%, and to the countries within the Caribbean basin (31.1%; the worst levels of land pollution correspond to Australia with New Zealand (2.1%, Melanesia (3.1%, and to Central Africa (3.8%. The most heavily polluted states are China (with the polluted area of 2400 thou km2, India (1460 thou km2, the USA (1156 thou km2, Russia (683 thou km2 and Brazil (657 thou km2.The findings, obtained by the Russian scientists V.G. Prokacheva and V.F. Usachev over the course of the last 30 years, are recognized as a fundamental contribution to glaciology and geoecology. The ProcUs method, suggested by Russian scientists, offers strong possibilities of obtaining quantitative indicators and studying spatiotemporal variability of pollutants. It is recommended that the method should be expanded and sophisticated on the basis of special-purpose ground-truth pilot observations to be used in implementing the Earth’s global ecological monitoring program.

  19. The ATLAS IBL CO2 Cooling System

    CERN Document Server

    Verlaat, Bartholomeus; The ATLAS collaboration

    2016-01-01

    The Atlas Pixel detector has been equipped with an extra B-layer in the space obtained by a reduced beam pipe. This new pixel detector called the ATLAS Insertable B-Layer (IBL) is installed in 2014 and is operational in the current ATLAS data taking. The IBL detector is cooled with evaporative CO2 and is the first of its kind in ATLAS. The ATLAS IBL CO2 cooling system is designed for lower temperature operation (<-35⁰C) than the previous developed CO2 cooling systems in High Energy Physics experiments. The cold temperatures are required to protect the pixel sensors for the high expected radiation dose up to 550 fb^-1 integrated luminosity. This paper describes the design, development, construction and commissioning of the IBL CO2 cooling system. It describes the challenges overcome and the important lessons learned for the development of future systems which are now under design for the Phase-II upgrade detectors.

  20. The ATLAS semiconductor tracker (SCT)

    International Nuclear Information System (INIS)

    Jackson, J.N.

    2005-01-01

    The ATLAS detector (CERN,LHCC,94-43 (1994)) is designed to study a wide range of physics at the CERN Large Hadron Collider (LHC) at luminosities up to 10 34 cm -2 s -1 with a bunch-crossing rate of 40 MHz. The Semiconductor Tracker (SCT) forms a key component of the Inner Detector (vol. 1, ATLAS TDR 4, CERN,LHCC 97-16 (1997); vol. 2, ATLAS TDR 5, CERN,LHCC 97-17 (1997)) which is situated inside a 2 T solenoid field. The ATLAS Semiconductor Tracker (SCT) utilises 4088 silicon modules with binary readout mounted on carbon fibre composite structures arranged in the forms of barrels in the central region and discs in the forward region. The construction of the SCT is now well advanced. The design of the SCT modules, services and support structures will be briefly outlined. A description of the various stages in the construction process will be presented with examples of the performance achieved and the main difficulties encountered. Finally, the current status of the construction is reviewed

  1. The ATLAS semiconductor tracker (SCT)

    CERN Document Server

    Jackson, J N

    2005-01-01

    The ATLAS detector (CERN/LHCC/94-43 (1994)) is designed to study a wide range of physics at the CERN Large Hadron Collider (LHC) at luminosities up to 10**3**4 cm**-**2 s**-**1 with a bunch-crossing rate of 40 MHz. The Semiconductor Tracker (SCT) forms a key component of the Inner Detector (vol. 1, ATLAS TDR 4, CERN/LHCC 97-16 (1997); vol. 2, ATLAS TDR 5, CERN/LHCC 97-17 (1997)) which is situated inside a 2 T solenoid field. The ATLAS Semiconductor Tracker (SCT) utilises 4088 silicon modules with binary readout mounted on carbon fibre composite structures arranged in the forms of barrels in the central region and discs in the forward region. The construction of the SCT is now well advanced. The design of the SCT modules, services and support structures will be briefly outlined. A description of the various stages in the construction process will be presented with examples of the performance achieved and the main difficulties encountered. Finally, the current status of the construction is reviewed.

  2. SUSY (ATLAS)

    CERN Document Server

    Sopczak, Andre; The ATLAS collaboration

    2017-01-01

    During the data-taking period at LHC (Run-II), several searches for supersymmetric particles were performed. The results from searches by the ATLAS collaborations are concisely reviewed. Model-independent and model-dependent limits on new particle production are set, and interpretations in supersymmetric models are given.

  3. SUSY (ATLAS)

    CERN Document Server

    Sopczak, Andre; The ATLAS collaboration

    2017-01-01

    During the LHC Run-II data-taking period, several searches for supersymmetric particles were performed by the ATLAS collaboration. The results from these searches are concisely reviewed. Model-independent and model-dependent limits on new particle production are set, and interpretations in supersymmetric models are given.

  4. The ATLAS positive ion injector

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Bollinger, L.M.; Pardo, R.C.

    1990-01-01

    This paper reviews the design, construction status, and beam tests to date of the positive ion injector (PII) which is replacing the tandem injector for the ATLAS heavy-ion facility. PII consists of an ECR ion source on a 350 KV platform injecting a very low velocity superconducting linac. The linac is composed of an independently-phased array of superconducting four-gap interdigital resonators which accelerate over a velocity range of .006 to .05c. In finished form, PII will be able to inject ions as heavy as uranium into the existing ATLAS linac. Although at the present time little more than 50% of the linac is operational, the indenpently-phased array is sufficiently flexible that ions in the lower half of the periodic table can be accelerated and injected into ATLAS. Results of recent operational experience will be discussed. 5 refs.

  5. The ATLAS positive ion injector

    International Nuclear Information System (INIS)

    Shepard, K.W.; Bollinger, L.M.; Pardo, R.C.

    1990-01-01

    This paper reviews the design, construction status, and beam tests to date of the positive ion injector (PII) which is replacing the tandem injector for the ATLAS heavy-ion facility. PII consists of an ECR ion source on a 350 KV platform injecting a very low velocity superconducting linac. The linac is composed of an independently-phased array of superconducting four-gap interdigital resonators which accelerate over a velocity range of .006 to .05c. In finished form, PII will be able to inject ions as heavy as uranium into the existing ATLAS linac. Although at the present time little more than 50% of the linac is operational, the indenpently-phased array is sufficiently flexible that ions in the lower half of the periodic table can be accelerated and injected into ATLAS. Results of recent operational experience will be discussed. 5 refs

  6. Status of the ATLAS pixel detector

    CERN Document Server

    Saavedra Aldo, F

    2005-01-01

    The ATLAS pixel detector is currently being constructed and will be installed in 2006 to be ready for commissioning at the Large Hadron Collider. The complete pixel detector is composed of three concentric barrels and six disks that are populated by 1744 ATLAS Pixel modules. The main components of the pixel module are the readout electronics and the silicon sensor whose active region is instrumented with rectangular pixels. The module has been designed to be able to survive 10 years of operation within the ATLAS detector. A brief description of the pixel detector will be presented with results and problems encountered during the production stage.

  7. ATLAS Silicon Microstrip Tracker Operation and Performance

    CERN Document Server

    Nagai, K; The ATLAS collaboration

    2012-01-01

    The Semi-Conductor Tracker (SCT) is one of the key precision tracking devices in the ATLAS experiment at CERN Large Hadron Collider (LHC). The SCT was constructed of 4088 modules for a total of 6.3 million silicon strips and was installed into the ATLAS experiment in 2007. The SCT has been fully operational since then, and achieves a good tracking performance from the startup of the LHC operation.

  8. Encoding Probabilistic Brain Atlases Using Bayesian Inference

    OpenAIRE

    Van Leemput, Koen

    2008-01-01

    This paper addresses the problem of creating probabilistic brain atlases from manually labeled training data. Probabilistic atlases are typically constructed by counting the relative frequency of occurrence of labels in corresponding locations across the training images. However, such an “averaging” approach generalizes poorly to unseen cases when the number of training images is limited, and provides no principled way of aligning the training datasets using deformable registration. In this p...

  9. Status report on the ATLAS superconducting linear accelerator

    International Nuclear Information System (INIS)

    Aron, J.; Benaroya, R.; Bogaty, J.; Bollinger, L.M.; Clifft, B.E.; Den Hartog, P.; Johnson, K.W.; Kutschera, W.; Markovich, P.; Nixon, J.M.; Pardo, R.; Shepard, K.W.; Zinkann, G.

    1984-01-01

    ATLAS, the Argonne Tandem-Linac Accelerator System, is a project to upgrade the existing Argonne superconducting linac heavy-ions booster which began providing beams of heavy-ions for experimental nuclear research in 1979. When completed ATLAS will provide beams of heavy ions up to approximately mass 130 at energies as high as 25 MeV/A. The construction of ATLAS is approximately 60% complete. First beam from the accelerator is expected in spring of 1985. (orig.)

  10. Status report on the ATLAS superconducting linear accelerator

    International Nuclear Information System (INIS)

    Argon, J.; Benaroya, R.; Bogaty, J.

    1984-05-01

    ATLAS, the Argonne Tandem-Linac Accelerator System, is a project to upgrade the existing Argonne superconducting linac heavy-ion booster which began providing beams of heavy-ions for experimental nuclear research in 1979. When completed ATLAS will provide beams of heavy ions up to approximately mass 130 at energies as high as 25 MeV/A. The construction of ATLAS is approximately 60% complete. First beam from the accelerator is expected in spring of 1985

  11. ATLAS Recordings

    CERN Multimedia

    Steven Goldfarb; Mitch McLachlan; Homer A. Neal

    Web Archives of ATLAS Plenary Sessions, Workshops, Meetings, and Tutorials from 2005 until this past month are available via the University of Michigan portal here. Most recent additions include the Trigger-Aware Analysis Tutorial by Monika Wielers on March 23 and the ROOT Workshop held at CERN on March 26-27.Viewing requires a standard web browser with RealPlayer plug-in (included in most browsers automatically) and works on any major platform. Lectures can be viewed directly over the web or downloaded locally.In addition, you will find access to a variety of general tutorials and events via the portal.Feedback WelcomeOur group is making arrangements now to record plenary sessions, tutorials, and other important ATLAS events for 2007. Your suggestions for potential recording, as well as your feedback on existing archives is always welcome. Please contact us at wlap@umich.edu. Thank you.Enjoy the Lectures!

  12. ATLAS Outreach Highlights

    CERN Document Server

    Cheatham, Susan; The ATLAS collaboration

    2016-01-01

    The ATLAS outreach team is very active, promoting particle physics to a broad range of audiences including physicists, general public, policy makers, students and teachers, and media. A selection of current outreach activities and new projects will be presented. Recent highlights include the new ATLAS public website and ATLAS Open Data, the very recent public release of 1 fb-1 of ATLAS data.

  13. ATLAS Thesis Award 2017

    CERN Multimedia

    Anthony, Katarina

    2018-01-01

    Winners of the ATLAS Thesis Award were presented with certificates and glass cubes during a ceremony on 22 February, 2018. They are pictured here with Karl Jakobs (ATLAS Spokesperson), Max Klein (ATLAS Collaboration Board Chair) and Katsuo Tokushuku (ATLAS Collaboration Board Deputy Chair).

  14. Preparing an ATLAS toroid magnet end-cap for lowering

    CERN Multimedia

    Claudia Marcelloni

    2007-01-01

    One of the two 13-m high toroid magnet end-caps for the ATLAS experiment being transported from the construction hall to the experimental area. The end-cap will be lowered into the ATLAS cavern and attached to an end of the detector.

  15. Preparing a new book on ATLAS

    CERN Multimedia

    Claudia Marcelloni de Oliveira

    A book about the ATLAS project and the ATLAS collaboration is going to be published and available for sale in mid 2008. The book is intended to be a symbol of appreciation for all the people from ATLAS institutes, triggering fond memories through photos, interviews, short commentaries and anecdotes about the daily life and milestones encountered while designing, constructing and completing ATLAS. We would like to give you the opportunity to collaborate with this project in two different ways: Firstly, please send us the best anecdotes related to ATLAS that you remember. To submit anecdotes, send an email to Claudia.Marcelloni@cern.ch. Secondly, you are invited to participate in our PHOTO COMPETITION. Please send the best photos you have of ATLAS attached with a description, the location, and date taken. The categories are: Milestones in the process of designing and building the detector, People at work and Important gatherings. To submit photos you should go to the CDS page and select ATLAS Photo Competi...

  16. Desarrollo de metgis, un sistema combinado de información geográfica, meteorológica y de cobertura de nieve de alta resolución, para la región andina Development of metgis, a combined high-resolution system of geographic, meteorological and snow cover information for the andes region

    Directory of Open Access Journals (Sweden)

    Gerald Spreitzhofer

    2006-12-01

    Shuttle Radar Topographic Mission (SRTM and representations of roads, railway lines, rivers, frontiers and cities. On top of various modes of terrain (elevation, slope, aspect, meteorological and snow information can be visualized in a variety of styles. The combined display of observations from various networks, of forecasts from numerical models like MM5 and of forecast errors will be possible. For a variety of parameters, meteorological input data may be subject to downscaling procedures using the VERA system (Vienna Enhanced Resolution Analysis. Regarding features of the system specifically related to mountain areas, the SRTM data combined with VERA allows a good estimation of areas with temperatures below zero and snow accumulation. For the future the inclusion of the Swiss model SNOWPACK is planned which provides simulations of the snow cover.

  17. A Lego version of ATLAS

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    There's nothing very unusual about a small child making simple objects out of Lego. But wouldn't you be surprised to learn that one six-year old has just made a life-like model of the ATLAS detector?   Bastian with his Lego ATLAS detector. © Photo provided by Kai Nicklas, Bastian's father. It all began a month ago when the boy's father was watching a video about the construction of the ATLAS detector on the Internet. He hadn't noticed that his son was watching it over his shoulder. The small boy was fascinated by what he was seeing on the computer screen and his first reaction was to exclaim: "Wow! That's a terrific machine! I think the people who built it must be really clever." The detector must have really fired his imagination because, after asking his father a few questions, he decided to make a Lego model of it. Look at the photo and you will see how closely the model he produced resembles the actual ATLAS detector. Is the little boy in question, Bastia...

  18. ATLAS: Now under new management

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    On 1 March, the ATLAS Collaboration welcomed a new spokesperson, Dave Charlton (University of Birmingham), and two new deputy spokespersons, Thorsten Wengler (CERN) and Beate Heinemann (University of California, Berkeley and LBNL). The Bulletin takes a look at what’s in store for one of the world’s largest scientific collaborations.   ATLAS members at the 2010 collaboration meeting in Copenhagen. Image: Rune Johansen and Troels Petersen. ATLAS spokesperson Dave Charlton has seen the collaboration through countless milestones: from construction to start-up to the 4 July 2012 announcement, he’s been an integral part of the team. Now, after twelve years with the collaboration, Dave is moving into the main office for the next two years. “2012 was a landmark year for ATLAS,” says Dave. “We spent a lot of time in the limelight and, in many ways, all eyes are still on us. But with the shutdown now under way, our focus is ...

  19. ATLAS Recordings

    CERN Multimedia

    Jeremy Herr; Homer A. Neal; Mitch McLachlan

    The University of Michigan Web Archives for the 2006 ATLAS Week Plenary Sessions, as well as the first of 2007, are now online. In addition, there are a wide variety of Software and Physics Tutorial sessions, recorded over the past couple years, to chose from. All ATLAS-specific archives are accessible here.Viewing requires a standard web browser with RealPlayer plug-in (included in most browsers automatically) and works on any major platform. Lectures can be viewed directly over the web or downloaded locally.In addition, you will find access to a variety of general tutorials and events via the portal. Shaping Collaboration 2006The Michigan group is happy to announce a complete set of recordings from the Shaping Collaboration conference held last December at the CICG in Geneva.The event hosted a mix of Collaborative Tool experts and LHC Users, and featured presentations by the CERN Deputy Director General, Prof. Jos Engelen, the President of Internet2, and chief developers from VRVS/EVO, WLAP, and other tools...

  20. EnviroAtlas

    Data.gov (United States)

    City and County of Durham, North Carolina — This EnviroAtlas web service supports research and online mapping activities related to EnviroAtlas (https://www.epa.gov/enviroatlas). The layers in this web...

  1. A new sub-detector for ATLAS

    CERN Multimedia

    Marco Bruschi

    Since last August, the ATLAS detector family has been joined by a new little member named LUCID, from the acronym "LUminosity Cerenkov Integrating Detector". This may well surprise you if you are already aware that LUCID construction started only in February after its approval by an ATLAS-management mandated review committee. The rapid progress from approval to installation is the result of the close collaboration between groups from Alberta (Canada), INFN Bologna (Italy), Lund (Sweden) and CERN. LUCID is primarily intended to measure the luminosity delivered by the LHC to ATLAS with a systematic uncertainty in the range of a few percent. To achieve such a precision and still meet the demanding installation schedule, the LUCID developers prized simplicity and robustness above all. One of the LUCID vessels while under construction. One can see the aluminum Cerenkov tubes and the photomultiplier mount (plugged into the upper flange). The two fully assembled LUCID vessels seen from the front end elect...

  2. Berliner Philarmoniker ATLAS visit

    CERN Multimedia

    ATLAS Collaboration

    2017-01-01

    The Berliner Philarmoniker in on tour through Europe. They stopped on June 27th in Geneva, for a concert at the Victoria Hall. An ATLAS visit was organised the morning after, lead by the ATLAS spokesperson Karl Jakobs (welcome and overview talk) and two ATLAS guides (AVC visit and 3D movie).

  3. ATLAS Facility and Instrumentation Description Report

    International Nuclear Information System (INIS)

    Kang, Kyoung Ho; Moon, Sang Ki; Park, Hyun Sik

    2009-06-01

    A thermal-hydraulic integral effect test facility, ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), has been constructed at KAERI (Korea Atomic Energy Research Institute). The ATLAS is a half-height and 1/288-volume scaled test facility with respect to the APR1400. The fluid system of the ATLAS consists of a primary system, a secondary system, a safety injection system, a break simulating system, a containment simulating system, and auxiliary systems. The primary system includes a reactor vessel, two hot legs, four cold legs, a pressurizer, four reactor coolant pumps, and two steam generators. The secondary system of the ATLAS is simplified to be of a circulating looptype. Most of the safety injection features of the APR1400 and the OPR1000 are incorporated into the safety injection system of the ATLAS. In the ATLAS test facility, about 1300 instrumentations are installed to precisely investigate the thermal-hydraulic behavior in simulation of the various test scenarios. This report describes the scaling methodology, the geometric data of the individual component, and the specification and the location of the instrumentations which are specific to the simulation of 50% DVI line break accident of the APR1400 for supporting the 50 th OECD/NEA International Standard Problem Exercise (ISP-50)

  4. The ATLAS Detector Control System

    International Nuclear Information System (INIS)

    Lantzsch, K; Braun, H; Hirschbuehl, D; Kersten, S; Arfaoui, S; Franz, S; Gutzwiller, O; Schlenker, S; Tsarouchas, C A; Mindur, B; Hartert, J; Zimmermann, S; Talyshev, A; Oliveira Damazio, D; Poblaguev, A; Martin, T; Thompson, P D; Caforio, D; Sbarra, C; Hoffmann, D

    2012-01-01

    The ATLAS experiment is one of the multi-purpose experiments at the Large Hadron Collider (LHC) at CERN, constructed to study elementary particle interactions in collisions of high-energy proton beams. Twelve different sub detectors as well as the common experimental infrastructure are controlled and monitored by the Detector Control System (DCS) using a highly distributed system of 140 server machines running the industrial SCADA product PVSS. Higher level control system layers allow for automatic control procedures, efficient error recognition and handling, manage the communication with external systems such as the LHC controls, and provide a synchronization mechanism with the ATLAS data acquisition system. Different databases are used to store the online parameters of the experiment, replicate a subset used for physics reconstruction, and store the configuration parameters of the systems. This contribution describes the computing architecture and software tools to handle this complex and highly interconnected control system.

  5. The ATLAS Detector Control System

    Science.gov (United States)

    Lantzsch, K.; Arfaoui, S.; Franz, S.; Gutzwiller, O.; Schlenker, S.; Tsarouchas, C. A.; Mindur, B.; Hartert, J.; Zimmermann, S.; Talyshev, A.; Oliveira Damazio, D.; Poblaguev, A.; Braun, H.; Hirschbuehl, D.; Kersten, S.; Martin, T.; Thompson, P. D.; Caforio, D.; Sbarra, C.; Hoffmann, D.; Nemecek, S.; Robichaud-Veronneau, A.; Wynne, B.; Banas, E.; Hajduk, Z.; Olszowska, J.; Stanecka, E.; Bindi, M.; Polini, A.; Deliyergiyev, M.; Mandic, I.; Ertel, E.; Marques Vinagre, F.; Ribeiro, G.; Santos, H. F.; Barillari, T.; Habring, J.; Huber, J.; Arabidze, G.; Boterenbrood, H.; Hart, R.; Iakovidis, G.; Karakostas, K.; Leontsinis, S.; Mountricha, E.; Ntekas, K.; Filimonov, V.; Khomutnikov, V.; Kovalenko, S.; Grassi, V.; Mitrevski, J.; Phillips, P.; Chekulaev, S.; D'Auria, S.; Nagai, K.; Tartarelli, G. F.; Aielli, G.; Marchese, F.; Lafarguette, P.; Brenner, R.

    2012-12-01

    The ATLAS experiment is one of the multi-purpose experiments at the Large Hadron Collider (LHC) at CERN, constructed to study elementary particle interactions in collisions of high-energy proton beams. Twelve different sub detectors as well as the common experimental infrastructure are controlled and monitored by the Detector Control System (DCS) using a highly distributed system of 140 server machines running the industrial SCADA product PVSS. Higher level control system layers allow for automatic control procedures, efficient error recognition and handling, manage the communication with external systems such as the LHC controls, and provide a synchronization mechanism with the ATLAS data acquisition system. Different databases are used to store the online parameters of the experiment, replicate a subset used for physics reconstruction, and store the configuration parameters of the systems. This contribution describes the computing architecture and software tools to handle this complex and highly interconnected control system.

  6. The ATLAS TRT Barrel Detector

    Science.gov (United States)

    ATLAS TRT Collaboration; Abat, E.; Addy, T. N.; Åkesson, T. P. A.; Alison, J.; Anghinolfi, F.; Arik, E.; Arik, M.; Atoian, G.; Auerbach, B.; Baker, O. K.; Banas, E.; Baron, S.; Bault, C.; Becerici, N.; Beddall, A.; Beddall, A. J.; Bendotti, J.; Benjamin, D. P.; Bertelsen, H.; Bingul, A.; Blampey, H.; Bocci, A.; Bochenek, M.; Bondarenko, V. G.; Bychkov, V.; Callahan, J.; Capeáns Garrido, M.; Cardiel Sas, L.; Catinaccio, A.; Cetin, S. A.; Chandler, T.; Chritin, R.; Cwetanski, P.; Dam, M.; Danielsson, H.; Danilevich, E.; David, E.; Degenhardt, J.; Di Girolamo, B.; Dittus, F.; Dixon, N.; Dogan, O. B.; Dolgoshein, B. A.; Dressnandt, N.; Driouchi, C.; Ebenstein, W. L.; Eerola, P.; Egede, U.; Egorov, K.; Evans, H.; Farthouat, P.; Fedin, O. L.; Fowler, A. J.; Fratina, S.; Froidevaux, D.; Fry, A.; Gagnon, P.; Gavrilenko, I. L.; Gay, C.; Ghodbane, N.; Godlewski, J.; Goulette, M.; Gousakov, I.; Grigalashvili, N.; Grishkevich, Y.; Grognuz, J.; Hajduk, Z.; Hance, M.; Hansen, F.; Hansen, J. B.; Hansen, P. H.; Hanson, G.; Hare, G. A.; Harvey, A., Jr.; Hauviller, C.; High, A.; Hulsbergen, W.; Huta, W.; Issakov, V.; Istin, S.; Jain, V.; Jarlskog, G.; Jeanty, L.; Kantserov, V. A.; Kaplan, B.; Kapliy, A. S.; Katounine, S.; Kayumov, F.; Keener, P. T.; Kekelidze, G. D.; Khabarova, E.; Khristachev, A.; Kisielewski, B.; Kittelmann, T. H.; Kline, C.; Klinkby, E. B.; Klopov, N. V.; Ko, B. R.; Koffas, T.; Kondratieva, N. V.; Konovalov, S. P.; Koperny, S.; Korsmo, H.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; LeBihan, A.-C.; LeGeyt, B. C.; Levterov, K.; Lichard, P.; Lindahl, A.; Lisan, V.; Lobastov, S.; Loginov, A.; Loh, C. W.; Lokwitz, S.; Long, M. C.; Lucas, S.; Lucotte, A.; Luehring, F.; Lundberg, B.; Mackeprang, R.; Maleev, V. P.; Manara, A.; Mandl, M.; Martin, A. J.; Martin, F. F.; Mashinistov, R.; Mayers, G. M.; McFarlane, K. W.; Mialkovski, V.; Mills, B. M.; Mindur, B.; Mitsou, V. A.; Mjörnmark, J. U.; Morozov, S. V.; Morris, E.; Mouraviev, S. V.; Muir, A. M.; Munar, A.; Nadtochi, A. V.; Nesterov, S. Y.; Newcomer, F. M.; Nikitin, N.; Novgorodova, O.; Novodvorski, E. G.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olivito, D.; Olszowska, J.; Ostrowicz, W.; Passmore, M. S.; Patrichev, S.; Penwell, J.; Perez-Gomez, F.; Peshekhonov, V. D.; Petersen, T. C.; Petti, R.; Placci, A.; Poblaguev, A.; Pons, X.; Price, M. J.; hne, O. Rø; Reece, R. D.; Reilly, M. B.; Rembser, C.; Romaniouk, A.; Rousseau, D.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Söderberg, M.; Savenkov, A.; Saxon, J.; Scandurra, M.; Schegelsky, V. A.; Scherzer, M. I.; Schmidt, M. P.; Schmitt, C.; Sedykh, E.; Seliverstov, D. M.; Shin, T.; Shmeleva, A.; Sivoklokov, S.; Smirnov, S. Yu; Smirnova, L.; Smirnova, O.; Smith, P.; Sosnovtsev, V. V.; Sprachmann, G.; Subramania, S.; Suchkov, S. I.; Sulin, V. V.; Szczygiel, R. R.; Tartarelli, G.; Thomson, E.; Tikhomirov, V. O.; Tipton, P.; Valls Ferrer, J. A.; Van Berg, R.; Vassilakopoulos, V. I.; Vassilieva, L.; Wagner, P.; Wall, R.; Wang, C.; Whittington, D.; Williams, H. H.; Zhelezko, A.; Zhukov, K.

    2008-02-01

    The ATLAS TRT barrel is a tracking drift chamber using 52,544 individual tubular drift tubes. It is one part of the ATLAS Inner Detector, which consists of three sub-systems: the pixel detector spanning the radius range 4 to 20 cm, the semiconductor tracker (SCT) from 30 to 52 cm, and the transition radiation tracker (TRT) from 56 to 108 cm. The TRT barrel covers the central pseudo-rapidity region |η|< 1, and the TRT while endcaps cover the forward and backward eta regions. These TRT systems provide a combination of continuous tracking with many measurements in individual drift tubes (or straws) and of electron identification based on transition radiation from fibers or foils interleaved between the straws themselves. This paper describes the recently-completed construction of the TRT Barrel detector, including the quality control procedures used in the fabrication of the detector.

  7. Recent ATLAS Articles on WLAP

    CERN Multimedia

    J. Herr

    As reported in the September 2004 ATLAS eNews, the Web Lecture Archive Project is a system for the archiving and publishing of multimedia presentations, using the Web as medium. We list here newly available WLAP items relating to ATLAS: Atlas Physics Workshop 6-11 June 2005 June 2005 ATLAS Week Plenary Session Click here to browse WLAP for all ATLAS lectures.

  8. Frontier use in ATLAS

    CERN Document Server

    Smith, D A; The ATLAS collaboration; DeStefano, J; Dewhurst, A; Donno, F; Dykstra, D; Front, D; Gallas, E; Hawkings, R; Luehring, F; Walker, R

    2010-01-01

    Frontier is a distributed database access system, including data caching, that was developed originally for the CMS experiment. This system has been in production for CMS for some time, providing world-wide access to the experiment's conditions data for all user jobs. The ATLAS experiment, which has had similar problems with global data distribution, investigated the use of the system for ATLAS jobs. After months of trials and verification, ATLAS put the Frontier system into production late in 2009. Frontier now supplies database access for ATLAS jobs at over 50 computing sites. This successful deployment of Frontier in ATLAS will be described, along with the scope of the system and necessary resources.

  9. Development and Implementation of a Corriedale Ovine Brain Atlas for Use in Atlas-Based Segmentation.

    Directory of Open Access Journals (Sweden)

    Kishan Andre Liyanage

    Full Text Available Segmentation is the process of partitioning an image into subdivisions and can be applied to medical images to isolate anatomical or pathological areas for further analysis. This process can be done manually or automated by the use of image processing computer packages. Atlas-based segmentation automates this process by the use of a pre-labelled template and a registration algorithm. We developed an ovine brain atlas that can be used as a model for neurological conditions such as Parkinson's disease and focal epilepsy. 17 female Corriedale ovine brains were imaged in-vivo in a 1.5T (low-resolution MRI scanner. 13 of the low-resolution images were combined using a template construction algorithm to form a low-resolution template. The template was labelled to form an atlas and tested by comparing manual with atlas-based segmentations against the remaining four low-resolution images. The comparisons were in the form of similarity metrics used in previous segmentation research. Dice Similarity Coefficients were utilised to determine the degree of overlap between eight independent, manual and atlas-based segmentations, with values ranging from 0 (no overlap to 1 (complete overlap. For 7 of these 8 segmented areas, we achieved a Dice Similarity Coefficient of 0.5-0.8. The amygdala was difficult to segment due to its variable location and similar intensity to surrounding tissues resulting in Dice Coefficients of 0.0-0.2. We developed a low resolution ovine brain atlas with eight clinically relevant areas labelled. This brain atlas performed comparably to prior human atlases described in the literature and to intra-observer error providing an atlas that can be used to guide further research using ovine brains as a model and is hosted online for public access.

  10. ATLAS Distributed Computing Automation

    CERN Document Server

    Schovancova, J; The ATLAS collaboration; Borrego, C; Campana, S; Di Girolamo, A; Elmsheuser, J; Hejbal, J; Kouba, T; Legger, F; Magradze, E; Medrano Llamas, R; Negri, G; Rinaldi, L; Sciacca, G; Serfon, C; Van Der Ster, D C

    2012-01-01

    The ATLAS Experiment benefits from computing resources distributed worldwide at more than 100 WLCG sites. The ATLAS Grid sites provide over 100k CPU job slots, over 100 PB of storage space on disk or tape. Monitoring of status of such a complex infrastructure is essential. The ATLAS Grid infrastructure is monitored 24/7 by two teams of shifters distributed world-wide, by the ATLAS Distributed Computing experts, and by site administrators. In this paper we summarize automation efforts performed within the ATLAS Distributed Computing team in order to reduce manpower costs and improve the reliability of the system. Different aspects of the automation process are described: from the ATLAS Grid site topology provided by the ATLAS Grid Information System, via automatic site testing by the HammerCloud, to automatic exclusion from production or analysis activities.

  11. A review of atlas-based segmentation for magnetic resonance brain images.

    Science.gov (United States)

    Cabezas, Mariano; Oliver, Arnau; Lladó, Xavier; Freixenet, Jordi; Cuadra, Meritxell Bach

    2011-12-01

    Normal and abnormal brains can be segmented by registering the target image with an atlas. Here, an atlas is defined as the combination of an intensity image (template) and its segmented image (the atlas labels). After registering the atlas template and the target image, the atlas labels are propagated to the target image. We define this process as atlas-based segmentation. In recent years, researchers have investigated registration algorithms to match atlases to query subjects and also strategies for atlas construction. In this paper we present a review of the automated approaches for atlas-based segmentation of magnetic resonance brain images. We aim to point out the strengths and weaknesses of atlas-based methods and suggest new research directions. We use two different criteria to present the methods. First, we refer to the algorithms according to their atlas-based strategy: label propagation, multi-atlas methods, and probabilistic techniques. Subsequently, we classify the methods according to their medical target: the brain and its internal structures, tissue segmentation in healthy subjects, tissue segmentation in fetus, neonates and elderly subjects, and segmentation of damaged brains. A quantitative comparison of the results reported in the literature is also presented. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. ERCP atlas

    International Nuclear Information System (INIS)

    Pott, G.; Schrameyer, B.

    1989-01-01

    Endoscopic-retrograde cholangio-pancreatography is a diagnostic tool that has become a routine method also in medical centres other than those specializing in the field of gastroenterology. It is estimated that there are about 1000 hospitals in the Federal Republic of Germany applying cholangio-pancreatography as a diagnostic method. Frequently, data interpretation is difficult, because imaging of subsequently detected lesions is found to have been insufficiently differential, or incomplete. The experienced examiner, who knows the pathological processes involved and hence to be expected, will perform the ERCP examination in a specific manner, i.e. purposefully. The ERCP atlas now presents a selection of typical, frequently found conditions, and of rarely encountered lesions. The material has been chosen from a total of 15 000 retrograde cholangio-pancreatographies. The introductory text is relatively short, as it is not so much intended to enhance experienced readers' skill in endoscopic diagnostics, - there is other literature for this purpose -, but rather as a brief survey for less experienced readers. (orig./MG) With 280 figs [de

  13. GNAM and OHP Monitoring Tools for ATLAS experiment at LHC.

    CERN Document Server

    Adragna, P; Della Pietra, M; Dotti, A; Ferrari, R; Gaudio, G; Roda, C; Salvatore, D; Vandelli, W; Zema, P F; 2006 Nuclear Science Symposium, Medical Imaging Conference and 15th International Room Temperature Semiconductor Detector Workshop

    2007-01-01

    ATLAS is one of the four experiments under construction along the Large Hadron Collider (LHC) ring at CERN. The LHC will produce interactions at a center-of-mass energy equal to √s = 14 TeV at 40 MHz rate. The detector consists of more than 140 million electronic channels. The challenging experimental environment and the extreme detector complexity impose the necessity of a common scalable distributed monitoring framework, which can be tuned for the optimal use by different ATLAS sub-detectors at the various levels of the ATLAS data flow. This note presents two monitoring tools that have been developed for this aim within the architecture ATLAS Monitoring Framework and the Data Acquisition System: GNAM and OHP. The first one is a framework for online histogram production; the second one is graphical application for histogram presentation. This tools are now widely used during the ATLAS commissioning and their performances are reported in this note

  14. Performance of the ATLAS semiconductor tracker

    CERN Document Server

    Alpigiani, C; The ATLAS collaboration

    2014-01-01

    We report the operation and performance of the ATLAS Semi-Conductor Tracker (SCT) functioning in a high luminosity and high radiation environment. The SCT is part of the inner tracking system of the ATLAS experiment at CERN and is constructed of 4088 modules assembled from silicon-strip sensors for a total of 6.3 million channels more than 99 % of which were fully functional throughout all data taking periods. Noise occupancy and hit efficiency as well as the Lorentz angle and radiation damage measurements will be discussed in details.

  15. ATLAS honours one of its suppliers

    CERN Multimedia

    2003-01-01

    On 12 February the Netherlands firm Schelde Exotech was awarded a prize for best ATLAS supplier for the construction of the two vacuum chambers for the ATLAS endcap toroid magnets. The award for best supplier is handed over to representatives of the firm Schelde Exotech in front of one of the two vacuum chambers built by the firm. From left to right: E. Baynham (RAL), H. Geerink (NIKHEF), Y. Lefevere (NIKHEF), J. Engelen (NIKHEF), P. Jenni (CERN), E. Holtom (RAL), R. Boddaert (Schelde Exotech), G. Luijckx (NIKHEF), H. Klumpus (Schelde Exotech), M. Nessi (CERN), H. ten Kate (CERN), M. Nordberg (CERN), H. Hoffmann (CERN).This ceremony has now become something of a tradition. For the third consecutive year, ATLAS has given best supplier awards for the most exceptional contributors to the construction of the future detector. The Netherlands firm Schelde Exotech has just received the award for the construction of the two vacuum chambers for the ATLAS endcap toroid magnets. With a diameter of 11 metres and a volum...

  16. New observations indicate the possible presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco

    Directory of Open Access Journals (Sweden)

    G. Vieira

    2017-07-01

    Full Text Available Relict and present-day periglacial features have been reported in the literature for the upper reaches of the High Atlas mountains, which is the highest range in North Africa (Djebel Toubkal – 4167 m a.s.l.. A lobate feature in the Irhzer Ikhibi south at 3800 m a.s.l. has been previously interpreted as an active rock glacier, but no measurements of ground or air temperatures are known to exist for the area. In order to assess the possible presence of permafrost, we analyse data from June 2015 to June 2016 from two air temperature measurement sites at 2370 and 3210 m a.s.l. and from four ground surface temperature (GST sites at 3220, 3815, 3980 and 4160 m a.s.l. to characterize conditions along an altitudinal gradient along the Oued Ihghyghaye valley to the summit of the Djebel Toubkal. GSTs were collected at 1 h intervals, and the presence of snow cover at the monitoring sites was validated using Landsat 8 and Sentinel-2 imagery. Two field visits allowed for logger installation and collection and for assessing the geomorphological features in the area. The results show that snow plays a major role on the thermal regime of the shallow ground, inducing important spatial variability. The lowest site at 3220 m had a thermal regime characterized by frequent freeze–thaw cycles during the cold season but with few days of snow. When snow settled, the ground surface remained isothermal at 0 °C , indicating the absence of permafrost. The highest sites at 3980 and 4160 m a.s.l. showed very frequent freeze–thaw cycles and a small influence of the snow cover on GST, reflecting the lack of snow accumulation due to the wind-exposed settings on a ridge and on the summit plateau. The site located at 3815 m in the Irhzer Ikhibi south valley had a cold, stable thermal regime with GST varying from −4.5 to −6 °C from December to March, under a continuous snow cover. The site's location in a concave setting favours wind

  17. ATLAS: Applications experiences and further developments

    International Nuclear Information System (INIS)

    Beraha, D.; Pointner, W.; Voggenberger, T.

    1999-01-01

    An overview of the plant analyzer ATLAS is given, describing its configuration, the process models and the supplementary modules which enhance the functionality of ATLAS for a range of applications in reactor safety analysis. These modules include the Reliability Advisory System, which supports the user by information from probabilistic safety analysis, the Procedure Analysis for development and test of emergency operating procedures, and a diagnostic system for steam-generator tube rupture. The development of plant specific analysers for various power plants is described, and the user experience related. Finally, the intended further development directions are discussed, centering on a tracking simulator, the migration of the visualisation system to Windows NT, and the construction of the Analysis Center as a multimedia environment for the operation of ATLAS. (author)

  18. Resonance Project; Music from the ATLAS Experiment

    CERN Document Server

    Claudia Marcelloni

    2010-01-01

    The ATLAS Collaboration comprises physicists, engineers, technicians and support staff from 38 countries who have come together at CERN to build and run one of the largest, most complex scientific experiments known to mankind. Drawn together by our common love of science, many of us are also passionate about music. In October 2008, we marked the completion of the ATLAS detector construction with a series of live performances, and thus was born the idea for Resonance. The recording experience was exciting and enjoyable for all of us, many of whom had never entered a studio before. Resonance is a double CD featuring a variety of musical styles from classical to heavy metal. It also includes a DVD with footage of the recording sessions and interviews with some of the musicians. For more information go to www.atlas-resonance.ch

  19. Status of the uranium upgrade of ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Bollinger, L.M.; Billquist, P.J.; Bogaty, J.M.; Clifft, B.E.; Markovich, P.; Munson, F.H.; Pardo, R.C.; Shepard, K.W.; Zinkann, G.P.

    1991-01-01

    The ATLAS Positive Ion Injector (PII) is designed to replace the tandem injector for the ATLAS heavy-ion facility. When the PII project is complete, ATLAS will be able to accelerate all ions through uranium to energies above the Coulomb barrier. PII consists of an ECR ion source on a 350 KV platform and a very low-velocity superconducting linac. The linac is composed of an independently-phased array of superconducting four-gap interdigital resonators which accelerate over a velocity range of .007c to .05c. the PII project is approximately 75% complete. Beam tests and experiments using the partially completed PII have demonstrated that the technical design goals are being met. The design, construction status, and results of recent operational experience using the PII will be discussed. 10 refs., 2 figs., 1 tab.

  20. Status of the uranium upgrade of ATLAS

    International Nuclear Information System (INIS)

    Bollinger, L.M.; Billquist, P.J.; Bogaty, J.M.; Clifft, B.E.; Markovich, P.; Munson, F.H.; Pardo, R.C.; Shepard, K.W.; Zinkann, G.P.

    1991-01-01

    The ATLAS Positive Ion Injector (PII) is designed to replace the tandem injector for the ATLAS heavy-ion facility. When the PII project is complete, ATLAS will be able to accelerate all ions through uranium to energies above the Coulomb barrier. PII consists of an ECR ion source on a 350 KV platform and a very low-velocity superconducting linac. The linac is composed of an independently-phased array of superconducting four-gap interdigital resonators which accelerate over a velocity range of .007c to .05c. the PII project is approximately 75% complete. Beam tests and experiments using the partially completed PII have demonstrated that the technical design goals are being met. The design, construction status, and results of recent operational experience using the PII will be discussed. 10 refs., 2 figs., 1 tab

  1. The ATLAS Analysis Model

    CERN Multimedia

    Amir Farbin

    The ATLAS Analysis Model is a continually developing vision of how to reconcile physics analysis requirements with the ATLAS offline software and computing model constraints. In the past year this vision has influenced the evolution of the ATLAS Event Data Model, the Athena software framework, and physics analysis tools. These developments, along with the October Analysis Model Workshop and the planning for CSC analyses have led to a rapid refinement of the ATLAS Analysis Model in the past few months. This article introduces some of the relevant issues and presents the current vision of the future ATLAS Analysis Model. Event Data Model The ATLAS Event Data Model (EDM) consists of several levels of details, each targeted for a specific set of tasks. For example the Event Summary Data (ESD) stores calorimeter cells and tracking system hits thereby permitting many calibration and alignment tasks, but will be only accessible at particular computing sites with potentially large latency. In contrast, the Analysis...

  2. Project of the ATLAS experiment by LHC of CERN

    International Nuclear Information System (INIS)

    Andrieux, M.L.; Belhorma, B.; Collot, J.; Saintignon, P. de; Dzahini, D.; Ferrari, A.; Hostachy, J.Y.; Martin, Ph.; Rey-Campagnolle, M.; Belymam, A.; Wielers, B.

    1997-01-01

    The group is involved in the construction of the liquid argon calorimeter of the ATLAS detector. Following an intense R and D phase, the final detailed design at the ATLAS calorimeter was finalized, written and approved by the LHC committee. ATLAS is now in a pre-construction phase which implies that the group activities are mainly devoted to the installation of the assembly line of the electromagnetic pre-sampler sectors. Our R and D activities on the calorimeter electronics were pursued along two lines: the optimization of the filtering amplifiers and a participation to the development of optical links for data transmission. Liquid argon pollution tests under radiation were also achieved at SARA. They proved the radiation hardness of the liquid argon calorimeter. We recently showed that the search for heavy right-handed neutrinos up to m N < 3 TeV is possible with the ATLAS detector. (authors)

  3. Future ATLAS Higgs Studies

    CERN Document Server

    Smart, Ben; The ATLAS collaboration

    2017-01-01

    The High-Luminosity LHC will prove a challenging environment to work in, with for example $=200$ expected. It will however also provide great opportunities for advancing studies of the Higgs boson. The ATLAS detector will be upgraded, and Higgs prospects analyses have been performed to assess the reach of ATLAS Higgs studies in the HL-LHC era. These analyses are presented, as are Run-2 ATLAS di-Higgs analyses for comparison.

  4. The Irish Wind Atlas

    Energy Technology Data Exchange (ETDEWEB)

    Watson, R. [Univ. College Dublin, Dept. of Electronic and Electrical Engineering, Dublin (Ireland); Landberg, L. [Risoe National Lab., Meteorology and Wind Energy Dept., Roskilde (Denmark)

    1999-03-01

    The development work on the Irish Wind Atlas is nearing completion. The Irish Wind Atlas is an updated improved version of the Irish section of the European Wind Atlas. A map of the irish wind resource based on a WA{sup s}P analysis of the measured data and station description of 27 measuring stations is presented. The results of previously presented WA{sup s}P/KAMM runs show good agreement with these results. (au)

  5. Genus zero Gromov-Witten axioms via Kuranishi atlases

    OpenAIRE

    Castellano, Robert

    2016-01-01

    A Kuranishi atlas is a structure used to build a virtual fundamental class on moduli spaces of $J$-holomorphic curves. They were introduced by McDuff and Wehrheim to resolve some of the challenges in this field. This paper completes the construction of genus zero Gromov-Witten invariants using Kuranishi atlases and proves the Gromov-Witten axioms of Kontsevich and Manin. To do so, we introduce the notion of a transverse subatlas, a useful tool for working with Kuranishi atlases.

  6. The ATLAS liquid argon calorimeter--status and expected performance

    International Nuclear Information System (INIS)

    Schacht, Peter

    2004-01-01

    For the ATLAS detector at the LHC, the liquid argon technique is exploited for the electromagnetic calorimetry in the central part and for the electromagnetic and hadronic calorimetry in the forward and backward regions. The construction of the calorimeter is well advanced with full cold tests of the barrel calorimeter and first endcap calorimeter only months away. The status of the project is discussed as well as the related results from beam test studies of the various calorimeter subdetectors. The results show that the expected performance meets the ATLAS requirements as specified in the ATLAS Technical Design Report

  7. Dynamic Efficiency Measurements for Irradiated ATLAS Pixel Single Chip Modules

    CERN Document Server

    Pfaff, Mike; Grosse-Knetter, Jorn

    2011-01-01

    The ATLAS pixel detector is the innermost subdetector of the ATLAS experiment. Due to this, the pixel detector has to be particularly radiation hard. In this diploma thesis effects on the sensor and the electronics which are caused by irradiation are examined. It is shown how the behaviour changes between an unirradiated sample and a irradiated sample, which was treated with the same radiation dose that is expected at the end of the lifetime of ATLAS. For this study a laser system, which is used for dynamic efficiency measurements was constructed. Furthermore, the behaviour of the noise during the detection of a particle was evaluated studied.

  8. Differential top-antitop cross-section measurements as a function of observables constructed from final-state particles using pp collisions at √s = 7 TeV in the ATLAS detector

    Czech Academy of Sciences Publication Activity Database

    Aad, G.; Abbott, B.; Abdallah, J.; Chudoba, Jiří; Havránek, Miroslav; Hejbal, Jiří; Jakoubek, Tomáš; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Lysák, Roman; Marčišovský, Michal; Mikeštíková, Marcela; Němeček, Stanislav; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Vrba, Václav

    2015-01-01

    Roč. 2015, č. 6 (2015), s. 100 ISSN 1029-8479 R&D Projects: GA MŠk(CZ) LG13009 Institutional support: RVO:68378271 Keywords : hadron-hadron scattering * top physics * ATLAS * LHC Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 6.023, year: 2015

  9. Operating experience and construction status of ATLAS

    International Nuclear Information System (INIS)

    Pardo, R.C.; DenHartog, P.; Shepard, K.W.; Zinkann, G.

    1984-01-01

    The present Argonne Tandem-Linac accelerator has operated in a reliable manner during the past year. The accelerator system provided 4402 hours of experimental beam time with a wide variety of heavy-ions. Figure 1 shows the beams which have been provided during the past year. New beams accelerated by the linac include 300 MeV 82 Se and 390 MeV 109 Ag. In tests, the tandem accelerated 102 MeV 127 I. This is the heaviest beam ever accelerated by the Argonne tandem. The long-term performance of the niobium resonators appears to be good. No significant degradation of performance has been observed for most resonators over many years of use with the exceptions of problems caused by catastrophic vacuum accidents. Resonators whose performance has deteriorated after vacuum accidents have recently been restored to their original performance state by a simple technique. The technique used is to rinse the interior of the resonator with a sequence of baths of solvents and water

  10. Project of the ATLAS experiment by LHC of CERN; Projet d`experience ATLAS au LHC du CERN

    Energy Technology Data Exchange (ETDEWEB)

    Andrieux, M.L.; Belhorma, B.; Collot, J.; Saintignon, P. de; Dzahini, D.; Ferrari, A.; Hostachy, J.Y.; Martin, Ph.; Rey-Campagnolle, M. [Inst. des Sciences Nucleaires, Grenoble-1 Univ., 38 (France); Belymam, A. [Universite de Casablanca, Morocco (Morocco); Wielers, B. [Centre de Physique des Particules de Marseille, 163, avenue de Luminy, Case 907-13288, Marseille, Cedex 9 (France)

    1997-12-31

    The group is involved in the construction of the liquid argon calorimeter of the ATLAS detector. Following an intense R and D phase, the final detailed design at the ATLAS calorimeter was finalized, written and approved by the LHC committee. ATLAS is now in a pre-construction phase which implies that the group activities are mainly devoted to the installation of the assembly line of the electromagnetic pre-sampler sectors. Our R and D activities on the calorimeter electronics were pursued along two lines: the optimization of the filtering amplifiers and a participation to the development of optical links for data transmission. Liquid argon pollution tests under radiation were also achieved at SARA. They proved the radiation hardness of the liquid argon calorimeter. We recently showed that the search for heavy right-handed neutrinos up to m{sub N} < 3 TeV is possible with the ATLAS detector. (authors) 2 refs., 4 figs.

  11. Toward the holistic, reference, and extendable atlas of the human brain, head, and neck.

    Science.gov (United States)

    Nowinski, Wieslaw L

    2015-06-01

    Despite numerous efforts, a fairly complete (holistic) anatomical model of the whole, normal, adult human brain, which is required as the reference in brain studies and clinical applications, has not yet been constructed. Our ultimate objective is to build this kind of atlas from advanced in vivo imaging. This work presents the taxonomy of our currently developed brain atlases and addresses the design, content, functionality, and current results in the holistic atlas development as well as atlas usefulness and future directions. We have developed to date 35 commercial brain atlases (along with numerous research prototypes), licensed to 63 companies and institutions, and made available to medical societies, organizations, medical schools, and individuals. These atlases have been applied in education, research, and clinical applications. Hundreds of thousands of patients have been treated by using our atlases. Based on this experience, the first version of the holistic and reference atlas of the brain, head, and neck has been developed and made available. The atlas has been created from multispectral 3 and 7 Tesla and high-resolution CT in vivo scans. It is fully 3D, scalable, interactive, and highly detailed with about 3,000 labeled components. This atlas forms a foundation for the development of a multi-level molecular, cellular, anatomical, physiological, and behavioral brain atlas platform.

  12. Report to users of Atlas

    International Nuclear Information System (INIS)

    Ahmad, I.; Glagola, B.

    1996-06-01

    This report contains the following topics: Status of the ATLAS Accelerator; Highlights of Recent Research at ATLAS; Program Advisory Committee; ATLAS User Group Executive Committee; FMA Information Available On The World Wide Web; Conference on Nuclear Structure at the Limits; and Workshop on Experiments with Gammasphere at ATLAS

  13. Recent ATLAS Articles on WLAP

    CERN Multimedia

    Goldfarb, S

    2005-01-01

    As reported in the September 2004 ATLAS eNews, the Web Lecture Archive Project is a system for the archiving and publishing of multimedia presentations, using the Web as medium. We list here newly available WLAP items relating to ATLAS: Atlas Software Week Plenary 6-10 December 2004 North American ATLAS Physics Workshop (Tucson) 20-21 December 2004 (17 talks) Physics Analysis Tools Tutorial (Tucson) 19 December 2004 Full Chain Tutorial 21 September 2004 ATLAS Plenary Sessions, 17-18 February 2005 (17 talks) Coming soon: ATLAS Tutorial on Electroweak Physics, 14 Feb. 2005 Software Workshop, 21-22 February 2005 Click here to browse WLAP for all ATLAS lectures.

  14. DIGITAL GEOECOLOGICAL MAPS AND SEVERAL METHODS OF ITS CONSTRUCTING IN A GIS ARCGIS

    Directory of Open Access Journals (Sweden)

    S. V. Lebedev

    2015-01-01

    Full Text Available This article is focused on methods of digital geoecological maps construction with using GIS ArcGIS technologies. The technique of GIS ArcGIS mapping is illustrated by examples of GIS maps of radioactive and chemical pollution in the snow cover on the territory of St. Petersburg’s (Russia. The geostatistic and deterministic approaches were applied for interpolation of input data. The input data were presented by the coordinates of points located on territory according to the scheme of measurements. The most optimal amount of classification intervals describing the natural processes and the phenomena of all-over distribution on the geoeclogical GIS maps is the 3–5 intervals of the parameter that will be considered. The borders of classes of intervals are set in depend on existing normative of pollution in different components of environment and empirical character of study parameter distribution on territory under consideration.

  15. ATLAS brochure (Spanish version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world, which will start up in 2008. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  16. ATLAS Colouring Book

    CERN Multimedia

    Anthony, Katarina

    2016-01-01

    The ATLAS Experiment Colouring Book is a free-to-download educational book, ideal for kids aged 5-9. It aims to introduce children to the field of High-Energy Physics, as well as the work being carried out by the ATLAS Collaboration.

  17. ATLAS fast physics monitoring

    Indian Academy of Sciences (India)

    The ATLAS experiment at the Large Hadron Collider is recording data from proton–proton collisions at a centre-of-mass energy of 7 TeV since the spring of 2010. The integrated luminosity has grown nearly exponentially since then and continues to rise fast. The ATLAS Collaboration has set up a framework to automatically ...

  18. ATLAS OF EUROPEAN VALUES

    NARCIS (Netherlands)

    M Ed Uwe Krause

    2008-01-01

    Uwe Krause: Atlas of Eurpean Values De Atlas of European Values is een samenwerkingsproject met bijbehorende website van de Universiteit van Tilburg en Fontys Lerarenopleiding in Tilburg, waarbij de wetenschappelijke data van de European Values Study (EVS) voor het onderwijs toegankelijk worden

  19. The ATLAS tile calorimeter

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Louis Rose-Dulcina, a technician from the ATLAS collaboration, works on the ATLAS tile calorimeter. Special manufacturing techniques were developed to mass produce the thousands of elements in this detector. Tile detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

  20. ATLAS people can run!

    CERN Multimedia

    Claudia Marcelloni de Oliveira; Pauline Gagnon

    It must be all the training we are getting every day, running around trying to get everything ready for the start of the LHC next year. This year, the ATLAS runners were in fine form and came in force. Nine ATLAS teams signed up for the 37th Annual CERN Relay Race with six runners per team. Under a blasting sun on Wednesday 23rd May 2007, each team covered the distances of 1000m, 800m, 800m, 500m, 500m and 300m taking the runners around the whole Meyrin site, hills included. A small reception took place in the ATLAS secretariat a week later to award the ATLAS Cup to the best ATLAS team. For the details on this complex calculation which takes into account the age of each runner, their gender and the color of their shoes, see the July 2006 issue of ATLAS e-news. The ATLAS Running Athena Team, the only all-women team enrolled this year, won the much coveted ATLAS Cup for the second year in a row. In fact, they are so good that Peter Schmid and Patrick Fassnacht are wondering about reducing the women's bonus in...

  1. ATLAS Thesis Awards 2015

    CERN Multimedia

    Biondi, Silvia

    2016-01-01

    Winners of the ATLAS Thesis Award were presented with certificates and glass cubes during a ceremony on Thursday 25 February. The winners also presented their work in front of members of the ATLAS Collaboration. Winners: Javier Montejo Berlingen, Barcelona (Spain), Ruth Pöttgen, Mainz (Germany), Nils Ruthmann, Freiburg (Germany), and Steven Schramm, Toronto (Canada).

  2. ATLAS brochure (French version)

    CERN Multimedia

    Lefevre, C

    2012-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  3. ATLAS Brochure (English version)

    CERN Multimedia

    Lefevre, Christiane

    2011-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world, which will start up in 2008. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  4. ATLAS brochure (German version)

    CERN Multimedia

    Lefevre, C

    2012-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  5. Higgs Measurement from ATLAS

    CERN Document Server

    Liu, Bo; The ATLAS collaboration

    2015-01-01

    Using run-I data record by ATLAS detector, many searches on the higgs decay modes have been done. Also some properties measurement of the Higgs Boson has been done. This talk will summarise the recent result of Higgs search and measurement from ATLAS.

  6. ATLAS Visitors Centre

    CERN Multimedia

    claudia Marcelloni

    2009-01-01

    ATLAS Visitors Centre has opened its shiny new doors to the public. Officially launched on Monday February 23rd, 2009, the permanent exhibition at Point 1 was conceived as a tour resource for ATLAS guides, and as a way to preserve the public’s opportunity to get a close-up look at the experiment in action when the cavern is sealed.

  7. ATLAS rewards industry

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    For contributing vital pieces to the ATLAS puzzle, three industries were recognized on Friday 5 May during a supplier awards ceremony. After a welcome and overview of the ATLAS experiment by spokesperson Peter Jenni, CERN Secretary-General Maximilian Metzger stressed the importance of industry to CERN's scientific goals. Picture 30 : representatives of the three award-wining companies after the ceremony

  8. ATLAS brochure (Polish version)

    CERN Multimedia

    Lefevre, C

    2007-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world, which will start up in 2008. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  9. ATLAS brochure (Catalan version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world, which will start up in 2008. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  10. ATLAS brochure (Danish version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  11. ATLAS brochure (Italian version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter.

  12. ATLAS brochure (Norwegian version)

    CERN Multimedia

    Lefevre, C

    2009-01-01

    ATLAS is the largest detector at the LHC, the most powerful particle accelerator in the world. ATLAS is a multi-purpose detector, designed to throw light on fundamental questions such as the origin of mass and the nature of the Universe's dark matter. Français

  13. A Slice of ATLAS

    CERN Multimedia

    2004-01-01

    An entire section of the ATLAS detector is being assembled at Prévessin. Since May the components have been tested using a beam from the SPS, giving the ATLAS team valuable experience of operating the detector as well as an opportunity to debug the system.

  14. ATLAS presents award to a Russian manufacturer within an ISTC project

    CERN Multimedia

    2004-01-01

    On 28 January the Russian machine building plant Molniya was awarded a prize for best ATLAS suppliers, for excellence in the construction of 29 modules for the Hadronic End-Cap Calorimeter of ATLAS. An ATLAS supplier award ceremony was held on Wednesday 28th January. The award for the most exceptional contribution to construction of the future detector was presented to the Russian company Molniya, a former weapons manufacturer based near Moscow. The Molniya machine building plant constructed a total of 29 modules for the LAr Hadronic End-Cap Calorimeter (HEC) of ATLAS. Thirteen are series modules which have already been integrated into the four wheels of the detector. The remaining 16 are calibration modules, designed for the ATLAS beam tests. To manufacture the unique copper plates and module structures required, the company set up a dedicated production process and developed stringent quality control criteria. The task was completed on time, within budget and the completed modules surpassed required qua...

  15. ATLAS' major cooling project

    CERN Document Server

    2005-01-01

    In 2005, a considerable effort has been put into commissioning the various units of ATLAS' complex cryogenic system. This is in preparation for the imminent cooling of some of the largest components of the detector in their final underground configuration. The liquid helium and nitrogen ATLAS refrigerators in USA 15. Cryogenics plays a vital role in operating massive detectors such as ATLAS. In many ways the liquefied argon, nitrogen and helium are the life-blood of the detector. ATLAS could not function without cryogens that will be constantly pumped via proximity systems to the superconducting magnets and subdetectors. In recent weeks compressors at the surface and underground refrigerators, dewars, pumps, linkages and all manner of other components related to the cryogenic system have been tested and commissioned. Fifty metres underground The helium and nitrogen refrigerators, installed inside the service cavern, are an important part of the ATLAS cryogenic system. Two independent helium refrigerators ...

  16. Wind Atlas for Egypt

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling; Said Said, Usama; Badger, Jake

    2006-01-01

    The results of a comprehensive, 8-year wind resource assessment programme in Egypt are presented. The objective has been to provide reliable and accurate wind atlas data sets for evaluating the potential wind power output from large electricityproducing wind turbine installations. The regional wind...... climates of Egypt have been determined by two independent methods: a traditional wind atlas based on observations from more than 30 stations all over Egypt, and a numerical wind atlas based on long-term reanalysis data and a mesoscale model (KAMM). The mean absolute error comparing the two methods is about...... 10% for two large-scale KAMM domains covering all of Egypt, and typically about 5% for several smaller-scale regional domains. The numerical wind atlas covers all of Egypt, whereas the meteorological stations are concentrated in six regions. The Wind Atlas for Egypt represents a significant step...

  17. Wind Atlas for Egypt

    DEFF Research Database (Denmark)

    The results of a comprehensive, 8-year wind resource assessment programme in Egypt are presented. The objective has been to provide reliable and accurate wind atlas data sets for evaluating the potential wind power output from large electricityproducing wind turbine installations. The regional wind...... climates of Egypt have been determined by two independent methods: a traditional wind atlas based on observations from more than 30 stations all over Egypt, and a numerical wind atlas based on long-term reanalysis data and a mesoscale model (KAMM). The mean absolute error comparing the two methods is about...... 10% for two large-scale KAMM domains covering all of Egypt, and typically about 5% for several smaller-scale regional domains. The numerical wind atlas covers all of Egypt, whereas the meteorological stations are concentrated in six regions. The Wind Atlas for Egypt represents a significant step...

  18. Dear ATLAS colleagues,

    CERN Multimedia

    PH Department

    2008-01-01

    We are collecting old pairs of glasses to take out to Mali, where they can be re-used by people there. The price for a pair of glasses can often exceed 3 months salary, so they are prohibitively expensive for many people. If you have any old spectacles you can donate, please put them in the special box in the ATLAS secretariat, bldg.40-4-D01 before the Christmas closure on 19 December so we can take them with us when we leave for Africa at the end of the month. (more details in ATLAS e-news edition of 29 September 2008: http://atlas-service-enews.web.cern.ch/atlas-service-enews/news/news_mali.php) many thanks! Katharine Leney co-driver of the ATLAS car on the Charity Run to Mali

  19. ATLAS TRT 2002 Workshop

    CERN Multimedia

    Capeans, M.

    Starting on 17th May, the ATLAS TRT 2002 Workshop was organised by Ken MacFarlane and his team at Hampton University, Virginia, USA. During a welcome break in the very dense workshop programme, the group enjoyed a half-day long boat trip along the waterways, offering a first-hand look at the history and heritage of this part of America. The attendance during the six-day workshop was about 50 people representing most of the collaborating institutes, although many Russian colleagues had stayed in their institutes to pursue the start-up of end-cap wheel production at PNPI and DUBNA. The meeting clearly showed that, during the year 2002, the TRT community is focusing on final design issues and module/wheel construction, while moving at the same time towards acceptance testing and integration, including the front-end electronics. The two main topics treated at the workshop were the preparation for beginning full production of the FE electronics, and the wire-joint problem that the US barrel colleagues have been fa...

  20. An important step for the ATLAS toroid magnet

    CERN Multimedia

    2000-01-01

    The ATLAS experiment's prototype toroid coil arrives at CERN from the CEA laboratory in Saclay on 6 October. The world's largest superconducting toroid magnet is under construction for the ATLAS experiment. A nine-metre long fully functional prototype coil was delivered to CERN at the beginning of October and has since been undergoing tests in the West Area. Built mainly by companies in France and Italy under the supervision of engineers from the CEA-Saclay laboratory near Paris and Italy's INFN-LASA, the magnet is a crucial step forward in the construction of the ATLAS superconducting magnet system. Unlike any particle detector that has gone before, the ATLAS detector's magnet system consists of a large toroidal system enclosing a small central solenoid. The barrel part of the toroidal system will use eight toroid coils, each a massive 25 metres in length. These will dwarf the largest toroids in the world when ATLAS was designed, which measure about six metres. So the ATLAS collaboration decided to build a...

  1. Michigan ATLAS MDT Chamber Mass Production

    CERN Document Server

    Diehl, E; Levin, D; McKee, S; Neal, H; Schick, H; Tarle, G; Thun, R; Weaverdyck, C; Xu, Q; Zhao, Z; Zhou, B

    2001-01-01

    This paper describes the ATLAS MDT precision muon chamber construction at the University of Michigan. The chamber assembly facilities, the jigging set up, alignment procedures, and other measurements necessary for chamber assembly are described. The chamber quality assurance monitoring procedures and data for the first year mass production are presented. The chamber gas system assembly facilities, and the chamber leak test procedure together with data also reported. The chamber production database, which monitors chamber production, is also discussed.

  2. Highlights from ATLAS

    CERN Document Server

    Charlton, D; The ATLAS collaboration

    2013-01-01

    Highlights of recent results from ATLAS were presented. The data collected to date, the detector and physics performance, and measurements of previously established Standard Model processes were reviewed briefly before summarising the latest ATLAS results in the Brout-Englert-Higgs sector, where big progress has been made in the year since the discovery. Finally, selected prospects for measurements including the data from the HL-LHC luminosity upgrade were presented, for both ATLAS and CMS. Many of the results mentioned are preliminary. These proceedings reflect only a brief summary of the material presented, and the status at the time of the conference is reported.

  3. Ceremony for ATLAS cavern

    CERN Multimedia

    2003-01-01

    Wednesday 4 June will be a special day for CERN. The President of the Swiss Confederation, Pascal Couchepin, will officially inaugurate the huge ATLAS cavern now that the civil engineering works have ended. The inauguration ceremony will be held in the ATLAS surface building, with speeches by Pascal Couchepin and CERN, ATLAS and civil engineering personalities. This ceremony will be Webcast live. To access the Webcast on 4 June at 18h00 go to CERN Intranet home page or the following address : http://webcast.cern.ch/live.php

  4. ATLAS Data Preservation

    CERN Document Server

    Jones, Roger; The ATLAS collaboration

    2015-01-01

    Complementary to parallel open access and analysis preservation initiatives, ATLAS is taking steps to ensure that the data taken by the experiment during run-1 remain accessible and available for future analysis by the collaboration. An evaluation of what is required to achieve this is underway, examining the ATLAS data production chain to establish the effort required and potential problems. Several alternatives are explored, but the favoured solution is to bring the run 1 data and software in line with the equivalent to that which will be used for run 2. This will result in a coherent ATLAS dataset for the data already taken and that to come in the future.

  5. VT Planning Atlas

    Data.gov (United States)

    Vermont Center for Geographic Information — The Planning Atlas provides easy access to commonly requested land use planning data – the status of local planning and regulation, state designation boundaries and...

  6. ATLAS soft QCD results

    CERN Document Server

    Sykora, Tomas; The ATLAS collaboration

    2018-01-01

    Recent results of soft QCD measurements performed by the ATLAS collaboration are reported. The measurements include total, elastic and inelastic cross sections, inclusive spectra, underlying event and particle correlations in p-p and p-Pb collisions.

  7. Apollo Image Atlas

    Data.gov (United States)

    National Aeronautics and Space Administration — The Apollo Image Atlas is a comprehensive collection of Apollo-Saturn mission photography. Included are almost 25,000 lunar images, both from orbit and from the...

  8. Lunar Sample Atlas

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Sample Atlas provides pictures of the Apollo samples taken in the Lunar Sample Laboratory, full-color views of the samples in microscopic thin-sections,...

  9. ATLAS Metadata Task Force

    Energy Technology Data Exchange (ETDEWEB)

    ATLAS Collaboration; Costanzo, D.; Cranshaw, J.; Gadomski, S.; Jezequel, S.; Klimentov, A.; Lehmann Miotto, G.; Malon, D.; Mornacchi, G.; Nemethy, P.; Pauly, T.; von der Schmitt, H.; Barberis, D.; Gianotti, F.; Hinchliffe, I.; Mapelli, L.; Quarrie, D.; Stapnes, S.

    2007-04-04

    This document provides an overview of the metadata, which are needed to characterizeATLAS event data at different levels (a complete run, data streams within a run, luminosity blocks within a run, individual events).

  10. Consolidated Lunar Atlas

    Data.gov (United States)

    National Aeronautics and Space Administration — The Consolidated Lunar Atlas is a collection of the best photographic images of the moon, including low-oblique photography, full-moon photography, and tabular and...

  11. The Latest from ATLAS

    CERN Multimedia

    2009-01-01

    Since November 2008, ATLAS has undertaken detailed maintenance, consolidation and repair work on the detector (see Bulletin of 20 July 2009). Today, the fraction of the detector that is operational has increased compared to last year: less than 1% of dead channels for most of the sub-systems. "We are going to start taking data this year with a detector which is even more efficient than it was last year," agrees ATLAS Spokesperson, Fabiola Gianotti. By mid-September the detector was fully closed again, and the cavern sealed. The magnet system has been operated at nominal current for extensive periods over recent months. Once the cavern was sealed, ATLAS began two weeks of combined running. Right now, subsystems are joining the run incrementally until the point where the whole detector is integrated and running as one. In the words of ATLAS Technical Coordinator, Marzio Nessi: "Now we really start physics." In parallel, the analysis ...

  12. Printed circuit for ATLAS

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    A printed circuit board made by scientists in the ATLAS collaboration for the transition radiaton tracker (TRT). This will read data produced when a high energy particle crosses the boundary between two materials with different electrical properties.

  13. California Ocean Uses Atlas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a result of the California Ocean Uses Atlas Project: a collaboration between NOAA's National Marine Protected Areas Center and Marine Conservation...

  14. PeptideAtlas

    Data.gov (United States)

    U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...

  15. EnviroAtlas - Memphis, TN - EnviroAtlas Community Boundary

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset shows the boundary of the Memphis, TN EnviroAtlas Community. It represents the outside edge of all the block groups included in the...

  16. The ATLAS electromagnetic calorimeter

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Michel Mathieu, a technician for the ATLAS collaboration, is cabling the ATLAS electromagnetic calorimeter's first end-cap, before insertion into its cryostat. Millions of wires are connected to the electromagnetic calorimeter on this end-cap that must be carefully fed out from the detector so that data can be read out. Every element on the detector will be attached to one of these wires so that a full digital map of the end-cap can be recreated.

  17. ATLAS@AWS

    Science.gov (United States)

    Gehrcke, Jan-Philip; Kluth, Stefan; Stonjek, Stefan

    2010-04-01

    We show how the ATLAS offline software is ported on the Amazon Elastic Compute Cloud (EC2). We prepare an Amazon Machine Image (AMI) on the basis of the standard ATLAS platform Scientific Linux 4 (SL4). Then an instance of the SLC4 AMI is started on EC2 and we install and validate a recent release of the ATLAS offline software distribution kit. The installed software is archived as an image on the Amazon Simple Storage Service (S3) and can be quickly retrieved and connected to new SL4 AMI instances using the Amazon Elastic Block Store (EBS). ATLAS jobs can then configure against the release kit using the ATLAS configuration management tool (cmt) in the standard way. The output of jobs is exported to S3 before the SL4 AMI is terminated. Job status information is transferred to the Amazon SimpleDB service. The whole process of launching instances of our AMI, starting, monitoring and stopping jobs and retrieving job output from S3 is controlled from a client machine using python scripts implementing the Amazon EC2/S3 API via the boto library working together with small scripts embedded in the SL4 AMI. We report our experience with setting up and operating the system using standard ATLAS job transforms.

  18. ATLAS-AWS

    International Nuclear Information System (INIS)

    Gehrcke, Jan-Philip; Stonjek, Stefan; Kluth, Stefan

    2010-01-01

    We show how the ATLAS offline software is ported on the Amazon Elastic Compute Cloud (EC2). We prepare an Amazon Machine Image (AMI) on the basis of the standard ATLAS platform Scientific Linux 4 (SL4). Then an instance of the SLC4 AMI is started on EC2 and we install and validate a recent release of the ATLAS offline software distribution kit. The installed software is archived as an image on the Amazon Simple Storage Service (S3) and can be quickly retrieved and connected to new SL4 AMI instances using the Amazon Elastic Block Store (EBS). ATLAS jobs can then configure against the release kit using the ATLAS configuration management tool (cmt) in the standard way. The output of jobs is exported to S3 before the SL4 AMI is terminated. Job status information is transferred to the Amazon SimpleDB service. The whole process of launching instances of our AMI, starting, monitoring and stopping jobs and retrieving job output from S3 is controlled from a client machine using python scripts implementing the Amazon EC2/S3 API via the boto library working together with small scripts embedded in the SL4 AMI. We report our experience with setting up and operating the system using standard ATLAS job transforms.

  19. Recent ATLAS Articles on WLAP

    CERN Multimedia

    Goldfarb, S.

    As reported in the September 2004 ATLAS eNews, the Web Lecture Archive Project is a system for the archiving and publishing of multimedia presentations, using the Web as medium. We list here newly available WLAP items relating to ATLAS: June ATLAS Plenary Meeting Tutorial on Physics EDM and Tools (June) Freiburg Overview Week Ketevi Assamagan's Tutorial on Analysis Tools Click here to browse WLAP for all ATLAS lectures.

  20. Report to users of ATLAS

    International Nuclear Information System (INIS)

    Ahmad, I.; Glagola, B.

    1997-03-01

    This report covers the following topics: (1) status of the ATLAS accelerator; (2) progress in R and D towards a proposal for a National ISOL Facility; (3) highlights of recent research at ATLAS; (4) the move of gammasphere from LBNL to ANL; (5) Accelerator Target Development laboratory; (6) Program Advisory Committee; (7) ATLAS User Group Executive Committee; and (8) ATLAS user handbook available in the World Wide Web. A brief summary is given for each topic

  1. Comparaison of Atlas Tilecal module

    CERN Document Server

    Batusov1, V; Gayde, J C; Khubua, J I; Lasseur, C; Lyablin, M V; Miralles-Verge, L; Nessi, Marzio; Rusakovitch, N A; Sissakian, A N; Topilin, N D

    2002-01-01

    The high precision assembly of a large experimental set-ups is of a principal necessity for the successful execution of the forthcoming LHC research program in the TeV-beams. The creation of an adequate Survey&Control METROLOGY METHODs are an essential part of the detector construction scenario. This work contains the dimension measurement data for ATLAS hadron calorimeter MODULE#8 (6m long, 22tons) which were obtained by LASER and by PHOTOGRAMMETRY methods. The comparative data analysis demonstrates the measurements agreement within ±70mm. It means these two clearly independent methods can be combined and lead to the rise of a new generation engineering culture: high precision metrology when precision assembly of large scale massive objects.

  2. ATLAS Status and First Results

    CERN Document Server

    Lankford, AJ; The ATLAS collaboration

    2010-01-01

    The ATLAS Experiment at the CERN Large Hadron Collider will study a broad range of particle physics at the highest available laboratory energies, from measurements of the standard model to searches for new physics beyond the standard model. The status of ATLAS commissioning and the ATLAS physics program will be reported, and physics prospects for the 2010 LHC run will be discussed.

  3. Optimizing the energy measurement of the ATLAS electromagnetic calorimeter

    International Nuclear Information System (INIS)

    Lampl, W.

    2005-12-01

    This PhD-thesis addresses the calibration of the ATLAS electromagnetic calorimeter. ATLAS is a high-energy physics experiment at the Large Hadron Collider (LHC) which is currently under construction at CERN in Geneva. LHC and ATLAS are foreseen to start up in 2007. In summer 2004, an extensive beam-test was carried out. This means that individual detector modules are exposed to a particle beam of known energy in order to verify the detector performance. At this occasion, all ATLAS subdetectors where operated together for the first time. The thesis contains a comprehensive description of the ATLAS electromagnetic calorimeter, the reconstruction software and the test-beam experiment that was carried out at CERN in 2004. Furthermore, the physics of the electromagnetic shower is discussed in detail. Data from the test beam as well as a detailed Monte-Carlo simulation are used to develop a novel energy-reconstruction method for the ATLAS EM calorimeter that achieves an excellent energy resolution (sampling term ∼ 11 %) as well as a very good linearity (< 0.4 %). Data taken during the beam test is also used to verify the accuracy of the simulation and to test the new energy-reconstruction method. (author)

  4. Pre-Test Analysis of Major Scenarios for ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Euh, Dong-Jin; Choi, Ki-Yong; Park, Hyun-Sik; Kwon, Tae-Soon

    2007-02-15

    A thermal-hydraulic integral effect test facility, ATLAS was constructed at the Korea Atomic Energy Research Institute (KAERI). The ATLAS is a 1/2 reduced height and 1/288 volume scaled test facility based on the design features of the APR1400. The simulation capability of the ATLAS for major design basis accidents (DBAs), including a large-break loss-of-coolant (LBLOCA), DVI line break and main steam line break (MSLB) accidents, is evaluated by the best-estimate system code, MARS, with the same control logics, transient scenarios and nodalization scheme. The validity of the applied scaling law and the thermal-hydraulic similarity between the ATLAS and the APR1400 for the major design basis accidents are assessed. It is confirmed that the ATLAS has a capability of maintaining an overall similarity with the reference plant APR1400 for the major design basis accidents considered in the present study. However, depending on the accident scenarios, there are some inconsistencies in certain thermal hydraulic parameters. It is found that the inconsistencies are mainly due to the reduced power effect and the increased stored energy in the structure. The present similarity analysis was successful in obtaining a greater insight into the unique design features of the ATLAS and would be used for developing the optimized experimental procedures and control logics.

  5. Pre-Test Analysis of Major Scenarios for ATLAS

    International Nuclear Information System (INIS)

    Euh, Dong-Jin; Choi, Ki-Yong; Park, Hyun-Sik; Kwon, Tae-Soon

    2007-02-01

    A thermal-hydraulic integral effect test facility, ATLAS was constructed at the Korea Atomic Energy Research Institute (KAERI). The ATLAS is a 1/2 reduced height and 1/288 volume scaled test facility based on the design features of the APR1400. The simulation capability of the ATLAS for major design basis accidents (DBAs), including a large-break loss-of-coolant (LBLOCA), DVI line break and main steam line break (MSLB) accidents, is evaluated by the best-estimate system code, MARS, with the same control logics, transient scenarios and nodalization scheme. The validity of the applied scaling law and the thermal-hydraulic similarity between the ATLAS and the APR1400 for the major design basis accidents are assessed. It is confirmed that the ATLAS has a capability of maintaining an overall similarity with the reference plant APR1400 for the major design basis accidents considered in the present study. However, depending on the accident scenarios, there are some inconsistencies in certain thermal hydraulic parameters. It is found that the inconsistencies are mainly due to the reduced power effect and the increased stored energy in the structure. The present similarity analysis was successful in obtaining a greater insight into the unique design features of the ATLAS and would be used for developing the optimized experimental procedures and control logics

  6. Ultimate Performance of the ATLAS Superconducting Solenoid

    CERN Document Server

    Ruber, R; Kawai, M; Kondo, Y; Doi, Y; Haruyama, T; Haug, F; Kate, H ten; Kondo, T; Pirotte, O; Metselaar, J; Mizumaki, S; Olesen, G; Sbrissa, E; Yamamoto, A

    2007-01-01

    A 2 tesla, 7730 ampere, 39 MJ, 45 mm thin superconducting solenoid with a 2.3 meters warm bore and 5.3 meters length, is installed in the center of the ATLAS detector and successfully commissioned. The solenoid shares its cryostat with one of the detector's calorimeters and provides the magnetic field required for the inner detectors to accurately track collision products from the LHC at CERN. After several years of a stepwise construction and test program, the solenoid integration 100 meters underground in the ATLAS cavern is completed. Following the on-surface acceptance test, the solenoid is now operated with its final cryogenic, powering and control system. A re-validation of all essential operating parameters is completed. The performance and test results of underground operation are reported and compared to those previously measured.

  7. Operational Experience with the ATLAS Pixel Detector

    CERN Document Server

    Djama, Fares; The ATLAS collaboration

    2017-01-01

    Run-2 of the LHC is providing new challenges to track and vertex reconstruction imposed by the higher collision energy, pileup and luminosity that are being delivered. The ATLAS tracking performance relies critically on the Pixel Detector, therefore, in view of Run-2 of LHC, the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). Pixel detector was refurbished with a new service quarter panel to recover about 3% of defective modules lost during run-1 and an additional optical link per module was added to overcome in some layers the readout bandwidth limitation when LHC will exceed the nominal peak luminosity by almost a factor of 3. The key features and challenges met during the IBL project will be presented, as well as its operational experience and Pixel Detector performance in LHC.

  8. The ATLAS TRT end-cap detectors

    Science.gov (United States)

    ATLAS TRT Collaboration; Abat, E.; Addy, T. N.; Åkesson, T. P. A.; Alison, J.; Anghinolfi, F.; Arik, E.; Arik, M.; Atoian, G.; Auerbach, B.; Baker, O. K.; Banas, E.; Baron, S.; Bault, C.; Becerici, N.; Beddall, A.; Beddall, A. J.; Bendotti, J.; Benjamin, D. P.; Bertelsen, H.; Bingul, A.; Blampey, H.; Bocci, A.; Bochenek, M.; Bondarenko, V. G.; Bychkov, V.; Callahan, J.; Capeáns Garrido, M.; Cardiel Sas, L.; Catinaccio, A.; Cetin, S. A.; Chandler, T.; Chritin, R.; Cwetanski, P.; Dam, M.; Danielsson, H.; Danilevich, E.; David, E.; Degenhardt, J.; Di Girolamo, B.; Dittus, F.; Dixon, N.; Dobos, D.; Dogan, O. B.; Dolgoshein, B. A.; Dressnandt, N.; Driouchi, C.; Ebenstein, W. L.; Eerola, P.; Egede, U.; Egorov, K.; Evans, H.; Farthouat, P.; Fedin, O. L.; Fowler, A. J.; Fratina, S.; Froidevaux, D.; Fry, A.; Gagnon, P.; Gavrilenko, I. L.; Gay, C.; Ghodbane, N.; Godlewski, J.; Goulette, M.; Gousakov, I.; Grigalashvili, N.; Grishkevich, Y.; Grognuz, J.; Hajduk, Z.; Hance, M.; Hansen, F.; Hansen, J. B.; Hansen, J. D.; Hansen, P. H.; Hare, G. A.; Harvey, A., Jr.; Hauviller, C.; High, A.; Hulsbergen, W.; Huta, W.; Issakov, V.; Istin, S.; Jain, V.; Jarlskog, G.; Jeanty, L.; Kantserov, V. A.; Kaplan, B.; Kapliy, A. S.; Katounine, S.; Kayumov, F.; Keener, P. T.; Kekelidze, G. D.; Khabarova, E.; Khristachev, A.; Kisielewski, B.; Kittelmann, T. H.; Kline, C.; Klinkby, E. B.; Klopov, N. V.; Ko, B. R.; Koffas, T.; Kondratieva, N. V.; Konovalov, S. P.; Koperny, S.; Korsmo, H.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; LeBihan, A.-C.; LeGeyt, B. C.; Levterov, K.; Lichard, P.; Lindahl, A.; Lisan, V.; Lobastov, S.; Loginov, A.; Loh, C. W.; Lokwitz, S.; Long, M. C.; Lucas, S.; Lucotte, A.; Luehring, F.; Lundberg, B.; Mackeprang, R.; Maleev, V. P.; Manara, A.; Mandl, M.; Martin, A. J.; Martin, F. F.; Mashinistov, R.; Mayers, G. M.; McFarlane, K. W.; Mialkovski, V.; Mills, B. M.; Mindur, B.; Mitsou, V. A.; Mjörnmark, J. U.; Morozov, S. V.; Morris, E.; Mouraviev, S. V.; Muir, A. M.; Munar, A.; Nadtochi, A. V.; Nesterov, S. Y.; Newcomer, F. M.; Nikitin, N.; Novgorodova, O.; Novodvorski, E. G.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olivito, D.; Olszowska, J.; Ostrowicz, W.; Passmore, M. S.; Patrichev, S.; Penwell, J.; Perez-Gomez, F.; Peshekhonov, V. D.; Petersen, T. C.; Petti, R.; Placci, A.; Poblaguev, A.; Pons, X.; Price, M. J.; hne, O. Rø; Reece, R. D.; Reilly, M. B.; Rembser, C.; Romaniouk, A.; Rousseau, D.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Söderberg, M.; Savenkov, A.; Saxon, J.; Scandurra, M.; Schegelsky, V. A.; Scherzer, M. I.; Schmidt, M. P.; Schmitt, C.; Sedykh, E.; Seliverstov, D. M.; Shin, T.; Shmeleva, A.; Sivoklokov, S.; Smirnov, S. Yu; Smirnova, L.; Smirnova, O.; Smith, P.; Sosnovtsev, V. V.; Sprachmann, G.; Subramania, S.; Suchkov, S. I.; Sulin, V. V.; Szczygiel, R. R.; Tartarelli, G.; Thomson, E.; Tikhomirov, V. O.; Tipton, P.; Valls Ferrer, J. A.; Van Berg, R.; Vassilakopoulos, V. I.; Vassilieva, L.; Wagner, P.; Wall, R.; Wang, C.; Whittington, D.; Williams, H. H.; Zhelezko, A.; Zhukov, K.

    2008-10-01

    The ATLAS TRT end-cap is a tracking drift chamber using 245,760 individual tubular drift tubes. It is a part of the TRT tracker which consist of the barrel and two end-caps. The TRT end-caps cover the forward and backward pseudo-rapidity region 1.0 < |η| < 2.0, while the TRT barrel central η region |η| < 1.0. The TRT system provides a combination of continuous tracking with many measurements in individual drift tubes (or straws) and of electron identification based on transition radiation from fibers or foils interleaved between the straws themselves. Along with other two sub-system, namely the Pixel detector and Semi Conductor Tracker (SCT), the TRT constitutes the ATLAS Inner Detector. This paper describes the recently completed and installed TRT end-cap detectors, their design, assembly, integration and the acceptance tests applied during the construction.

  9. ATLAS Review Office

    CERN Multimedia

    Szeless, B

    The ATLAS internal reviews, be it the mandatory Production Readiness Reviews, the now newly installed Production Advancement Reviews, or the more and more requested different Design Reviews, have become a part of our ATLAS culture over the past years. The Activity Systems Status Overviews are, for the time being, a one in time event and should be held for each system as soon as possible to have some meaning. There seems to a consensus that the reviews have become a useful project tool for the ATLAS management but even more so for the sub-systems themselves making achievements as well as possible shortcomings visible. One other recognized byproduct is the increasing cross talk between the systems, a very important ingredient to make profit all the systems from the large collective knowledge we dispose of in ATLAS. In the last two months, the first two PARs were organized for the MDT End Caps and the TRT Barrel Modules, both part of the US contribution to the ATLAS Project. Furthermore several different design...

  10. ATLAS: Exceeding all expectations

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    “One year ago it would have been impossible for us to guess that the machine and the experiments could achieve so much so quickly”, says Fabiola Gianotti, ATLAS spokesperson. The whole chain – from collision to data analysis – has worked remarkably well in ATLAS.   The first LHC proton run undoubtedly exceeded expectations for the ATLAS experiment. “ATLAS has worked very well since the beginning. Its overall data-taking efficiency is greater than 90%”, says Fabiola Gianotti. “The quality and maturity of the reconstruction and simulation software turned out to be better than we expected for this initial stage of the experiment. The Grid is a great success, and right from the beginning it has allowed members of the collaboration all over the world to participate in the data analysis in an effective and timely manner, and to deliver physics results very quickly”. In just a few months of data taking, ATLAS has observed t...

  11. Baby brain atlases.

    Science.gov (United States)

    Oishi, Kenichi; Chang, Linda; Huang, Hao

    2018-04-03

    The baby brain is constantly changing due to its active neurodevelopment, and research into the baby brain is one of the frontiers in neuroscience. To help guide neuroscientists and clinicians in their investigation of this frontier, maps of the baby brain, which contain a priori knowledge about neurodevelopment and anatomy, are essential. "Brain atlas" in this review refers to a 3D-brain image with a set of reference labels, such as a parcellation map, as the anatomical reference that guides the mapping of the brain. Recent advancements in scanners, sequences, and motion control methodologies enable the creation of various types of high-resolution baby brain atlases. What is becoming clear is that one atlas is not sufficient to characterize the existing knowledge about the anatomical variations, disease-related anatomical alterations, and the variations in time-dependent changes. In this review, the types and roles of the human baby brain MRI atlases that are currently available are described and discussed, and future directions in the field of developmental neuroscience and its clinical applications are proposed. The potential use of disease-based atlases to characterize clinically relevant information, such as clinical labels, in addition to conventional anatomical labels, is also discussed. Copyright © 2018. Published by Elsevier Inc.

  12. ATLAS MPGD production status

    CERN Document Server

    Schioppa, Marco; The ATLAS collaboration

    2018-01-01

    Micromegas (MICRO MEsh GAseous Structure) chambers are Micro-Pattern Gaseous Detectors designed to provide a high spatial resolution and reasonable good time resolution in highly irradiated environments. In 2007 an ambitious long-term R\\&D activity was started in the context of the ATLAS experiment, at CERN: the Muon ATLAS Micromegas Activity (MAMMA). After years of tests on prototypes and technology breakthroughs, Micromegas chambers were chosen as tracking detectors for an upgrade of the ATLAS Muon Spectrometer. These novel detectors will be installed in 2020 at the end of the second long shutdown of the Large Hadron Collider, and will serve mainly as precision detectors in the innermost part of the forward ATLAS Muon Spectrometer. Four different types of Micromegas modules, eight layers each, up to $3 m^2$ area (of unprecedented size), will cover a surface of $150 m^2$ for a total active area of about $1200 m^2$. With this upgrade the ATLAS muon system will maintain the full acceptance of its excellent...

  13. Distributed analysis in ATLAS

    CERN Document Server

    Dewhurst, Alastair; The ATLAS collaboration

    2015-01-01

    The ATLAS experiment accumulated more than 140 PB of data during the first run of the Large Hadron Collider (LHC) at CERN. The analysis of such an amount of data for the distributed physics community is a challenging task. The Distributed Analysis (DA) system of the ATLAS experiment is an established and stable component of the ATLAS distributed computing operations. About half a million user jobs are daily running on DA resources, submitted by more than 1500 ATLAS physicists. The reliability of the DA system during the first run of the LHC and the following shutdown period has been high thanks to the continuous automatic validation of the distributed analysis sites and the user support provided by a dedicated team of expert shifters. During the LHC shutdown, the ATLAS computing model has undergone several changes to improve the analysis workflows, including the re-design of the production system, a new analysis data format and event model, and the development of common reduction and analysis frameworks. We r...

  14. Signal feedthroughs for the ATLAS barrel and endcap calorimeters

    CERN Document Server

    Axen, D A; Hoffman, A; Kane, S; Lissauer, D; Makowiecki, D S; Müller, T; Pate, D; Radeka, V; Rahm, David Charles; Rehak, M; Rescia, S; Sexton, K; Sondericker, J; Birney, P; Dowling, A W; Fincke-Keeler, M; Hodges, T; Holness, F; Honkanen, N; Keeler, R; Langstaf, R; Lenckowski, M; Lefebvre, M; Poffenberger, P R; Vowles, G

    2005-01-01

    The construction of the signal feedthroughs for the barrel and endcap ATLAS liquid argon calorimeters is described. The feedthroughs provide a high density and radiation hard method to extract signals from the cryogenic environment of the calorimeters using a novel design based on flexible kapton circuit board transmission lines.

  15. The ATLAS Tau Trigger

    CERN Document Server

    Rados, PK; The ATLAS collaboration

    2014-01-01

    Physics processes involving tau leptons play a crucial role in understanding particle physics at the high energy frontier. The ability to efficiently trigger on events containing hadronic tau decays is therefore of particular importance to the ATLAS experiment. During the 2012 run, the Large Hadronic Collder (LHC) reached instantaneous luminosities of nearly $10^{34} cm^{-2}s^{-1}$ with bunch crossings occurring every $50 ns$. This resulted in a huge event rate and a high probability of overlapping interactions per bunch crossing (pile-up). With this in mind it was necessary to design an ATLAS tau trigger system that could reduce the event rate to a manageable level, while efficiently extracting the most interesting physics events in a pile-up robust manner. In this poster the ATLAS tau trigger is described, its performance during 2012 is presented, and the outlook for the LHC Run II is briefly summarized.

  16. The ATLAS Inner Detector

    CERN Document Server

    Gray, HM; The ATLAS collaboration

    2012-01-01

    The ATLAS experiment at the LHC is equipped with a charged particle tracking system, the Inner Detector, built on three subdetectors, which provide high precision measurements made from a fine detector granularity. The Pixel and microstrip (SCT) subdetectors, which use the silicon technology, are complemented with the Transition Radiation Tracker. Since the LHC startup in 2009, the ATLAS inner tracker has played a central role in many ATLAS physics analyses. Rapid improvements in the calibration and alignment of the detector allowed it to reach nearly the nominal performance in the timespan of a few months. The tracking performance proved to be stable as the LHC luminosity increased by five orders of magnitude during the 2010 proton run, New developments in the offline reconstruction for the 2011 run will improve the tracking performance in high pile-up conditions as well as in highly boosted jets will be discussed.

  17. Two ATLAS suppliers honoured

    CERN Multimedia

    2007-01-01

    The ATLAS experiment has recognised the outstanding contribution of two firms to the pixel detector. Recipients of the supplier award with Peter Jenni, ATLAS spokesperson, and Maximilian Metzger, CERN Secretary-General.At a ceremony held at CERN on 28 November, the ATLAS collaboration presented awards to two of its suppliers that had produced sensor wafers for the pixel detector. The CiS Institut für Mikrosensorik of Erfurt in Germany has supplied 655 sensor wafers containing a total of 1652 sensor tiles and the firm ON Semiconductor has supplied 515 sensor wafers (1177 sensor tiles) from its foundry at Roznov in the Czech Republic. Both firms have successfully met the very demanding requirements. ATLAS’s huge pixel detector is very complicated, requiring expertise in highly specialised integrated microelectronics and precision mechanics. Pixel detector project leader Kevin Einsweiler admits that when the project was first propo...

  18. The ATLAS Trigger System

    CERN Document Server

    Hauser, R

    2004-01-01

    ATLAS is one of two general-purpose detectors at the next generation proton-proton collider, the LHC. The high rate of interactions and the large number of read-out channels make the trigger system for ATLAS a challenging task. The initial bunch crossing rate of 40~MHz has to be reduced to about 200 Hz while preserving the physics signals against a large background. ATLAS uses a three-level trigger system, with the first level implemented in custom hardware, while the high level trigger systems are implemented in software on commodity hardware. This note describes the physics motivation, the various selection strategies for different channels as well as the physical implementation of the trigger system.

  19. Forward Physics with ATLAS

    CERN Document Server

    Carquin, E; The ATLAS collaboration

    2013-01-01

    An overview of the latest results of physical measurements in the forward region (|eta|>3) using the ATLAS detector at the LHC is presented. The data used comprise the 2010 proton-proton data taken at sqrt(s)=7TeV by ATLAS at low luminosity and with low pile-up contamination. In particular, the measurement of (forward) rapidity gap differential cross section as function of the rapidity gap size, the inclusive forward jet cross section, the total forward energy and the energy density flow measured with the ATLAS Forward Calorimeter (FCAL) are discussed. The main results and the conclusions of the comparison with theoretical models incorporated in montecarlo event generators is drawn. Performance results of the Zero Degree Calorimeter (ZDC) detector in pp and in HI collisions are shown and the potential of this detector to tag forward going neutrons produced in Ultraperipheral collisions (UPCs) in ion-ion and ion-proton interactions is shown.

  20. Event visualization in ATLAS

    Science.gov (United States)

    Bianchi, R. M.; Boudreau, J.; Konstantinidis, N.; Martyniuk, A. C.; Moyse, E.; Thomas, J.; Waugh, B. M.; Yallup, D. P.; ATLAS Collaboration

    2017-10-01

    At the beginning, HEP experiments made use of photographical images both to record and store experimental data and to illustrate their findings. Then the experiments evolved and needed to find ways to visualize their data. With the availability of computer graphics, software packages to display event data and the detector geometry started to be developed. Here, an overview of the usage of event display tools in HEP is presented. Then the case of the ATLAS experiment is considered in more detail and two widely used event display packages are presented, Atlantis and VP1, focusing on the software technologies they employ, as well as their strengths, differences and their usage in the experiment: from physics analysis to detector development, and from online monitoring to outreach and communication. Towards the end, the other ATLAS visualization tools will be briefly presented as well. Future development plans and improvements in the ATLAS event display packages will also be discussed.

  1. ATLAS production system

    CERN Document Server

    Borodin, Mikhail; The ATLAS collaboration; De, Kaushik; Klimentov, Alexei; Golubkov, Dmitry; Maeno, Tadashi; Mashinistov, Ruslan; Wenaus, Torre; Padolski, Siarhei

    2016-01-01

    The second generation of the ATLAS production system called ProdSys2 is a distributed workload manager which used by thousands of physicists to analyze the data remotely, with the volume of processed data is beyond the exabyte scale, across a more than hundred heterogeneous sites. It achieves high utilization by combining dynamic job definition based on many criterias, such as input and output size, memory requirements and CPU consumption with manageable scheduling policies and by supporting different kind of computational resources, such as GRID, clouds, supercomputers and volunteering computers. Besides jobs definition Production System also includes flexible web user interface, which implements user-friendly environment for main ATLAS workflows, e.g. simple way of combining different data flows, and real-time monitoring, optimised for using with huge amount of information to present. We present an overview of the ATLAS Production System major components: job and task definition, workflow manager web user i...

  2. ATLAS rewards industry

    CERN Multimedia

    2006-01-01

    Showing excellence in mechanics, electronics and cryogenics, three industries are honoured for their contributions to the ATLAS experiment. Representatives of the three award-wining companies after the ceremony. For contributing vital pieces to the ATLAS puzzle, three industries were recognized on Friday 5 May during a supplier awards ceremony. After a welcome and overview of the ATLAS experiment by spokesperson Peter Jenni, CERN Secretary-General Maximilian Metzger stressed the importance of industry to CERN's scientific goals. Close interaction with CERN was a key factor in the selection of each rewarded company, in addition to the high-quality products they delivered to the experiment. Alu Menziken Industrie AG, of Switzerland, was honoured for the production of 380,000 aluminium tubes for the Monitored Drift Tube Chambers (MDT). As Giora Mikenberg, the Muon System Project Leader stressed, the aluminium tubes were delivered on time with an extraordinary quality and precision. Between October 2000 and Jan...

  3. ATLAS TDAQ System Administration:

    CERN Document Server

    Lee, Christopher Jon; The ATLAS collaboration; Bogdanchikov, Alexander; Ballestrero, Sergio; Contescu, Alexandru Cristian; Dubrov, Sergei; Fazio, Daniel; Korol, Aleksandr; Scannicchio, Diana; Twomey, Matthew Shaun; Voronkov, Artem

    2015-01-01

    The ATLAS Trigger and Data Acquisition (TDAQ) system is responsible for the online processing of live data, streaming from the ATLAS experiment at the Large Hadron Collider (LHC) at CERN. The online farm is composed of ̃3000 servers, processing the data readout from ̃100 million detector channels through multiple trigger levels. During the two years of the first Long Shutdown (LS1) there has been a tremendous amount of work done by the ATLAS TDAQ System Administrators, implementing numerous new software applications, upgrading the OS and the hardware, changing some design philosophies and exploiting the High Level Trigger farm with different purposes. During the data taking only critical security updates are applied and broken hardware is replaced to ensure a stable operational environment. The LS1 provided an excellent opportunity to look into new technologies and applications that would help to improve and streamline the daily tasks of not only the System Administrators, but also of the scientists who wil...

  4. Calorimetry triggering in ATLAS

    CERN Document Server

    Igonkina, O; Adragna, P; Aharrouche, M; Alexandre, G; Andrei, V; Anduaga, X; Aracena, I; Backlund, S; Baines, J; Barnett, B M; Bauss, B; Bee, C; Behera, P; Bell, P; Bendel, M; Benslama, K; Berry, T; Bogaerts, A; Bohm, C; Bold, T; Booth, J R A; Bosman, M; Boyd, J; Bracinik, J; Brawn, I, P; Brelier, B; Brooks, W; Brunet, S; Bucci, F; Casadei, D; Casado, P; Cerri, A; Charlton, D G; Childers, J T; Collins, N J; Conde Muino, P; Coura Torres, R; Cranmer, K; Curtis, C J; Czyczula, Z; Dam, M; Damazio, D; Davis, A O; De Santo, A; Degenhardt, J; Delsart, P A; Demers, S; Demirkoz, B; Di Mattia, A; Diaz, M; Djilkibaev, R; Dobson, E; Dova, M, T; Dufour, M A; Eckweiler, S; Ehrenfeld, W; Eifert, T; Eisenhandler, E; Ellis, N; Emeliyanov, D; Enoque Ferreira de Lima, D; Faulkner, P J W; Ferland, J; Flacher, H; Fleckner, J E; Flowerdew, M; Fonseca-Martin, T; Fratina, S; Fhlisch, F; Gadomski, S; Gallacher, M P; Garitaonandia Elejabarrieta, H; Gee, C N P; George, S; Gillman, A R; Goncalo, R; Grabowska-Bold, I; Groll, M; Gringer, C; Hadley, D R; Haller, J; Hamilton, A; Hanke, P; Hauser, R; Hellman, S; Hidvgi, A; Hillier, S J; Hryn'ova, T; Idarraga, J; Johansen, M; Johns, K; Kalinowski, A; Khoriauli, G; Kirk, J; Klous, S; Kluge, E-E; Koeneke, K; Konoplich, R; Konstantinidis, N; Kwee, R; Landon, M; LeCompte, T; Ledroit, F; Lei, X; Lendermann, V; Lilley, J N; Losada, M; Maettig, S; Mahboubi, K; Mahout, G; Maltrana, D; Marino, C; Masik, J; Meier, K; Middleton, R P; Mincer, A; Moa, T; Monticelli, F; Moreno, D; Morris, J D; Mller, F; Navarro, G A; Negri, A; Nemethy, P; Neusiedl, A; Oltmann, B; Olvito, D; Osuna, C; Padilla, C; Panes, B; Parodi, F; Perera, V J O; Perez, E; Perez Reale, V; Petersen, B; Pinzon, G; Potter, C; Prieur, D P F; Prokishin, F; Qian, W; Quinonez, F; Rajagopalan, S; Reinsch, A; Rieke, S; Riu, I; Robertson, S; Rodriguez, D; Rogriquez, Y; Rhr, F; Saavedra, A; Sankey, D P C; Santamarina, C; Santamarina Rios, C; Scannicchio, D; Schiavi, C; Schmitt, K; Schultz-Coulon, H C; Schfer, U; Segura, E; Silverstein, D; Silverstein, S; Sivoklokov, S; Sjlin, J; Staley, R J; Stamen, R; Stelzer, J; Stockton, M C; Straessner, A; Strom, D; Sushkov, S; Sutton, M; Tamsett, M; Tan, C L A; Tapprogge, S; Thomas, J P; Thompson, P D; Torrence, E; Tripiana, M; Urquijo, P; Urrejola, P; Vachon, B; Vercesi, V; Vorwerk, V; Wang, M; Watkins, P M; Watson, A; Weber, P; Weidberg, T; Werner, P; Wessels, M; Wheeler-Ellis, S; Whiteson, D; Wiedenmann, W; Wielers, M; Wildt, M; Winklmeier, F; Wu, X; Xella, S; Zhao, L; Zobernig, H; de Seixas, J M; dos Anjos, A; Asman, B; Özcan, E

    2009-01-01

    The ATLAS experiment is preparing for data taking at 14 TeV collision energy. A rich discovery physics program is being prepared in addition to the detailed study of Standard Model processes which will be produced in abundance. The ATLAS multi-level trigger system is designed to accept one event in 2 105 to enable the selection of rare and unusual physics events. The ATLAS calorimeter system is a precise instrument, which includes liquid Argon electro-magnetic and hadronic components as well as a scintillator-tile hadronic calorimeter. All these components are used in the various levels of the trigger system. A wide physics coverage is ensured by inclusively selecting events with candidate electrons, photons, taus, jets or those with large missing transverse energy. The commissioning of the trigger system is being performed with cosmic ray events and by replaying simulated Monte Carlo events through the trigger and data acquisition system.

  5. Event visualization in ATLAS

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00211497; The ATLAS collaboration; Boudreau, Joseph; Konstantinidis, Nikolaos; Martyniuk, Alex; Moyse, Edward; Thomas, Juergen; Waugh, Ben; Yallup, David

    2017-01-01

    At the beginning, HEP experiments made use of photographical images both to record and store experimental data and to illustrate their findings. Then the experiments evolved and needed to find ways to visualize their data. With the availability of computer graphics, software packages to display event data and the detector geometry started to be developed. Here, an overview of the usage of event display tools in HEP is presented. Then the case of the ATLAS experiment is considered in more detail and two widely used event display packages are presented, Atlantis and VP1, focusing on the software technologies they employ, as well as their strengths, differences and their usage in the experiment: from physics analysis to detector development, and from online monitoring to outreach and communication. Towards the end, the other ATLAS visualization tools will be briefly presented as well. Future development plans and improvements in the ATLAS event display packages will also be discussed.

  6. Atlas-based delineation of lymph node levels in head and neck computed tomography images

    International Nuclear Information System (INIS)

    Commowick, Olivier; Gregoire, Vincent; Malandain, Gregoire

    2008-01-01

    Purpose: Radiotherapy planning requires accurate delineations of the tumor and of the critical structures. Atlas-based segmentation has been shown to be very efficient to automatically delineate brain critical structures. We therefore propose to construct an anatomical atlas of the head and neck region. Methods and materials: Due to the high anatomical variability of this region, an atlas built from a single image as for the brain is not adequate. We address this issue by building a symmetric atlas from a database of manually segmented images. First, we develop an atlas construction method and apply it to a database of 45 Computed Tomography (CT) images from patients with node-negative pharyngo-laryngeal squamous cell carcinoma manually delineated for radiotherapy. Then, we qualitatively and quantitatively evaluate the results generated by the built atlas based on Leave-One-Out framework on the database. Results: We present qualitative and quantitative results using this atlas construction method. The evaluation was performed on a subset of 12 patients among the original CT database of 45 patients. Qualitative results depict visually well delineated structures. The quantitative results are also good, with an error with respect to the best achievable results ranging from 0.196 to 0.404 with a mean of 0.253. Conclusions: These results show the feasibility of using such an atlas for radiotherapy planning. Many perspectives are raised from this work ranging from extensive validation to the construction of several atlases representing sub-populations, to account for large inter-patient variabilities, and populations with node-positive tumors

  7. Exotic physics in ATLAS

    CERN Document Server

    Delsart, P A

    2006-01-01

    At the LHC, the program of research in particle physics is extremely rich. With the ATLAS detector, besides the SM Higgs search or SUSY mainstream studies, the implications of many other theoretical models are investigated. They range from compositeness of fundamental fermions to extra dimension scenarios through GUT models and include many variants. I shall review some selected typical studies by the ATLAS collaboration on exotic physics beyond the SM, highlighting the discovery prospects and the recent analyses using the latest full detector simulations.

  8. The ATLAS Simulation Infrastructure

    CERN Document Server

    Aad, G.; Abdallah, J.; Abdelalim, A.A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acharya, B.S.; Adams, D.L.; Addy, T.N.; Adelman, J.; Adorisio, C.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J.A.; Aharrouche, M.; Ahlen, S.P.; Ahles, F.; Ahmad, A.; Ahmed, H.; Ahsan, M.; Aielli, G.; Akdogan, T.; Akesson, T.P.A.; Akimoto, G.; Akimov, A.V.; Aktas, A.; Alam, M.S.; Alam, M.A.; Albrand, S.; Aleksa, M.; Aleksandrov, I.N.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P.P.; Allwood-Spiers, S.E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M.G.; Amako, K.; Amelung, C.; Amorim, A.; Amoros, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C.F.; Anderson, K.J.; Andreazza, A.; Andrei, V.; Anduaga, X.S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antos, J.; Antunovic, B.; Anulli, F.; Aoun, S.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A.T.H.; Archambault, J.P.; Arfaoui, S.; Arguin, J-F.; Argyropoulos, T.; Arik, M.; Armbruster, A.J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Arutinov, D.; Asai, M.; Asai, S.; Asfandiyarov, R.; Ask, S.; Asman, B.; Asner, D.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Auerbach, B.; Augsten, K.; Aurousseau, M.; Austin, N.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M.A.; Bach, A.M.; Bachacou, H.; Bachas, K.; Backes, M.; Badescu, E.; Bagnaia, P.; Bai, Y.; Bain, T.; Baines, J.T.; Baker, O.K.; Baker, M.D.; Baker, S; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, S.; Banfi, D.; Bangert, A.; Bansal, V.; Baranov, S.P.; Baranov, S.; Barashkou, A.; Barber, T.; Barberio, E.L.; Barberis, D.; Barbero, M.; Bardin, D.Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B.M.; Barnett, R.M.; Baroncelli, A.; Barr, A.J.; Barreiro, F.; Barreiro Guimaraes da Costa, J.; Barrillon, P.; Bartoldus, R.; Bartsch, D.; Bates, R.L.; Batkova, L.; Batley, J.R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H.S.; Bazalova, M.; Beare, B.; Beau, T.; Beauchemin, P.H.; Beccherle, R.; Becerici, N.; Bechtle, P.; Beck, G.A.; Beck, H.P.; Beckingham, M.; Becks, K.H.; Beddall, A.J.; Beddall, A.; Bednyakov, V.A.; Bee, C.; Begel, M.; Behar Harpaz, S.; Behera, P.K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P.J.; Bell, W.H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Bendel, M.; Benedict, B.H.; Benekos, N.; Benhammou, Y.; Benincasa, G.P.; Benjamin, D.P.; Benoit, M.; Bensinger, J.R.; Benslama, K.; Bentvelsen, S.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Besana, M.I.; Besson, N.; Bethke, S.; Bianchi, R.M.; Bianco, M.; Biebel, O.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K.M.; Blair, R.E.; Blanchard, J-B; Blanchot, G.; Blocker, C.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G.J.; Bocci, A.; Boehler, M.; Boek, J.; Boelaert, N.; Boser, S.; Bogaerts, J.A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bondarenko, V.G.; Bondioli, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E.V.; Boulahouache, C.; Bourdarios, C.; Boveia, A.; Boyd, J.; Boyko, I.R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G.W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J.E.; Braun, H.M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F.M.; Brock, I.; Brock, R.; Brodet, E.; Bromberg, C.; Brooijmans, G.; Brooks, W.K.; Brown, G.; Bruckman de Renstrom, P.A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Bucci, F.; Buchanan, J.; Buchholz, P.; Buckley, A.G.; Budagov, I.A.; Budick, B.; Buscher, V.; Bugge, L.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C.P.; Butin, F.; Butler, B.; Butler, J.M.; Buttar, C.M.; Butterworth, J.M.; Byatt, T.; Caballero, J.; Cabrera Urban, S.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L.P.; Calvet, D.; Camarri, P.; Cameron, D.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M.D.M.; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carrillo Montoya, G.D.; Carron Montero, S.; Carter, A.A.; Carter, J.R.; Carvalho, J.; Casadei, D.; Casado, M.P.; Cascella, M.; Castaneda Hernandez, A.M.; Castaneda-Miranda, E.; Castillo Gimenez, V.; Castro, N.F.; 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Mijovic, L.; Mikenberg, G.; Mikestikova, M.; Mikuz, M.; Miller, D.W.; Mills, W.J.; Mills, C.M.; Milov, A.; Milstead, D.A.; Milstein, D.; Minaenko, A.A.; Minano, M.; Minashvili, I.A.; Mincer, A.I.; Mindur, B.; Mineev, M.; Ming, Y.; Mir, L.M.; Mirabelli, G.; Misawa, S.; Miscetti, S.; Misiejuk, A.; Mitrevski, J.; Mitsou, V.A.; Miyagawa, P.S.; Mjornmark, J.U.; Mladenov, D.; Moa, T.; Moed, S.; Moeller, V.; Monig, K.; Moser, N.; Mohr, W.; Mohrdieck-Mock, S.; Moles-Valls, R.; Molina-Perez, J.; Monk, J.; Monnier, E.; Montesano, S.; Monticelli, F.; Moore, R.W.; Mora Herrera, C.; Moraes, A.; Morais, A.; Morel, J.; Morello, G.; Moreno, D.; Moreno Llacer, M.; Morettini, P.; Morii, M.; Morley, A.K.; Mornacchi, G.; Morozov, S.V.; Morris, J.D.; Moser, H.G.; Mosidze, M.; Moss, J.; Mount, R.; Mountricha, E.; Mouraviev, S.V.; Moyse, E.J.W.; Mudrinic, M.; Mueller, F.; Mueller, J.; Mueller, K.; Muller, T.A.; Muenstermann, D.; Muir, A.; Munwes, Y.; Murillo Garcia, R.; Murray, W.J.; Mussche, I.; Musto, E.; Myagkov, A.G.; Myska, M.; Nadal, J.; Nagai, K.; Nagano, K.; Nagasaka, Y.; Nairz, A.M.; Nakamura, K.; Nakano, I.; Nakatsuka, H.; Nanava, G.; Napier, A.; Nash, M.; Nation, N.R.; Nattermann, T.; Naumann, T.; Navarro, G.; Nderitu, S.K.; Neal, H.A.; Nebot, E.; Nechaeva, P.; Negri, A.; Negri, G.; Nelson, A.; Nelson, T.K.; Nemecek, S.; Nemethy, P.; Nepomuceno, A.A.; Nessi, M.; Neubauer, M.S.; Neusiedl, A.; Neves, R.N.; Nevski, P.; Newcomer, F.M.; Nickerson, R.B.; Nicolaidou, R.; Nicolas, L.; Nicoletti, G.; Nicquevert, B.; Niedercorn, F.; Nielsen, J.; Nikiforov, A.; Nikolaev, K.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, H.; Nilsson, P.; Nisati, A.; Nishiyama, T.; Nisius, R.; Nodulman, L.; Nomachi, M.; Nomidis, I.; Nordberg, M.; Nordkvist, B.; Notz, D.; Novakova, J.; Nozaki, M.; Nozicka, M.; Nugent, I.M.; Nuncio-Quiroz, A.E.; Nunes Hanninger, G.; Nunnemann, T.; Nurse, E.; O'Neil, D.C.; O'Shea, V.; Oakham, F.G.; Oberlack, H.; Ochi, A.; Oda, S.; Odaka, S.; Odier, J.; Ogren, H.; Oh, A.; Oh, S.H.; Ohm, C.C.; Ohshima, T.; Ohshita, H.; Ohsugi, T.; Okada, S.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olchevski, A.G.; Oliveira, M.; Oliveira Damazio, D.; Oliver, J.; Oliver Garcia, E.; Olivito, D.; Olszewski, A.; Olszowska, J.; Omachi, C.; Onofre, A.; Onyisi, P.U.E.; Oram, C.J.; Oreglia, M.J.; Oren, Y.; Orestano, D.; Orlov, I.; Oropeza Barrera, C.; Orr, R.S.; Ortega, E.O.; Osculati, B.; Ospanov, R.; Osuna, C.; Ottersbach, J.P; Ould-Saada, F.; Ouraou, A.; Ouyang, Q.; Owen, M.; Owen, S.; Oyarzun, A; Ozcan, V.E.; Ozone, K.; Ozturk, N.; Pacheco Pages, A.; Padilla Aranda, C.; Paganis, E.; Pahl, C.; Paige, F.; Pajchel, K.; Palestini, S.; Pallin, D.; Palma, A.; Palmer, J.D.; Pan, Y.B.; Panagiotopoulou, E.; Panes, B.; Panikashvili, N.; Panitkin, S.; Pantea, D.; Panuskova, M.; Paolone, V.; Papadopoulou, Th.D.; Park, S.J.; Park, W.; Parker, M.A.; Parker, S.I.; Parodi, F.; Parsons, J.A.; Parzefall, U.; Pasqualucci, E.; Passeri, A.; Pastore, F.; Pastore, Fr.; Pasztor, G.; Pataraia, S.; Pater, J.R.; Patricelli, S.; Patwa, A.; Pauly, T.; Peak, L.S.; Pecsy, M.; Pedraza Morales, M.I.; Peleganchuk, S.V.; Peng, H.; Penson, A.; Penwell, J.; Perantoni, M.; Perez, K.; Perez Codina, E.; Perez Garcia-Estan, M.T.; Perez Reale, V.; Perini, L.; Pernegger, H.; Perrino, R.; Persembe, S.; Perus, P.; Peshekhonov, V.D.; Petersen, B.A.; Petersen, T.C.; Petit, E.; Petridou, C.; Petrolo, E.; Petrucci, F.; Petschull, D; Petteni, M.; Pezoa, R.; Phan, A.; Phillips, A.W.; Piacquadio, G.; Piccinini, M.; Piegaia, R.; Pilcher, J.E.; Pilkington, A.D.; Pina, J.; Pinamonti, M.; Pinfold, J.L.; Pinto, B.; Pizio, C.; Placakyte, R.; Plamondon, M.; Pleier, M.A.; Poblaguev, A.; Poddar, S.; Podlyski, F.; Poffenberger, P.; Poggioli, L.; Pohl, M.; Polci, F.; Polesello, G.; Policicchio, A.; Polini, A.; Poll, J.; Polychronakos, V.; Pomeroy, D.; Pommes, K.; Ponsot, P.; Pontecorvo, L.; Pope, B.G.; Popeneciu, G.A.; Popovic, D.S.; Poppleton, A.; Popule, J.; Portell Bueso, X.; Porter, R.; Pospelov, G.E.; Pospisil, S.; Potekhin, M.; Potrap, I.N.; Potter, C.J.; Potter, C.T.; Potter, K.P.; Poulard, G.; Poveda, J.; Prabhu, R.; Pralavorio, P.; Prasad, S.; Pravahan, R.; Pribyl, L.; Price, D.; Price, L.E.; Prichard, P.M.; Prieur, D.; Primavera, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Prudent, X.; Przysiezniak, H.; Psoroulas, S.; Ptacek, E.; Puigdengoles, C.; Purdham, J.; Purohit, M.; Puzo, P.; Pylypchenko, Y.; Qi, M.; Qian, J.; Qian, W.; Qin, Z.; Quadt, A.; Quarrie, D.R.; Quayle, W.B.; Quinonez, F.; Raas, M.; Radeka, V.; Radescu, V.; Radics, B.; Rador, T.; Ragusa, F.; Rahal, G.; Rahimi, A.M.; Rajagopalan, S.; Rammensee, M.; Rammes, M.; Rauscher, F.; Rauter, E.; Raymond, M.; Read, A.L.; Rebuzzi, D.M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Reinherz-Aronis, E.; Reinsch, A; Reisinger, I.; Reljic, D.; Rembser, C.; Ren, Z.L.; Renkel, P.; Rescia, S.; Rescigno, M.; Resconi, S.; Resende, B.; Reznicek, P.; Rezvani, R.; Richards, A.; Richards, R.A.; Richter, R.; Richter-Was, E.; Ridel, M.; Rijpstra, M.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Rios, R.R.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Roa Romero, D.A.; Robertson, S.H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, JEM; Robinson, M.; Robson, A.; Rocha de Lima, J.G.; Roda, C.; Roda Dos Santos, D.; Rodriguez, D.; Rodriguez Garcia, Y.; Roe, S.; Rohne, O.; Rojo, V.; Rolli, S.; Romaniouk, A.; Romanov, V.M.; Romeo, G.; Romero Maltrana, D.; Roos, L.; Ros, E.; Rosati, S.; Rosenbaum, G.A.; Rosselet, L.; Rossetti, V.; Rossi, L.P.; Rotaru, M.; Rothberg, J.; Rousseau, D.; Royon, C.R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Ruckert, B.; Ruckstuhl, N.; Rud, V.I.; Rudolph, G.; Ruhr, F.; Ruggieri, F.; Ruiz-Martinez, A.; Rumyantsev, L.; Rurikova, Z.; Rusakovich, N.A.; Rutherfoord, J.P.; Ruwiedel, C.; Ruzicka, P.; Ryabov, Y.F.; Ryan, P.; Rybkin, G.; Rzaeva, S.; Saavedra, A.F.; Sadrozinski, H.F-W.; Sadykov, R.; Sakamoto, H.; Salamanna, G.; Salamon, A.; Saleem, M.S.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvachua Ferrando, B.M.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sampsonidis, D.; Samset, B.H.; Sandaker, H.; Sander, H.G.; Sanders, M.P.; Sandhoff, M.; Sandhu, P.; Sandstroem, R.; Sandvoss, S.; Sankey, D.P.C.; Sanny, B.; Sansoni, A.; Santamarina Rios, C.; Santoni, C.; Santonico, R.; Saraiva, J.G.; Sarangi, T.; Sarkisyan-Grinbaum, E.; Sarri, F.; Sasaki, O.; Sasao, N.; Satsounkevitch, I.; Sauvage, G.; Savard, P.; Savine, A.Y.; Savinov, V.; Sawyer, L.; Saxon, D.H.; Says, L.P.; Sbarra, C.; Sbrizzi, A.; Scannicchio, D.A.; Schaarschmidt, J.; Schacht, P.; Schafer, U.; Schaetzel, S.; Schaffer, A.C.; Schaile, D.; Schamberger, R.D.; Schamov, A.G.; Schegelsky, V.A.; Scheirich, D.; Schernau, M.; Scherzer, M.I.; Schiavi, C.; Schieck, J.; Schioppa, M.; Schlenker, S.; Schmidt, E.; Schmieden, K.; Schmitt, C.; Schmitz, M.; Schott, M.; Schouten, D.; Schovancova, J.; Schram, M.; Schreiner, A.; Schroeder, C.; Schroer, N.; Schroers, M.; Schultes, J.; Schultz-Coulon, H.C.; Schumacher, J.W.; Schumacher, M.; Schumm, B.A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W.G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S.C.; Seiden, A.; Seifert, F.; Seixas, J.M.; Sekhniaidze, G.; Seliverstov, D.M.; Sellden, B.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M.E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L.Y.; Shank, J.T.; Shao, Q.T.; Shapiro, M.; Shatalov, P.B.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M.J.; Shupe, M.A.; Sicho, P.; Sidoti, A.; Siegert, F; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S.B.; Simak, V.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N.B.; Sipica, V.; Siragusa, G.; Sisakyan, A.N.; Sivoklokov, S.Yu.; Sjoelin, J.; Sjursen, T.B.; Skovpen, K.; Skubic, P.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloper, J.; Sluka, T.; Smakhtin, V.; Smirnov, S.Yu.; Smirnov, Y.; Smirnova, L.N.; Smirnova, O.; Smith, B.C.; Smith, D.; Smith, K.M.; Smizanska, M.; Smolek, K.; Snesarev, A.A.; Snow, S.W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C.A.; Solar, M.; Solc, J.; Solfaroli Camillocci, E.; Solodkov, A.A.; Solovyanov, O.V.; Soluk, R.; Sondericker, J.; Sopko, V.; Sopko, B.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spano, F.; Spencer, E.; Spighi, R.; Spigo, G.; Spila, F.; Spiwoks, R.; Spousta, M.; Spreitzer, T.; Spurlock, B.; St. Denis, R.D.; Stahl, T.; Stahlman, J.; Stamen, R.; Stancu, S.N.; Stanecka, E.; Stanek, R.W.; Stanescu, C.; Stapnes, S.; Starchenko, E.A.; Stark, J.; Staroba, P.; Starovoitov, P.; Stastny, J.; Stavina, P.; Steele, G.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H.J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G.A.; Stockton, M.C.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A.R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, M.; Strizenec, P.; Strohmer, R.; Strom, D.M.; Stroynowski, R.; Strube, J.; Stugu, B.; Soh, D.A.; Su, D.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suk, M.; Sulin, V.V.; Sultansoy, S.; Sumida, T.; Sun, X.H.; Sundermann, J.E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M.R.; Suzuki, T.; Suzuki, Y.; Sykora, I.; Sykora, T.; Szymocha, T.; Sanchez, J.; Ta, D.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M.C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G.F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F.E.; Taylor, G.N.; Taylor, R.P.; Taylor, W.; Teixeira-Dias, P.; Ten Kate, H.; Teng, P.K.; Tennenbaum-Katan, Y.D.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R.J.; Thioye, M.; Thoma, S.; Thomas, J.P.; Thompson, E.N.; Thompson, P.D.; Thompson, P.D.; Thompson, R.J.; Thompson, A.S.; Thomson, E.; Thun, R.P.; Tic, T.; Tikhomirov, V.O.; Tikhonov, Y.A.; Tipton, P.; Tique Aires Viegas, F.J.; Tisserant, S.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokar, S.; Tokushuku, K.; Tollefson, K.; Tomasek, L.; Tomasek, M.; Tomoto, M.; Tompkins, L.; Toms, K.; Tonoyan, A.; Topfel, C.; Topilin, N.D.; Torrence, E.; Torro Pastor, E.; Toth, J.; Touchard, F.; Tovey, D.R.; Trefzger, T.; Tremblet, L.; Tricoli, A.; Trigger, I.M.; Trincaz-Duvoid, S.; Trinh, T.N.; Tripiana, M.F.; Triplett, N.; Trischuk, W.; Trivedi, A.; Trocme, B.; Troncon, C.; Trzupek, A.; Tsarouchas, C.; Tseng, J.C-L.; Tsiakiris, M.; Tsiareshka, P.V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E.G.; Tsukerman, I.I.; Tsulaia, V.; Tsung, J.W.; Tsuno, S.; Tsybychev, D.; Tuggle, J.M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Tuts, P.M.; Twomey, M.S.; Tylmad, M.; Tyndel, M.; Uchida, K.; Ueda, I.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urquijo, P.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J.A.; Van Berg, R.; van der Graaf, H.; van der Kraaij, E.; van der Poel, E.; van der Ster, D.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Vari, R.; Varnes, E.W.; Varouchas, D.; Vartapetian, A.; Varvell, K.E.; Vasilyeva, L.; Vassilakopoulos, V.I.; Vazeille, F.; Vellidis, C.; Veloso, F.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J.C.; Vetterli, M.C.; Vichou, I.; Vickey, T.; Viehhauser, G.H.A.; Villa, M.; Villani, E.G.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M.G.; Vinek, E.; Vinogradov, V.B.; Viret, S.; Virzi, J.; Vitale, A.; Vitells, O.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, M.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T.T.; Vossebeld, J.H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vudragovic, D.; Vuillermet, R.; Vukotic, I.; Wagner, P.; Walbersloh, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Wang, C.; Wang, H.; Wang, J.; Wang, S.M.; Warburton, A.; Ward, C.P.; Warsinsky, M.; Wastie, R.; Watkins, P.M.; Watson, A.T.; Watson, M.F.; Watts, G.; Watts, S.; Waugh, A.T.; Waugh, B.M.; Weber, M.D.; Weber, M.; Weber, M.S.; Weber, P.; Weidberg, A.R.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wells, P.S.; Wen, M.; Wenaus, T.; Wendler, S.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Werthenbach, U.; Wessels, M.; Whalen, K.; White, A.; White, M.J.; White, S.; Whitehead, S.R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F.J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik, L.A.M.; Wildauer, A.; Wildt, M.A.; Wilkens, H.G.; Williams, E.; Williams, H.H.; Willocq, S.; Wilson, J.A.; Wilson, M.G.; Wilson, A.; Wingerter-Seez, I.; Winklmeier, F.; Wittgen, M.; Wolter, M.W.; Wolters, H.; Wosiek, B.K.; Wotschack, J.; Woudstra, M.J.; Wraight, K.; Wright, C.; Wright, D.; Wrona, B.; Wu, S.L.; Wu, X.; Wulf, E.; Wynne, B.M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xu, D.; Xu, N.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, U.K.; Yang, Z.; Yao, W-M.; Yao, Y.; Yasu, Y.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.P.; Yu, D.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zaidan, R.; Zaitsev, A.M.; Zajacova, Z.; Zambrano, V.; Zanello, L.; Zaytsev, A.; Zeitnitz, C.; Zeller, M.; Zemla, A.; Zendler, C.; Zenin, O.; Zenis, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi della Porta, G.; Zhan, Z.; Zhang, H.; Zhang, J.; Zhang, Q.; Zhang, X.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C.G.; Zhu, H.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zivkovic, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zutshi, V.

    2010-01-01

    The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.

  9. Multiple brain atlas database and atlas-based neuroimaging system.

    Science.gov (United States)

    Nowinski, W L; Fang, A; Nguyen, B T; Raphel, J K; Jagannathan, L; Raghavan, R; Bryan, R N; Miller, G A

    1997-01-01

    For the purpose of developing multiple, complementary, fully labeled electronic brain atlases and an atlas-based neuroimaging system for analysis, quantification, and real-time manipulation of cerebral structures in two and three dimensions, we have digitized, enhanced, segmented, and labeled the following print brain atlases: Co-Planar Stereotaxic Atlas of the Human Brain by Talairach and Tournoux, Atlas for Stereotaxy of the Human Brain by Schaltenbrand and Wahren, Referentially Oriented Cerebral MRI Anatomy by Talairach and Tournoux, and Atlas of the Cerebral Sulci by Ono, Kubik, and Abernathey. Three-dimensional extensions of these atlases have been developed as well. All two- and three-dimensional atlases are mutually preregistered and may be interactively registered with an actual patient's data. An atlas-based neuroimaging system has been developed that provides support for reformatting, registration, visualization, navigation, image processing, and quantification of clinical data. The anatomical index contains about 1,000 structures and over 400 sulcal patterns. Several new applications of the brain atlas database also have been developed, supported by various technologies such as virtual reality, the Internet, and electronic publishing. Fusion of information from multiple atlases assists the user in comprehensively understanding brain structures and identifying and quantifying anatomical regions in clinical data. The multiple brain atlas database and atlas-based neuroimaging system have substantial potential impact in stereotactic neurosurgery and radiotherapy by assisting in visualization and real-time manipulation in three dimensions of anatomical structures, in quantitative neuroradiology by allowing interactive analysis of clinical data, in three-dimensional neuroeducation, and in brain function studies.

  10. EnviroAtlas Community Boundaries Web Service

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset shows the boundaries of all EnviroAtlas Communities. It represents the outside edge of all the block groups included in each EnviroAtlas...

  11. Recent test results on the ATLAS SCT detector

    International Nuclear Information System (INIS)

    Pernegger, H.

    2003-01-01

    The ATLAS Semiconductor Tracker (SCT) will be a central part of the tracking system of the ATLAS experiment. The SCT, which is currently under construction, will consist of four concentric barrels of silicon detectors as well as two silicon endcap detectors formed by nine disks each. After an overview of the SCT and the detector module layout, the paper will summarize recent test results obtained from silicon detector modules, which have been extensively tested before starting their large series production. The tests presented here cover electrical performance of individual modules, their performance after irradiation, as well as system tests in a multi-module setup

  12. Electron signals in the Forward Calorimeter prototype for ATLAS

    International Nuclear Information System (INIS)

    Armitage, J C; Artamonov, A; Babukhadia, L; Dixit, M; Embry, T M; Epshteyn, V; Estabrooks, P; Gravelle, P; Hamm, J; Khovansky, V; Koolbeck, D A; Krieger, P; Loch, P; Losty, M; Mayer, J; Mazini, R; Oakham, F Gerald; O'Neill, M; Orr, R S; Rutherfoord, J P; Ryabinin, M; Savine, A; Seely, C Jason; Shatalov, P; Shaver, L S; Shupe, M A; Stairs, G; Tompkins, D; Trischuk, W; Vincent, K; Zaitsev, V

    2007-01-01

    A pre-production prototype of the Forward Calorimeter (FCal) for the ATLAS detector presently under construction at the Large Hadron Collider (LHC) at CERN, Geneva, Switzerland, was exposed to electrons in the momentum range from 20 to 200 GeV/c in a test beam experiment at CERN in 1998. The measured performance, including a signal linearity within about ±1% and a high energy limit in the relative energy resolution of about 4%, meets the expectations for this kind of calorimeter, and exceeds the physics requirements for successful application in ATLAS

  13. ATLAS Inner Detector: Commissioning with Cosmics Data

    CERN Document Server

    The ATLAS collaboration

    2009-01-01

    The ATLAS experiment at the CERN Large Hadron Collider (LHC) has started taking data last autumn with the inauguration of the LHC. Determination of vertex position and charged particle tracks is performed in the Inner Detector which consists of pixel and microstrip Silicon sensors and transition radiation tubes. In this talk construction and commissioning of these three detectors will be presented. The Pixel Detector is the innermost detector of the ATLAS experiment with approx. 80 million readout channels. After connection of cooling and services and verification of their operation the ATLAS Pixel Detector is now in the final stage of its commissioning phase. Prior to the first beams expected in Autumn 2009, a full characterization of the detector is performed. The SemiConductor Tracker (SCT) is made up from silicon micro-strip detectors processed in the planar p-in-n technology. Sensors are assembled into 4000 modules with 6 million readout channels. The completed SCT detector was operated for many months u...

  14. Silicon sensor technologies for ATLAS IBL upgrade

    CERN Document Server

    Grenier, P; The ATLAS collaboration

    2011-01-01

    New pixel sensors are currently under development for ATLAS Upgrades. The first upgrade stage will consist in the construction of a new pixel layer that will be installed in the detector during the 2013 LHC shutdown. The new layer (Insertable-B-Layer, IBL) will be inserted between the inner most layer of the current pixel detector and the beam pipe at a radius of 3.2cm. The expected high radiation levels require the use of radiation hard technology for both the front-end chip and the sensor. Two different pixel sensor technologies are envisaged for the IBL. The sensor choice will occur in July 2011. One option is developed by the ATLAS Planar Pixel Sensor (PPS) Collaboration and is based on classical n-in-n planar silicon sensors which have been used for the ATLAS Pixel detector. For the IBL, two changes were required: The thickness was reduced from 250 um to 200 um to improve the radiation hardness. In addition, so-called "slim edges" were designed to reduce the inactive edge of the sensors from 1100 um to o...

  15. Differential top--antitop cross-section measurements as a function of observables constructed from final-state particles using pp collisions at $\\sqrt{s}=7$ TeV in the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdel Khalek, Samah; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Agatonovic-Jovin, Tatjana; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Allbrooke, Benedict; Allison, Lee John; Allport, Phillip; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amaral Coutinho, Yara; 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