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Sample records for terrain indices lake

  1. Hydrogeologic controls on the groundwater interactions with an acidic lake in karst terrain, Lake Barco, Florida

    Science.gov (United States)

    Lee, T.M.

    1996-01-01

    Transient groundwater interactions and lake stage were simulated for Lake Barco, an acidic seepage lake in the mantled karst of north central Florida. Karst subsidence features affected groundwater flow patterns in the basin and groundwater fluxes to and from the lake. Subsidence features peripheral to the lake intercepted potential groundwater inflow and increased leakage from the shallow perimeter of the lake bed. Simulated groundwater fluxes were checked against net groundwater flow derived from a detailed lake hydrologic budget with short-term lake evaporation computed by the energy budget method. Discrepancies between modeled and budget-derived net groundwater flows indicated that the model underestimated groundwater inflow, possibly contributed to by transient water table mounding near the lake. Recharge from rainfall reduced lake leakage by 10 to 15 times more than it increased groundwater inflow. As a result of the karst setting, the contributing groundwater basin to the lake was 2.4 ha for simulated average rainfall conditions, compared to the topographically derived drainage basin area of 81 ha. Short groundwater inflow path lines and rapid travel times limit the contribution of acid-neutralizing solutes from the basin, making Lake Barco susceptible to increased acidification by acid rain.

  2. Lake Storage Change Automatic Detection by Multi-source Remote Sensing without Underwater Terrain Data

    Directory of Open Access Journals (Sweden)

    ZHU Changming

    2015-03-01

    Full Text Available Focusing on lake underwater terrain unknown and dynamic storage that is difficult to obtain by the traditional methods, a new method is proposed for lake dynamic storage estimation by multi-source and multi-temporal remote sensing without underwater terrain data. The details are as follows. Firstly, extraction dynamic lake boundary through steps by steps adaptive iteration water body detection algorithm from multi-temporal remote sensing imagery. And then, retrieve water level information from ICESat GLAS laser point data. Thirdly, comprehensive utilizing lake area and elevation data, the lake boundary is converted to contour of water by the water level is assigned to the lake boundary line, according to the time and water level information. Fourthly, through the contour line construction TIN (triangulated irregular network model and Kriging interpolation, it is gotten that the simulated three-dimensional lake digital elevation model. Finally, on the basis of simulated DEM, it is calculated that the dynamic lake volume, lake area distribution and water level information. The Bosten lake is selected as a case studying to verify the algorithm. The area and dynamic water storage variations of Bosten lake are detected since 2000. The results show that, the maximum error is 2.21× 108 m3, the minimum error is 0.00002× 108 m3, the average error is 0.044×108 m3, the root mean square is 0.59 and the correlation coefficient reached 0.99.

  3. Assessing the Utility of Temporally Dynamic Terrain Indices in Alaskan Moose Resource Selection

    Science.gov (United States)

    Jennewein, J. S.; Hebblewhite, M.; Meddens, A. J.; Gilbert, S.; Vierling, L. A.; Boelman, N.; Eitel, J.

    2017-12-01

    The accelerated warming in arctic and boreal regions impacts ecosystem structure and plant species distribution, which have secondary effects on wildlife. In summer months, moose (Alces alces) are especially vulnerable to changes in the availability and quality of forage and foliage cover due to their thermoregulatory needs and high energetic demands post calving. Resource selection functions (RSFs) have been used with great success to model such tradeoffs in habitat selection. Recently, RSFs have expanded to include more dynamic representations of habitat selection through the use of time-varying covariates such as dynamic habitat indices. However, to date few studies have investigated dynamic terrain indices, which incorporate long-term, highly-dynamic meteorological data (e.g., albedo, air temperature) and their utility in modeling habitat selection. The purpose of this study is to compare two dynamic terrain indices (i.e., solar insolation and topographic wetness) to their static counterparts in Alaskan moose resource selection over a ten-year period (2008-2017). Additionally, the utility of a dynamic wind-shelter index is assessed. Three moose datasets (n=130 total), spanning a north-to-south gradient in Alaska, are analyzed independently to assess location-specific resource selection. The newly-released, high-resolution Arctic Digital Elevation Model (5m2) is used as the terrain input into both dynamic and static indices. Dynamic indices are programmed with meteorological data from the North American Regional Analysis (NARR) and NASA's Goddard Earth Sciences Data and Information Services Center (GES-DISC) databases. Static wetness and solar insolation indices are estimated using only topographic parameters (e.g., slope, aspect). Preliminary results from pilot analyses suggest that dynamic terrain indices may provide novel insights into resource selection of moose that could not be gained when using static counterparts. Future applications of such dynamic

  4. Sensitivity of plankton indices to lake trophic conditions

    OpenAIRE

    Ochocka, A.; Pasztaleniec, A.

    2016-01-01

    Herein, we report the response of indices based on phytoplankton and zooplankton and their combination to different nutrient concentrations in lakes. The study was carried out in ten lakes in northeastern Poland. Integrated samples were collected from the epilimnion during the summer of 2012?2013. Secchi disk visibility (SD), total phosphorus (TP), total nitrogen (TN), and chlorophyll a were used as proxies for eutrophication. We calculated 16 plankton indices: two phytoplankton indices, six ...

  5. Spatially Modeling the Impact of Terrain on Wind Speed and Dry Particle Deposition Across Lake Perris in Southern California to Determine In Situ Sensor Placement

    Science.gov (United States)

    Brooks, A. N.

    2014-12-01

    While developed countries have implemented engineering techniques and sanitation technologies to keep water resources clean from runoff and ground contamination, air pollution and its contribution of harmful contaminants to our water resources has yet to be fully understood and managed. Due to the large spatial and temporal extent and subsequent computational intensity required to understand atmospheric deposition as a pollutant source, a geographic information system (GIS) was utilized. This project developed a multi-step workflow to better define the placement of in situ sensors on Lake Perris in Southern California. Utilizing a variety of technologies including ArcGIS 10.1 with 3D and Spatial Analyst extensions and WindNinja, the impact of terrain on wind speed and direction was simulated and the spatial distribution of contaminant deposition across Lake Perris was calculated as flux. Specifically, the flux of particulate matter (PM10) at the air - water interface of a lake surface was quantified by season for the year of 2009. Integrated Surface Hourly (ISH) wind speed and direction data and ground station air quality measurements from the California Air Resources Board were processed and integrated for use within ModelBuilder. Results indicate that surface areas nearest Alessandro Island and the dam of Lake Perris should be avoided when placing in situ sensors. Furthermore, the location of sensor placement is dependent on seasonal fluctuations of PM10 which can be modeled using the techniques used in this study.

  6. Field validation of the ΔRIX performance indicator for flow in complex terrain

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling; Tindal, Andrew; Landberg, Lars

    Reanalyses of a case study using field measurements taken over 3½ years over rugged terrain in northern Portugal have been carried out using contemporary calculation procedures and topographical input data. The significance of the site ruggedness index (RIX) and the associated performance indicator...... (ΔRIX) are confirmed and the consequences of applying WAsP outside its operating envelope are quantified. A log-linear relation between WAsP prediction errors and the performance indicator ΔRIX is found to describe the field measurements and modelling results well. The largest coefficient...... the case study in northern Portugal, employing five meteorological stations with ruggedness indices between 10 and 33%, indicate an average improvement of WAsP power production predictions of 69%. Cross-predictions between sites with ΔRIX values larger than 5% are improved by more than 90% on average...

  7. TERRAIN, Lake county, Illinois, USA-- BOGUS METADATA SEE NON-FEMA PROFILE METADATA PROVIDED BY VENDOR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. TERRAIN DATA, CITY OF SOUTH LAKE TAHOE, EL DORADO COUNTY, CA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  9. Long term records of lake clarity as an indicator for final ecosystem goods and services of lakes

    Science.gov (United States)

    We reviewed available long-term records of lake clarity (via secchi disc readings) as an indicator of final ecosystem goods and services of lakes. Lake water quality assessments are often based on biophysical indicators not explicitly or quantifiably linked to the ecosystem servi...

  10. Development of indicators for assessment of Lake Malawi Basin in an Integrated Lake Basin Management (ILBM framework

    Directory of Open Access Journals (Sweden)

    Clara Limbitso Chidammodzi

    2015-03-01

    Full Text Available This paper sought to understand the current state of the management environment of Lake Malawi Basin, deduce a lake vision and develop indicators for assessing Integrated Lake Basin Management (ILBM in the lake basin. The premise of the study was that targeted indicators are necessary to effectively monitor the lake basin and manage it sustainably. The study focused on the Malawian side of the lake. Interviews, field observations and review of existing lake management and indicator development approaches around the world were the methods employed. It was found that Malawi lacks focus on lakes in its strategies and the existing management of the lake is on a sector-to-sector basis with little coordination. Furthermore, the capacity of lake-related sector institutions is hampered by inadequate resources and unstable flow of funds. It was concluded that the current management of the lake basin is unsustainable and there is need to comprehensively monitor the lake basin as well as formulate and implement management plans and strategies that are based on the knowledge obtained from targeted monitoring. A set of governance indicators was developed taking into account the characteristics of the lake, the values that it offers and the threats that it is facing.

  11. Sensitivity of plankton indices to lake trophic conditions.

    Science.gov (United States)

    Ochocka, A; Pasztaleniec, A

    2016-11-01

    Herein, we report the response of indices based on phytoplankton and zooplankton and their combination to different nutrient concentrations in lakes. The study was carried out in ten lakes in northeastern Poland. Integrated samples were collected from the epilimnion during the summer of 2012-2013. Secchi disk visibility (SD), total phosphorus (TP), total nitrogen (TN), and chlorophyll a were used as proxies for eutrophication. We calculated 16 plankton indices: two phytoplankton indices, six crustacean indices, five rotiferan indices, two zooplankton diversity indices, and one combined phytoplankton and zooplankton index. Among them, nine indices with the strongest correlations with TP were selected: percentage share of Crustacean species indicative of high trophy in the indicative group's numbers (IHT CRU ), percentage share of Rotifera species indicative of high trophy in the indicative group's numbers IHT ROT , Crustacean ratio of biomass to numbers B/N CRU , phytoplankton trophic index (TI TP+TN ), Margalef's index, percentage share of cyclopoid biomass in total biomass of Crustacea (CB), Rotifera numbers (N ROT ), biomass of Cyclopoida (B CY ), and ratio of the cyclopoid biomass to the biomass of Cladocera (CY/CL). The sensitivity of the normalized values of these indices to proxies of eutrophication was tested. IHT CRU , IHT ROT , and B/N CRU were the most sensitive and gave the strongest responses at lower TP concentrations (trophic index, TI TP+TN , together with the zooplankton-based Margalef's index and CB were very sensitive in both low (60 μg/L) TP conditions. On the other hand, N ROT , B CY , and CY/CL were slightly sensitive at low TP concentrations while their reaction was notable at high TP concentrations. A similar pattern of response was observed for TN concentration and SD visibility.

  12. Air Quality Indicators at Lake Merritt, Oakland, California

    Science.gov (United States)

    Bulatov, D.; Collins, B.; Hsiao, J.; Majors, A.; Liang, J.

    2007-12-01

    Lake Merritt is significant in its role as both a recreational center for humans, as well as a refuge for migratory wild birds. It is, however, closely surrounded by streets and highways, and even sees a large amount of water traffic by motor-driven boats and pontoons. These two factors contribute to what we suspect is a generally high level of emissions in the atmosphere surrounding the lake. While the harmful components of these emissions can be measured directly using specialized and generally expensive tools, the goal of our research is to explore the use of tree leaves as indicators of air quality. Properties of atmospheric air directly affect the quality of leaves because of plants' reliance on photosynthesis. In brief, photosynthesis requires the input of sunlight, water, and carbon dioxide to produce oxygen and glucose. The gateways through which many of these inputs and outputs pass are essential to every leaf's survival and are called stomata. However, water is an exception; since its entry into the plant's vascular system is through the roots, water generally diffuses outward at stomatal openings rather than inward. Therefore, plants must strike a balance between gaining carbon dioxide and losing water, as well as risk exposure to toxic compounds in the air itself. Primarily, guard cells fulfill this purpose by closing over stomatal openings to conserve water. However, we also believe that over generations of leaves, the absolute number of stomata itself can change to reflect the surrounding environment. That is, increases in carbon dioxide must coincide with higher levels of toxic compounds, which force the number of stomata to decrease over time. Our research examined the relationship between quantitative presence of stomata for several species of trees and the levels of carbon dioxide, oxygen, and wind-speed for ten sites around Lake Merritt. Wind-speed is one of our primary measures because increasing wind velocity leads to water diffusing out of the

  13. Digital soil mapping using remote sensing indices, terrain attributes, and vegetation features in the rangelands of northeastern Iran.

    Science.gov (United States)

    Mahmoudabadi, Ebrahim; Karimi, Alireza; Haghnia, Gholam Hosain; Sepehr, Adel

    2017-09-11

    Digital soil mapping has been introduced as a viable alternative to the traditional mapping methods due to being fast and cost-effective. The objective of the present study was to investigate the capability of the vegetation features and spectral indices as auxiliary variables in digital soil mapping models to predict soil properties. A region with an area of 1225 ha located in Bajgiran rangelands, Khorasan Razavi province, northeastern Iran, was chosen. A total of 137 sampling sites, each containing 3-5 plots with 10-m interval distance along a transect established based on randomized-systematic method, were investigated. In each plot, plant species names and numbers as well as vegetation cover percentage (VCP) were recorded, and finally one composite soil sample was taken from each transect at each site (137 soil samples in total). Terrain attributes were derived from a digital elevation model, different bands and spectral indices were obtained from the Landsat7 ETM+ images, and vegetation features were calculated in the plots, all of which were used as auxiliary variables to predict soil properties using artificial neural network, gene expression programming, and multivariate linear regression models. According to R 2 RMSE and MBE values, artificial neutral network was obtained as the most accurate soil properties prediction function used in scorpan model. Vegetation features and indices were more effective than remotely sensed data and terrain attributes in predicting soil properties including calcium carbonate equivalent, clay, bulk density, total nitrogen, carbon, sand, silt, and saturated moisture capacity. It was also shown that vegetation indices including NDVI, SAVI, MSAVI, SARVI, RDVI, and DVI were more effective in estimating the majority of soil properties compared to separate bands and even some soil spectral indices.

  14. Influence of precipitation, landscape and hydrogeomorphic lake features on pelagic allochthonous indicators in two connected ultraoligotrophic lakes of North Patagonia

    International Nuclear Information System (INIS)

    Queimaliños, Claudia; Reissig, Mariana; Diéguez, María del Carmen; Arcagni, Marina; Ribeiro Guevara, Sergio; Campbell, Linda; Soto Cárdenas, Carolina; Rapacioli, Raúl

    2012-01-01

    We investigated the terrestrial influence on two chained deep ultraoligotrophic lakes of North Patagonia (Argentina) through the seasonal analysis of two pelagic allochthonous indicators: i) water color, as a proxy of allochthonous dissolved organic matter in lakes; and ii) the color to chlorophyll a ratio (Color:Chla), as an indicator of the relationship between allochthonous and autochthonous carbon pools. We also evaluated the potential transfer pathways of the allochthonous dissolved organic matter into the pelagic food webs of these deep lakes, including the natural zooplankton δ 13 C in the analysis. The dynamics of the allochthonous indicators were related to the precipitation regime, water level fluctuations, and hydrogeomorphic and catchment features of lakes Moreno East and Moreno West. The water color (absorbance at 440 nm) was extremely low ( −1 ) in both lakes regardless of the season. However, precipitation and snowmelt regimes drove the increase and decrease of water color, respectively. A significant positive relationship between the zooplankton bulk δ 13 C with the water color would suggest an input of allochthonous organic carbon into the pelagic consumers. The incorporation of the dissolved allochthonous material into higher trophic levels is likely favored by the bacterivorous behavior of planktonic organisms, mixotrophic flagellates and ciliates, which dominate the pelagic food webs of these Patagonian lakes. Morphometric aspects, mainly the higher water residence time, led to lower values of allochthony in Moreno East compared to Moreno West, probably accentuated by its upper position in the lake chain. Overall, our results suggest that these allochthonous signals can bring insight into the magnitude of the interaction between terrestrial environments and lake ecosystems, even in extremely clear and ultraoligotrophic systems, such as the Andean Patagonian lakes. - Highlights: ► Pelagic allochthonous indicators were detected in two

  15. Influence of precipitation, landscape and hydrogeomorphic lake features on pelagic allochthonous indicators in two connected ultraoligotrophic lakes of North Patagonia

    Energy Technology Data Exchange (ETDEWEB)

    Queimalinos, Claudia, E-mail: queimalinosc@comahue-conicet.gob.ar [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Reissig, Mariana; Dieguez, Maria del Carmen [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Arcagni, Marina; Ribeiro Guevara, Sergio [Laboratorio de Analisis por Activacion Neutronica (LAAN), Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Av. Bustillo 9500, R8402AGP Bariloche, Rio Negro (Argentina); Campbell, Linda [School of Environmental Studies, Saint Mary' s University, 923 Robie Street, Halifax, Nova Scotia, Canada B3H-3C3 (Canada); Soto Cardenas, Carolina [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Rapacioli, Raul [Facultad de Ingenieria, Universidad Nacional del Comahue, Buenos Aires1400, Q8300IBX Neuquen (Argentina); and others

    2012-06-15

    We investigated the terrestrial influence on two chained deep ultraoligotrophic lakes of North Patagonia (Argentina) through the seasonal analysis of two pelagic allochthonous indicators: i) water color, as a proxy of allochthonous dissolved organic matter in lakes; and ii) the color to chlorophyll a ratio (Color:Chla), as an indicator of the relationship between allochthonous and autochthonous carbon pools. We also evaluated the potential transfer pathways of the allochthonous dissolved organic matter into the pelagic food webs of these deep lakes, including the natural zooplankton {delta}{sup 13}C in the analysis. The dynamics of the allochthonous indicators were related to the precipitation regime, water level fluctuations, and hydrogeomorphic and catchment features of lakes Moreno East and Moreno West. The water color (absorbance at 440 nm) was extremely low (< 0.28 m{sup -1}) in both lakes regardless of the season. However, precipitation and snowmelt regimes drove the increase and decrease of water color, respectively. A significant positive relationship between the zooplankton bulk {delta}{sup 13}C with the water color would suggest an input of allochthonous organic carbon into the pelagic consumers. The incorporation of the dissolved allochthonous material into higher trophic levels is likely favored by the bacterivorous behavior of planktonic organisms, mixotrophic flagellates and ciliates, which dominate the pelagic food webs of these Patagonian lakes. Morphometric aspects, mainly the higher water residence time, led to lower values of allochthony in Moreno East compared to Moreno West, probably accentuated by its upper position in the lake chain. Overall, our results suggest that these allochthonous signals can bring insight into the magnitude of the interaction between terrestrial environments and lake ecosystems, even in extremely clear and ultraoligotrophic systems, such as the Andean Patagonian lakes. - Highlights: Black-Right-Pointing-Pointer Pelagic

  16. A comparison of different biotic indices based on benthic macro-invertebrates in italian lakes

    Directory of Open Access Journals (Sweden)

    Laura MARZIALI

    2011-02-01

    Full Text Available Benthic macroinvertebrates samples were taken from Italian lakes with different geological, morphological and chemical characteristics. Thirty-two lowland small and large lakes sampled using a grab in soft substrate were selected to develop biotic indices. Diversity indices based on species numbers - abundances and indices using species sensitivity values were compared. The lakes selected were all situated in the Alpine Ecoregion below 800 m a.s.l. and had similar chemical composition but different levels of anthropogenic pressure. Lakes with data available in different years were included as separate lakes in the analysis; littoralsublittoral samples of large lakes were also separated from profundal samples yielding a total of 41 sites for analysis. Seven different biotic indices were compared: (1 Shannon diversity index (H, (2 weighted Shannon diversity index (Hw including in the calculation a sensitivity value assigned to each species, (3 a benthic quality index based on means of three different environmental variables, measuring trophic status, weighted by species abundances (BQITS, (4 an index based on weighted means using a larger set of environmental variables (BQIENV, (5 a modified BQITS, which included both species numbers and total abundance of individuals (BQIES, (6 an index calculated according to a rarefaction method (ES, (7 an index considering indicator species based on experts judgment (BQIEJ. The indices were compared with a trophic status index (TSI constructed by joining three environmental variables: O2% saturation in the hypolimnion during summer stratification, total phosphorous and transparency during full circulation. Comparisons were also made with another environmental stress index (ENI constructed on a larger number of variables. All the biotic indices had significant correlations with both TSI and ENI. BQIES, WFD compliant and well correlated with TSI and ENI, was selected to tentatively assign the investigated lakes

  17. Coherent responses of sulphate concentration in Norwegian lakes: relationships with sulphur deposition and climate indices

    Directory of Open Access Journals (Sweden)

    P. J. Dillon

    2003-01-01

    Full Text Available The coherence or synchrony in the trends in SO42– concentration in a set of 100 lakes in Norway that have a long-term chemical record was evaluated. Using a statistical technique that compares patterns or trends that are not uni-directional, the lakes were grouped into 18 subsets or clusters, each with between 2 and 11 lakes that had similar trends. These temporal trends were strongly correlated with several climate indices, notably the Arctic Oscillation Index (AOI measured in the autumn, and the annual North Atlantic Oscillation Index (NAOI. Because these clusters of lakes were spatially dispersed, they could not be compared directly with trends in wet S deposition, because S deposition varied substantially between lakes within each cluster. However, the average trend in SO42– concentration was evaluated in each of 10 regions of Norway that were defined previously on the basis of pollution load, meteorological variables and biogeography. Although these regions did not match the statistically-selected clusters of lakes with equal trends very closely, there were similar, strong correlations between climate indices (the AOI and NAOI and the 10 average SO42– trends, although there were even stronger relationships with average wet S deposition in the regions. When subsets of lakes with coherent SO42– trends were selected from within each of the 10 regions, both wet S deposition and the climate indices were strongly correlated with those SO42– trends. Hence, lakes in Norway respond to changes in wet S deposition and are influenced by large-scale, i.e. global, climate signals. Future evaluation of recovery of lakes affected by acid deposition must therefore consider the confounding effects of climate and potential climate change. Keywords: recovery, acid deposition, coherence, sulphate, climate change

  18. Phytoplankton community and chlorophyll a as trophic state indices of Lake Skadar (Montenegro, Balkan).

    Science.gov (United States)

    Rakocevic-Nedovic, Jelena; Hollert, Henner

    2005-01-01

    Phytoplankton, as a first step in trophic cascades of lakes, can be a good indicator of trophic states, considering that every environmental change affects this community and many species of this community are sensitive to changes, and that they response very quickly. In this study, we tried to assess and predict the trophic state of Lake Skadar according to phytoplankton data. Water samples were collected using Ruttner sampling bottle. Temperature, dissolved oxygen, ph, conductivity and transparence were measured in situ using portable equipment. Nutrients and chlorophyll a were measured using standard spectrophotometric methods. A determination of phytoplankton species was performed using relevant keys and the counting of cells was performed using sedimentation methods. The species composition of Lake Skadar revealed 95 taxa, with Chlorophyceae and Bacillariophyceae being represented best. According to an average chlorophyll a concentration of 5.9 pg/l, Lake Skadar belongs to the mesotrophic level of the trophic scale. Developed prediction equation for chlorophyll a revealed a good prediction (R2 = 0.71) and the parameter Secchi depth was primarily correlated with chlorophyll a concentration. Trophic state indices derived from chlorophyll a and transparency, were close together, but both were below the phosphorous index. Values of trophic state indices rank the Lake Skadar as being mesotrophic. This study also showed that indices of diversity based on phytoplankton are weak indicators of trophic status and that they can well characterize only differences between assemblages and associations. According to calculated saprobic indices (ranging from 1.5 to 2.15), Lake Skadar is on betamesosaprobic level of saprobity, which means that it is moderately polluted with organic compounds. Total phosphorus is not the main limiting factor for the phytoplankton community in Lake Skadar. Disagreements between chlorophyll and the transparency index, on the one hand, and the

  19. Arcellacea (testate amoebae) as bio-indicators of road salt contamination in lakes.

    Science.gov (United States)

    Roe, Helen M; Patterson, R Timothy

    2014-08-01

    Winter deicing operations occur extensively in mid- to high-latitude metropolitan regions around the world and result in a significant reduction in road accidents. Deicing salts can, however, pose a major threat to water quality and aquatic organisms. In this paper, we examine the utility of Arcellacea (testate amoebae) for monitoring lakes that have become contaminated by winter deicing salts, particularly sodium chloride. We analysed 50 sediment samples and salt-related water property variables (chloride concentrations; conductivity) from 15 lakes in the Greater Toronto Area and adjacent areas of southern Ontario, Canada. The sampled lakes included lakes in proximity to major highways and suburban roads and control lakes in forested settings away from road influences. Samples from the most contaminated lakes, with chloride concentrations in excess of 400 mg/l and conductivities of >800 μS/cm, were dominated by species typically found in brackish and/or inhospitable lake environments and by lower faunal diversities (lowest Shannon diversity index values) than samples with lower readings. Q-R-mode cluster analysis and detrended correspondence analysis (DCA) resulted in the recognition of four assemblage groupings. These reflect varying levels of salt contamination in the study lakes, along with other local influences, including nutrient loading. The response to nutrients can, however, be isolated if the planktic eutrophic indicator species Cucurbitella tricuspis is removed from the counts. The findings show that the group has considerable potential for biomonitoring in salt-contaminated lakes, and their presence in lake sediment cores may provide significant insights into long-term benthic community health, which is integral for remedial efforts.

  20. Chemical indicators of anthropogenic impacts in sediments of the pristine karst lakes.

    Science.gov (United States)

    Mikac, I; Fiket, Z; Terzić, S; Barešić, J; Mikac, N; Ahel, M

    2011-08-01

    The anthropogenic impact on the pristine karst lakes was investigated using combination of specific parameters, including multielemental analysis of major inorganic constituents (Al, K, Fe) and trace metals (Li, Ag, Cd, Sn, Pb, Bi, Cr, Co, Ni, Cu, Zn and Sb), polycyclic aromatic hydrocarbons (PAHs) and anionic surfactants of linear alkylbenzene sulfonate (LAS) type. The study was performed in the Plitvice Lakes National Park, situated in a sparsely populated area of the northwestern Dinarides, central Croatia. Dated cores of recent sediments from the two biggest lakes, Lake Prosce and Lake Kozjak, were analysed for the selected contaminants using highly specific methods, involving inductively coupled plasma mass spectrometry (ICP/MS), gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). The concentration of inorganic constituents reflected primarily the geological background of the area as well as geomorphological and geochemical characteristics of the Plitvice Lakes. Due to the higher terrigenous input, the concentration of all elements was significantly higher in the Lake Prosce. The concentration of toxic metals was relatively low in both lakes, except for Cd (>1 mg kg(-1)) and Pb (up to 40 mg kg(-1)). The vertical profiles of these metals suggested that elevated concentrations of Cd were of natural origin, derived from the erosion of the Jurassic dolomite bedrock, while Pb was predominately of recent anthropogenic origin. A similar distribution pattern, suggesting the same prevailing mechanism of input, was observed for pyrolytic PAHs. The characteristic diagnostic PAH ratios revealed that higher PAHs prevailingly originated from the combustion of biomass and fossil fuels. LAS, which represent highly specific indicators of untreated wastewaters, were found in rather high concentrations in the recent sediment layers (up to 4.7 mg kg(-1)), suggesting that contaminated household and hotel wastewaters reach the

  1. Evaluation of the lake Lyabiazhie (Kazan, Russia) state by indicators of communities of hydrobionts

    Science.gov (United States)

    Derevenskaya, O.; Urazaeva, N.

    2018-01-01

    The article presents the results of studies of zooplankton and zoobenthos communities of Lake Lebyazhye (Kazan, Russia) performed in 2015-2016. Over the past decades, under the influence of anthropogenic and natural factors, the level of water decreased and the area of Lake Lebyazhye decreased. Now the water level in the lake is artificially maintained by the supply of groundwater, which led to a change in the type of water, an increase in mineralization. As a result, species composition of zooplankton decreased, a complex of dominant species changed, and quantitative indicators of zooplankton and zoobenthos communities decreased. The results of studies of the zooplankton and zoobenthos communities of Lake Lebyazhye can be used to justify measures for the lake’s eco-rehabilitation.

  2. Associations between cyanobacteria and indices of secondary production in the western basin of Lake Erie

    Science.gov (United States)

    Larson, James H.; Evans, Mary Anne; Kennedy, Robert J.; Bailey, Sean; Loftin, Keith A.; Laughrey, Zachary; Femmer, Robin; Schaeffer, Jeff; Richardson, William B.; Wynne, Timothy; Nelson, J. C.; Duris, Joseph W.

    2018-01-01

    Large lakes provide a variety of ecological services to surrounding cities and communities. Many of these services are supported by ecological processes that are threatened by the increasing prevalence of cyanobacterial blooms which occur as aquatic ecosystems experience cultural eutrophication. Over the past 10 yr, Lake Erie experienced cyanobacterial blooms of increasing severity and frequency, which have resulted in impaired drinking water for the surrounding communities. Cyanobacterial blooms may impact ecological processes that support other services, but many of these impacts have not been documented. Secondary production (production of primary consumers) is an important process that supports economically important higher trophic levels. Cyanobacterial blooms may influence secondary production because cyanobacteria are a poor‐quality food resource and cyanotoxins may be harmful to consumers. Over 3 yr at 34 sites across the western basin of Lake Erie, we measured three indices of secondary production that focus on the dominant bivalve taxa: (1) growth of a native unionid mussel, (2) the size of young‐of‐year dreissenid mussels, and (3) the mass of colonizing animals on a Hester‐Dendy sampler. Associations between these indices and cyanobacterial data were estimated to assess whether cyanobacteria are associated with variation in secondary production in the western basin of Lake Erie. The results suggest cyanobacterial abundance alone is only weakly associated with secondary production, but that cyanotoxins have a larger effect on secondary production. Given recurring late‐summer cyanobacterial blooms, this impact on secondary production has the potential to undermine Lake Erie's ability to sustain important ecosystem services.

  3. The use of invertebrates as indicators of environmental change in alpine rivers and lakes

    International Nuclear Information System (INIS)

    Khamis, K.; Hannah, D.M.; Brown, L.E.; Tiberti, R.; Milner, A.M.

    2014-01-01

    In alpine regions climatic change will alter the balance between water sources (rainfall, ice-melt, snowmelt, and groundwater) for aquatic systems, particularly modifying the relative contributions of meltwater, groundwater and rain to both rivers and lakes. While these changes are expected to have implications for alpine aquatic ecosystems, little is known about potential ecological tipping points and associated indicator taxa. We examined changes in biotic communities along a gradient of glacier influence for two study systems: (1) a stream network in the French Pyrénées; and (2) a network of lakes in the Italian Alps, with the aim of identifying potential indicator taxa (macroinvertebrates and zooplankton) of glacier retreat in these environments. To assess parallels in biotic responses across streams and lakes, both primary data and findings from other publications were synthesised. Using TITAN (Threshold Indicator Taxa ANalysis) changes in community composition of river taxa were identified at thresholds of < 5.1% glacier cover and < 66.6% meltwater contribution. Below these thresholds the loss of cold stenothermic benthic invertebrate taxa, Diamesa spp. and the Pyrenean endemic Rhyacophila angelieri was apparent. Some generalist taxa including Protonemura sp., Perla grandis, Baetis alpinus, Rhithrogena loyolaea and Microspectra sp. increased when glacier cover was < 2.7% and < 52% meltwater. Patterns were not as distinct for the alpine lakes, due to fewer sampling sites; however, Daphnia longispina grp. and the benthic invertebrate groups Plectopera and Planaria were identified as potential indicator taxa. While further work is required to assess potential indicator taxa for alpine lake systems, findings from alpine river systems were consistent between methods for assessing glacier influence (meltwater contribution/glacier cover). Hence, it is clear that TITAN could become a useful management tool, enabling: (i) the identification of taxa particularly

  4. The use of invertebrates as indicators of environmental change in alpine rivers and lakes

    Energy Technology Data Exchange (ETDEWEB)

    Khamis, K.; Hannah, D.M. [School of Geography Earth and Environmental Science, University of Birmingham, Birmingham B15 2TT (United Kingdom); Brown, L.E. [School of Geography/water@leeds, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Tiberti, R. [DSTA, Dipartimento di Scienze della Terra e dell' Ambiente, University of Pavia, Via Ferrata 9, 27100 Pavia (Italy); Alpine Wildlife Research Centre, Gran Paradiso National Park, Degioz 11, I-1101 Valsavarenche, Aosta (Italy); Milner, A.M., E-mail: a.m.milner@bham.ac.uk [School of Geography Earth and Environmental Science, University of Birmingham, Birmingham B15 2TT (United Kingdom); Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775 (United States)

    2014-09-15

    In alpine regions climatic change will alter the balance between water sources (rainfall, ice-melt, snowmelt, and groundwater) for aquatic systems, particularly modifying the relative contributions of meltwater, groundwater and rain to both rivers and lakes. While these changes are expected to have implications for alpine aquatic ecosystems, little is known about potential ecological tipping points and associated indicator taxa. We examined changes in biotic communities along a gradient of glacier influence for two study systems: (1) a stream network in the French Pyrénées; and (2) a network of lakes in the Italian Alps, with the aim of identifying potential indicator taxa (macroinvertebrates and zooplankton) of glacier retreat in these environments. To assess parallels in biotic responses across streams and lakes, both primary data and findings from other publications were synthesised. Using TITAN (Threshold Indicator Taxa ANalysis) changes in community composition of river taxa were identified at thresholds of < 5.1% glacier cover and < 66.6% meltwater contribution. Below these thresholds the loss of cold stenothermic benthic invertebrate taxa, Diamesa spp. and the Pyrenean endemic Rhyacophila angelieri was apparent. Some generalist taxa including Protonemura sp., Perla grandis, Baetis alpinus, Rhithrogena loyolaea and Microspectra sp. increased when glacier cover was < 2.7% and < 52% meltwater. Patterns were not as distinct for the alpine lakes, due to fewer sampling sites; however, Daphnia longispina grp. and the benthic invertebrate groups Plectopera and Planaria were identified as potential indicator taxa. While further work is required to assess potential indicator taxa for alpine lake systems, findings from alpine river systems were consistent between methods for assessing glacier influence (meltwater contribution/glacier cover). Hence, it is clear that TITAN could become a useful management tool, enabling: (i) the identification of taxa particularly

  5. Assessing modern ground survey methods and airborne laser scanning for digital terrain modelling: A case study from the Lake District, England

    Science.gov (United States)

    Gallay, Michal; Lloyd, Christopher D.; McKinley, Jennifer; Barry, Lorraine

    2013-02-01

    This paper compares the applicability of three ground survey methods for modelling terrain: one man electronic tachymetry (TPS), real time kinematic GPS (GPS), and terrestrial laser scanning (TLS). Vertical accuracy of digital terrain models (DTMs) derived from GPS, TLS and airborne laser scanning (ALS) data is assessed. Point elevations acquired by the four methods represent two sections of a mountainous area in Cumbria, England. They were chosen so that the presence of non-terrain features is constrained to the smallest amount. The vertical accuracy of the DTMs was addressed by subtracting each DTM from TPS point elevations. The error was assessed using exploratory measures including statistics, histograms, and normal probability plots. The results showed that the internal measurement accuracy of TPS, GPS, and TLS was below a centimetre. TPS and GPS can be considered equally applicable alternatives for sampling the terrain in areas accessible on foot. The highest DTM vertical accuracy was achieved with GPS data, both on sloped terrain (RMSE 0.16 m) and flat terrain (RMSE 0.02 m). TLS surveying was the most efficient overall but veracity of terrain representation was subject to dense vegetation cover. Therefore, the DTM accuracy was the lowest for the sloped area with dense bracken (RMSE 0.52 m) although it was the second highest on the flat unobscured terrain (RMSE 0.07 m). ALS data represented the sloped terrain more realistically (RMSE 0.23 m) than the TLS. However, due to a systematic bias identified on the flat terrain the DTM accuracy was the lowest (RMSE 0.29 m) which was above the level stated by the data provider. Error distribution models were more closely approximated by normal distribution defined using median and normalized median absolute deviation which supports the use of the robust measures in DEM error modelling and its propagation.

  6. Developing fish trophic interaction indicators of climate change for the Great Lakes

    Science.gov (United States)

    Kraus, Richard T.; Knight, Carey T.; Gorman, Ann Marie; Kocovsky, Patrick M.; Weidel, Brian C.; Rogers, Mark W.

    2016-01-01

    This project addressed regional climate change effects on aquatic food webs in the Great Lakes. We sought insights by examining Lake Erie as a representative system with a high level of anthropogenic impacts, strong nutrient gradients, seasonal hypoxia, and spatial overlap of cold- and cool-water fish guilds. In Lake Erie and in large embayments throughout the Great Lakes basin, this situation is a concern for fishery managers, as climate change may exacerbate hypoxia and reduce habitat volume for some species. We examined fish community composition, fine-scale distribution, prey availability, diets, and biochemical tracers for dominant fishes from study areas with medium-high nutrient levels (mesotrophic, Fairport study area), and low nutrient levels (oligotrophic, Erie study area). This multi-year database (2011-2013) provides the ability to contrast years with wide variation in rainfall, winter ice-cover, and thermal stratification. In addition, multiple indicators of dietary and distributional responses to environmental variability will allow resource managers to select the most informative approach for addressing specific climate change questions. Our results support the incorporation of some relatively simple and cost-efficient approaches into existing agency monitoring programs to track the near-term condition status of fish and fish community composition by functional groupings. Other metrics appear better suited for understanding longer-term changes, and may take more resources to implement on an ongoing basis. Although we hypothesized that dietary overlap and similarity in selected species would be sharply different during thermal stratification and hypoxic episodes, we found little evidence of this. Instead, to our surprise, this study found that fish tended to aggregate at the edges of hypoxia, highlighting potential spatial changes in catch efficiency of the fishery. This work has had several positive impacts on a wide range of resource management and

  7. Patterns of lake occupancy by fish indicate different adaptations to life in a harsh Arctic environment

    Science.gov (United States)

    Haynes, Trevor B.; Rosenberger, Amanda E.; Lindberg, Mark S.; Whitman, Matthew; Schmutz, Joel A.

    2014-01-01

    Summary For six fish species sampled from 86 lakes on the Arctic Coastal Plain, Alaska, we examined whether lake occupancy was related to variables representing lake size, colonisation potential and/or the presence of overwintering habitat.

  8. Climate and landscape influence on indicators of lake carbon cycling through spatial patterns in dissolved organic carbon.

    Science.gov (United States)

    Lapierre, Jean-Francois; Seekell, David A; Del Giorgio, Paul A

    2015-12-01

    Freshwater ecosystems are strongly influenced by both climate and the surrounding landscape, yet the specific pathways connecting climatic and landscape drivers to the functioning of lake ecosystems are poorly understood. Here, we hypothesize that the links that exist between spatial patterns in climate and landscape properties and the spatial variation in lake carbon (C) cycling at regional scales are at least partly mediated by the movement of terrestrial dissolved organic carbon (DOC) in the aquatic component of the landscape. We assembled a set of indicators of lake C cycling (bacterial respiration and production, chlorophyll a, production to respiration ratio, and partial pressure of CO2 ), DOC concentration and composition, and landscape and climate characteristics for 239 temperate and boreal lakes spanning large environmental and geographic gradients across seven regions. There were various degrees of spatial structure in climate and landscape features that were coherent with the regionally structured patterns observed in lake DOC and indicators of C cycling. These different regions aligned well, albeit nonlinearly along a mean annual temperature gradient; whereas there was a considerable statistical effect of climate and landscape properties on lake C cycling, the direct effect was small and the overall effect was almost entirely overlapping with that of DOC concentration and composition. Our results suggest that key climatic and landscape signals are conveyed to lakes in part via the movement of terrestrial DOC to lakes and that DOC acts both as a driver of lake C cycling and as a proxy for other external signals. © 2015 John Wiley & Sons Ltd.

  9. Quantitative assessment of Naegleria fowleri and fecal indicator bacteria in brackish water of Lake Pontchartrain, Louisiana.

    Science.gov (United States)

    Xue, Jia; Lamar, Frederica G; Zhang, Bowen; Lin, Siyu; Lamori, Jennifer G; Sherchan, Samendra P

    2018-05-01

    Brackish water samples from Lake Pontchartrain in Louisiana were assessed for the presence of pathogenic amoeba Naegleria fowleri, which causes primary amoebic meningoencephalitis (PAM). In our study, quantitative polymerase chain reaction (qPCR) methods were used to determine N. fowleri, E. coli, and enterococci in water collected from Lake Pontchartrain. N. fowleri target sequence was detected in 35.4% (56/158) of the water samples from ten sites around the lake. Statistically significant positive correlations between N. fowleri concentration and water temperature as well as E. coli (qPCR) were observed. Multiple linear regression (MLR) model shows seasonal factor (summer or winter) has significant effect on the concentration of N. fowleri, E. coli and enterococci (qPCR) concentration. Significant positive relationships between E. coli and enterococci was observed from both qPCR (r=0.25) and culture based method (r=0.54). Meanwhile, significant positive correlation between qPCR and culture based methods for enterococci concentration was observed (r=0.33). In our study, water temperature and E. coli concentration were indicative of N. fowleri concentrations in brackish water environment. Future research is needed to determine whether sediment is a source of N. fowleri found in the water column. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. [Microorganisms of Lake Baikal and Lake Nyasa as indicators of anthropogenic influence: prospects of use in biotechnology].

    Science.gov (United States)

    Verkhozina, V A; Verkhozina, E V; Gonchar, D A; Dedkov, V S; Degtiarev, S Kh; Kusner, Iu S

    2004-01-01

    Restriction endonucleases (RENs) were detected in 650 microbial strains isolated from water columns and bottom sediments of deep rift lakes, Baikal (Russia) and Nyasa (Southeastern Africa). They enzymes included unique (Fan I, Aca I, and Sse 91) and very rare (Bsi I, and Cci N I) species not typical of aquatic ecosystems. Water columns, deep cores, and bottom sediments of pure areas of the lakes contained no microorganisms with new RENs. Thus, inshore areas of Lake Baikal exposed to anthropogenic influence may contain mutant bacterial strains expressing RENs that have not been described previously.

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

    Science.gov (United States)

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

    2017-12-01

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

  12. MULTIMETRIC INDICES BASED ON VEGETATION DATA FOR ASSESSING ECOLOGICAL AND HYDROMORPHOLOGICAL QUALITY OF A MAN-REGULATED LAKE

    Directory of Open Access Journals (Sweden)

    R. Bolpagni

    2013-04-01

    Full Text Available A functional characterization of the littoral and shore vegetation was performed in the Lake Idro to assess its ecological quality and hydromorphological alteration. A detailed survey of hydro-hygrophilous vegetation was carried out in 2010-2012. Three multimetric indices were calculated: the MacroIMMI (the Italian macrophytic index for mid-size subalpine lakes with a maximum depth < 125 m, the SFI (Shorezone Functional Index, and the LHS (Lake Habitat Survey. The MacroIMMI (0.76 classified the lake in a good ecological status, although the dominant aquatic species were exotic (Elodea nuttallii and Lagarosiphon major. The SFI pointed out that the 50% of total shorelines displayed a very good or excellent conservation status; conversely, the LHS revealed high levels of morphological alteration coupled with rather good levels of habitat diversity, likely due to the high colonization rates of macrophytes along the lake shore. The lacustrine multimetric indices seem suitable for assessing the conservation status of mid-size lakes. However, for the present case-study, the metrics used require further implementation to suit the peculiarities of Italian subalpine lakes.

  13. High and Increasing Shoreline Erosion Rates of Thermokarst Lakes Set in Ice-Rich Permafrost Terrain of the Arctic Coastal Plain of Alaska

    Science.gov (United States)

    Bondurant, A. C.; Arp, C. D.; Jones, B. M.; Shur, Y.; Daanen, R. P.

    2017-12-01

    Thermokarst lakes are a dominant landform shaping landscapes and impacting permafrost on the Arctic Coastal Plain (ACP) of northern Alaska, a region of continuous permafrost. Here lakes cover greater than 20% of the landscape and drained lake basins cover an additional 50 to 60% of the landscape. The formation, expansion, and drainage of thaw lakes has been described by some researchers as part of a natural cycle that has reworked the ACP landscape during the Holocene. Yet the factors and processes controlling contemporary thermokarst lake expansion remain poorly described. This study focuses on the factors controlling expansion rates of thermokarst lakes in three ACP regions that vary in landscape history, ground-ice content, and lake morphology (i.e. size and depth), as well as evaluating changes through time. Through the use of historical aerial imagery, satellite imagery, and field observations, this study identifies the controlling factors at multiple spatial and temporal scales to better understand the processes relating to thermokarst lake expansion. Studies of 35 lakes across the ACP shows regional differences in expansion rate related to permafrost ice content ranging from an average expansion rate of 0.62 m/yr where ice content is highest ( 86%) to 0.16 m/yr where ice content is lowest (45%-71%). A subset of these lakes analyzed over multiple time periods show increasing rates of erosion, with average rates being 37% higher over the period 1979-2002 (0.73 m/yr) compared to 1948-1979 (0.53 m/yr). These increased rates of erosion have important implications for the regional hydrologic cycle and localized permafrost degradation. Predicting how thermokarst lakes will behave locally and on a landscape scale is increasingly important for managing habitat and water resources and informing models of land-climate interactions in the Arctic.

  14. For creating an expert system of Lake Onega: optimization of monitoring the state of the ecosystem on zooplankton indicators

    Directory of Open Access Journals (Sweden)

    Kalinkina Nataliya Mikhailovna

    2017-03-01

    Full Text Available In Lake Onega zooplankton is considered as a convenient and reliable indicator of the state of the lake ecosystem. As a formal basis for the consolidation of the accumulated information on the biota of Lake Onega, it is proposed to create an expert system using zooplankton as a prototype of an intelligent computer environment on all biotic components. In this context, it is proposed to review the organization of monitoring the state of zooplankton to increase the number of samples taken and to expand the geography of sampling as well as to simplify and computerize the sample analysis.

  15. Can we use redox sensitive elements to indicate past stable state transitions? Preliminary results from three shallow lakes

    Science.gov (United States)

    Czeck, B. C.; Deschamp, M. L.; Hagen, S.; Theissen, K. M.; Hobbs, W.

    2010-12-01

    Shallow lakes are known to exist in two distinct stable states; either a clear-water state which is dominated by macrophytes or a turbid state which is dominated by algae. Results of past studies suggest that when lakes exist in the clear-water state they are more efficient at sequestering organic carbon. This is because lakes in the clear-water state generally have longer periods of low oxygen conditions which prevent the decomposition of organic matter, allowing lakes in this state to bury more organic carbon. With this in mind we decided to test redox sensitive elements’ ability to distinguish trends in the redox status of the lakes through time. We performed acid digestions to extract the environmentally available metals from the sediments of three shallow lakes in West-Central Minnesota. We used an ICP-AES to analyze 11 metals (Co, Cr, Fe, Mn, Mo, Ni, Pb, Th, U, V and Zn) while using Al as an indicator of the erosion of weathered materials. 210-Pb age dates were determined for cores from all three lakes, providing strong chronologies for each record. Near the time of settlement there is an overall increase in metal concentrations other than Th and U, which show an overall decrease. The accumulation rates of metals show similar trends to the sedimentation rates for each lake. After normalizing against Al, both Pb and Co have sharp increases around the time of settlement and Pb:Al doubles. Most other elements show a decrease in concentrations after settlement, suggesting that something other than erosion of weathered materials is a factor in the concentrations of metals in the lake. We attempt to determine whether this signal is due to changes in redox status or another factor. Elemental and stable isotopic values for C and N were also analyzed to get a better understanding of the source of organic matter and how productive the lakes have been through time.

  16. The long-term dynamics of hydrochemical indices of low-mineralized subarctic lakes in reducing the acid load

    Directory of Open Access Journals (Sweden)

    Kashulina T. G.

    2016-03-01

    Full Text Available The results of long-term studies (1990–2013 of dynamics of the main hydrochemical indices of the subarctic Shuonijavr Lake located in the zone of airborne pollution from a metallurgical plant have been considered. The following facts have been revealed: significant increase of alkalinity and acid neutralizing capacity (ANC of the lake water; reduction in the range of seasonal fluctuations of ph and alkalinity; reduction of in the lake water during the observation period as a result of reducing the acid load due to the decrease of SO2 emission. Despite the stabilization of the lake water ANC the pollution indicators in six elements of polluters foreground for the region remain high values

  17. Ecological risk evaluation of sediment core samples, Lake Tortum (Erzurum, NE Turkey using environmental indices

    Directory of Open Access Journals (Sweden)

    Hakan Kaya

    2017-11-01

    Full Text Available This study aimed to determine the vertical distribution of heavy metals in a 72 cm-long core sample from Lake Tortum in order to shed light on the implications of potential ecological risks. Analysis was based on the use of environmental indices such as the Integrated Pollution Load Index (PLI and Potential Ecological Risk Index (PER. Results reveal that, except for Pb, Mn and Hg, the lowest concentrations of heavy metals occur at a core depth of between 2 cm and 20 cm for Cu, Zn, Ni, Fe, As, Cd, Cr and Al. The highest concentration was found at sampling intervals of 36 cm and 50 cm, with the exception of Pb, Mn, Hg and Ni. The PLI values from bottom to top are less than 1 while the level with the nearest value to the background value lies at a depth between 24 cm and 26 cm. The PER index results suggest a low ecological risk level for Cu, Pb, Zn, Ni, Mn, Fe, As, Cr, and Al; however, Cd and Hg constitute an ecological threat to the lake ecosystem.

  18. Lake trout otolith chronologies as multidecadal indicators of high-latitude freshwater ecosystems

    Science.gov (United States)

    Black, B.A.; Von Biela, V.R.; Zimmerman, C.E.; Brown, Randy J.

    2013-01-01

    High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout (Salvelinus namaycush) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval (p otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales.

  19. Selecting indicators to assess the fisheries of Lake Malawi and Lake Malombe: Knowledge base and evaluative capacity

    NARCIS (Netherlands)

    Zwieten, van P.A.M.; Banda, M.; Kolding, J.

    2011-01-01

    The provision of management information on the fisheries of Lakes Malawi and Malombe has been characterised by top–down controlled single species steady-state assessment techniques originating from single gear industrial fisheries but applied to an open access highly diverse and adaptive small-scale

  20. Microcystin mcyA and mcyE Gene Abundances Are Not Appropriate Indicators of Microcystin Concentrations in Lakes.

    Directory of Open Access Journals (Sweden)

    Lucas J Beversdorf

    Full Text Available Cyanobacterial harmful algal blooms (cyanoHABs are a primary source of water quality degradation in eutrophic lakes. The occurrence of cyanoHABs is ubiquitous and expected to increase with current climate and land use change scenarios. However, it is currently unknown what environmental parameters are important for indicating the presence of cyanoHAB toxins making them difficult to predict or even monitor on time-scales relevant to protecting public health. Using qPCR, we aimed to quantify genes within the microcystin operon (mcy to determine which cyanobacterial taxa, and what percentage of the total cyanobacterial community, were responsible for microcystin production in four eutrophic lakes. We targeted Microcystis-16S, mcyA, and Microcystis, Planktothrix, and Anabaena-specific mcyE genes. We also measured microcystins and several biological, chemical, and physical parameters--such as temperature, lake stability, nutrients, pigments and cyanobacterial community composition (CCC--to search for possible correlations to gene copy abundance and MC production. All four lakes contained Microcystis-mcyE genes and high percentages of toxic Microcystis, suggesting Microcystis was the dominant microcystin producer. However, all genes were highly variable temporally, and in few cases, correlated with increased temperature and nutrients as the summer progressed. Interestingly, toxin gene abundances (and biomass indicators were anti-correlated with microcystin in all lakes except the largest lake, Lake Mendota. Similarly, gene abundance and microcystins differentially correlated to CCC in all lakes. Thus, we conclude that the presence of microcystin genes are not a useful tool for eliciting an ecological role for toxins in the environment, nor are microcystin genes (e.g. DNA a good indicator of toxins in the environment.

  1. Indicators of the environmental state of the Bilećko Jezero Lake

    Directory of Open Access Journals (Sweden)

    Dekic R.

    2011-01-01

    Full Text Available The research refers to the physical, chemical and microbiological parameters of the Bilećko Jezero Lake water quality. The monitoring of physical and chemical parameters and their interaction with other parameters helps estimate the water quality and any possible changes. Some parameter values and their alteration directly affect the water life. The research was performed at three sites: the Grančarevo watergate, the Trebisnjica River fountain and Orah in the period 2006-2009, and the results of conducted physical and chemical analyses indicate that the water quality was satisfactory, albeit with certain deviations. Bacteriological analyses showed that the water of Bileća accumulation, especially at the Izvor site, was burdened with fecal material.

  2. Diatom species composition and indices for determining the ecological status of coastal Mediterranean Spanish lakes

    Directory of Open Access Journals (Sweden)

    Antón-Garrido, Beatriz

    2013-12-01

    Full Text Available Diatom indices have been used and tested mainly for assessing the ecological status of rivers and deep lakes, but there are scarce studies that determine their effectiveness in shallow lakes and in coastal Mediterranean lakes. This study evaluates the validity of several common diatom indices (SPI, BDI, CEC and TDIL for the determination of the ecological quality of three coastal lakes (Valencia, Spain and presents descriptions and ecological data of the main diatom species recorded. Diatom samples were collected from phytobenthos, both from epiphyton of the dominant submerged macrophytes and the sediment. The ecological status of the systems was determined according to different physico-chemical variables and was compared with the results obtained from epiphytic diatom communities. The results showed discrepancies among diatom indices and also with the state determined by the environmental variables. The effectiveness of the indices depended on the number of species assessed for each index with respect to the total species recorded and the suitability of the weight assigned to each species. The results reveal the need to gather more information about the composition and ecology of the diatoms and microalgae characteristic of coastal Mediterranean standing waters. This work contributes to their better knowledge.Los índices de diatomeas han sido aplicados y contrastados principalmente en la evaluación del estado ecológico de los sistemas lóticos y lagos profundos, pero son escasos los estudios sobre su eficacia en lagos someros y lagunas litorales mediterráneas. Este trabajo evalúa la validez de varios índices conocidos de diatomeas (IPS, IBD, CEE y TDIL para la determinación de la calidad ecológica de tres lagunas litorales (Valencia, España y presenta las descripciones y datos ecológicos de las principales especies de diatomeas registradas. Las muestras de diatomeas se recogieron del fitobentos, tanto del epifiton desarrollado sobre

  3. Bioremediation of Contaminated Lake Sediments and Evaluation of Maturity Indicies as Indicators of Compost Stability

    Directory of Open Access Journals (Sweden)

    Y. Anjaneyulu

    2005-08-01

    Full Text Available Land contamination is one of the widely addressed problems, which is gaining importance in many developed and developing countries. International efforts are actively envisaged to remediate contaminated sites as a response to adverse health effects. Popular conventional methodologies only transfer the phase of the contaminant involving cost intensive liabilities besides handling risk of the hazardous waste. Physico-chemical methods are effective for specific wastes, but are technically complex and lack public acceptance for land remediation. “Bioremediation”, is one of the emerging low-cost technologies that offer the possibility to destroy various contaminants using natural biological activities. Resultant non -toxic end products due to the microbial activity and insitu applicability of this technology is gaining huge public acceptance. In the present study, composting is demonstrated as a bioremediation methodology for the stabilization of contaminated lake sediments of Hyderabad, A.P, India. Lake sediment contaminated with organics is collected from two stratums – upper (0.25 m and lower (0.5m to set up as Pile I (Upper and Pile II (Lower in the laboratory. Lime as a pretreatment to the lake sediments is carried out to ensure metal precipitation. The pretreated sediment is then mixed with organic and inorganic fertilizers like cow dung, poultry manure, urea and super phosphate as initial seeding amendments. Bulking agents like sawdust and other micronutrients are provided. Continuous monitoring of process control parameters like pH, moisture content, electrical conductivity, total volatile solids and various forms of nitrogen were carried out during the entire course of the study. The stability of the compost was evaluated by assessing maturity indices like C/N, Cw (water soluble carbon, CNw (Cw/Nw, nitrification index (NH4/NO-3, Cation Exchange Capacity (CEC, germination index, humification ratio, compost

  4. Spatial and temporal dynamics of lake whitefish (Coregonus clupeaformis) health indicators: linking individual-based indicators to a management-relevant endpoint

    Science.gov (United States)

    Wagner, Tyler; Jones, Michael L.; Ebener, Mark P.; Arts, Michael T.; Brenden, Travis O.; Honeyfield, Dale C.; Wright, Gregory M.; Faisal, Mohamed

    2010-01-01

    We examined the spatial and temporal dynamics of health indicators in four lake whitefish (Coregonus clupeaformis) stocks located in northern lakes Michigan and Huron from 2003 to 2006. The specific objectives were to (1) quantify spatial and temporal variability in health indicators; (2) examine relationships among nutritional indicators and stock-specific spatial and temporal dynamics of pathogen prevalence and intensity of infection; and (3) examine relationships between indicators measured on individual fish and stock-specific estimates of natural mortality. The percent of the total variation attributed to spatial and temporal sources varied greatly depending on the health indicator examined. The most notable pattern was a downward trend in the concentration of highly unsaturated fatty acids (HUFAs), observed in all stocks, in the polar lipid fraction of lake whitefish dorsal muscle tissue over the three study years. Variation among stocks and years for some indicators were correlated with the prevalence and intensity of the swimbladder nematode Cystidicola farionis, suggesting that our measures of fish health were related, at some level, with disease dynamics. We did not find relationships between spatial patterns in fish health indicators and estimates of natural mortality rates for the stocks. Our research highlights the complexity of the interactions between fish nutritional status, disease dynamics, and natural mortality in wild fish populations. Additional research that identifies thresholds of health indicators, below (or above) which survival may be reduced, will greatly help in understanding the relationship between indicators measured on individual fish and potential population-level effects.

  5. MODIS Land Surface Temperature time series reconstruction with Open Source GIS: A new quality of temperature based ecological indicators in complex terrain (Invited)

    Science.gov (United States)

    Neteler, M.

    2009-12-01

    In complex terrain like the Central European Alps, meteorological stations and ground surveys are usually sparsely and/or irregularly distributed and often favor agricultural areas. The application of traditional geospatial interpolation methods in complex terrain remains challenging and difficult to optimize. An alternative data source is remote sensing: high temporal resolution satellite data are continuously gaining interest since these data are intrinsically spatialized: continuous field of observations is obtained with this tool instead of point data. The increasing data availability suggests using these time series as surrogate to certain measures from meteorological stations, especially for temperature and related derivatives. The Terra and Aqua satellites with the Moderate Resolution Imaging Spectroradiometer (MODIS) provide four Earth coverages per day at various resolutions. We analyzed 8 years (2000 to 2008) of daily land surface temperature (LST) data from MODIS in an area located in the Southern European Alps. A method was developed to reconstruct incomplete maps (cloud coverage, invalid pixels) based on image statistics and on a model that includes additional GIS layers. The original LST map resolution of 1000m could be improved to 200m in this process which renders the resulting LST maps applicable at regional scales. We propose the use of these reconstructed daily LST time series as surrogate to meteorological observations especially in the area of epidemiological modeling where data are typically aggregated to decadal indicators. From these daily LST map series, derivable indicators include: 1) temperatures minima, means and maxima for annual/monthly/decadal periods; 2) unusual hot summers;3) the calculation of growing degree days, and 4) spring temperature increase or autumnal temperature decrease. Since more than 8 years of MODIS LST data are available today, even preliminary gradients can be extracted to assess multi-annual temperature trends

  6. Trace metals in floodplain lake sediments : SEM/AVS as indicator of bioavailability and ecological effects

    NARCIS (Netherlands)

    Griethuysen, van C.

    2006-01-01

    This thesis addresses the geochemical aspects of AVS (Acid Volatile Sulfide) and SEM (Simultaneously Extracted Metals) in floodplain lake sediment, its spatial distribution in floodplain lakes and dynamics over time, the link with effects on single species (bioassays), as well as the impact of

  7. Landscape-scale modeling of water quality in Lake Superior and Lake Michigan watersheds: How useful are forest-based indicators? Journal of Great Lakes Research

    Science.gov (United States)

    Titus S. Seilheimer; Patrick L. Zimmerman; Kirk M. Stueve; Charles H. Perry

    2013-01-01

    The Great Lakes watersheds have an important influence on the water quality of the nearshore environment, therefore, watershed characteristics can be used to predict what will be observed in the streams. We used novel landscape information describing the forest cover change, along with forest census data and established land cover data to predict total phosphorus and...

  8. Partial least squares for efficient models of fecal indicator bacteria on Great Lakes beaches

    Science.gov (United States)

    Brooks, Wesley R.; Fienen, Michael N.; Corsi, Steven R.

    2013-01-01

    At public beaches, it is now common to mitigate the impact of water-borne pathogens by posting a swimmer's advisory when the concentration of fecal indicator bacteria (FIB) exceeds an action threshold. Since culturing the bacteria delays public notification when dangerous conditions exist, regression models are sometimes used to predict the FIB concentration based on readily-available environmental measurements. It is hard to know which environmental parameters are relevant to predicting FIB concentration, and the parameters are usually correlated, which can hurt the predictive power of a regression model. Here the method of partial least squares (PLS) is introduced to automate the regression modeling process. Model selection is reduced to the process of setting a tuning parameter to control the decision threshold that separates predicted exceedances of the standard from predicted non-exceedances. The method is validated by application to four Great Lakes beaches during the summer of 2010. Performance of the PLS models compares favorably to that of the existing state-of-the-art regression models at these four sites.

  9. Investigating and Modelling Effects of Climatically and Hydrologically Indicators on the Urmia Lake Coastline Changes Using Time Series Analysis

    Science.gov (United States)

    Ahmadijamal, M.; Hasanlou, M.

    2017-09-01

    Study of hydrological parameters of lakes and examine the variation of water level to operate management on water resources are important. The purpose of this study is to investigate and model the Urmia Lake water level changes due to changes in climatically and hydrological indicators that affects in the process of level variation and area of this lake. For this purpose, Landsat satellite images, hydrological data, the daily precipitation, the daily surface evaporation and the daily discharge in total of the lake basin during the period of 2010-2016 have been used. Based on time-series analysis that is conducted on individual data independently with same procedure, to model variation of Urmia Lake level, we used polynomial regression technique and combined polynomial with periodic behavior. In the first scenario, we fit a multivariate linear polynomial to our datasets and determining RMSE, NRSME and R² value. We found that fourth degree polynomial can better fit to our datasets with lowest RMSE value about 9 cm. In the second scenario, we combine polynomial with periodic behavior for modeling. The second scenario has superiority comparing to the first one, by RMSE value about 3 cm.

  10. Water pH and temperature in Lake Biwa from MBT'/CBT indices during the last 280 000 years

    Science.gov (United States)

    Ajioka, T.; Yamamoto, M.; Takemura, K.; Hayashida, A.; Kitagawa, H.

    2014-10-01

    We generated a 280 000 yr record of water pH and temperature in Lake Biwa, central Japan, by analysing the methylation index (MBT') and cyclisation ratio (CBT) of branched tetraethers in sediments from piston and borehole cores. Our aim was to understand the responses of precipitation and air temperature in central Japan to the East Asian monsoon variability on orbital timescales. Because the water pH in Lake Biwa is determined by phosphorus and alkali cation inputs, the record of water pH should indicate the changes in precipitation and temperature in central Japan. Comparison with a pollen assemblage in a Lake Biwa core suggests that lake water pH was determined by summer temperature in the low-eccentricity period before 55 ka, while it was determined by summer precipitation in the high-eccentricity period after 55 ka. From 130 to 55 ka, the variation in lake pH (summer precipitation) lagged behind that in summer temperature by several thousand years. This perspective is consistent with the conclusions of previous studies (Igarashi and Oba, 2006; Yamamoto, 2009), in that the temperature variation preceded the precipitation variation in central Japan.

  11. Radio-transmitted electromyogram signals as indicators of swimming speed in lake trout and brown trout

    DEFF Research Database (Denmark)

    Thorstad, E.B.; Økland, F.; Koed, Anders

    2000-01-01

    Swimming speed and average electromyogram (EMG) pulse intervals were highly correlated in individual lake trout Salvelinus namaycush (r(2)=0.52-0.89) and brown trout Salmo trutta (r(2)=0.45-0.96). High correlations were found also for pooled data in both lake trout (r(2)=0.90) and brown trout...... of the Ema stock (r(2)=0.96) and Laerdal stock (r(2)=0.96). The linear relationship between swimming speed and average EMG pulse intervals differed significantly among lake trout and the brown trout stocks. This successful calibration of EMGs to swimming speed opens the possibility of recording swimming...... speed of free swimming lake trout and brown trout in situ. EMGs can also be calibrated to oxygen consumption to record energy expenditure. (C) 2000 The Fisheries Society of the British Isles...

  12. Long-term changes in the trophic state of Suwalki lakes – an analysis by means of indices based on abundance and composition of their rotifer fauna

    Directory of Open Access Journals (Sweden)

    Ejsmont-Karabin Jolanta

    2016-12-01

    Full Text Available Rotifer abundance and species composition in lakes of the Suwalki Landscape Park were studied in the years 1983–1985, 2009, 2012 and 2015. Rotifer trophic state indices (TSIROT were used to assess changes in the trophic state of the studied lakes. In most lakes of the Suwalki Landscape Park, there were no changes in rotifer communities over the 25–32 year period to indicate a decline in trophy of the lakes. However, in lakes with the strongest decline in TSIROT values, the values of indicative parameters widely varied in 2015, which may indicate that the status of rotifer communities in the lakes may be dependent on non-trophic factors.

  13. Comparative analysis of the spatio-temporal dynamics of rotifer community structure based on taxonomic indices and functional groups in two subtropical lakes.

    Science.gov (United States)

    Wen, Xinli; Zhai, Pan; Feng, Ruonan; Yang, Ruijie; Xi, Yilong

    2017-04-03

    Little research has focused on how rotifer communities respond to eutrophication based on their combined taxonomic and functional indices. In this research, the relationship of the environment and rotifer communities was comparatively investigated in two subtropical lakes over one year. The taxon-based indices, including species number (S), Margalef index (D), Simpson index (d), Shannon-wiener index (H'), and functional traits relying on the guild ratio (GR) and the modified guild ratio (GR') from the moderately eutrophic Lake Xiyanghu were significantly lower than those from the slightly eutrophic Lake Jinghu. Redundancy analysis (RDA) showed that both lakes were distinct from each other. Taken together, the findings indicate that trophic state was an important factor affecting rotifer community structure. In addition, the average annual GR' of Lake Xiyanghu was trophic state and the rotifer community in seriously eutrophic lakes.

  14. Inter-annual climate variability and zooplankton: applying teleconnection indices to two deep subalpine lakes in Italy

    Directory of Open Access Journals (Sweden)

    Marina Manca

    2014-08-01

    Full Text Available Investigating relation between meteo-climatic indices and between-year variation in Daphnia population density and phenology is crucial for e.g. predicting impact of climate change on lake ecosystem structure and functioning. We tested whether and how two teleconnection indices calculated for the winter period, namely the East Atlantic pattern (EADJF and the Eastern Mediterranean Pattern (EMPDJF were correlated with Daphnia population growth in two Italian subalpine lakes, Garda and Maggiore. We investigated between-lake temporal coherence in: i water temperature within the water layer in which Daphnia is distributed; ii timing of Daphnia initial and spring maximum population density peak and iii the level of Daphnia spring maximum population density peak over an eleven-year period (1998-2008 of unchanged predation pressure by fish and invertebrates, and of common oligotrophy. Between-lake temporal coherence was high for an earlier start, an earlier, and lower, Daphnia population spring density peak after milder winters. Peak density level was coherently, positively correlated with soluble reactive phosphorus (SRP concentration. We hypothesized that Daphnia peak densities were related to atmospheric modes of variability in winter and to the degree of late winter mixing promoting replenishment of algal nutrients into upper water layers and phytoplankton growth, enhancing food availability and Daphnia fecundity, promoting Daphnia peak. 

  15. Aquatic biota as potential biological indicators of the contamination, bioaccumulation and health risks caused by organochlorine pesticides in a large, shallow Chinese lake (Lake Chaohu)

    DEFF Research Database (Denmark)

    Liu, Wen-Xiu; Wang, Yan; He, Wei

    2016-01-01

    Aquatic biota have long been recognized as bioindicators of the contamination caused by hydrophobic organic contaminants (HOCs) in aquatic environments. The primary purpose of the present study is to identify which species of aquatic biota are the most sensitive to organochlorine pesticides (OCPs...... to OCPs and may serve as the most effective bioindicators for monitoring OCP contamination in the water and suspended solids of Lake Chaohu. Megalobrama amblycephala, which contained the highest wet weight mean OCP concentration, is the most sensitive OCP indicator and can be used to assess the human...

  16. Occurrence and distribution of fecal indicator bacteria and gene markers of pathogenic bacteria in Great Lakes tributaries, March-October 2011

    Science.gov (United States)

    Brennan, Angela K.; Johnson, Heather E.; Totten, Alexander R.; Duris, Joseph W.

    2015-01-01

    From March through October 2011, the U.S. Geological Survey (USGS), conducted a study to determine the frequency of occurrence of pathogen gene markers and densities of fecal indicator bacteria (FIB) in 22 tributaries to the Great Lakes. This project was funded as part of the Great Lakes Restoration Initiative (GLRI) and included sampling at 22 locations throughout 6 states that border the Great Lakes.

  17. Mapping ecosystem service indicators in a Great Lakes estuarine Area of Concern

    Science.gov (United States)

    Estuaries provide multiple ecosystem services from which humans benefit. Currently, thirty-six Great Lakes estuaries in the United States and Canada are designated as Areas of Concern (AOCs) due to a legacy of chemical contamination, degraded habitat, and non-point-source polluti...

  18. Using aquatic macrophyte community indices to define the ecological status of European lakes

    NARCIS (Netherlands)

    Penning, W.E.; Dudley, B.; Mjelde, M.; Hellsten, S.; Hanganu, J.; Kolada, A.; van den Berg, Marcel S.; Poikane, S.; Phillips, G.; Willby, N.; Ecke, F.

    2008-01-01

    Defining the overall ecological status of lakes according to the Water Framework Directive (WFD) is to be partially based on the species composition of the aquatic macrophyte community. We tested three assessment methods to define the ecological status of the macrophyte community in response to a

  19. Indicators of Lake Temsah Potential by some heavy metals Heavy Metals in Sediment

    International Nuclear Information System (INIS)

    Abdel Sabour, M.F.; Aly, R.O.; Khalil, M.T.; Attwa, A.H.A.

    1999-01-01

    The Environmental impact of industrial, agricultural and domestic waster on heavy metals sediment content in lake Temsah has been investigated. Seven sites were chosen, differ in nature of activity and quantity of wastes, namely from south to north-west; Arab contractors shipyard workshop(A), The junction between the western logon and the lake(B), El-Temsah workshop (C), El-Temsah shipyard (private workshop) (D), El-Karakat workshop for SCA (E), El-Forsan drain out fall to the lake (F) and SCA Press outlet (G). Eight of heavy metal concentrations of concern (Fe, Mn, Zn, Cu, Co, Ni, Cd and Pb) were estimated in sediment samples collected from different chosen sites during the seasons; summer , autumn 1995 and winter , spring 1996. Results of this study reveal that pollution is directly related to the type of the activity in each site. Sediment samples results showed that the most suffering sites were found to be in the order of B> D> C> G> F, and the least polluted ones were E> A. And the highest polluted season was summer, whereas the least one was winter. It is obvious that the general mean values of Cu, Ni and Cd are exceeding the allowed concentrations documented for diverse trace components in coastal sediments. Strict regulations that must be followed in order to minimize this pollution specially, by heavy metals from marine workshop

  20. Quantitative assessment of Naegleria fowleri and fecal indicator bacteria in brackish water of Lake Pontchartrain, Louisiana

    Science.gov (United States)

    Xue, J.; Sherchan, S. P.; Lamar, F. G.; Lin, S.; Lamori, J. G.

    2017-12-01

    Brackish water samples from Lake Pontchartrain in Louisiana were assessed for the presence of pathogenic amoeba Naegleria fowleri, which causes primary amoebic meningoencephalitis (PAM). In our study, quantitative polymerase chain reaction (qPCR) methods were used to determine N. fowleri, E. coli, and Enterococcus in water collected from Lake Pontchartrain. A total of 158 water samples were analyzed over the 10- month sampling period. Statistically significant positive correlation between water temperature and N. fowleri concentration was observed. N. fowleri target sequence was detected at 35.4% (56/158) of the water samples from ten sites around the Lake ranged from 11.6 GC/100 ml water to 457.8 GC/100 ml water. A single factor (ANOVA) analysis shows the average concentration of N. fowleri in summer (119.8 GC/100 ml) was significantly higher than in winter (58.6 GC/100 ml) (p Statistically significant positive correlations were found between N. fowleri and qPCR E. coli results and N. fowleri and colilert E. coli (culture method), respectively. A weak positive correlation between E. coli and Enterococcus was observed from both qPCR (r = 0.27, p method (r = 0.52, p methods for E. coli (r = 0.30, p research is needed to determine whether sediment is a source of N. fowleri found in the water column.

  1. Diatoms as paleoecological indicators of environmental change in the Lake Czechowskie catchments ecosystem (Northern Tuchola Pinewoods, Poland)

    Science.gov (United States)

    Rzodkiewicz, Monika; Zawiska, Izabela; Noryśkiewicz, Agnieszka Maria; Obremska, Milena; Ott, Florian; Kramkowski, Mateusz; Słowiński, Michał; Błaszkiewicz, Mirosław; Brauer, Achim

    2016-04-01

    In this study we investigated four cores of biogenic sediments from the lakes located in close vicinity. Three cores are situated along a transect in the Lake Czechowskie basin from its deepest point towards a former lake bay. The fourth sediment core was retrieved from the nearby Trzechowskie paleolake. Lake Czechowskie is located in the northern part of the Tuchola Pinewoods District (Northern Poland) in a young glacial landscape. At present, the majority of the area is forested or used for agriculture. The main focus was of the study was Late Glacial and early Holocene period. We performed diatom, Cladocera and pollen analyses, the chronology was established by varve counting, confirmed by AMS 14C dating and Laacher See Tephra (Wulf et. all 2013). In this study we focused on the results of diatom analyses. Diatom assemblages are integrated indicators of environmental change because their distributions are closely linked to water quality parameters including such as nutrient availability. At the beginning of Allerød there are more eutrophic diatom taxa such as Staurosira construens, Pseudostaurosira brevistriata, Staurosira pinnata. These species are widely distributed in the littoral mainly freshwater, many of which are species of epiphytic, preferring water rich in nutrients. At the end of the Allerød we observe significant changes within diatom assemblages. The increase of planktonic Cyclotella comensis together with the decrease of benthic Stauroseria construens indicate the shortening of time with ice cove on the lake and longer time with summer stratification. In the Younger Dryas cooling we can see the increase of the abundance of diatom Staurosira construens which indicate cold spring and late ice-out (Bradbury et al., 2002). At the early Holocene planktonic diatoms increase in particular Cyclotella comensis, Punciculata radiosa and Cyclotella praetermissa. Some of Aulacoseira species at the end of Younger Dryas. The Holocene sediments showed no

  2. Cesium-137 inventories in Alaskan Tundra, lake and marine sediments: An indicator of recent organic material transport?

    International Nuclear Information System (INIS)

    Grebmeier, J.M.; Cooper, L.W.; Larsen, I.L.; Solis, C.; Olsen, C.R.

    1993-01-01

    Tundra sampling was accomplished in 1989--1990 at Imnavait Creek, Alaska (68 degree 37' N, 149 degree 17' W). Inventories of 137 Cs (102--162 mBq/cm 2 ) are close to expectations, based upon measured atmospheric deposition for this latitude. Accumulated inventories of 137 Cs in tundra decrease by up to 50% along a transect to Prudhoe Bay (70 degree 13' N, 148 degree 30' W). Atmospheric deposition of 137 Cs decreased with latitude in the Arctic, but declines in deposition would have been relatively small over this distance (200 km). This suggests a recent loss of 137 Cs and possibly associated organic matter from tundra over the northern portions of the transect between Imnavait Creek and Prudhoe Bay. Sediments from Toolik Lake (68 degree 38' N, 149 degree 38' W) showed widely varying 137 Cs inventories, from a low of 22 mBq/cm 2 away from the lake inlet, to a high between 140 to >200 mBq/cm 2 near the main stream inflow. This was indicative of recent accumulation of cesium and possibly organic material associated with it in arctic lakes, although additional sampling is needed

  3. [COMPARATIVE ANALYSIS OF LIPID METABOLISM INDICES IN SOME PARASITES OF THE WHITE CHARR (SALVELINUS ALBUS) FROM THE LAKE KRINOTSKOE].

    Science.gov (United States)

    Gordeev, I I; Mikryakov, D V; Silkina, N I

    2015-01-01

    Comparative study of lipid metabolism indices (total lipids, separate lipid fractions, level of the lipid peroxidation processes, and antioxidant protection) was carried out in three parasite species collected from the white char in the Lake Kronotskoe: Diphyllobothrium ditremum Crepin, 1825 (Cestoda), Philonema oncorhynchi Kuitunen-Ekbaum, 1933 (Nematoda) H Neoechinorhynchus salmonis Ching, 1984 (Acanthocephala). Acanthocephalans possessed significantly greater levels of total lipids, triacylglycerol, and malondialdehyde; nematodes, of cholesterol and sterol esters; and cestodes, in phospholipids and constants of the substrate oxidation. Dependence between lipid metabolism of helminths and their taxonomic affiliation, morpho-functional features, the stage of the life cycle, and the site of infection in the host are discussed.

  4. Use of crayfishes as ecological indicator of water quality in natural lakes and city water grid

    Science.gov (United States)

    Sapunov, Valentin; Fedotov, Valery

    2017-04-01

    Crayfishes are organisms having strong demands for water quality. Their different species have different ecological limits. Nobel crayfishes Astacus astacus are organisms with narrow ecological limits need clear water that crayfish Pontastacus leptodactylus. Relation between populations of different crayfishes is criteria of water pollution, level of water bodies eutrofication and ecological pressure. Environmental policy of all countries is directed to water supply by drinking water of high quality and preserving the rivers, lakes and seas, suitable for people and wildlife. However, now freshwater reservoirs and water bodies, as well as including centralized drinking water supply, have been exposed to escalating anthropogenic loading, and risk of sudden emergency pollution. Besides, the problem of providing an ecological safety of the population and prevention of threats of ecological crime and terrorism in a zone of drinking water for many countries. The work is devoted to realization and perspectives of use of the biological early warning stations about changes of quality of surface waters, dangerous to a biota, on the basis of bioelectronic systems as elements of environmental monitoring of water areas. Regular monitoring of crayfish population is a way to follow ecological evolution of ponds. Such a monitoring took place in some lakes of Pskov and Leningrad regions. Ecological characters of crayfishes are appropriate for control of water quality in St. Petersburg and Khabarovsk grids. Fore species were used: Procambarus clarcii, Cherax quadricarinatus, A. astacus and P. leptodactilus. The results of the present work and experiments carried out us to conclude that before assessing any concentration of pollutant on water organisms, it is necessary to investigate not only their development, growth and survival, also their adaptive capacity relative to the variation of environmental parameters. Regular monitoring of heart oscillation was base for control of water

  5. Fossil pigments as indicators of phototrophic response to salinity and climatic change in lakes of Western Canada

    Energy Technology Data Exchange (ETDEWEB)

    Vinebrooke, R. D.; Hall, R. I.; Leavitt, R. [Regina Univ., SK (Canada). Dept. of Biology; Cumming, B. F. [Queen`s Univ., Kingston, ON (Canada). Paleoecological Environmental Assessment and Research Lab

    1998-03-01

    Changes in fossil pigments among 111 saline lakes in British Columbia were quantified and past changes in phototrophic communities in three closed-basin prairie lakes (Antelope Lake, Kenosee Lake and Clearwater Lake) were reconstructed. Using redundancy analysis, it was found that pigment concentrations were greatest in deep stratified lakes but were unaffected by ion concentrations, pH or conductivity. Algal standing crop was correlated only with fossil measures of total algal abundance, however, relative abundance of fossil carotenoids varied with lake chemistry. Increase in salinity caused fucoxanthin to be replaced by lutein-zeaxanthin and diatoxanthin, while alloxanthin and myxoxanthophyll were most commonly found in lakes with low calcium and high dissolved organic carbon content. Post-depositional degradation did not appear to alter the relation between pigment abundance and environmental characteristics. Considered as a whole, these results suggest that in saline lakes, fossil pigments are paleoecological proxies for phototrophic community change. 43 refs., 8 figs.

  6. Water pH and temperature in Lake Biwa from MBT'/CBT indices during the last 282 000 years

    Science.gov (United States)

    Ajioka, T.; Yamamoto, M.; Takemura, K.; Hayashida, A.

    2014-03-01

    We generated a 282 000-year record of water pH and temperature in Lake Biwa, central Japan, by analysing the methylation index (MBT') and cyclisation ratio (CBT) of branched tetraethers in sediments from piston and borehole cores to understand the responses of precipitation and air temperature in central Japan to the East Asian monsoon variability on the orbital timescale. Because water pH in Lake Biwa is determined by phosphorus input driven by precipitation, the record of water pH should indicate changes in summer precipitation in central Japan. The estimated pH showed significant periodicity at 19 and 23 ka (precession) and at 41 ka (obliquity). The variation in the estimated pH agrees with variation in the pollen temperature index. This indicates synchronous variation in summer air temperature and precipitation in central Japan, which contradicts the conclusions of previous studies. The variation in estimated pH was also synchronous with the variation of oxygen isotopes in stalagmites in China, suggesting that East Asian summer monsoon precipitation was governed by Northern Hemisphere summer insolation on orbital timescales. However, the estimated winter temperatures were higher during interglacials and lower during glacials, showing an eccentricity cycle. This suggests that the temperature variation reflected winter monsoon variability.

  7. Lake Diatoms as Indicators of Land Use Effects, Changing Environmental Conditions, and the Effectiveness of Management Practices

    Science.gov (United States)

    Lakes continue to face escalating pressures associated with land cover change and growing human populations. The U.S. EPA National Lakes Assessment, which sampled more than 1000 lakes in a probabilistic survey, was the first large scale effort to characterize the condition of lak...

  8. Use of Landsat Land Surface Temperature and Vegetation Indices for Monitoring Drought in the Salt Lake Basin Area, Turkey

    Directory of Open Access Journals (Sweden)

    Osman Orhan

    2014-01-01

    Full Text Available The main purpose of this paper is to investigate multitemporal land surface temperature (LST changes by using satellite remote sensing data. The study included a real-time field work performed during the overpass of Landsat-5 satellite on 21/08/2011 over Salt Lake, Turkey. Normalized vegetation index (NDVI, vegetation condition index (VCI, and temperature vegetation index (TVX were used for evaluating drought impact over the region between 1984 and 2011. In the image processing step, geometric and radiometric correction procedures were conducted to make satellite remote sensing data comparable with in situ measurements carried out using thermal infrared thermometer supported by hand-held GPS. The results showed that real-time ground and satellite remote sensing data were in good agreement with correlation coefficient (R2 values of 0.90. The remotely sensed and treated satellite images and resulting thematic indices maps showed that dramatic land surface temperature changes occurred (about 2∘C in the Salt Lake Basin area during the 28-year period (1984–2011. Analysis of air temperature data also showed increases at a rate of 1.5–2∘C during the same period. Intensification of irrigated agriculture particularly in the southern basin was also detected. The use of water supplies, especially groundwater, should be controlled considering particularly summer drought impacts on the basin.

  9. The coming and going of a marl lake: multi-indicator palaeolimnology reveals abrupt ecological change and alternative views of reference conditions

    Directory of Open Access Journals (Sweden)

    Emma eWiik

    2015-08-01

    Full Text Available Eutrophication is the most pressing threat to highly calcareous (marl lakes in Europe. Despite their unique chemistry and biology, comprehensive studies into their unimpacted conditions and eutrophication responses are underrepresented in conservation literature. A multi-indicator palaeolimnological study spanning ca 1260 to 2009 was undertaken at Cunswick Tarn (UK, a small, presently eutrophic marl lake, in order to capture centennial timescales of impact. Specific aims were to 1 establish temporal patterns of change (gradual/abrupt across biological groups, thereby testing theories of resistance of marl lake benthic communities to enrichment, and 2 compare the core record of reference condition with prevailing descriptions of high ecological status. Analyses of sediment calcium (Ca, phosphorus (P, pigments, diatoms, testate amoebae, cladocerans, and macrofossils, revealed three abrupt changes in ecosystem structure. The first (1900s, with biomass increases in charophytes and other benthic nutrient-poor indicators, supported ideas of resistance to eutrophication in Chara lakes. The second transition (1930s, from charophyte to angiosperm dominance, occurred alongside reductions in macrophyte cover, increases in eutrophic indicators, and a breakdown in marling, in support of ideas of threshold responses to enrichment. Core P increased consistently into the 1990s when rapid transitions into pelagic shallow lake ecology occurred and Cunswick Tarn became biologically unidentifiable as a marl lake. The moderate total P at which these changes occurred suggests high sensitivity of marl lakes to eutrophication. Further, the early record challenges ideas of correlation between ecological condition, charophyte biomass and sediment Ca. Instead, low benthic production, macrophyte cover, and Ca sedimentation, was inferred. Management measures must focus on reducing external nutrient and sediment loads at early stages of impact in order to preserve marl lakes.

  10. Sediment amino acids as indicators of anthropogenic activities and potential environmental risk in Erhai Lake, Southwest China.

    Science.gov (United States)

    Ni, Zhaokui; Wang, Shengrui; Zhang, Mianmian

    2016-05-01

    Total hydrolysable amino acids (THAAs) constitute the most important fraction of labile nitrogen. Anthropogenic activities directly influence various biogeochemical cycles and then accelerate lake ecosystem deterioration. This is the first study that has established the relationship between sediment THAAs and anthropogenic activities using dated sediment cores, and evaluated the possibility of THAAs release at the sediment interface based on changes in environmental conditions in Erhai Lake. The results showed that historical distribution and fractions of THAAs could be divided into three stages: a stable period before the 1970s, a clear increasing period from the 1970s to 1990s, and a gradually steady period that started after the 1990s. The chemical fraction, aromatic and sulfur amino acids (AAs) accounted for only ≤3% of THAAs. Basic AAs accounted for 5-17% of THAAs, and remained at a relatively stable level. However, acidic and neutral AAs, which accounted for 19-44% and 35-69% of THAAs, respectively, were the predominant factors causing THAAs to increase due to rapid agricultural intensification and intensification of contemporary sedimentation of phytoplankton or macrophytes since the 1970s. These trends were closely related to both anthropogenic activities and natural processes, which implied that sediment THAAs could act as an effective indicator that reflects anthropogenic activities and aquatic environmental characteristics. The current contributions of sediment THAAs on TN and TOC were sediment cores indicated that there was a huge potential source of labile nitrogen for the overlying water under certain environmental conditions. Correlation analysis suggested that the release of THAAs was negatively correlated with pH, whereas positively correlated with bacterial number and degree of OM mineralization, which particularly depend on the stability of HFOM. Therefore, the risk of sediment THAAs release might increase when the sediment environment

  11. A DPSIR model for ecological security assessment through indicator screening: a case study at Dianchi Lake in China.

    Science.gov (United States)

    Wang, Zhen; Zhou, Jingqing; Loaiciga, Hugo; Guo, Huaicheng; Hong, Song

    2015-01-01

    Given the important role of lake ecosystems in social and economic development, and the current severe environmental degradation in China, a systematic diagnosis of the ecological security of lakes is essential for sustainable development. A Driving-force, Pressure, Status, Impact, and Risk (DPSIR) model, combined with data screening for lake ecological security assessment was developed to overcome the disadvantages of data selection in existing assessment methods. Correlation and principal component analysis were used to select independent and representative data. The DPSIR model was then applied to evaluate the ecological security of Dianchi Lake in China during 1988-2007 using an ecological security index. The results revealed a V-shaped trend. The application of the DPSIR model with data screening provided useful information regarding the status of the lake's ecosystem, while ensuring information efficiency and eliminating multicollinearity. The modeling approach described here is practical and operationally efficient, and provides an attractive alternative approach to assess the ecological security of lakes.

  12. The estimation of future surface water bodies at Olkiluoto area based on statistical terrain and land uplift models

    International Nuclear Information System (INIS)

    Pohjola, J.; Turunen, J.; Lipping, T.; Ikonen, A.

    2014-03-01

    In this working report the modelling effort of future landscape development and surface water body formation at the modelling area in the vicinity of the Olkiluoto Island is presented. Estimation of the features of future surface water bodies is based on probabilistic terrain and land uplift models presented in previous working reports. The estimation is done using a GIS-based toolbox called UNTAMO. The future surface water bodies are estimated in 10 000 years' time span with 1000 years' intervals for the safety assessment of disposal of spent nuclear fuel at the Olkiluoto site. In the report a brief overview on the techniques used for probabilistic terrain modelling, land uplift modelling and hydrological modelling are presented first. The latter part of the report describes the results of the modelling effort. The main features of the future landscape - the four lakes forming in the vicinity of the Olkiluoto Island - are identified and the probabilistic model of the shoreline displacement is presented. The area and volume of the four lakes is modelled in a probabilistic manner. All the simulations have been performed for three scenarios two of which are based on 10 realizations of the probabilistic digital terrain model (DTM) and 10 realizations of the probabilistic land uplift model. These two scenarios differ from each other by the eustatic curve used in the land uplift model. The third scenario employs 50 realizations of the probabilistic DTM while a deterministic land uplift model, derived solely from the current land uplift rate, is used. The results indicate that the two scenarios based on the probabilistic land uplift model behave in a similar manner while the third model overestimates past and future land uplift rates. The main features of the landscape are nevertheless similar also for the third scenario. Prediction results for the volumes of the future lakes indicate that a couple of highly probably lake formation scenarios can be identified with other

  13. TERRAIN, NEWTON COUNTY, GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographical data that were used to create...

  14. TERRAIN, DARKE COUNTY, OH

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  15. TERRAIN, TROUSDALE COUNTY, TENNESSEE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN, PIERCE, COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. TERRAIN, KITSAP COUNTY, WASHINGTON

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  18. TERRAIN, WAYNE COUNTY, TENNESSEE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. TERRAIN, Norfolk County, Massachusetts

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  20. TERRAIN, BARNSTABLE COUNTY, MASSACHUSETTS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. TERRAIN, HANCOCK COUNTY, OH

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. TERRAIN, POTTER COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that were used to create...

  3. TERRAIN, WRIGHT COUNTY, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  4. TERRAIN, BERKS COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. TERRAIN, TRAVIS COUNTY, TEXAS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  6. TERRAIN, UNION PARISH, LOUSIANA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. TERRAIN, SNOHOMISH COUNTY, WASHINGTON

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  8. TERRAIN, RANKIN COUNTY, MS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN, FRANKLIN COUNTY, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN, Clinton COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN, HOWARD COUNTY, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  12. Zoobenthic Indicators of Environmental Condition At Great Lakes Coastal Margins Derived From Standardized Multivariate Analyses Across Anthropogenic Stress Gradients.

    Science.gov (United States)

    Ciborowski, J. J.; Johnson, L. B.; Gathman, J. P.; Brady, V. J.; Holland, J.; Hollenhorst, T.; Schuldt, J. A.; Host, G. E.; Richards, C.

    2005-05-01

    We used multivariate methods to derive and map multiple indices of zoobenthic community composition across anthropogenic stress gradients at Great Lakes coastal margins (shorelines - 10 m depth). We collected up to 24 benthic samples and measured environmental characteristics in each of 150 "segment sheds", ranging from minimally disturbed (=reference) to greatly modified. "K" distinct suites of co-occurring biota from minimally stressed locations were identified using cluster analysis. Discriminant function analysis identified the environmental attributes of sample locations best distinguishing each of the suites (=habitat types). Benthic community data of all samples from each habitat type (ranging across the entire stress gradient) were individually ordinated. The benthic taxa best characterizing the ends of each stress gradient were used to create a gradient-specific biotic index with a standardized scale (0=minimum, 100=maximum stress) for each habitat type, providing a stress-specific score for each sample. Contour surface analysis of mapped sample-specific scores shows the spatial pattern and limits of the overall biotic response to stress, independently of habitat type. The spatial concordance between biotic index scores and environmental stress can indicate the degree to which equivalent-to-reference conditions exist in a particular area.

  13. Sedimentary Bacteriopheophytin a as an indicator of meromixis in varved lake sediments of Lake Jaczno, north-east Poland, CE 1891-2010

    Science.gov (United States)

    Butz, Christoph; Grosjean, Martin; Poraj-Górska, Anna; Enters, Dirk; Tylmann, Wojciech

    2016-09-01

    Trends in eutrophication and meromixis pose serious threats to water quality and biodiversity in freshwater ecosystems around the world. Because long-term observational data rarely exist, it is very difficult to assess whether meromixis is the result of anthropogenic impacts, climate variability, natural ecosystem development or a combination of these factors. Lake sediment proxy-data may help understand how and why eutrophication and meromixis occurred and disappeared in the past. In this study, we present a novel method and proxy to investigate past episodes of meromixis and hypolimnetic anoxia recorded in lake sediments. We use high-resolution (70 × 70 μm/pixel) calibrated hyperspectral imaging of a varved lake sediment core from meromictic Lake Jaczno (north-east Poland), to quantitatively map the spatial distribution of Bacteriopheophytin a (Bphe a) at very high sub-varve (i.e. seasonal) resolution. Bphe a is a bacterial pigment and stable degradation product of Bacteriochlorophyll a (Bchl a), which is produced by anoxygenic phototrophic bacteria (APBs) at the chemocline of meromictic lakes. Using sedimentary Bphe a we infer episodes of meromixis (i.e. long-term hypolimnetic anoxia) and changing mixing conditions (i.e. seasonal temperature, event-based water mixing) for the past ca. 120 years. Absence of meromixis occurred on several occasions. From the beginning of our record in CE 1891 until ca. CE 1918, meromixis was not observed. During this time, green pigments (mainly chlorophyll a [Chl a] and diagenetic products) produced by phototrophic algae were deposited while Bphe a was absent. This suggests that regular lake overturning prevented the formation of a persistent chemocline. Bphe a was identified before CE 1890 (Butz et al. 2015), but over the studied period 1891-2011, meromixis was established in CE 1918 and generally persisted through modern times. However, short-term interruptions of the chemocline were observed following events of rapid

  14. Quantification of human-associated fecal indicators reveal sewage from urban watersheds as a source of pollution to Lake Michigan

    Science.gov (United States)

    Olds, Hayley T.; Dila, Deborah K.; Bootsma, Melinda J.; Corsi, Steven; McLellan, Sandra L.

    2016-01-01

    Sewage contamination of urban waterways from sewer overflows and failing infrastructure is a major environmental and public health concern. Fecal coliforms (FC) are commonly employed as fecal indicator bacteria, but do not distinguish between human and non-human sources of fecal contamination. Human Bacteroides and humanLachnospiraceae, two genetic markers for human-associated indicator bacteria, were used to identify sewage signals in two urban rivers and the estuary that drains to Lake Michigan. Grab samples were collected from the rivers throughout 2012 and 2013 and hourly samples were collected in the estuary across the hydrograph during summer 2013. Human Bacteroides and human Lachnospiraceae were highly correlated with each other in river samples (Pearson’s r = 0.86), with average concentrations at most sites elevated during wet weather. These human indicators were found during baseflow, indicating that sewage contamination is chronic in these waterways. FC are used for determining total maximum daily loads (TMDLs) in management plans; however, FC concentrations alone failed to prioritize river reaches with potential health risks. While 84% of samples with >1000 CFU/100 ml FC had sewage contamination, 52% of samples with moderate (200–1000 CFU/100 ml) and 46% of samples with low (<200 CFU/100 ml) FC levels also had evidence of human sewage. Load calculations in the in the Milwaukee estuary revealed storm-driven sewage contamination varied greatly among events and was highest during an event with a short duration of intense rain. This work demonstrates urban areas have unrecognized sewage inputs that may not be adequately prioritized for remediation by the TMDL process. Further analysis using these approaches could determine relationships between land use, storm characteristics, and other factors that drive sewage contamination in urban waterways.

  15. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  16. A DPSIR model for ecological security assessment through indicator screening: a case study at Dianchi Lake in China.

    Directory of Open Access Journals (Sweden)

    Zhen Wang

    Full Text Available Given the important role of lake ecosystems in social and economic development, and the current severe environmental degradation in China, a systematic diagnosis of the ecological security of lakes is essential for sustainable development. A Driving-force, Pressure, Status, Impact, and Risk (DPSIR model, combined with data screening for lake ecological security assessment was developed to overcome the disadvantages of data selection in existing assessment methods. Correlation and principal component analysis were used to select independent and representative data. The DPSIR model was then applied to evaluate the ecological security of Dianchi Lake in China during 1988-2007 using an ecological security index. The results revealed a V-shaped trend. The application of the DPSIR model with data screening provided useful information regarding the status of the lake's ecosystem, while ensuring information efficiency and eliminating multicollinearity. The modeling approach described here is practical and operationally efficient, and provides an attractive alternative approach to assess the ecological security of lakes.

  17. Benthic foraminiferal assemblages as bio-indicators of metals contamination in sediments, Qarun Lake as a case study, Egypt

    Science.gov (United States)

    Abd El Naby, Ahmed; Al Menoufy, Safia; Gad, Ahmed

    2018-03-01

    Qarun Lake, in the Fayoum Depression of the Western Desert of Egypt, lies within the deepest area in the River Nile flood plain. The drainage water in the Qarun Lake is derived from the discharge of the natural and artificial drainage systems in the Fayoum. Mixed domestic and agricultural pollutants, including heavy metals, nitrates, phosphates, sulfates and pesticides, are discharged into Qarun Lake. Forty-six samples, collected from the undisturbed layer of sediments were used for benthic foraminiferal analysis. Concentrations of some selected trace metal elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V, and Zn) were also determined. Statistical analysis of the abiotic variables (Texture distribution of sediments, Physico-chemical parameters, and metals concentrations) and of the biotic variables (distribution of benthic foraminiferal species) were also performed. The Q-mode cluster analysis of benthic foraminiferal distribution has provided evidence that the Qarun Lake can be subdivided into two cluster groups (A and B), reflecting environmental changes in the lake ecosystem. Cluster B can also be subdivided into two sub-clusters (B1 and B2). The presence of only pollution tolerant taxa with higher faunal density and lower diversity and the absence of the other foraminiferal assemblages in cluster A were attributed to the high concentration of trace metal elements and the strong environmental stress at the eastern and central parts of the Qarun Lake.

  18. Is water age a reliable indicator for evaluating water quality effectiveness of water diversion projects in eutrophic lakes?

    Science.gov (United States)

    Zhang, Xiaoling; Zou, Rui; Wang, Yilin; Liu, Yong; Zhao, Lei; Zhu, Xiang; Guo, Huaicheng

    2016-11-01

    Water diversion has been applied increasingly to promote the exchange of lake water and to control eutrophication of lakes. The accelerated water exchange and mass transport by water diversion can usually be represented by water age. But the responses of water quality after water diversion is still disputed. The reliability of using water age for evaluating the effectiveness of water diversion projects in eutrophic lakes should be thereby explored further. Lake Dianchi, a semi-closed plateau lake in China, has suffered severe eutrophication since the 1980s, and it is one of the three most eutrophic lakes in China. There was no significant improvement in water quality after an investment of approximately 7.7 billion USD and numerous project efforts from 1996 to 2015. After the approval of the Chinese State Council, water has been transferred to Lake Dianchi to alleviate eutrophication since December 2013. A three-dimensional hydrodynamic and water quality model and eight scenarios were developed in this study to quantity the influence of this water diversion project on water quality in Lake Dianchi. The model results showed that (a) Water quality (TP, TN, and Chla) could be improved by 13.5-32.2%, much lower than the approximate 50% reduction in water age; (b) Water exchange had a strong positive relationship with mean TP, and mean Chla had exactly the same response to water diversion as mean TN; (c) Water level was more beneficial for improving hydrodynamic and nutrient concentrations than variation in the diverted inflowing water volume; (d) The water diversion scenario of doubling the diverted inflow rate in the wet season with the water level of 1886.5 m and 1887 m in the remaining months was the best water diversion mode for mean hydrodynamics and TP, but the scenario of doubling the diverted inflow rate in the wet season with 1887 m throughout the year was optimum for mean TN and Chla; (e) Water age influenced the effectiveness of water diversion on the

  19. AL:PE - Acidification of Mountain Lakes: Palaeolimnology and Ecology. Part 2 - Remote Mountain Lakes as Indicators of Air Pollution and Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Wathne, Bente M.; Patrick, Simon; Cameron, Nigel [eds.

    1997-07-01

    AL:PE is a multi-disciplinary and multi-national project coordinated by research groups in London and Oslo. It is funded by the European Commission, The project is described in this report. The project is the first comprehensive study of remote mountain lakes on a European scale. It is concerned with ecosystems in the arctic and alpine regions of Europe that are threatened by acid deposition, toxic air pollutants and climatic change despite their remoteness. The studies are important not only for ecosystems of the lakes, for which they were designed, but for the arctic and alpine regions in general, since the lakes with their sediment records act as environmental sensors. The AL:PE results illustrate two overarching issues: (1) the importance of these remote and sensitive ecosystems as sensors of long-range transported pollutants and as providers of early warning signals for more widespread environmental change; and (2) the importance and urgency of understanding the present and future impact of pollutants, both singly and in combination, on aquatic ecosystems. Currently, acid deposition is considered the most potent threat. In the context of global warming, however, it is a formidable scientific challenge to disentangle the interactions between the effects of changing deposition patterns of acids, nutrients, trace metals and trace organics. The AL:PE programme has begun to address this challenge and its successor EU project, MOLAR, is designed to tackle the issues more more specifically by focusing on in-depth studies of key sites. 97 refs., 192 figs., 100 tabs.

  20. Flow on noisy terrains

    DEFF Research Database (Denmark)

    Tsirogiannis, Konstantinos; Haverkort, Herman

    2011-01-01

    Computing watersheds on triangulated terrain models in a robust manner is a difficult task as it is sensitive to noise that appears in the elevation values of the input. This is amplified by the existence of many very small watersheds (corresponding to spurious minima) that obscure the overall hy...... to use a robust flow model together with exact arithmetic....

  1. Using of zooplankton indicators in assessing the quality of waters in two lakes in the Gulf of Finland basin

    Directory of Open Access Journals (Sweden)

    Kulakov Dmitry

    2017-09-01

    Full Text Available In 2012–2015 zooplankton studies were carried out and the quality of the waters of the Kopanskoe and the Gorovaldayskoe lakes belonging to the Gulf of Finland basin (Leningrad region was assessed. Under the frame of long-term monitoring studies on these waterbodies, such work has not previously been carried out. The sampling stations were located in the coastal part of the waterbodies. Zooplankton of the lakes included 46 taxons of species and subspecies ranks, it was typical of the North-West of Russia and represented mainly by eurybiontic species with high ecological plasticity. In Gorovaldayskoe lake most affected by the anthropogenic influence, in comparison with the Kopanskoe, showed the lowest species richness and the lowest values of the biodiversity index. Nevertheless, the mass development of Cladocera, which made the main contribution to the population and the biomass of the community, promoted the active development of the processes of biological self-purification of this lake, as evidenced by a decrease by coefficient trophicity. According to the saprobity index in the waters of the studied lakes belonged to the oligosaprobic – β-mesosaprobic zone.

  2. Evaluation of Hyperspectral Multi-Band Indices to Estimate Chlorophyll-A Concentration Using Field Spectral Measurements and Satellite Data in Dianshan Lake, China

    Directory of Open Access Journals (Sweden)

    Linna Li

    2013-04-01

    Full Text Available Chlorophyll-a (Chl-a concentration is considered as a key indicator of the eutrophic status of inland water bodies. Various algorithms have been developed for estimating Chl-a in order to improve the accuracy of predictive models. The objective of this study is to assess the potential of hyperspectral multi-band indices to estimate the Chl-a concentration in Dianshan Lake, which is the largest lake in Shanghai, an international metropolis of China. Based on field spectral measurements and in-situ Chl-a concentration collected on 7–8 September 2010, hyperspectral multi-band indices were calibrated to estimate the Chl-a concentration with optimal wavelengths selected by model tuning. A three-band index accounts for 87.36% (R2 = 0.8736 of the Chl-a variation. A four-band index, which adds a wavelength in the near infrared (NIR region, results in a higher R2 (0.8997 by removing the absorption and backscattering effects of suspended solids. To test the applicability of the proposed indices for routinely monitoring of Chl-a in inland lakes, simulated Hyperion and real HJ-1A satellite data were selected to estimate the Chl-a concentration. The results show that the explanatory powers of these satellite hyperspectral multi-band indices are relatively high with R2 = 0.8559, 0.8945, 0.7969, and 0.8241 for simulated Hyperion and real HJ-1A satellite data, respectively. All of the results provide strong evidence that hyperspectral multi-band indices are promising and applicable to estimate Chl-a in eutrophic inland lakes.

  3. Satellite Remote Sensing of Drinking Water Intakes in Lake Erie for Cyanobacteria Population Using Two MODIS-Based Indicators as a Potential Tool for Toxin Tracking

    Directory of Open Access Journals (Sweden)

    Feng Zhang

    2017-05-01

    Full Text Available The growth of toxic Cyanobacterium, Microcystis aeruginosa, and the production of toxins, microcystins, pose serious concerns for the ecological health of lakes, such as western Lake Erie. The toxins are also significant health hazards and could contaminate tap water when sufficient and effective water treatment fails. In this study, water from the intakes of two water treatment plants along Lake Erie (Toledo and Painesville were collected and examined for microcystins concentration (μg/L and M. aeruginosa abundance (gene copies/mL in concert with the performance of satellite-based cyanobacteria bloom indicators, chlorophyll-a and Cyanobacteria Index, a spectral shape index for monitoring the severity of cyanobacterial blooms from the Moderate Resolution Imaging Spectroradiometer (MODIS from May to October in 2013. Good correlations were observed between toxic M. aeruginosa, microcystins, and MODIS-retrieved bloom indicators for the Toledo water plant intake, where blooms were much more severe with higher chlorophyll-a, phycocyanin and microcystins, but not for the Painesville water plant intake in central Lake Erie where the blooms were less severe. The Spearman's correlation (0.815 suggested a high correlation between the level of microcystins and MODIS-retrieved chlorophyll-a concentration for the Toledo intake point in western Lake Erie. Both total and toxic Microcystis abundance showed a significant positive correlation with MODIS-retrieved chlorophyll-a for the Toledo water intake, as well as the two locations combined. This finding demonstrates the potential utility of satellite remote sensing for detection and monitoring of cyanobacterial blooms, and the method's potential use as an early warning system as a means of preventing human exposure to bloom-impacted waters.

  4. Conceptual models and sustainable groundwater resource indicators as transfer tools to stakeholders of the Lake Champlain transboundary aquifer

    Science.gov (United States)

    Lefebvre, René; Rivard, Christine; Carrier, Marc-André; Parent, Michel; Laurencelle, Marc; Beaudry, Châtelaine; Martin, Alex; Bleser, Joshua; Lavoie, Roxane; Bourque, Édith; Ouellet, Michel

    2016-04-01

    Regional aquifer assessments produce a wealth of scientific and technical information that is essential for the sound management of groundwater resources. However, regional water stakeholders are not generally groundwater specialists and cannot be expected to readily handle specialized hydrogeological maps and data. Without efficient information transfer, groundwater resources cannot be adequately considered in water governance by watershed organizations and in land-use planning by regional municipalities. This presentation provides an overview of the efforts undertaken to transfer information as part of a four-year regional aquifer assessment in the transboundary Canada-USA Champlain Lake watershed, with an emphasis on the southern Quebec part. This project was part of both the provincial aquifer assessment program (Programme d'acquisition des connaissances sur les eaux souterraines, PACES) of the Quebec Environment Ministry and the National inventory of regional key aquifers of Natural Resources Canada. In Quebec, the study area extends over 9 000 km2 and includes three major watersheds and 106 municipalities with 792 000 inhabitants. Five distinct hydrogeological contexts were defined based on bedrock geology and hydrogeological conditions: St. Lawrence Lowlands (North and South), Appalachian Piedmont, Appalachian Uplands, and Monteregian Hills. Extensive fieldwork filled knowledge and spatial data gaps identified during the compilation of existing data. To illustrate hydrogeological contexts, two conceptual models of different areas were developed. These conceptual models reflect three aspects of aquifer conditions: geological context, groundwater dynamics and groundwater quality. The first representation of the conceptual model presents the geological context including typical surficial geology units as well as major bedrock geology units (including faults and dykes). The second representation shows schematic groundwater flow paths, relative well yields of

  5. Respiration of midges (Diptera; Chironomidae) in British Columbian lakes: oxy-regulation, temperature and their role as palaeo-indicators

    DEFF Research Database (Denmark)

    Brodersen, Klaus Peter; Pedersen, Ole; Walker, Ian R.

    2008-01-01

    1. The specific respiration rate of 13 chironomid taxa and Chaoborus were measured to test the hypothesis of the relation between a species' ability to regulate their oxygen uptake and their distributional patterns among nine study lakes in British Columbia, Canada. 2. Respiration patterns of ind...

  6. Temporal variation in viral hemorrhagic septicemia virus antibodies in freshwater drum (Aplodinotus grunniens) indicates cyclic transmission in Lake Winnebago, Wisconsin

    Science.gov (United States)

    Wilson-Rothering, Anna; Marcquenski, Susan; Koenigs, Ryan P.; Bruch, Ronald; Kamke, Kendall; Isermann, Daniel A.; Thurman, Andrew; Toohey-Kurth, Kathy; Goldberg, Tony

    2015-01-01

    Viral hemorrhagic septicemia virus (VHSV) is an emerging pathogen that causes mass mortality in multiple fish species. In 2007, the Great Lakes freshwater strain, type IVb, caused a large die-off of freshwater drum (Aplodinotus grunniens) in Lake Winnebago, Wisconsin, USA. To evaluate the persistence and transmission of VHSV, freshwater drum from Lake Winnebago were tested for antibodies to the virus using recently developed virus neutralization (VN) and enzyme-linked immunosorbent (ELISA) assays. Samples were also tested by real-time reverse transcription-PCR (rRT-PCR) to detect viral RNA. Of 548 serum samples tested, 44 (8.03%) were positive by VN (titers ranging from 1:16 to 1:1,024) and 45 (8.21%) were positive by ELISA, including 7 fish positive by both assays. Antibody prevalence increased with age and was higher in one northwestern area of Lake Winnebago than in other areas. Of 3,864 tissues sampled from 551 fish, 1 spleen and 1 kidney sample from a single adult female fish collected in the spring of 2012 tested positive for VHSV by rRT-PCR, and serum from the same fish tested positive by VN and ELISA. These results suggest that VHSV persists and viral transmission may be active in Lake Winnebago even in years following outbreaks and that wild fish may survive VHSV infection and maintain detectable antibody titers while harboring viral RNA. Influxes of immunologically naive juvenile fish through recruitment may reduce herd immunity, allow VHSV to persist, and drive superannual cycles of transmission that may sporadically manifest as fish kills.

  7. Recirculation over complex terrain

    Science.gov (United States)

    Kutter, Eric; Yi, Chuixiang; Hendrey, George; Liu, Heping; Eaton, Timothy; Ni-Meister, Wenge

    2017-06-01

    This study generated eddy covariance data to investigate atmospheric dynamics leeward of a small, forested hillside in upstate New York. The causes and effects of recirculation eddies were examined to support the larger goal of improving measurement of the exchange of energy, moisture, and trace gases between the terrestrial biosphere and the atmosphere over complex terrain. Sensors operated at five different altitudes on two separate towers—one at the top of the hill and one down the slope to the east—for approximately 8 weeks in the spring of 2013. During the experiment, the vertical potential temperature gradient was found to be the primary factor for determining whether winds interacting with the terrain features caused a recirculating eddy leeward of the hill. The study found evidence that the recirculation influenced carbon dioxide flux and caused the air column to be vertically well mixed.

  8. Quantifying Human Terrain

    Science.gov (United States)

    2008-06-01

    streaming media and instantaneous communications, nearly instant gratification has become the norm for most of the world. An investment in human terrain...Information is often thought of only as free when it resides on the unclassified enclave because the internet has made such tremendous amounts of information...freely available to anyone with access to the internet . This freedom of information fosters a self-perpetuating cycle of growth, where the freedom

  9. Ecological response to climate change and human activities indicated by n-alkane proxy during the mid- to late Holocene: a case study from an alpine lake

    Science.gov (United States)

    Zhang, C.; Zhao, C.

    2017-12-01

    Paleolimonological records provide long-term dynamics information of past climate, environment, human activities and ecological variations and give evolutionary perspectives to understand responses process of ecological shift to internal or external trigger. In this study, a powerful biomarkers, n-alkanes, was used to reconstruct the past 5000 years organic matter sources and ecological evolution history of Beilianchi Lake in the southwestern of Loess Plateau after preliminary investigation of modern samples. Climate-environment change and human activities were also traced by total organic matter (TOC), magnetic susceptibility (MS) and relevant proxies. The results showed that the ecosystem related to organic matter composition in Beilianchi Lake might be mainly controlled by climate change before 1400 cal B.P., whereas after that, it was significantly influenced by soil erosion induced by increasing population and enhanced human activities. Lake ecosystem experienced periodical change from relatively stable stage with combination of allochthonous-autochthonous organic sources prior to 1400 cal B.P. to extremely instability and final return to steady state with allochthonous-dominant organic source since 300 cal B.P.. During the period of instability, organic matter composition during 1400-800 cal B.P. indicated a obvious bimodal distribution based on probability density distribution analysis, which reflected the lake ecosystem might stay at bistable state and switched repeatedly from more-macrophytes state (regime A with low ACL) towards less-macrophytes state (regime B with high ACL) controlled by disturbance of soil erosion. The flickering during this period could serve as the early warning signal of transition towards more-macrophytes state or less-macrophytes state in lake ecosystems.

  10. The dark side of the Albano crater lake

    Directory of Open Access Journals (Sweden)

    F. De Giosa

    2006-06-01

    Full Text Available The Albano Lake is the deepest volcanic lake among the volcanoes located in the Italian peninsula. It belongs to the Colli Albani volcanic complex whose last largest eruptions are dated back to about ~30 Kyr, although minor events likely occurred during historical times at 7000 yr B.P. or earlier. After the end of the volcanic activity the Crater of Albano became a lake whose level changes are known since historical times. On November 2005, was performed the first very high resolution bathymetric survey of the Albano lake by means of a multibeam echo sounder, integrated with the GPS/RTK positioning technique A particular effort was devoted to produce a high resolution morphobathimetric map, which aims to provide a Digital Terrain Model of the lake floor for wide applications. The surveys did not revealed significant gas exhalative centres, which should indicate a current active gas release from the lake floor. Here we show the technical details of the bathymetric surveys, the very high resolution bathymetric map and the main morphological features of the Albano Lake bottom.

  11. Wind turbine wake measurement in complex terrain

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.; Menke, Robert

    2016-01-01

    SCADA data from a wind farm and high frequency time series measurements obtained with remote scanning systems have been analysed with focus on identification of wind turbine wake properties in complex terrain. The analysis indicates that within the flow regime characterized by medium to large...

  12. Cyanobacteria during low-wind summers indicate increased lake sensitivity to warming at high nutrient availability (Tiefer See, NE Germany)

    Science.gov (United States)

    Kienel, Ulrike; Dräger, Nadine; Plessen, Birgit; Kirillin, Georgiy; Lami, Andrea; Ott, Florian; Brademann, Brian; Pinkerneil, Sylvia; Gerli, Stefano; Brauer, Achim

    2017-04-01

    Deposition of varved sediments in Lake Tiefer See (max. 63 m deep, mesotrophic, hardwater lake), today as well as millennia ago (Kienel et al. 2013; Dräger et al. 2016) provides the unique opportunity to monitor ongoing formation of diatom, calcite, and organic matter (OM) varve sublayers and link their characteristics to climate and lake conditions. During the years 2012 to 2015, the particulate matter deposition was trapped at bi-weekly to monthly resolution in 12m and 50m depths. Lake conditions (temperature, ph, oxygen content) and meteorological variables (temperature, wind speed, precipitation) were logged by an in-situ sensor station. The 13-C concentration in authigenic OM during the summer seasons (2012 to 2015) is related to the duration of low-wind periods (LWP). Enrichment of 13-C above the average of -33 to -30‰ δ13C OM was strongest during summer 2014. Wind speeds below average (3.5 m s-1) and water mixing depth less than 3.5 m for 50 days after 28 June promoted a huge cyanobacteria bloom (Limnothrix redekekei). At that time, δ13C OM increased to -26‰. During the shortest summer LWP in 2013 (12 days from 2nd July), neither cyanobacteria nor 13-C enrichment in OM were observed. During intermediate summer LWPs in 2012 and 2015, 13-C of OM was enriched by no more than 2‰. The observed relation of 13-C enrichment of OM during extended summer LWPs was tested using δ13C OM measured from individual varves (i.e. annual resolution) from the Tiefer See sediments for the period AD1924 to 2008 and the mixing depth as derived from FLake-model calculations (for 1951 to 2008 based on DWD data from Schwerin). Accordingly, the duration of summer LWPs with shallow mixing explains 25% of the variability of 13-C enrichment in OM for the full period. The explained variability more than doubles when the period with increased nutrient load from 1970 onwards is considered. In terms of explained variability of lake production, this relation complements the inverse

  13. Use of Sediment Quality Guidelines and pollution indicators for the assessment of heavy metal and PAH contamination in Greek surficial sea and lake sediments.

    Science.gov (United States)

    Hahladakis, John; Smaragdaki, Eleftheria; Vasilaki, Georgia; Gidarakos, Evangelos

    2013-03-01

    Eight different surface sediment samples (K1-K8) were collected from two separate areas of Lake Koumoundourou and two samples (E1 and E2) from one area of Elefsis Bay, Athens, Greece. The level of pollution attributed to heavy metals was evaluated using several pollution indicators. Degree of Contamination, Modified Contamination Degree and Geoaccumulation Indexes were applied in order to determine and assess the anthropogenic contribution of the selected six elements (Cr, Ni, Cu, Zn, As and Pb). Moreover, the adverse effects of the sediments to aquatic organisms, from both heavy metals and polycyclic aromatic hydrocarbons (PAHs), were determined by using Sediment Quality Guidelines. The results indicated that Lake Koumoundourou is contaminated with heavy metals in a moderate degree and almost 50 % of the sediments are associated with frequent observation of adverse effects, when it comes to Ni and occasional observation of adverse effects, when it comes to Cu, Zn and Pb. As far as PAHs are concerned, around 60 % of the samples can be occasionally associated to toxic biological effects according to the effect-range classification for phenanthrene, benzo(a)anthracene, chrysene and pyrene. Finally, samples taken from the north side of the lake are more contaminated with PAHs than the ones taken from the east side probably due to the existence of the water barrier which acts as a reservoir of PAHs.

  14. Urban Terrain Zone Characteristics

    Science.gov (United States)

    1987-09-01

    concern in this study centers largely on whether the site is restrictive to urban expansion or permits it. For example, • Tel Aviv’s growth has been... urban growth has been rapid and have high proportions of framed buildings. These are Tel Aviv, Beirut, Panama City, Caracas, Kuala Lumpur, Tunis, and...Sea) 3) Asia and 4) Latin America. 56 Open SpKO 9.42 dethed 21-.0 27.32 42.3 X Figure 22. Urban terrain zones, major groups: Area. 57 Table 3 Urban

  15. Navigating Hypermasculine Terrains

    DEFF Research Database (Denmark)

    Henriksen, Ann-Karina Eske

    2017-01-01

    The study addresses how young women navigate urban terrains that are characterized by high levels of interpersonal aggression and crime. It is argued that young women apply a range of gendered tactics to establish safety and social mastery, and that these are framed by the limits and possibilities...... imposed by a street-based hypermasculine script. The analysis rests on an ethnographic study among 25 young Danish women aged 13 to 23 experienced in engaging in street-based physical violence. The study suggests that explorations of female tactics can provide a useful method of analysis for understanding...

  16. Probing the Terrain

    DEFF Research Database (Denmark)

    Johannessen, Runa

    2016-01-01

    navigational agility in everyday life conduct. The essay presents the case of the covert building of a chicken farm and house-to-become, where Palestinian landowner HH speculates in the territorial uncertainty and potential flexibility of the line dividing Area B from Area C, crossing his plot. HH’s disguised......Whether manifest in built structures or invisible infrastructures, architectures of control in the occupied Palestinian West Bank is structurally defined by endemic uncertainty. Shifting lines and frontiers are recorded on the terrain, creating elastic zones of uncertainty necessitating...

  17. Information measures for terrain visualization

    Science.gov (United States)

    Bonaventura, Xavier; Sima, Aleksandra A.; Feixas, Miquel; Buckley, Simon J.; Sbert, Mateu; Howell, John A.

    2017-02-01

    Many quantitative and qualitative studies in geoscience research are based on digital elevation models (DEMs) and 3D surfaces to aid understanding of natural and anthropogenically-influenced topography. As well as their quantitative uses, the visual representation of DEMs can add valuable information for identifying and interpreting topographic features. However, choice of viewpoints and rendering styles may not always be intuitive, especially when terrain data are augmented with digital image texture. In this paper, an information-theoretic framework for object understanding is applied to terrain visualization and terrain view selection. From a visibility channel between a set of viewpoints and the component polygons of a 3D terrain model, we obtain three polygonal information measures. These measures are used to visualize the information associated with each polygon of the terrain model. In order to enhance the perception of the terrain's shape, we explore the effect of combining the calculated information measures with the supplementary digital image texture. From polygonal information, we also introduce a method to select a set of representative views of the terrain model. Finally, we evaluate the behaviour of the proposed techniques using example datasets. A publicly available framework for both the visualization and the view selection of a terrain has been created in order to provide the possibility to analyse any terrain model.

  18. Washboard Terrain on Pluto

    Science.gov (United States)

    Moore, Jeffrey M.; White, Oliver L.; Howard, Alan D.; Umurhan, Orkan M.; Schenk, Paul M.; Beyer, Ross A.; McKinnnon, William B.; Singer, Kelsi N.; Lauer, Tod R.; Cheng, Andrew F.; Young, Leslie; Stern, S. Alan; Weaver, Harold A.; Olkin, Catherine; Ennico, Kimberly; New Horizons Science Team

    2017-10-01

    Washboard texture or patterning consists of fields of parallel to sub-parallel ridges typically spaced ~1-2 km crest to crest and a few 100 m in amplitude (Fig. 4a in Moore et al., 2016, Science, 351, 1284-1293). For the most part, underlying topography can be easily discerned. We will refer to discrete, well-bounded patches of these landforms as Washboard Terrain (WT). WT is observed to occur along the rim, and just beyond the rim, of Sputnik basin from the West to NNW. Where it is seen in high-resolution data, it has clearly defined limits, beyond which it would be able to be seen if it were there. WT doesn’t occur at very low latitudes or very high latitudes (ranging from 22°N to 62°N). WT seems to occur most conspicuously on relatively level, gently sloping terrain. It is restricted to elevations between ~-2 km to Milankovitch timescales of ~1 Ma. If this hypothesis has validity, then perhaps the intermediate-albedo reddish material may be akin to ground moraine deposits.

  19. Physical and chemical characteristics of lakes across heterogeneous landscapes in arctic and subarctic Alaska

    Science.gov (United States)

    Larsen, A. S.; O'Donnell, J. A.; Schmidt, J. H.; Kristenson, H. J.; Swanson, D. K.

    2017-04-01

    Lakes are an important component of high-latitude regions, providing habitat for fish and wildlife and playing a critical role in biogeochemical and global carbon cycles. High-latitude lakes are sensitive to climate change, in part due to their development within permafrost soils. Considerable heterogeneity exists across arctic and subarctic landscapes, yet little is known about how this landscape variability influences chemical and physical attributes of lakes. We investigated the physical and chemical limnology of 617 lakes in Alaska's boreal forest and boreal-arctic transition zone. We categorized lakes into 10 basin types based on parent material, topography, genesis, and permafrost characteristics. Physical parameters varied across lake basin types, with the deepest lakes occurring in ice-poor glacial deposits and ice-rich terrain, while the shallowest lakes were observed in floodplain deposits and coastal lowlands. Dissolved inorganic nitrogen (N) and phosphorous (P) concentrations were generally low across all landscapes, whereas total N and P were highest in lakes underlain by ice-rich Pleistocene loess. Total N and P concentrations were significantly correlated with chlorophyll a, indicating a possible colimitation of primary productivity in these systems. Base cation concentrations helped elucidate lake basin hydrology and the relative influence of shallow versus deep groundwater inputs to surface water. Using these results, we developed a simple conceptual model for each lake and landscape type based on differences in physical and chemical parameters. Overall, we expect that the vulnerability of lake ecosystems to climate change will vary across lake basin types and will be mediated by spatial patterns in permafrost characteristics and subsurface hydrology.

  20. Indication of temperature inverted microbial assimilative capacities (extracellular enzymes activities in the pelagic of Lake Sevan (Armenia

    Directory of Open Access Journals (Sweden)

    Arevik MINASYAN

    2016-06-01

    Full Text Available Pioneering records of extracellular enzymes activities (EEA in Lake Sevan waters highlight dependence of heterotrophic functioning on physicochemical characteristics and bacterial assemblage. Values of EEA, ranged 0.11-30.39 µg C/P L-1h-1, were higher in upper layers compared to the omission in deeper parts. Particles associated (ecto- enzymes mainly predominated over free dissolved (exo- enzymes. In June activities of all studied enzymes followed similar pattern, particularly, decreasing at thermocline and increasing twice/more in cold deeper waters. Regardless higher bacterial density and temperature in June, with no similar records up to now, EEA revealed reverse relationship to temperature and bacteria data and were significantly lesser than in March. Our finding might be suggested as temperature inverted impact to heterotrophic activities in eutrophic conditions. We assume that observed, with temperature raise, declined EEA was due to blocked enzymatic active center from colloids and DOM components interaction, which, in overall, may suppress organic substrate utilization and result in weakening of first and rate limiting step of biological self-purification in Lake Sevan waters. Therefore, since temperature is co-regulator of assimilative/carrying capacity of aquatic ecosystems, climate warming might have unexpected negative feedbacks also through lowering assimilative capacities of water bodies, jeopardizing their quality and ecology.

  1. Washboard Terrain on Pluto

    Science.gov (United States)

    Moore, Jeffrey M.; White, Oliver L.; Howard, Alan D.; Umurhan, Orkan M.; Schenk, Paul M.; Beyer, Ross A.; McKinnon, William B.; Singer, Kelsi N.; Lauer, Tod R.; Cheng, Andrew F.; hide

    2017-01-01

    Washboard texture or patterning consists of fields of parallel to sub-parallel ridges typically spaced 1-2 km crest to crest and a few 100 m in amplitude (Fig. 4a in Moore et al., 2016, Science, 351, 1284-1293). For the most part, underlying topography can be easily discerned. We will refer to discrete, well-bounded patches of these landforms as Washboard Terrain (WT). WT is observed to occur along the rim, and just beyond the rim, of Sputnik basin from the West to NNW. Where it is seen in high-resolution data, it has clearly defined limits, beyond which it would be able to be seen if it were there. WT doesn't occur at very low latitudes or very high latitudes (ranging from 22degN to 62degN). WT seems to occur most conspicuously on relatively level, gently sloping terrain. It is restricted to elevations between approximately 2 km to less than +1.5 km (i.e. not at high elevations). The most noticeable regional aspect of the area in which WT occurs is the sinuous valley network, which is suspected to have been formed, or at least substantially modified, by glaciation. WT also appears to occur mainly on an intermediate-albedo reddish material, where seen in enhanced color data. Where it occurs in level terrain, WT tends to trend ENE - there doesn't seem to be a strong local control of its orientation in response to valley drainage directions. WT can display a greater range of orientations where it occurs in higher-relief (not higher elevation) settings such as spurs. WT appears superposed on very ancient landscapes, but is itself cratered locally by clusters of small (approximately 1-3 km) craters, which may be secondaries. This implies that WT may be intermediate in age. Of several working hypotheses, we currently provisionally favor that WT may be akin to terrestrial recessional moraines (or de Geer moraines) associated with the retreat of a higher stand of N2 glaciation that once overfilled Sputnik basin. These putative moraine features may owe their spacing to

  2. Polygonal terrains on Mars

    Directory of Open Access Journals (Sweden)

    Pedro Pina

    2009-06-01

    Full Text Available The presence of water ice on Mars is well established. Some featureson the planet point to the occurrence of processes similar to those that take place in periglacial areas of Earth. One of the clues for this is the existence of small-scale polygonal terrains. In this paper, we present a methodology that aims at the automated identification of polygonal patterns on high-spatial resolution images of the surface of Mars. In the context of the research project TERPOLI, this step will be complemented with a full characterization, in both geometric and topological terms, of thenetworks detected. In this manner, we hope to collect data that will lead to a better understanding of the conditions of formation of the polygons, and of their temporal evolution; namely, we intend to identify different groups of polygons and to compare them with terrestrial examples.

  3. Turbulence in complex terrain

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Jakob [Risoe National Lab., Wind Energy and Atmosheric Physics Dept., Roskilde (Denmark)

    1999-03-01

    The purpose of this work is to develop a model of the spectral velocity-tensor in neutral flow over complex terrain. The resulting equations are implemented in a computer code using the mean flow generated by a linear mean flow model as input. It estimates turbulence structure over hills (except on the lee side if recirculation is present) in the so-called outer layer and also models the changes in turbulence statistics in the vicinity roughness changes. The generated turbulence fields are suitable as input for dynamic load calculations on wind turbines and other tall structures and is under implementation in the collection of programs called WA{sup s}P Engineering. (au) EFP-97; EU-JOULE-3. 15 refs.

  4. On characterizing terrain visibility graphs

    Directory of Open Access Journals (Sweden)

    William Evans

    2015-06-01

    Full Text Available A terrain is an $x$-monotone polygonal line in the $xy$-plane. Two vertices of a terrain are mutually visible if and only if there is no terrain vertex on or above the open line segment connecting them. A graph whose vertices represent terrain vertices and whose edges represent mutually visible pairs of terrain vertices is called a terrain visibility graph. We would like to find properties that are both necessary and sufficient for a graph to be a terrain visibility graph; that is, we would like to characterize terrain visibility graphs.Abello et al. [Discrete and Computational Geometry, 14(3:331--358, 1995] showed that all terrain visibility graphs are “persistent”. They showed that the visibility information of a terrain point set implies some ordering requirements on the slopes of the lines connecting pairs of points in any realization, and as a step towards showing sufficiency, they proved that for any persistent graph $M$ there is a total order on the slopes of the (pseudo lines in a generalized configuration of points whose visibility graph is $M$.We give a much simpler proof of this result by establishing an orientation to every triple of vertices, reflecting some slope ordering requirements that are consistent with $M$ being the visibility graph, and prove that these requirements form a partial order. We give a faster algorithm to construct a total order on the slopes. Our approach attempts to clarify the implications of the graph theoretic properties on the ordering of the slopes, and may be interpreted as defining properties on an underlying oriented matroid that we show is a restricted type of $3$-signotope.

  5. Keystone indices probabilistic species sensitivity distribution in the case of the derivation of water quality criteria for copper in Tai Lake.

    Science.gov (United States)

    Hou, Jun; Zhao, Qianyuan; Wang, Peifang; Wang, Chao; Miao, Lingzhan; Feng, Chenglian

    2016-07-01

    An alternative method for species sensitivity distribution (SSD) that considers the interaction between species and the community importance is illustrated in this article. First, a food web based on the relationship between predator and prey was constructed, and the keystone indices of species were obtained based on the food web. Then, the probability density distribution of the sensitivity for each species was derived from all of the available endpoints of each species. Finally, the species sensitivity distribution for ecosystem was constructed by sampling a specific number of values from the probability density distribution of the sensitivity for each species. Data of copper toxicity to the aquatic organisms in Tai Lake were selected to derived site-specific water quality criteria (WQC). Ninety-seven endpoints of acute toxicity for 47 species and 188 endpoints of chronic toxicity for 29 species were included, and the acute and chronic WQC developed by keystone indices probabilistic species sensitivity distribution (K-PSSD) were 4.982 μg/L and 0.965 μg/L, respectively. Results showed that the aquatic organisms of Tai Lake might be underprotected. Compared with the SSD, the K-PSSD coped with the interactions between species, the community importance, and the intraspecies and interspecies variation more effectively and was better at depicting the tendency and information of raw data. The K-PSSD was especially applicable to site-specific WQC and provided an alternative or supplement to the SSD.

  6. Geochemistry of recent aragonite-rich sediments in Mediterranean karstic marine lakes: Trace elements as pollution and palaeoredox proxies and indicators of authigenic mineral formation.

    Science.gov (United States)

    Sondi, Ivan; Mikac, Nevenka; Vdović, Neda; Ivanić, Maja; Furdek, Martina; Škapin, Srečo D

    2017-02-01

    This study investigates the geochemical characteristics of recent shallow-water aragonite-rich sediments from the karstic marine lakes located in the pristine environment on the island of Mljet (Adriatic Sea). Different trace elements were used as authigenic mineral formation, palaeoredox and pollution indicators. The distribution and the historical record of trace elements deposition mostly depended on the sedimentological processes associated with the formation of aragonite, early diagenetic processes governed by the prevailing physico-chemical conditions and on the recent anthropogenic activity. This study demonstrated that Sr could be used as a proxy indicating authigenic formation of aragonite in a marine carbonate sedimentological environment. Distribution of the redox sensitive elements Mo, Tl, U and Cd was used to identify changes in redox conditions in the investigated lake system and to determine the geochemical cycle of these elements through environmental changes over the last 100 years. The significant enrichment of these elements and the presence of early formed nanostructured authigenic framboidal pyrite in laminated deeper parts of sediment in Malo Jezero, indicate sporadic events of oxygen-depleted euxinic conditions in the recent past. Concentrations of trace elements were in the range characteristic for non-contaminated marine carbonates. However, the increase in the concentrations of Zn, Cu, Pb, Sn, Bi in the upper-most sediment strata of Veliko Jezero indicates a low level of trace element pollution, resulting from anthropogenic inputs over the last 40 years. The presence of butyltin compounds (BuTs) in the surface sediment of Veliko Jezero additionally indicates the anthropogenic influence in the recent past. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Environmental changes and microbiological health risks. Satellite-derived turbidity: an indicator of "health hazard" for surface water in West Africa (Bagre lake, Burkina Faso).

    Science.gov (United States)

    Robert, E.; Grippa, M.; Kergoat, L.; Martinez, J.; Pinet, S.; Gal, L.; Soumaguel, N.

    2015-12-01

    A significant correlation exists between the concentration of parasites, bacteria and some water quality parameters including surface suspended solids (SSS) and turbidity. Suspended particles can carry viruses and pathogenic bacteria affecting human health and foster their development. High SSS, associated with high turbidity, can therefore be considered as a vector of microbiological contaminants, causing diarrheal diseases. Few studies have focused on the turbidity parameter in rural Africa, while many cases of intestinal parasitic infections are due to the consumption of unsafe water from ponds, lakes, and rivers. Monitoring turbidity may therefore contribute to health hazard monitoring. Turbidity refers to the optical properties of water and is known to impact water reflectance in the visible and near-infrared domain. Ideally, its spatial and temporal variability requires the use of high temporal resolution (MODIS) and spatial resolution (Landsat, SPOT, Sentinel-2). Here we investigate turbidity in West-Africa. Various algorithms and indices proposed in the literature for inland waters are applied to MODIS series and to Landsat 7 and 8 CDR images, and SPOT5 images. The data and algorithms are evaluated with field measurements: turbidity, SSS, and hyperspectral ground radiometry. We show that turbidity of the Bagre Lake displays a strong increase over 2000-2015, associated with the corresponding increase of the red and NIR reflectances, as well as a reduction of the seasonal variations. Water level derived from the Jason 2 altimeter does not explain such variations. The most probable hypothesis is a change in land use (increase in bare and degraded soils), that leads to an increase in the particles transported by surface runoff to the lake. Such an increase in turbidity reinforces the health risk. We will discuss the link between turbidity and health in view of data from health centers on diarrheal diseases as well as data on practices and uses of populations.

  8. Lake Roosevelt Fisheries Monitoring Program; Measurement of Thyroxin Concentration as an Indicator of the Critical Period for Imprinting in the Kokanee Salmon (Orcorhynchus Nerka) Implications for Operating Lake Roosevelt Kokanee Hatcheries; 1991 Supplement Report.

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, Allan T.; White, Ronald J.; Koehler, Valerie A. (Eastern Washington University, Upper Columbia United Tribes Fisheries Research Center, Cheney, WA)

    1992-05-01

    Previous investigations have determined that thyroid hormone surges activate olfactory imprinting in anadromous salmonid smolts. The mechanism of action appears to require binding of thyroid hormones to receptors in brain cell nuclei, which stimulates neuron differentiation and wires a pattern of neuron circuitry that allows for the permanent storage of the imprinted olfactory memory. In this study, thyroxine concentrations [T{sub 4}] were measured in 487 Lake Whatcom stock and 70 Lake Roosevelt stock Kokanee salmon to indicate the critical period for imprinting. Eggs, alevins and fry, reared at the Spokane Indian Kokanee Hatchery, were collected from January through August 1991. Sampled fish were flash frozen on dry ice and stored at {minus}80{degrees}C until T{sub 4} was extracted and concentrations determined by radioimmunassay. Mean concentration {+-} SEM of 10--20 individual fish (assayed in duplicate) were determined for each time period. T{sub 4} concentration peaked on the day of hatch at 16.8 ng/g body weight and again at swim-up at 16.0 {+-} 4.7 ng/g body weight. T{sub 4} concentration was 12.5 to 12.9 ng/g body weight in eggs, 7.1 to 15.2 ng/g body weight in. alevins, 4.5 to 11.4 ng/g body weight in 42 to 105 day old fry and 0.1 to 2.9 ng/g body weight in 112 to 185 day old fry. T{sub 4} concentrations were highest in eggs at 13.3 {+-} 2.8 ng/g body weight, then steadily decreased to 0.1 {+-} 0.1 ng/g body weight in older fry. Fry were released in Lake Roosevelt tributaries in July and August 1991, at about 170--180 days post hatching, in order to imprint them to those sites. The results of this study indicate that the time of release was not appropriate for imprinting. If T{sub 4} levels are an accurate guide for imprinting in kokanee, our results suggest that the critical period for imprinting in kokanee is at hatching or swim-up stages.

  9. New insights into deglacial climate variability in tropical South America from molecular fossil and isotopic indicators in Lake Titicaca

    Science.gov (United States)

    Shanahan, T. M.; Hughen, K. A.; Fornace, K.; Baker, P. A.; Fritz, S. C.

    2010-12-01

    As one of the main centers of tropical convection, the South American Altiplano plays a crucial role in the long-term climate variability of South America. However, both the timing and the drivers of climate variability on orbital to millennial timescales remain poorly understood for this region. New data from molecular fossil (e.g., TEX86) and compound specific hydrogen isotope (D/H) analyses provide new insights into the climate evolution of this region over the last ~50 kyr. TEX86 temperature reconstructions suggest that the Altiplano warmed as early as 19- 21 kyr ago and proceeded rapidly, consistent with published evidence for an early retreat of LGM glaciers at this time at some locations. The early warming signal observed at Lake Titicaca also appears to be synchronous with continental temperature reconstructions at some sites in tropical Africa, but leads tropical SST changes by several thousands of years. Although the initiation of warming coincided with the peak in southern hemisphere summer insolation, subsequent temperature increases were accompanied by decreases in southern hemisphere insolation, suggesting a northern hemisphere driver for temperature changes in tropical South America. Preliminary D/H ratios from leaf waxes appear to support existing data suggesting that wet conditions prevailed until the late glacial/early Holocene and are broadly consistent with local southern hemisphere summer insolation forcing of the summer monsoon. These data suggest that temperature and precipitation changes during the last deglaciation were decoupled and that both local and extratropical drivers are important for controlling climate change in this region on orbital timescales.

  10. TERRAIN, OVERTON COUNTY, TN, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN, STEWART COUNTY, TN, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. TERRAIN, HOUSTON COUNTY, TN, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, SHELBY COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. TERRAIN, SEBASTIAN COUNTY, AR, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographical data that were used to create...

  15. TERRAIN, Webster COUNTY, Missouri USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN, WALKER COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. TERRAIN, BOURBON COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. TERRAIN, BIBB COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. TERRAIN, WASHINGTON COUNTY, Ohio USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  20. TERRAIN, OWEN COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. TERRAIN, LAWRENCE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. TERRAIN, TALLAPOOSA COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  3. TERRAIN, SCOTT COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. TERRAIN, MARSHALL COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. TERRAIN, CHILTON COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  6. Terrain Adaptive Reconfiguration of Mobility

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop an algorithm (and software) to automatically adapt a reconfigurable robot to different types of terrains for improved mobility, that compared to SOA:...

  7. TERRAIN, TANEY COUNTY, Missouri USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. TERRAIN, HENRY COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN, BARREN COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN, MUHLENBERG COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN, NATCHITOCHES PARISH, LA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. TERRAIN, BUFFALO COUNTY, WISCONSIN, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, LOWNDES COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. TERRAIN, FRANKLIN COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  15. TERRAIN, ELMORE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN, GADSDEN COUNTY, FL, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. TERRAIN, CLARKE COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. TERRAIN, JEFFERSON COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. TERRAIN, FAYETTE COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  20. TERRAIN, MARENGO COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. TERRAIN, CAMPBELL COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. TERRAIN, HARRISON COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  3. TERRAIN Submission for CHICKASAW, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  4. TERRAIN, LOGAN COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. TERRAIN, HART COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  6. TERRAIN, BRADFORD COUNTY, FL, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. TERRAIN, MONROE COUNTY, Michigan USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  8. TERRAIN, PERRY COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN, UNION COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN, LEWIS COUNTY, Missouri USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN, NICHOLAS COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. TERRAIN, GRANT COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, HENDERSON COUNTY, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. TERRAIN, MADISON COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  15. TERRAIN, CHOCTAW COUNTY, ALABAMA USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN, LEVY COUNTY, FL, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. TERRAIN, ALLENDALE COUNTY, SOUTH CAROLINA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. Final Results From the Circumarctic Lakes Observation Network (CALON) Project

    Science.gov (United States)

    Hinkel, K. M.; Arp, C. D.; Eisner, W. R.; Frey, K. E.; Grosse, G.; Jones, B. M.; Kim, C.; Lenters, J. D.; Liu, H.; Townsend-Small, A.

    2015-12-01

    Since 2012, the physical and biogeochemical properties of ~60 lakes in northern Alaska have been investigated under CALON, a project to document landscape-scale variability of Arctic lakes in permafrost terrain. The network has ten nodes along two latitudinal transects extending inland 200 km from the Arctic Ocean. A meteorological station is deployed at each node and six representative lakes instrumented and continuously monitored, with winter and summer visits for synoptic assessment of lake conditions. Over the 4-year period, winter and summer climatology varied to create a rich range of lake responses over a short period. For example, winter 2012-13 was very cold with a thin snowpack producing thick ice across the region. Subsequent years had relatively warm winters, yet regionally variable snow resulted in differing gradients of ice thickness. Ice-out timing was unusually late in 2014 and unusually early in 2015. Lakes are typically well-mixed and largely isothermal, with minor thermal stratification occurring in deeper lakes during calm, sunny periods in summer. Lake water temperature records and morphometric data were used to estimate the ground thermal condition beneath 28 lakes. Application of a thermal equilibrium steady-state model suggests a talik penetrating the permafrost under many larger lakes, but lake geochemical data do not indicate a significant contribution of subpermafrost groundwater. Biogeochemical data reveal distinct spatial and seasonal variability in chlorophyll biomass, chromophoric dissolved organic carbon (CDOM), and major cations/anions. Generally, waters sampled beneath ice in April had distinctly higher concentrations of inorganic solutes and methane compared with August. Chlorophyll concentrations and CDOM absorption were higher in April, suggesting significant biological/biogeochemical activity under lake ice. Lakes are a positive source of methane in summer, and some also emit nitrous oxide and carbon dioxide. As part of the

  19. Terrain-Adaptive Navigation Architecture

    Science.gov (United States)

    Helmick, Daniel M.; Angelova, Anelia; Matthies, Larry H.; Helmick, Daniel M.

    2008-01-01

    A navigation system designed for a Mars rover has been designed to deal with rough terrain and/or potential slip when evaluating and executing paths. The system also can be used for any off-road, autonomous vehicles. The system enables vehicles to autonomously navigate different terrain challenges including dry river channel systems, putative shorelines, and gullies emanating from canyon walls. Several of the technologies within this innovation increase the navigation system s capabilities compared to earlier rover navigation algorithms.

  20. Water-quality effects on phytoplankton species and density and trophic state indices at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas, June through August, 2015

    Science.gov (United States)

    Driver, Lucas; Justus, Billy

    2016-01-01

    Big Base and Little Base Lakes are located on Little Rock Air Force Base, Arkansas, and their close proximity to a dense residential population and an active military/aircraft installation make the lakes vulnerable to water-quality degradation. The U.S. Geological Survey (USGS) conducted a study from June through August 2015 to investigate the effects of water quality on phytoplankton species and density and trophic state in Big Base and Little Base Lakes, with particular regard to nutrient concentrations. Nutrient concentrations, trophic-state indices, and the large part of the phytoplankton biovolume composed of cyanobacteria, indicate eutrophic conditions were prevalent for Big Base and Little Base Lakes, particularly in August 2015. Cyanobacteria densities and biovolumes measured in this study likely pose a low to moderate risk of adverse algal toxicity, and the high proportion of filamentous cyanobacteria in the lakes, in relation to other algal groups, is important from a fisheries standpoint because these algae are a poor food source for many aquatic taxa. In both lakes, total nitrogen to total phosphorus (N:P) ratios declined over the sampling period as total phosphorus concentrations increased relative to nitrogen concentrations. The N:P ratios in the August samples (20:1 and 15:1 in Big Base and Little Base Lakes, respectively) and other indications of eutrophic conditions are of concern and suggest that exposure of the two lakes to additional nutrients could cause unfavorable dissolved-oxygen conditions and increase the risk of cyanobacteria blooms and associated cyanotoxin issues.

  1. Dry Ice Etches Terrain

    Science.gov (United States)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1 Every year seasonal carbon dioxide ice, known to us as 'dry ice,' covers the poles of Mars. In the south polar region this ice is translucent, allowing sunlight to pass through and warm the surface below. The ice then sublimes (evaporates) from the bottom of the ice layer, and carves channels in the surface. The channels take on many forms. In the subimage shown here (figure 1) the gas from the dry ice has etched wide shallow channels. This region is relatively flat, which may be the reason these channels have a different morphology than the 'spiders' seen in more hummocky terrain. Observation Geometry Image PSP_003364_0945 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Apr-2007. The complete image is centered at -85.4 degrees latitude, 104.0 degrees East longitude. The range to the target site was 251.5 km (157.2 miles). At this distance the image scale is 25.2 cm/pixel (with 1 x 1 binning) so objects 75 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel . The image was taken at a local Mars time of 06:57 PM and the scene is illuminated from the west with a solar incidence angle of 75 degrees, thus the sun was about 15 degrees above the horizon. At a solar longitude of 219.6 degrees, the season on Mars is Northern Autumn.

  2. Spectra of Velocity components over Complex Terrain

    DEFF Research Database (Denmark)

    Panofsky, H. A.; Larko, D.; Lipschut, R.

    1982-01-01

    Spectra have been measured over a variety of types of complex terrain: on tops of hills and escarpments, over land downstream of a water surface, and over rolling terrain. Differences between spectra over many types of complex terrain, and over uniform terrain, can be explained by these hypothese...

  3. Greigite (Fe3S4) as an indicator of drought - The 1912-1994 sediment magnetic record from White Rock Lake, Dallas, Texas, USA

    Science.gov (United States)

    Reynolds, R.L.; Rosenbaum, J.G.; Van Metre, P.; Tuttle, M.; Callender, E.; Goldin, A.

    1999-01-01

    Combined magnetic and geochemical studies were conducted on sediments from White Rock Lake, a reservoir in suburban Dallas (USA), to investigate how land use has affected sediment and water quality since the reservoir was filled in 1912. The chronology of a 167-cm-long core is constrained by the recognition of the pre-reservoir surface and by 137Cs results. In the reservoir sediments, magnetic susceptibility (MS) and isothermal remanent magnetization (IRM) are largely carried by detrital titanomagnetite that originally formed in igneous rocks. Titanomagnetite and associated hematite are the dominant iron oxides in a sample from the surficial deposit in the watershed but are absent in the underlying Austin Chalk. Therefore, these minerals were transported by wind into the watershed. After about 1960, systematic decreases in Ti, Fe, and Al suggest diminished input of detrital Fe-Ti oxides from the surficial deposits. MS and IRM remain constant over this interval, however, implying compensation by an increase in strongly magnetic material derived from human activity. Anthropogenic magnetite in rust and ferrite spherules (from fly ash?) are more common in sediment deposited after about 1970 than before and may account for the constant magnetization despite the implied decrease in detrital Fe-Ti oxides. An unexpected finding is the presence of authigenic greigite (Fe3S4), the abundance of which is at least partly controlled by climate. Greigite is common in sediments that predate about 1975, with zones of concentration indicated by relatively high IRM/MS. High greigite contents in sediment deposited during the early to mid-1950s and during the mid-1930s correspond to several-year periods of below-average precipitation and drought from historical records. Relatively long water-residence times in the reservoir during these periods may have led to elevated levels of sulfate available for bacterial sulfate reduction. The sulfate was probably derived via the oxidation of

  4. Complete Scene Recovery and Terrain Classification in Textured Terrain Meshes

    Directory of Open Access Journals (Sweden)

    Kyhyun Um

    2012-08-01

    Full Text Available Terrain classification allows a mobile robot to create an annotated map of its local environment from the three-dimensional (3D and two-dimensional (2D datasets collected by its array of sensors, including a GPS receiver, gyroscope, video camera, and range sensor. However, parts of objects that are outside the measurement range of the range sensor will not be detected. To overcome this problem, this paper describes an edge estimation method for complete scene recovery and complete terrain reconstruction. Here, the Gibbs-Markov random field is used to segment the ground from 2D videos and 3D point clouds. Further, a masking method is proposed to classify buildings and trees in a terrain mesh.

  5. Processing Terrain Point Cloud Data

    KAUST Repository

    DeVore, Ronald

    2013-01-10

    Terrain point cloud data are typically acquired through some form of Light Detection And Ranging sensing. They form a rich resource that is important in a variety of applications including navigation, line of sight, and terrain visualization. Processing terrain data has not received the attention of other forms of surface reconstruction or of image processing. The goal of terrain data processing is to convert the point cloud into a succinct representation system that is amenable to the various application demands. The present paper presents a platform for terrain processing built on the following principles: (i) measuring distortion in the Hausdorff metric, which we argue is a good match for the application demands, (ii) a multiscale representation based on tree approximation using local polynomial fitting. The basic elements held in the nodes of the tree can be efficiently encoded, transmitted, visualized, and utilized for the various target applications. Several challenges emerge because of the variable resolution of the data, missing data, occlusions, and noise. Techniques for identifying and handling these challenges are developed. © 2013 Society for Industrial and Applied Mathematics.

  6. Sources of Organic-Carbon in the Littoral of Lake Gloomier as Indicated by Stable Carbon-Isotope and Carbohydrate Compositions

    NARCIS (Netherlands)

    Boschker, H.T.S.; Dekkers, E.M.J.; Pel, R.; Cappenberg, T.E.

    1995-01-01

    The relative importance of potential carbon sources in the littoral of Lake Gooimeer, a lake in the centre of the Netherlands, was studied using a combination of C-13/C-12-ratio analysis and carbohydrate composition analysis. The littoral is covered on the land side by a 80 m wide Phragmites

  7. Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

    Science.gov (United States)

    Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

    2009-01-01

    Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

  8. Complex terrain and wind lidars

    Energy Technology Data Exchange (ETDEWEB)

    Bingoel, F.

    2009-08-15

    This thesis includes the results of a PhD study about complex terrain and wind lidars. The study mostly focuses on hilly and forested areas. Lidars have been used in combination with cups, sonics and vanes, to reach the desired vertical measurement heights. Several experiments are performed in complex terrain sites and the measurements are compared with two different flow models; a linearised flow model LINCOM and specialised forest model SCADIS. In respect to the lidar performance in complex terrain, the results showed that horizontal wind speed errors measured by a conically scanning lidar can be of the order of 3-4% in moderately-complex terrain and up to 10% in complex terrain. The findings were based on experiments involving collocated lidars and meteorological masts, together with flow calculations over the same terrains. The lidar performance was also simulated with the commercial software WAsP Engineering 2.0 and was well predicted except for some sectors where the terrain is particularly steep. Subsequently, two experiments were performed in forested areas; where the measurements are recorded at a location deep-in forest and at the forest edge. Both sites were modelled with flow models and the comparison of the measurement data with the flow model outputs showed that the mean wind speed calculated by LINCOM model was only reliable between 1 and 2 tree height (h) above canopy. The SCADIS model reported better correlation with the measurements in forest up to approx6h. At the forest edge, LINCOM model was used by allocating a slope half-in half out of the forest based on the suggestions of previous studies. The optimum slope angle was reported as 17 deg.. Thus, a suggestion was made to use WAsP Engineering 2.0 for forest edge modelling with known limitations and the applied method. The SCADIS model worked better than the LINCOM model at the forest edge but the model reported closer results to the measurements at upwind than the downwind and this should be

  9. Treinta y Tres stratigraphic terrain: ex Cuchilla Dionisio terrain. Uruguay

    International Nuclear Information System (INIS)

    Bossi, J.

    2010-01-01

    From 1998 we are discussing if the eastern area of ZCSB is an allochtonous block named TCD or if it belongs to Dom Feliciano belt with an age of 500 - 700 Ma. This crustal block is difficult to study because Laguna Merin Graben cut it in two around 4000 k m2 crustal fragments distant s more de 100 km between them. Southern block which was named T PE by Masquelín (2006) was demonstrated as allochtonous by Bossi and Gaucher (2004) destroying the Cdf model but seriously complicating the stratigraphic terminology. It is proposed to do some changes in order to profit the general agreement about allochtomy. The CDT with change by Treinta y Tres terrane; T PE become sub - terrain Punta del Este; sub - terrain Cuchilla Dionisio for the septetrional block. From 1998 we are discussing if the eastern area of ZCSB is an allochtonous block named TCD or if it belongs to Dom Feliciano belt with an age of 500 - 700 Ma. This crustal block is difficult to study because Laguna Merín Graben cut it in two around 4000 k m2 crustal fragments distant s more de 100 km between them. Southern block which was named T PE by Masquelín (2006) was demonstrated as allochtonous by Bossi and Gaucher (2004) destroying the CDF model but seriously complicating the stratigraphic terminology. It is proposed to do some changes in order to profit the general agreement about allochtomy. The CDT with change by Treinta y Tres terrain; TPE become sub - terrain Punta del Este; sub - terrain Cuchilla Dionisio for the septetrional block

  10. Handling Massive and Dynamic Terrain Data

    DEFF Research Database (Denmark)

    Revsbæk, Morten

    models are increasingly being updated as a result of new data collection or editing done by users. This transforms a terrain model into a dynamic object, and presents a set of new algorithmic challenges. In this thesis we consider some of the above challenges. To enable analysis of massive terrain data...... we develop so-called I/O-efficient algorithms for a set of well-known terrain analysis problems. First, we present an I/O-efficient algorithm for terrain model simplification. This algorithm can be used in connection with terrain analysis to reduce the topological complexity of a detailed terrain...... model before performing the actual analysis. Then we present an I/O-efficient algorithm for extracting simplified yet precise contour maps from detailed terrain models. Finally, we present an I/O-efficient algorithm for estimating the flood risk from water collecting in basins of a terrain model during...

  11. Multi-angle Indicators System of Non-point Pollution Source Assessment in Rural Areas: A Case Study Near Taihu Lake

    Science.gov (United States)

    Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

    2013-04-01

    This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas.

  12. F-16 MMC Strafe in Mountainous Terrain

    Science.gov (United States)

    2016-04-01

    1 Background ...identification by analyzing the geometry of the two attack options against various degrees of rising terrain. Background On 27 November 2007...Operating in “mountainous” terrain requires the pilot to execute different IFR terrain clearance. Air Force Instruction 11-202 volume 3 defines

  13. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    Science.gov (United States)

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  14. Prediction models in complex terrain

    DEFF Research Database (Denmark)

    Marti, I.; Nielsen, Torben Skov; Madsen, Henrik

    2001-01-01

    The objective of the work is to investigatethe performance of HIRLAM in complex terrain when used as input to energy production forecasting models, and to develop a statistical model to adapt HIRLAM prediction to the wind farm. The features of the terrain, specially the topography, influence...... the performance of HIRLAM in particular with respect to wind predictions. To estimate the performance of the model two spatial resolutions (0,5 Deg. and 0.2 Deg.) and different sets of HIRLAM variables were used to predict wind speed and energy production. The predictions of energy production for the wind farms...... are calculated using on-line measurements of power production as well as HIRLAM predictions as input thus taking advantage of the auto-correlation, which is present in the power production for shorter pediction horizons. Statistical models are used to discribe the relationship between observed energy production...

  15. Spatio-temporal variation in the tap water isotope ratios of Salt Lake City: a novel indicator of urban water system structure and dynamics.

    Science.gov (United States)

    Jameel, M. Y.; Bowen, G. J.

    2015-12-01

    Public water supply systems are the life-blood of urban areas. How we use urban water systems affects more than human health and well-being. Our water use can alter a city's energy balance, including how much solar energy is absorbed as heat or reflected back into space. The severity of these effects, and the need to better understand connections between climate, water extraction, water use, and water use impacts, is strongest in areas of climatic aridity and substantial land-use change, such as the rapidly urbanizing areas of Utah. We have gathered and analyzed stable water isotope data from a series of semi-annual hydrological surveys (spring and fall, 2013 and 2014) in urban tap water sampled across the Salt Lake Valley. Our study has led to four major findings thus far: 1) Clear and substantial variation in tap water isotopic composition in space and time that can be linked to different water sources and management practices within the urban area, 2) There is a strong correlation between the range of observed isotope values and the population of water districts, reflecting use of water from multiple local and non-local sources in districts with high water demand, 3) Water isotopes reflect significant and variable loss of water due to evaporation of surface water resources and 4) Overall, tap water contains lower concentrations of the heavy H and O isotopes than does precipitation within the basin, reflecting the connection between city water supplies and mountain water sources. Our results highlight the utility of isotopic data as an indicator of heterogeneities within urban water systems, management practices and their variation across a major metropolitan area, and effects of climate variability on urban water supplies

  16. Honeybee odometry: performance in varying natural terrain.

    Directory of Open Access Journals (Sweden)

    Juergen Tautz

    2004-07-01

    Full Text Available Recent studies have shown that honeybees flying through short, narrow tunnels with visually textured walls perform waggle dances that indicate a much greater flight distance than that actually flown. These studies suggest that the bee's "odometer" is driven by the optic flow (image motion that is experienced during flight. One might therefore expect that, when bees fly to a food source through a varying outdoor landscape, their waggle dances would depend upon the nature of the terrain experienced en route. We trained honeybees to visit feeders positioned along two routes, each 580 m long. One route was exclusively over land. The other was initially over land, then over water and, finally, again over land. Flight over water resulted in a significantly flatter slope of the waggle-duration versus distance regression, compared to flight over land. The mean visual contrast of the scenes was significantly greater over land than over water. The results reveal that, in outdoor flight, the honeybee's odometer does not run at a constant rate; rather, the rate depends upon the properties of the terrain. The bee's perception of distance flown is therefore not absolute, but scene-dependent. These findings raise important and interesting questions about how these animals navigate reliably.

  17. Biomarkers and Metabolic Patterns in the Sediments of Evolving Glacial Lakes as a Proxy for Planetary Lake Exploration.

    Science.gov (United States)

    Parro, Víctor; Blanco, Yolanda; Puente-Sánchez, Fernando; Rivas, Luis A; Moreno-Paz, Mercedes; Echeverría, Alex; Chong-Díaz, Guillermo; Demergasso, Cecilia; Cabrol, Nathalie A

    2016-11-28

    Oligotrophic glacial lakes in the Andes Mountains serve as models to study the effects of climate change on natural biological systems. The persistent high UV regime and evolution of the lake biota due to deglaciation make Andean lake ecosystems potential analogues in the search for life on other planetary bodies. Our objective was to identify microbial biomarkers and metabolic patterns that represent time points in the evolutionary history of Andean glacial lakes, as these may be used in long-term studies as microscale indicators of climate change processes. We investigated a variety of microbial markers in shallow sediments from Laguna Negra and Lo Encañado lakes (Región Metropolitana, Chile). An on-site immunoassay-based Life Detector Chip (LDChip) revealed the presence of sulfate-reducing bacteria, methanogenic archaea, and exopolymeric substances from Gammaproteobacteria. Bacterial and archaeal 16S rRNA gene sequences obtained from field samples confirmed the results from the immunoassays and also revealed the presence of Alpha-, Beta-, Gamma-, and Deltaproteobacteria, as well as cyanobacteria and methanogenic archaea. The complementary immunoassay and phylogenetic results indicate a rich microbial diversity with active sulfate reduction and methanogenic activities along the shoreline and in shallow sediments. Sulfate inputs from the surrounding volcanic terrains during deglaciation may explain the observed microbial biomarker and metabolic patterns, which differ with depth and between the two lakes. A switch from aerobic and heterotrophic metabolisms to anaerobic ones such as sulfate reduction and methanogenesis in the shallow shores likely reflects the natural evolution of the lake sediments due to deglaciation. Hydrodynamic deposition of sediments creates compartmentalization (e.g., sediments with different structure and composition surrounded by oligotrophic water) that favors metabolic transitions. Similar phenomena would be expected to occur on other

  18. Complex Terrain and Wind Lidars

    DEFF Research Database (Denmark)

    Bingöl, Ferhat

    software WAsP Engineering 2.0 and was well predicted except for some sectors where the terrain is particularly steep. Subsequently, two experiments were performed in forested areas; where the measurements are recorded at a location deep-in forest and at the forest edge. Both sites were modelled with flow...... edge, LINCOM model was used by allocating a slope half-in half out of the forest based on the suggestions of previous studies. The optimum slope angle was reported as 17º. Thus, a suggestion was made to use WAsP Engineering 2.0 for forest edge modelling with known limitations and the applied method...

  19. Archaean TTG of Vodlozero Terrain, Fennoscandian Shield

    Science.gov (United States)

    Chekulaev, Valery; Arestova, Natalia

    2014-05-01

    The Vodlozero terrain is the largest (about 270*240 km) early Archaean fragment of Fennoscandian Shield and composes its eastern part. The granitoids of TTG suite are predominant component of the terrain. The greenstone belts are placed along the margins of the terrain. Several stages of TTG formation can be distinguished in Achaean crust history. (1) The oldest TTG are trondhjemites and tonalities with age of 3240 Ma. They contain rare and small amphibolite inclusions of the same age. These TTG are characterized by high Sr (av. 412 ppm), Sr/Y (70), (La/Yb)n (54) and low Y (av. 7 ppm), Yb (0.32 ppm) and Nb (4 ppm). It was shown (Lobach-Zhuchenko et al., 2000), that the source of these TTG could be basic rocks, having composition similar with TH1 by K.Condie. (2) The tonalities and granodiorites with age of 3150 Ma are disposed near greenstone belts and contain compared to TTG of the first group less Sr (av. 250 ppm), Sr/Y (22), (La/Yb)n (18) and more K, Rb (av. 70 ppm), Ba (470 ppm), Y (11 ppm),Yb (1.16 ppm). TTG of both groups have identical T(DM)Nd (3250-3400 Ma) and differences in composition is evidently connected with lower level of source melting of the second group and also with K-metasomatism. The volcanics of the greenstone belts have age 3020 - 2940 Ma. Dykes of gabbro-amphibolites and andesites with the same age and composition cut TTG of the first and the second groups. The age of the third TTG group is about 2900 Ma ago. These rocks form leucosoma of migmatites within TTG of the second group. The composition of the third TTG and Nd isotope data suppose their origin by the melting of ancient TTG crust simultaneously with greenstone belt emplacement. The fourth TTG group with age 2780-2850 Ma forms a small intrusions, cutting older TTG and greenstone rocks. Their composition is similar to 3150 Ma TTG. Nd isotope data indicate that these TTG have younger (about 2850 Ma) source. Thus there are four TTG groups formed into interval more 400 Ma. The age and

  20. Lipid and compound-specific carbon isotope analysis of Lake Pupuke sediments as indicators of environmental change in the Auckland region over the last 50,000 years

    Science.gov (United States)

    Atkin, Daniel; Augustinus, Paul; Stephens, Thomas; Ficken, Katherine

    2010-05-01

    Lake Pupuke exists as a fresh water lake located on the North Shore of Auckland City, New Zealand. Accumulated sediments within Lake Pupuke represent a continuous record from crater formation ca. 200 Ka to Present, making them an important record of climatic change in northern New Zealand. Lipid composition and compound-specific carbon isotope analyses were carried out on Lake Pupuke sediment cores spanning ca. 50,000 cal. yr BP to Present. Compounds of interest included n-alkanes, n-alkanols, n-alkanoic acids and botryococcenes. Bulk sediment and compound-specific carbon isotope records exhibit a positive excursion during the period 18,000 to 27,000 cal. yr BP. This coincides with the Last Glacial Cold Period (LGCP) and in the absence of native C4 plant species most likely reflects decreased discrimination of the 13C isotope as a result of low pCO2. Termination of the glacial period occurs ca. 18,000 cal. yr BP and is defined by a steady increase in organic carbon content with a decrease in bulk and compound-specific δ13C which continues until ca. 10,000 cal. yr BP. Both aquatic and terrestrial biomarkers (represented by botryococcene and long chain n-alkyl compounds respectively) exhibit an increase in δ13C values beginning ca. 7,500 cal. yr BP through to present day. This is not reflected in the aquatic macrophyte biomarkers (mid chain length n-alkyl compounds) and may be caused by increased carbon recycling as a result of greater lake productivity and an increased canopy effect during this period. A marked increase in botryococcene biomarkers is noted during the period 7,500 to 9,500 cal. yr BP, reaching total concentrations as high as 19 mg/g. This is accompanied by a relative increase in C29 and C31 n-alkane terrestrial biomarkers. This zone is also evident to a lesser degree in the bulk sediment proxies, which exhibit increased carbon content, C/N ratio and δ13C values. The abundance of botryococcenes would suggest algal blooms of Botryococcus Braunii

  1. Waterfront on the Martian Planitia: Algorithmic emergent catchments on disordered terrain

    OpenAIRE

    Handmer, Casey J.

    2016-01-01

    Under a terraforming scenario, a reactivated hydrological cycle on Mars will result in upwards movement of water due to evaporation and precipitation. If Mars' embryonic fossilized catchments provide inadequate drainage, Mars' limited supplies of water may be absorbed entirely by crater lakes and glaciers, with negative consequences for the terraforming effort. We demonstrate a stable, convergent algorithm for the efficient modeling of water flow over disordered terrain. This model is applied...

  2. Comparison of ArcToolbox and Terrain Tiles processing procedures for inundation mapping in mountainous terrain.

    Science.gov (United States)

    Darnell, Andrew; Wise, Richard; Quaranta, John

    2013-01-01

    Floodplain management consists of efforts to reduce flood damage to critical infrastructure and to protect the life and health of individuals from flooding. A major component of this effort is the monitoring of flood control structures such as dams because the potential failure of these structures may have catastrophic consequences. To prepare for these threats, engineers use inundation maps that illustrate the flood resulting from high river stages. To create the maps, the structure and river systems are modeled using engineering software programs, and hydrologic events are used to simulate the conditions leading to the failure of the structure. The output data are then exported to other software programs for the creation of inundation maps. Although the computer programs for this process have been established, the processing procedures vary and yield inconsistent results. Thus, these processing methods need to be examined to determine the functionality of each in floodplain management practices. The main goal of this article is to present the development of a more integrated, accurate, and precise graphical interface tool for interpretation by emergency managers and floodplain engineers. To accomplish this purpose, a potential dam failure was simulated and analyzed for a candidate river system using two processing methods: ArcToolbox and Terrain Tiles. The research involved performing a comparison of the outputs, which revealed that both procedures yielded similar inundations for single river reaches. However, the results indicated key differences when examining outputs for large river systems. On the basis of criteria involving the hydrologic accuracy and effects on infrastructure, the Terrain Tiles inundation surpassed the ArcToolbox inundation in terms of following topography and depicting flow rates and flood extents at confluences, bends, and tributary streams. Thus, the Terrain Tiles procedure is a more accurate representation of flood extents for use by

  3. Application of atmospheric transport models for complex terrain

    International Nuclear Information System (INIS)

    King, D.S.; Bunker, S.S.

    1984-01-01

    Numerical modeling techniques are applied to several diverse situations to study mesoscale transport of effluents in the earth's atmosphere. Simulations of a tracer release in complex terrain are compared with experiments carried out in the Northern California Geysers area during a period when nighttime drainage flow was the dominant feature. In addition, we study two situations, the Idaho National Engineering Laboratory and the Savannah River Laboratory, for which the terrain is assumed to not be a factor. These involve large modeling areas and in one case, time periods extending over more than two diurnal cycles. These model simulations indicate that a diagnostic wind model utilizing terrain-following coordinates gives reasonable agreement with observations obtained over simple as well as complex terrain. In order to increase the accuracy in simulations of pollutant concentration distribution, much more refinement in wind measurements in space and time is needed since small differences in wind direction, for example, can produce a large difference in computed and measured concentration sufficiently downwind of a source

  4. Multiattribute prediction of terrain stability above underground mining operations

    Directory of Open Access Journals (Sweden)

    Vujić Slobodan

    2011-01-01

    Full Text Available This paper is dedicated to the problem of stability prediction of the terrain above underground mining operations. After the initial introduction to the problem, then the short analysis of the model approaches used to solve it, and giving the algorithm for rock massif stability prediction, we describe the concept of the multiattirbute terrain stability prediction method. The application of the multiattribute prediction method for stability of the terrain above underground mining operations is presented on the example of the Brown Coal Mine Aleksinac. The used method is original, essentially different from the other methods of mathematical modeling, because its prognosis of the rock massif stability under the influence of underground mining operations is based on the balance of the stability indicators. Our comparative analysis of the results obtained by multiattribute prediction and the data obtained by measurements of real deformations and terrain settling in multiple mines shows high mutual correlation, with an average deviation of less than ±10%. These results are confirmed entirely on the example of the Brown Coal Mine Aleksinac.

  5. Crenulated "Brain Terrain" in Arcadia Planitia, Mars

    Science.gov (United States)

    Williams, N. R.; Hibbard, S. M.; Golombek, M. P.

    2017-12-01

    The plains of Arcadia Planitia on Mars at 40°N and 200°E straddle the southern boundary of a latitude-dependent mantle (LDM) of shallow water-ice that holds key records for the planet's climate. Ice is not stable at mid-latitude surfaces today, but is expected to have precipitated in the past during different obliquities and climatic conditions with remnant excess ice preserved in the subsurface under a veneer of soil partially isolating it from the atmosphere. One indicator of ice in Arcadia is crenulated "brain coral" terrain comprised of alternating sinuous troughs and ridges, clearly resolved in 25 cm/pixel High Resolution Imaging Science Experiment (HiRISE) images. Similar morphologies have previously been identified in localized deposits within some craters at Utopia Planitia. However, this morphology is widespread in Arcadia - occurring over hundreds of kilometers and it transitions into pitted and more familiar polygonal terrain. It has been interpreted to form by differential sublimation of shallow subsurface ice, but the details of its formation and underlying structure are poorly understood leaving many basic questions unanswered. How much soil overburden is there, and how does soil thickness change from ridge to trough? Is the underlying ice pore-filling or massive? Why do the crenulations have a regular pattern with a consistent wavelength? What causes preferred orientations in some patches? No rocks are visible in the troughs, but are there any other foci that could cause differential sublimation over meter scales? Are there any direct analogs on Earth or icy satellites? And why is this morphology so widespread across the plains of Arcadia, but not elsewhere on Mars? Further analysis may shed light on this weird and wonderful morphology.

  6. Terrain Classification of Norwegian Slab Avalanche Accidents

    Science.gov (United States)

    Hallandvik, Linda; Aadland, Eivind; Vikene, Odd Lennart

    2016-01-01

    It is difficult to rely on snow conditions, weather, and human factors when making judgments about avalanche risk because these variables are dynamic and complex; terrain, however, is more easily observed and interpreted. Therefore, this study aimed to investigate (1) the type of terrain in which historical fatal snow avalanche accidents in Norway…

  7. Terrain assessment guidelines : CAGC best practice. Version 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This terrain classification assessment guideline discussed the steps required for personnel to understand terrain hazards present during seismic operations. Maps and other sources must be used to classify terrain steepness and surface conditions using geographical information systems (GIS), LIDAR, or satellite photographs. The impact of managing steep terrain within projects must also be considered when class 3, 4, 5, or 6 terrain has been identified. Terrains must also be classified according to colours. Secondary terrain assessments must be conducted when class 3, 4, 5, or 6 terrain has been identified. Terrain management plans should included methods of keeping untrained workers out of areas with classes greater than 3. Methods of entering and exiting steep terrain must be identified. Workers must be trained to work in areas with steep terrains. Methods of rescue and evacuation must also be established. Procedures were outlined for all terrain classes. Footwear, head protection and general safety requirements were outlined. 14 figs.

  8. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2009-06-01

    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  9. Lunar terrain mapping and relative-roughness analysis

    Science.gov (United States)

    Rowan, Lawrence C.; McCauley, John F.; Holm, Esther A.

    1971-01-01

    Terrain maps of the equatorial zone (long 70° E.-70° W. and lat 10° N-10° S.) were prepared at scales of 1:2,000,000 and 1:1,000,000 to classify lunar terrain with respect to roughness and to provide a basis for selecting sites for Surveyor and Apollo landings as well as for Ranger and Lunar Orbiter photographs. The techniques that were developed as a result of this effort can be applied to future planetary exploration. By using the best available earth-based observational data and photographs 1:1,000,000-scale and U.S. Geological Survey lunar geologic maps and U.S. Air Force Aeronautical Chart and Information Center LAC charts, lunar terrain was described by qualitative and quantitative methods and divided into four fundamental classes: maria, terrae, craters, and linear features. Some 35 subdivisions were defined and mapped throughout the equatorial zone, and, in addition, most of the map units were illustrated by photographs. The terrain types were analyzed quantitatively to characterize and order their relative-roughness characteristics. Approximately 150,000 east-west slope measurements made by a photometric technique (photoclinometry) in 51 sample areas indicate that algebraic slope-frequency distributions are Gaussian, and so arithmetic means and standard deviations accurately describe the distribution functions. The algebraic slope-component frequency distributions are particularly useful for rapidly determining relative roughness of terrain. The statistical parameters that best describe relative roughness are the absolute arithmetic mean, the algebraic standard deviation, and the percentage of slope reversal. Statistically derived relative-relief parameters are desirable supplementary measures of relative roughness in the terrae. Extrapolation of relative roughness for the maria was demonstrated using Ranger VII slope-component data and regional maria slope data, as well as the data reported here. It appears that, for some morphologically homogeneous

  10. Human Robotic Systems (HRS): Extreme Terrain Mobility Element

    Data.gov (United States)

    National Aeronautics and Space Administration — During 2014, the Extreme Terrain Mobility project element is developing five technologies:Exoskeleton Development for ISS EvaluationExtreme Terrain Mobility...

  11. Where and in What Quantity Are Lakes Observable by SWOT?

    Science.gov (United States)

    Sheng, Y.; Song, C.; Lettenmaier, D. P.; Ke, L.

    2016-12-01

    The SWOT mission's scientific requirements state that SWOT should provide a global inventory of terrestrial surface water bodies whose surface area exceeds 250x250 m2. However, our knowledge about locations and quantities of SWOT-observable lakes is rather limited. This research intends to produce a SWOT-observable lake map using our recently produced global lake database, SWOT orbits, and terrain layover effect simulation based on KaRIn's sensing geometry. The lake database was recently produced using 20,000+ Landsat images (and terrain data) acquired during lake-stable seasons in circa-2000, and captures 8 million lakes larger than 0.5 ha. This product has gone through nearly three-year's intensive quality assurance and quality control procedures, and provides a reliable inventory of global lakes. Based on this detailed database, we have produced a global map of lakes larger than 250x250 m2. We have found that about 28% of global lakes may be captured above this SWOT-targeted minimum size, but covering 94% of total lake area. However, SWOT may miss even more lakes due to its orbit design and SAR layover effects. To the end, SWOT swath coverages are generated from designed SWOT orbits and used to achieve the temporal coverage of these lakes to identify lakes partially or even completely missed by SWOT in gaps between orbits. In addition, terrain-induced layover effects on lakes are included in this study. Since the SWOT/KaRIn sensor will sense the Earth at near-nadir incidence, the SAR layover effects, expected to be serious and ubiquitous, occlude some lakes in relief areas entirely or partially. With all the above factors considered, this study will produce a SWOT-observable lake map and present a report about the impacts of SWOT orbit coverage and layover effects on lake observations, to directly address one of the key questions in the SWOT mission: "where are locations of lakes likely to be observable by SWOT prior to launch?"

  12. Hydrographic Basins Analysis Using Digital Terrain Modelling

    Science.gov (United States)

    Mihaela, Pişleagă; -Minda Codruţa, Bădăluţă; Gabriel, Eleş; Daniela, Popescu

    2017-10-01

    The paper, emphasis the link between digital terrain modelling and studies of hydrographic basins, concerning the hydrological processes analysis. Given the evolution of computing techniques but also of the software digital terrain modelling made its presence felt increasingly, and established itself as a basic concept in many areas, due to many advantages. At present, most digital terrain modelling is derived from three alternative sources such as ground surveys, photogrammetric data capture or from digitized cartographic sources. A wide range of features may be extracted from digital terrain models, such as surface, specific points and landmarks, linear features but also areal futures like drainage basins, hills or hydrological basins. The paper highlights how the use appropriate software for the preparation of a digital terrain model, a model which is subsequently used to study hydrographic basins according to various geomorphological parameters. As a final goal, it shows the link between digital terrain modelling and hydrographic basins study that can be used to optimize the correlation between digital model terrain and hydrological processes in order to obtain results as close to the real field processes.

  13. Terrain identification for RHex-type robots

    Science.gov (United States)

    Ordonez, Camilo; Shill, Jacob; Johnson, Aaron; Clark, Jonathan; Collins, Emmanuel

    2013-05-01

    Terrain identification is a key enabling ability for generating terrain adaptive behaviors that assist both robot planning and motor control. This paper considers running legged robots from the RHex family) which the military plans to use in the field to assist troops in reconnaissance tasks. Important terrain adaptive behaviors include the selection of gaits) modulation of leg stiffness) and alteration of steering control laws that minimize slippage) maximize speed and/or reduce energy consumption. These terrain adaptive behaviors can be enabled by a terrain identification methodology that combines proprioceptive sensors already available in RHex-type robots. The proposed classification approach is based on the characteristic frequency signatures of data from leg observers) which combine current sensing with a dynamic model of the leg motion. The paper analyzes the classification accuracy obtained using both a single leg and groups of legs (through a voting scheme) on different terrains such as vinyl) asphalt) grass) and pebbles. Additionally) it presents a terrain classifier that works across various gait speeds and in fact almost as good as an overly specialized classifier.

  14. Mechanisms Controlling Variability of Lake Salinity in Dune Environments in a Semi-arid Climate: The Nebraska Sand Hills (Invited)

    Science.gov (United States)

    Zlotnik, V. A.; Ong, J. T.; Swinehart, J. B.; Fritz, S. C.; Lenters, J. D.; Schmieder, J. U.; Lane, J. W.; Halihan, T.

    2010-12-01

    Shallow endorheic saline lakes are common in semi-arid environments in North America, Africa, Asia, and Australia. These lakes receive minimal surface runoff and are supported by groundwater seepage. A combination of hydrologic and geologic factors (regional groundwater flow, evaporation, precipitation, lake size, groundwater recharge, and geologic setting) may preclude seepage out of these lakes, even in the presence of ambient regional flow. Solutes from groundwater are captured by these lakes and become enriched over time by evaporation. The importance of understanding lake dynamics in these arid and semi-arid systems is increasing with societal concerns, including water availability and quality, the use of aquatic ecosystems by waterfowl and other biota, and dangers of dust emissions associated with lake desiccation. We consider the salinity of shallow lakes as a useful indicator of hydroclimatic factors operating at centennial and millennial scales. The Nebraska Sand Hills cover 58 000 km2 of the central Great Plains and are the largest dunefield in the Western Hemisphere. The grass-stabilized dunes attain heights up to 130 m and have been modified by soil development and erosion. In an area 4 ha and depths salinity of natural lakes in the Nebraska Sand Hills ranges from fresh (~0.3 g L-1) to hypersaline (>100 g L-1), with pH values as high as ~10. We assess the mechanisms that control lake salinity in a group of lakes with different subsurface flow regimes. Our methods combine aquifer coring, electromagnetic and electrical resistivity tomography geophysics, hydraulic testing, lakebed dating using 14C and optically stimulated luminescence, energy and water balance analysis, and salt crust and dust collection. Our theory and results show that terrain and water-table topography, lithology, and climate control the lake-aquifer solute exchanges. This study also brings attention to an underappreciated mechanism in the area, namely eolian deflation, which has not

  15. Shear wave velocity structure of the lower crust in southern Africa: evidence for compositional heterogeneity within Archaean and Proterozoic terrains

    CSIR Research Space (South Africa)

    Kgaswane, EM

    2009-12-01

    Full Text Available . For large parts of both Archaean and Proterozoic terrains, the velocity models obtained from the inversions show shear wave velocities =4.0 km/s below ~20–30 km depth, indicating a predominantly mafic lower crust. However, for much of the Kimberley terrain...

  16. DCS TERRAIN SUBMISSION FOR VOLUSIA COUNTY, FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  17. DCS TERRAIN SUBMISSION FOR PUTNAM COUNTY, FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  18. DCS TERRAIN SUBMISSION FOR SHELBY COUNTY, TN

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  19. DCS Terrain Submission for Lewis County, KY

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  20. DCS TERRAIN SUBMISSION FOR KNOX COUNTY, TN

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  1. DCS Terrain Submission for Mason County, KY

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  2. Fire whirlwind formation over flat terrain.

    Science.gov (United States)

    Donald A. Haines; Gerald H. Updike

    1971-01-01

    This paper examines the factors that lead to the genesis of fire whirlwinds over flat terrain. Also presented is an estimate of the number of days one might expect to encounter meteorological conditions that permit such formations.

  3. DCS Terrain Submission for Woodward, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. DCS Terrain for HOUSTON COUNTY, ALABAMA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain Submission for Houston TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  6. DCS Terrain Submission for Logan, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. TERRAIN, UPPER CUMBERLAND WATERSHED, PMR, TENNESSEE, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  8. DCS Terrain for ELBERT County, GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  9. DCS Terrain for Fannin County, GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  10. Terrain Data, Queen Anne's COUNTY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. TERRAIN Submission for CHISAGO COUNTY, MN

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  12. TERRAIN Submission for Forest Countywide DFIRM

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN Submission for Vilas Countywide DFIRM

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. Terrain, CEDAR RAPIDS, LINN COUNTY, IA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  15. TERRAIN, CERRO GORDO COUNTY, IOWA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. DCS Terrain Submission for Grady, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. DCS Terrain Submission for WHATCOM COUNTY, WASHINGTON

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. TERRAIN, VAN BUREN COUNTY, TN, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. DCS Terrain Submission for Rockland County NY

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  20. DCS Terrain Submission for Cass County, MO

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. DCS Terrain Submission for Bark River PMR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. DCS Terrain for Gilmer County, GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  3. DCS Terrain Submission for Carter, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. DCS Terrain for Williamson County, TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain Submission for Lee County MS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  6. DCS Terrain Submission for Mono, CA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. DCS TERRAIN Submission for STEARNS COUNTY, MN

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. DCS Terrain for Greer County, Oklahoma, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  9. DCS Terrain Submission for Angelina County, TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN, CITY OF DALLAS, DALLAS COUNTY, TEXAS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  11. DCS Terrain Submission for Sioux Falls

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  12. DCS Terrain Submission for Chippewa County, Wisconsin

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, ST. LOUIS COUNTY, Missouri USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. Terrain Sumbission for Howard County NE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  15. DCS Terrain for Washington County, GA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  16. TERRAIN Submission for Outagamie Countywide DFIRM

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. Terrain Adaptive Navigation for Mars Rovers

    Science.gov (United States)

    Matthies, Larry H.; Helmick, Daniel M.; Angelova, Anelia; Livianu, Matthew

    2007-01-01

    A navigation system for Mars rovers in very rough terrain has been designed, implemented, and tested on a research rover in Mars analog terrain. This navigation system consists of several technologies that are integrated to increase the capabilities compared to current rover navigation algorithms. These technologies include: goodness maps and terrain triage, terrain classification, remote slip prediction, path planning, high-fidelity traversability analysis (HFTA), and slip-compensated path following. The focus of this paper is not on the component technologies, but rather on the integration of these components. Results from the onboard integration of several of the key technologies described here are shown. Additionally, the results from independent demonstrations of several of these technologies are shown. Future work will include the demonstration of the entire integrated system described here.

  18. Digital Terrain Submittal for Duval County, FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. DCS Terrain Submission for Blount County, AL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  20. DCS Terrain Submission for Lancaster County, NE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  1. TERRAIN, UPPER CUMBERLAND WATERSHED, KENTUCKY USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  2. DCS Terrain Submission for Winston County, AL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  3. DCS Terrain Submission for Crittenden County AR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  4. TERRAIN-FREMONT COUNTY, WY, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain Submission for Ulster County NY

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  6. DCS Terrain Submission for Garvin, OK

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  7. DCS Terrain Submission for Nacogdoches County TX

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  8. DCS Terrain Submission for Benton County, AR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  9. DCS Terrain Submission for Chariton County, MO

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. Automatic terrain modeling using transfinite element analysis

    KAUST Repository

    Collier, Nathan

    2010-05-31

    An automatic procedure for modeling terrain is developed based on L2 projection-based interpolation of discrete terrain data onto transfinite function spaces. The function space is refined automatically by the use of image processing techniques to detect regions of high error and the flexibility of the transfinite interpolation to add degrees of freedom to these areas. Examples are shown of a section of the Palo Duro Canyon in northern Texas.

  11. Prediction of lake depth across a 17-state region in the United States

    Science.gov (United States)

    Oliver, Samantha K.; Soranno, Patricia A.; Fergus, C. Emi; Wagner, Tyler; Winslow, Luke A.; Scott, Caren E.; Webster, Katherine E.; Downing, John A.; Stanley, Emily H.

    2016-01-01

    Lake depth is an important characteristic for understanding many lake processes, yet it is unknown for the vast majority of lakes globally. Our objective was to develop a model that predicts lake depth using map-derived metrics of lake and terrestrial geomorphic features. Building on previous models that use local topography to predict lake depth, we hypothesized that regional differences in topography, lake shape, or sedimentation processes could lead to region-specific relationships between lake depth and the mapped features. We therefore used a mixed modeling approach that included region-specific model parameters. We built models using lake and map data from LAGOS, which includes 8164 lakes with maximum depth (Zmax) observations. The model was used to predict depth for all lakes ≥4 ha (n = 42 443) in the study extent. Lake surface area and maximum slope in a 100 m buffer were the best predictors of Zmax. Interactions between surface area and topography occurred at both the local and regional scale; surface area had a larger effect in steep terrain, so large lakes embedded in steep terrain were much deeper than those in flat terrain. Despite a large sample size and inclusion of regional variability, model performance (R2 = 0.29, RMSE = 7.1 m) was similar to other published models. The relative error varied by region, however, highlighting the importance of taking a regional approach to lake depth modeling. Additionally, we provide the largest known collection of observed and predicted lake depth values in the United States.

  12. Knowledge-inducing Global Path Planning for Robots in Environment with Hybrid Terrain

    Directory of Open Access Journals (Sweden)

    Yi-nan Guo

    2010-09-01

    Full Text Available In complex environment with hybrid terrain, different regions may have different terrain. Path planning for robots in such environment is an open NP-complete problem, which lacks effective methods. The paper develops a novel global path planning method based on common sense and evolution knowledge by adopting dual evolution structure in culture algorithms. Common sense describes terrain information and feasibility of environment, which is used to evaluate and select the paths. Evolution knowledge describes the angle relationship between the path and the obstacles, or the common segments of paths, which is used to judge and repair infeasible individuals. Taken two types of environments with different obstacles and terrain as examples, simulation results indicate that the algorithm can effectively solve path planning problem in complex environment and decrease the computation complexity for judgment and repair of infeasible individuals. It also can improve the convergence speed and have better computation stability.

  13. Dramatic water-level fluctuations in lakes under intense human impact: modelling the effect of vegetation, climate and hydrogeology

    Science.gov (United States)

    Vainu, M.

    2012-04-01

    Lakes form a highly important ecosystem in the glacial terrain of northern Europe and America, but their hydrology remains understudied. When the water-level of a lake drops significantly and rises again in a time span of half a century and the widespread explanation of the fluctuations seems insufficient, then it raises a question: how do different anthropogenic and natural processes actually affect the formation of a lakes' water body. The abovementioned scenario applies to three small closed-basin Estonian lakes (L. Ahnejärv, L. Kuradijärv and L. Martiska) analysed in the current study. These lakes suffered a major water-level drop (up to 3.8 m) between 1946 and 1987 and a major rise between 1987 and 2010, from 1 m (L. Ahnejärv) to 2.5 m (L. Kuradijärv). Decreasing and increasing groundwater abstraction near the lakes has been widely considered to be the only reason for the fluctuations. It is true that the most severe drop in the lake levels did occur after 1972 when groundwater abstraction for drinking water started in the vicinity of the lakes. However, the lake levels started to fall before the groundwater abstraction began and for the time being the lake levels have risen to a higher level than in the 1970s when the quantity of annually abstracted groundwater was similar to nowadays. Therefore the processes affecting the formation of the lakes' water body prove to be more complex than purely the hydrogeological change caused by groundwater abstraction. A new deterministic water balance model (where the evaporation from the lake surface was calculated by Penman equation and the catchment runoff by Thornthwaite-Mather soil-moisture model), compiled for the study, coupled with LiDAR-based GIS-modelling of the catchments was used to identify the different factors influencing the lakes' water level. The modelling results reveal that the moderate drop in lake water levels before the beginning of groundwater abstraction was probably caused by the growth of a

  14. Home destruction examination: Grass Valley Fire, Lake Arrowhead, California

    Science.gov (United States)

    Jack D. Cohen; Richard D. Stratton

    2008-01-01

    The Grass Valley Fire started October 22, 2007 at approximately 0508, one-mile west of Lake Arrowhead in the San Bernardino Mountains. Fuel and weather conditions were extreme due to drought, dry Santa Ana winds, and chaparral and conifer vegetation on steep terrain. The fire proceeded south through the Grass Valley drainage one-mile before impacting an area of dense...

  15. Bladed Terrain on Pluto: Possible origins and evolution

    Science.gov (United States)

    Moore, Jeffrey M.; Howard, Alan D.; Umurhan, Orkan M.; White, Oliver L.; Schenk, Paul M.; Beyer, Ross A.; McKinnon, William B.; Spencer, John R.; Singer, Kelsi N.; Grundy, William M.; Earle, Alissa M.; Schmitt, Bernard; Protopapa, Silvia; Nimmo, Francis; Cruikshank, Dale P.; Hinson, David P.; Young, Leslie A.; Stern, S. Alan; Weaver, Harold A.; Olkin, Cathy B.; Ennico, Kimberly; Collins, Geoffrey; Bertrand, Tanguy; Forget, François; Scipioni, Francesca; New Horizons Science Team

    2018-01-01

    Bladed Terrain on Pluto consists of deposits of massive CH4, which are observed to occur within latitudes 30° of the equator and are found almost exclusively at the highest elevations (> 2 km above the mean radius). Our analysis indicates that these deposits of CH4 preferentially precipitate at low latitudes where net annual solar energy input is lowest. CH4 and N2 will both precipitate at low elevations. However, since there is much more N2 in the atmosphere than CH4, the N2 ice will dominate at these low elevations. At high elevations the atmosphere is too warm for N2 to precipitate so only CH4 can do so. We conclude that following the time of massive CH4 emplacement; there have been sufficient excursions in Pluto's climate to partially erode these deposits via sublimation into the blades we see today. Blades composed of massive CH4 ice implies that the mechanical behavior of CH4 can support at least several hundred meters of relief at Pluto surface conditions. Bladed Terrain deposits may be widespread in the low latitudes of the poorly seen sub-Charon hemisphere, based on spectral observations. If these locations are indeed Bladed Terrain deposits, they may mark heretofore unrecognized regions of high elevation.

  16. Selection method of terrain matching area for TERCOM algorithm

    Science.gov (United States)

    Zhang, Qieqie; Zhao, Long

    2017-10-01

    The performance of terrain aided navigation is closely related to the selection of terrain matching area. The different matching algorithms have different adaptability to terrain. This paper mainly studies the adaptability to terrain of TERCOM algorithm, analyze the relation between terrain feature and terrain characteristic parameters by qualitative and quantitative methods, and then research the relation between matching probability and terrain characteristic parameters by the Monte Carlo method. After that, we propose a selection method of terrain matching area for TERCOM algorithm, and verify the method correctness with real terrain data by simulation experiment. Experimental results show that the matching area obtained by the method in this paper has the good navigation performance and the matching probability of TERCOM algorithm is great than 90%

  17. Improved Inlet Conditions for Terrain CFD

    DEFF Research Database (Denmark)

    Pedersen, Jesper Grønnegaard

    The atmospheric boundary layer flow over different types of terrain is studied through simulations made with the finite volume CFD code of Ellipsys 2D and 3D. The simulations are compared to measurements made at the Høvsøre test site and over the hill of Askervein.The primary objective...... for describing the flow after a change in the surface roughness. The derivation of these expressions is based on a range of simulations of flows over flat terrain with different types of roughness changes.The derived expressions show good agreement with simulations and could, as intended, be used to define inlet...... conditions for flow simulations over terrain, where an upstream roughness change is thought to have an influence. More thorough experimental verification is however, thought necessary to make the expressions sufficiently reliable. The same goes for the simulations-based conclusions regarding the flow over...

  18. Satellite Monitoring and Characterization of the 2010 Rockslide-Dammed Lake Gojal, North Pakistan

    Science.gov (United States)

    Leonard, G. J.; Kargel, J. S.; Crippen, R. E.; Evans, S. G.; Delaney, K. B.; Schneider, J. F.

    2010-12-01

    On January 4, 2010, a landslide blocked the Hunza River at Attabad, northern Pakistan (36.308°N, 74.820°E). The landslide destroyed the village of Attabad killing 19 people, and formed a dam approximately 1200m long, 350 meters wide, and 125 meters high. The flow of the Hunza river was blocked for 144 days, forming Lake Gojal. In addition to inundating several villages and submerging 22 km of the regionally critical Karakoram Highway, >25,000 people have been displaced or remain cut off from overland connection with the rest of the country. Lake overtopping began on May 29 via a 15m deep spillway excavated through the saddle of the dam. Remarkably, the slowly eroding natural structure remains largely intact and currently represents a new geologic feature, although a threat remains from possible catastrophic outburst flooding. We have monitored growth of the lake with multi-temporal satellite imagery collected from ASTER (Advanced Spaceborne Thermal and Reflection Radiometer) and ALI (Advanced Land Imager) sensors. We applied NASA’s ASTER Global Digital Elevation Model (GDEM) and SRTM-3 digital terrain data, along with field data obtained onsite by Schneider, and by Pakistan’s NDMA to derive volumes of the growing lake. Lake size peaked during mid-summer when it was ~22 km long, 12 km2, 119m deep, and contained 540 to 620 Mm3 water (SRTM-3 and GDEM +5m global correction estimates respectively). Our estimates indicated lake volumes three to four times higher than media quotes, and before spillover, were used to improve predictions of possible flood discharge and disaster management planning. Estimates of valley inflow based on a 31-year hydrographic history (Archer, D., 2003, Jour. Hydrology 274, 198-210) are consistent with our volume infilling estimates. As early as April 14 our volume assessments, coupled with hydrographic and seepage data were used to project a spillover date range of May 28-June 2, bracketing the actual overflow date. Additionally, we have

  19. PILOT STUDIES WITH A PHOTOGRAMMETRIC GLACIER LAKE OUTBURST FLOOD EARLY WARNING SYSTEM

    Directory of Open Access Journals (Sweden)

    H. G. Maas

    2012-07-01

    Full Text Available Glacier Lake Outburst Floods (GLOFs depict an environmental risk with an increasing damage potential in many regions of the world. GLOFs are often caused by glacier margin lakes, which suddenly find a drainage path underneath the bottom of a glacier, which is destabilized and retreating as a consequence of local or global climate changes. In a typical GLOF event, a glacier margin lake may drain completely in 24 hours, causing a large flood wave in the area downstream the glacier. The paper documents some recent GLOF events in the Northern Patagonian Icefield (Chile and presents a terrestrial photogrammetric glacier margin lake monitoring system. The system is based on a camera taking images at regular time intervals. In these images, variations of the water level can be detected by tracking the water-land interface at pre-defined image spots. Due to the drainage mechanism, which is characterized by progressive erosion and melting at the bottom of the glacier, GLOFs are indicated by a progressive water level drop in the lake. Water level changes may be detected with subpixel accuracy by image sequence processing methods. If a 3D model of the lake bottom topography (or at least one height profile through the lake exists, water level changes in monoscopic image sequences may be transformed into volume loss. The basic idea herein is the intersection of a terrain profile with a water level detected in the image and projected into object space. The camera orientation is determined through a GPS-supported photogrammetric network. Camera orientation changes, which may for instance be induced by wind, can be compensated by tracking some fiducial marks in the image. The system has been used in a pilot study at two glacier margin lakes in the Northern Patagonian Icefield. These lakes have a depth of about 80 - 100 meters. The larger one has a length of 5 km and a maximum volume of about 200,000,000 cubic meters. During the pilot study, several GLOF events

  20. Playa Lakes

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital dataset provides information about the spatial distribution of soil units associated with playa lakes. Specific soil types have been designated by the...

  1. Lake Cadagno

    DEFF Research Database (Denmark)

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

    2017-01-01

    Lake Cadagno (26 ha) is a crenogenic meromictic lake located in the Swiss Alps at 1921 m asl with a maximum depth of 21 m. The presence of crystalline rocks and a dolomite vein rich in gypsum in the catchment area makes the lake a typical “sulphuretum ” dominated by coupled carbon and sulphur...... cycles. The chemocline lies at about 12 m depth, stabilized by density differences of salt-rich water supplied by sub-aquatic springs to the monimolimnion and of electrolyte-poor surface water feeding the mixolimnion. Steep sulphide and light gradients in the chemocline support the growth of a large...... in the chemocline. Small-celled PSB together with the sulfate-reducing bacterium Desulfocapsa thiozymogenes sp. form stable aggregates in the lake, which represent small microenvironments with an internal sulphur cycle. Eukaryotic primary producers in the anoxic zones are dominated by Cryptomonas phaseolus...

  2. Digital terrain model generalization incorporating scale, semantic and cognitive constraints

    Science.gov (United States)

    Partsinevelos, Panagiotis; Papadogiorgaki, Maria

    2014-05-01

    Cartographic generalization is a well-known process accommodating spatial data compression, visualization and comprehension under various scales. In the last few years, there are several international attempts to construct tangible GIS systems, forming real 3D surfaces using a vast number of mechanical parts along a matrix formation (i.e., bars, pistons, vacuums). Usually, moving bars upon a structured grid push a stretching membrane resulting in a smooth visualization for a given surface. Most of these attempts suffer either in their cost, accuracy, resolution and/or speed. Under this perspective, the present study proposes a surface generalization process that incorporates intrinsic constrains of tangible GIS systems including robotic-motor movement and surface stretching limitations. The main objective is to provide optimized visualizations of 3D digital terrain models with minimum loss of information. That is, to minimize the number of pixels in a raster dataset used to define a DTM, while reserving the surface information. This neighborhood type of pixel relations adheres to the basics of Self Organizing Map (SOM) artificial neural networks, which are often used for information abstraction since they are indicative of intrinsic statistical features contained in the input patterns and provide concise and characteristic representations. Nevertheless, SOM remains more like a black box procedure not capable to cope with possible particularities and semantics of the application at hand. E.g. for coastal monitoring applications, the near - coast areas, surrounding mountains and lakes are more important than other features and generalization should be "biased"-stratified to fulfill this requirement. Moreover, according to the application objectives, we extend the SOM algorithm to incorporate special types of information generalization by differentiating the underlying strategy based on topologic information of the objects included in the application. The final

  3. IN LAKE TANA, ETHIOPIA

    African Journals Online (AJOL)

    biomass in the diet of small barbs (Eshete Dejen,. 2003). This indicates that the higher biomass of T. galebi throughout the year is possibly due to its poor consumption by the small zooplanktivorous barbs. High variability in mean dry mass of tropical copepods is reported (Table 3). In Lake Naivasha. (Kenya), Mavuti (1994) ...

  4. Trace-metal and organic constituent concentrations in bed sediment at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas—Comparisons to sediment-quality guidelines and indications for timing of exposure

    Science.gov (United States)

    Justus, B.G.; Hays, Phillip D.; Hart, Rheannon M.

    2015-09-16

    This report compares concentrations for a wide range of inorganic and organic constituents in bed sediment from Big Base Lake and Little Base Lake, which are located on Little Rock Air Force Base, Arkansas, to sediment-quality guidelines. This report also compares trace-metal concentrations in a bed-sediment core sample to sediment age to determine when the highest concentrations of trace metals were deposited in Big Base Lake.

  5. Processes Modifying Cratered Terrains on Pluto

    Science.gov (United States)

    Moore, J. M.

    2015-01-01

    The July encounter with Pluto by the New Horizons spacecraft permitted imaging of its cratered terrains with scales as high as approximately 100 m/pixel, and in stereo. In the initial download of images, acquired at 2.2 km/pixel, widely distributed impact craters up to 260 km diameter are seen in the near-encounter hemisphere. Many of the craters appear to be significantly degraded or infilled. Some craters appear partially destroyed, perhaps by erosion such as associated with the retreat of scarps. Bright ice-rich deposits highlight some crater rims and/or floors. While the cratered terrains identified in the initial downloaded images are generally seen on high-to-intermediate albedo surfaces, the dark equatorial terrain informally known as Cthulhu Regio is also densely cratered. We will explore the range of possible processes that might have operated (or still be operating) to modify the landscape from that of an ancient pristinely cratered state to the present terrains revealed in New Horizons images. The sequence, intensity, and type of processes that have modified ancient landscapes are, among other things, the record of climate and volatile evolution throughout much of the Pluto's existence. The deciphering of this record will be discussed. This work was supported by NASA's New Horizons project.

  6. Terrain mapping camera for Chandrayaan-1

    Indian Academy of Sciences (India)

    The Terrain Mapping Camera (TMC) on India's first satellite for lunar exploration, Chandrayaan-1, is for generating high-resolution 3-dimensional maps of the Moon. With this instrument, a complete topographic map of the Moon with 5 m spatial resolution and 10-bit quantization will be available for scientific studies.

  7. Declarative terrain modeling for military training games

    NARCIS (Netherlands)

    Smelik, R.M.; Tutenel, T.; Kraker, J.K.. de; Bidarra, R.

    2010-01-01

    Military training instructors increasingly often employ computer games to train soldiers in all sorts of skills and tactics. One of the difficulties instructors face when using games as a training tool is the creation of suitable content, including scenarios, entities, and corresponding terrain

  8. Maintaining Contour Trees of Dynamic Terrains

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Mølhave, Thomas; Revsbæk, Morten

    2015-01-01

    We study the problem of maintaining the contour tree T of a terrain Sigma, represented as a triangulated xy-monotone surface, as the heights of its vertices vary continuously with time. We characterize the combinatorial changes in T and how they relate to topological changes in Sigma. We present ...

  9. Vehicle Sprung Mass Estimation for Rough Terrain

    Science.gov (United States)

    2011-03-01

    a vehicle driving on rough terrain. An accurate onboard estimate of vehicle mass is valuable to active safety systems as well as chassis and... Automobile Eng., Vol. 214, No. 8, pp. 851-864. Kubus, D., Kröger, T, and Wahl, F.M., (2008), „On-line estimation of inertial parameters using a

  10. L-Lake macroinvertebrate community

    International Nuclear Information System (INIS)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake's macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors

  11. L-Lake macroinvertebrate community

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  12. Aquatic macrophytes as indicators of water quality in subtropical shallow lakes, Southern Brazil Macrófitas aquáticas como indicadores da qualidade da água em pequenos lagos rasos subtropicais, Sul do Brasil

    Directory of Open Access Journals (Sweden)

    Sabrina Amaral Pereira

    2012-03-01

    Full Text Available AIMS: We evaluated the potential of aquatic macrophyte communities as bioindicators in six small shallow lakes. METHODS: The sampling was conducted monthly for one year, during which all macrophytes were surveyed, and the water temperature, dissolved oxygen, pH, conductivity, total alkalinity, chlorophyll-a, suspended matter, total nitrogen (Nt and total phosphorus (Pt were measured. RESULTS: In total, forty-three species were recorded, and there were significant differences in the species richness and limnological conditions among the lakes studied. A canonical correspondence analysis showed that the concentration of nutrients (Nt and Pt, chlorophyll-a, suspended matter, dissolved oxygen and pH were the most important predictors of the distribution of macrophytes. Some emergents were related to the high concentration of nutrients, chlorophyll-a, and suspended matter. Moreover, the most submersed species were associated with environments with low nutrient concentrations and the lowest values chlorophyll-a and suspended matter. In addition, some species submerged and floating were related to low values pH, alkalinity and dissolved oxygen. Limnological differences between lakes may be cited as the main causes of the observed heterogeneous distribution of macrophytes. CONCLUSIONS: These results indicate the importance of limnological characteristics of the different environments in the macrophyte community composition and the potential role of this community as a bioindicator in shallow lakes in southern Brazil.OBJETIVO: Foi avaliado o potencial bioindicador da comunidade de macrófitas aquáticas em seis pequenos lagos rasos. MÉTODOS: O acompanhamento foi mensal durante um ano, sendo que em cada coleta, além do registro de todas as espécies de macrófitas foram determinadas a temperatura da água, oxigênio dissolvido, pH, condutividade elétrica, alcalinidade total, clorofila-a, material em suspensão, nitrogênio total (Nt e fósforo total

  13. Trophic diversity of Poznań Lakeland lakes

    OpenAIRE

    Dzieszko Piotr; Zwoliński Zbigniew

    2015-01-01

    The main goal of the presented work is to determine the current trophic state of 31 lakes located in Poznań Lakeland. These lakes are included in the lake monitoring programme executed by the Voivodship Environmental Protection Inspectorate in Poznań. The place in the trophic classification for investigated lakes was determined as well as the relationships between their trophic state indices. The trophic state of investigated lakes in the research area is poor. More than a half of the investi...

  14. Glacial Lake Lind, Wisconsin and Minnesota

    Science.gov (United States)

    Johnson, M.D.; Addis, K.L.; Ferber, L.R.; Hemstad, C.B.; Meyer, G.N.; Komai, L.T.

    1999-01-01

    Glacial Lake Lind developed in the pre-late Wisconsinan St. Croix River valley, Minnesota and Wisconsin, and lasted more than 1000 yr during the retreat of the Superior lobe at the end of the Wisconsinan glaciation. Lake Lind sediment consists primarily of red varved silt and clay, but also includes mud-flow deposits, nearshore silt (penecontemporaneously deformed in places), nearshore rippled sand, and deltaic sand. Lake Lind varved red clay is not part of glacial Lake Grantsburg, as suggested by earlier authors, because the red varves are separated from overlying glacial Lake Grantsburg silt and clay by a unit of deltaic and fluvial sand. Furthermore, varve correlations indicate that the base of the red varves is younger to the north, showing that the basin expanded as the Superior lobe retreated and was not a lake basin dammed to the southwest by the advancing Grantsburg sublobe. Varve correlations indicate that the Superior lobe retreated at a rate of about 200 m/yr. Uniform winter-clay thickness throughout most of the varve couplets suggests thermal stratification in the lake with clay trapped in the epilimnion; some clay would exit the lake at the outlet prior to winter freeze. Zones of thicker winter-clay layers, in places associated with mud-flow layers, indicate outlet incision, lake-level fall, and shoreline erosion and resuspension of lake clay. The most likely outlet for glacial Lake Lind was in the southwest part of the lake near the present site of Minneapolis, Minnesota. Nearshore sediment indicates that the lake level of glacial Lake Lind was around 280 m. The elevation of the base of the Lake Lind sediments indicates water depth was 20 to 55 m. Evidence in the southern part of the lake basin suggests that the Superior lobe readvanced at least once during the early stages of glacial Lake Lind. Lake Lind ended not by drainage but by being filled in by prograding deltas and outwash plains composed of sand derived from the retreating Superior lobe. It

  15. Trophic diversity of Poznań Lakeland lakes

    Directory of Open Access Journals (Sweden)

    Dzieszko Piotr

    2015-06-01

    Full Text Available The main goal of the presented work is to determine the current trophic state of 31 lakes located in Poznań Lakeland. These lakes are included in the lake monitoring programme executed by the Voivodship Environmental Protection Inspectorate in Poznań. The place in the trophic classification for investigated lakes was determined as well as the relationships between their trophic state indices. The trophic state of investigated lakes in the research area is poor. More than a half of the investigated lakes are eutrophic. Depending on the factor that is taken into account the trophic state of investigated lakes differs radically.

  16. Ice formation in subglacial Lake Vostok, Central Antarctica

    Science.gov (United States)

    Souchez, R.; Petit, J. R.; Tison, J.-L.; Jouzel, J.; Verbeke, V.

    2000-09-01

    The investigation of chemical and isotopic properties in the lake ice from the Vostok ice core gives clues to the mechanisms involved in ice formation within the lake. A small lake water salinity can be reasonably deduced from the chemical data. Possible implications for the water circulation of Lake Vostok are developed. The characteristics of the isotopic composition of the lake ice indicate that ice formation in Lake Vostok occurred by frazil ice crystal generation due to supercooling as a consequence of rising waters and a possible contrast in water salinity. Subsequent consolidation of the developed loose ice crystals results in the accretion of ice to the ceiling of the lake.

  17. [Spatial Distribution Characteristics of Different Species Mercury in Water Body of Changshou Lake in Three Gorges Reservoir Region].

    Science.gov (United States)

    Bai, Wei-yang; Zhang, Cheng; Zhao, Zheng; Tang, Zhen-ya; Wang, Ding-yong

    2015-08-01

    An investigation on the concentrations and the spatial distribution characteristics of different species of mercury in the water body of Changshou Lake in Three Gorges Reservoir region was carried out based on the AreGIS statistics module. The results showed that the concentration of the total mercury in Changshou Lake surface water ranged from 0.50 to 3.78 ng x L(-1), with an average of 1.51 ng x L(-1); the concentration of the total MeHg (methylmercury) ranged from 0.10 to 0.75 ng x L(-1), with an average of 0.23 ng x L(-1). The nugget effect value of total mercury in surface water (50.65%), dissolved mercury (49.80%), particulate mercury (29.94%) and the activity mercury (26.95%) were moderate spatial autocorrelation. It indicated that the autocorrelation was impacted by the intrinsic properties of sediments (such as parent materials and rocks, geological mineral and terrain), and on the other hand it was also disturbed by the exogenous input factors (such as aquaculture, industrial activities, farming etc). The nugget effect value of dissolved methylmercury (DMeHg) in Changshou lake surface water (3.49%) was less than 25%, showing significant strong spatial autocorrelation. The distribution was mainly controlled by environmental factors in water. The proportion of total MeHg in total Hg in Changshou Lake water reached 30% which was the maximum ratio of the total MeHg to total Hg in freshwater lakes and rivers. It implied that mercury was easily methylated in the environment of Chanashou Lake.

  18. Method for estimating road salt contamination of Norwegian lakes

    Science.gov (United States)

    Kitterød, Nils-Otto; Wike Kronvall, Kjersti; Turtumøygaard, Stein; Haaland, Ståle

    2013-04-01

    Consumption of road salt in Norway, used to improve winter road conditions, has been tripled during the last two decades, and there is a need to quantify limits for optimal use of road salt to avoid further environmental harm. The purpose of this study was to implement methodology to estimate chloride concentration in any given water body in Norway. This goal is feasible to achieve if the complexity of solute transport in the landscape is simplified. The idea was to keep computations as simple as possible to be able to increase spatial resolution of input functions. The first simplification we made was to treat all roads exposed to regular salt application as steady state sources of sodium chloride. This is valid if new road salt is applied before previous contamination is removed through precipitation. The main reasons for this assumption are the significant retention capacity of vegetation; organic matter; and soil. The second simplification we made was that the groundwater table is close to the surface. This assumption is valid for major part of Norway, which means that topography is sufficient to delineate catchment area at any location in the landscape. Given these two assumptions, we applied spatial functions of mass load (mass NaCl pr. time unit) and conditional estimates of normal water balance (volume of water pr. time unit) to calculate steady state chloride concentration along the lake perimeter. Spatial resolution of mass load and estimated concentration along the lake perimeter was 25 m x 25 m while water balance had 1 km x 1 km resolution. The method was validated for a limited number of Norwegian lakes and estimation results have been compared to observations. Initial results indicate significant overlap between measurements and estimations, but only for lakes where the road salt is the major contribution for chloride contamination. For lakes in catchments with high subsurface transmissivity, the groundwater table is not necessarily following the

  19. Great Lakes

    Science.gov (United States)

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

  20. EARTHWORK VOLUME CALCULATION FROM DIGITAL TERRAIN MODELS

    Directory of Open Access Journals (Sweden)

    JANIĆ Milorad

    2015-06-01

    Full Text Available Accurate calculation of cut and fill volume has an essential importance in many fields. This article shows a new method, which has no approximation, based on Digital Terrain Models. A relatively new mathematical model is developed for that purpose, which is implemented in the software solution. Both of them has been tested and verified in the praxis on several large opencast mines. This application is developed in AutoLISP programming language and works in AutoCAD environment.

  1. Mapping the Human Terrain in Afghanistan

    Science.gov (United States)

    2010-04-16

    attention when one must cover the entire gamut of possible considerations. This paper seeks to focus on a few key items that serve as enablers for the main...forensic discipline. Human terrain analysis ( HTA ) is defined as a process that is part of the intelligence cycle that should shape pre-deployment...colleagues detailed the HTTs, their deliverables to the Brigade Combat Team (BCT), and their reachback capability, but also drew appropriate attention to the

  2. Effects of complex terrain on net surface longwave radiation in China

    Science.gov (United States)

    Zhu, Xiaochen; Qiu, Xinfa; Zeng, Yan; Ren, Wei; Tao, Bo; Gao, Jiaqi; Liu, Haobo; Tan, Yunjuan

    2017-09-01

    Net surface longwave radiation (NSLR) is one of key meteorological factors and is strongly influenced by cloud cover, surface temperature, humidity, and local micrometeorological conditions as well as terrain conditions. Realistically estimating NSLR is vitally important for understanding surface radiation balance and investigating micrometeorological factors of air pollution dispersion, especially in regions with complicated terrain. In this study, we proposed a distributed model for estimating NSLR by considering effects of complex local terrain conditions in China. Meteorological data (including mean temperature, relative humidity, and sunshine percentage) and observed NSLR data from 1993 to 2001 together with the digital elevation model data were used to parametrize the model and account for the effects of atmospheric factors and surface terrain factors according to the isotropic principle. The monthly NSLR during 1961-2000 was estimated at a spatial resolution of 1 km. Topographic analysis suggests that the distribution characteristics of NSLR with elevation or slope are consistent with those of field observations. In particular, the estimated NSLR is favorably comparable with site-level observations on the Tibetan Plateau (average relative error < 11%). Our results indicate that this model can describe microscale distribution features in mountainous areas in detail and that this improved approach can be used for NSLR spatial estimation in other regions with complicated terrain.

  3. Analysing wind farm efficiency on complex terrains

    International Nuclear Information System (INIS)

    Castellani, Francesco; Astolfi, Davide; Terzi, Ludovico; Hansen, Kurt Schaldemose; Rodrigo, Javier Sanz

    2014-01-01

    Actual performances of onshore wind farms are deeply affected both by wake interactions and terrain complexity: therefore monitoring how the efficiency varies with the wind direction is a crucial task. Polar efficiency plot is therefore a useful tool for monitoring wind farm performances. The approach deserves careful discussion for onshore wind farms, where orography and layout commonly affect performance assessment. The present work deals with three modern wind farms, owned by Sorgenia Green, located on hilly terrains with slopes from gentle to rough. Further, onshore wind farm of Nprrekffir Enge has been analysed as a reference case: its layout is similar to offshore wind farms and the efficiency is mainly driven by wakes. It is shown and justified that terrain complexity imposes a novel and more consistent way for defining polar efficiency. Dependency of efficiency on wind direction, farm layout and orography is analysed and discussed. Effects of atmospheric stability have been also investigated through MERRA reanalysis data from NASA satellites. Monin-Obukhov Length has been used to discriminate climate regimes

  4. Mobility versus terrain: a game theoretic approach

    Science.gov (United States)

    Bednarz, David; Muench, Paul

    2016-05-01

    Mobility and terrain are two sides of the same coin. You cannot describe mobility unless you describe the terrain. For example, if my world is trench warfare, the tank may be the ideal vehicle. If my world is urban warfare, clearing buildings and such, the tank may not be an ideal vehicle, perhaps an anthropomorphic robot would be better. We seek a general framework for mobility that captures the relative value of different mobility strategies. Game theory is positively the right way to analyze the interactions of rational players who behave strategically. In this paper, we will describe the interactions between a mobility player, who is trying to make it from point A to point B with one chance to refuel, and a terrain player who is trying to minimize that probability by placing an obstacle somewhere along the path from A to B. In previous work [1], we used Monte Carlo methods to analyze this mobility game, and found optimal strategies for a discretized version of the game. Here we show the relationship of this game to a classic game of timing [2], and use solution methods from that literature to solve for optimal strategies in a continuous version of this mobility game.

  5. Sedimentary constraints on late Quaternary lake-level fluctuations at Bear Lake, Utah and Idaho

    Science.gov (United States)

    Smoot, J.P.; Rosenbaum, J.G.

    2009-01-01

    A variety of sedimentological evidence was used to construct the lake-level history for Bear Lake, Utah and Idaho, for the past ???25,000 years. Shorelines provide evidence of precise lake levels, but they are infrequently preserved and are poorly dated. For cored sediment similar to that in the modern lake, grain-size distributions provide estimates of past lake depths. Sedimentary textures provide a highly sensitive, continuous record of lake-level changes, but the modern distribution of fabrics is poorly constrained, and many ancient features have no modern analog. Combining the three types of data yields a more robust lake-level history than can be obtained from any one type alone. When smooth age-depth models are used, lake-level curves from multiple cores contain inconsistent intervals (i.e., one record indicates a rising lake level while another record indicates a falling lake level). These discrepancies were removed and the multiple records were combined into a single lake-level curve by developing age-depth relations that contain changes in deposition rate (i.e., gaps) where indicated by sedimentological evidence. The resultant curve shows that, prior to 18 ka, lake level was stable near the modern level, probably because the lake was overflowing. Between ca. 17.5 and 15.5 ka, lake level was ???40 m below the modern level, then fluctuated rapidly throughout the post-glacial interval. Following a brief rise centered ca. 15 ka ( = Raspberry Square phase), lake level lowered again to 15-20 m below modern from ca. 14.8-11.8 ka. This regression culminated in a lowstand to 40 m below modern ca. 12.5 ka, before a rapid rise to levels above modern ca. 11.5 ka. Lake level was typically lower than present throughout the Holocene, with pronounced lowstands 15-20 m below the modern level ca. 10-9, 7.0, 6.5-4.5, 3.5, 3.0-2.5, 2.0, and 1.5 ka. High lake levels near or above the modern lake occurred ca. 8.5-8.0, 7.0-6.5, 4.5-3.5, 2.5, and 0.7 ka. This lake-level history

  6. Megasplash at Lake Tahoe

    Science.gov (United States)

    Moore, J. G.; Schweickert, R. A.

    2013-12-01

    Backwash from a major ~10 km3 landslide in Lake Tahoe washed away Tioga age (21 ka) moraines (Schweickert, et al 2000; Howle, 2012). Coring in the lake demonstrates a 7700-8000 yr Mt. Mazama ash is widely distributed in lake sediments that overlie the landslide blocks. Moreover, core stratigraphy and radiocarbon ages indicate that all of the sediments cored (to about 3 m depth reaching back 12 ka) were deposited after the landslide (Smith et al., 2013). The age of the landslide is hence constrained at 12-21 ka. Fifteen major subaqueous sand wave channels 2.5 to 10.2 km in length originate from subaqueous delta-terraces at depths of 5-28 m on the margins of the lake. The channels, apparently formed by turbidity currents, are distinctly erosional in their upper part, and transform to deposition aprons in their lower part as they approach the flat lake floor at 500 m depth. The channels contain wave forms (giant ripple marks) convex upstream with maximum wavelengths of 450 m. The lower depositional aprons are surfaced by sand waves convex downstream with maximum wavelengths of 100-300 m. Sand wave convexity mimics the contour of the substrate. The sand wave channel systems are mantled by the post-slide 12 ka sediments and hence have been inactive since that time. These channel-fan structures were apparently produced by backwash from the giant Tahoe landslide, which splashed ~5 km3 of water onto the surrounding countryside thereby lowering lake level by ~10 m. The sediment-charged backwash first deposited the delta-terraces at the lowered lake level and then partly eroded them to generate the sand wave channels, within minutes or hours, while seiche activity resurfaced the delta-terraces. A remarkably similar, though smaller, presently-forming system of turbidity sand wave channels has been imaged at the mouth of the Squamish River in British Columbia (Hughes Clark et al., 2012). The Tahoe splash-induced backwash was briefly equivalent to more than fifteen Squamish

  7. Fast integral equation algorithms for the solution of electromagnetic wave propagation over general terrains

    Directory of Open Access Journals (Sweden)

    Ibrahim K. Abu Seif

    2015-01-01

    Full Text Available In this paper a fast numerical algorithm to solve an integral equation model for wave propagation along a perfectly conducting two-dimensional terrain is suggested. It is applied to different actual terrain profiles and the results indicate very good agreement with published work. In addition, the proposed algorithm has achieved considerable saving in processing time. The formulation is extended to solve the propagation over lossy dielectric surfaces. A combined field integral equation (CFIE for wave propagation over dielectric terrain is solved efficiently by utilizing the method of moments with complex basis functions. The numerical results for different cases of dielectric surfaces are compared with the results of perfectly conducting surface evaluated by the IE conventional algorithm.

  8. Cooperative terrain model acquisition by two point-robots in planar polygonal terrains

    Energy Technology Data Exchange (ETDEWEB)

    Rao, N.S.V.; Protopopescu, V.

    1994-11-29

    We address the model acquisition problem for an unknown terrain by a team of two robots. The terrain may be cluttered by a finite number of polygonal obstacles with unknown shapes and positions. The robots are point-sized and equipped with visual sensors which acquire all visible parts of the terrain by scanning from their locations. The robots communicate with each other via wireless connection. The performance is measured by the number of the sensor (scan) operations which are assumed to be the most time-consuming/expensive of all the robot operations. We employ the restricted visibility graph methods in a hierarchiacal setup. For terrains with convex obstacles, the sensing time can be halved compared to a single robot implementation. For terrains with concave corners, the performance of the algorithm depends on the number of concave regions and their depths. A hierarchical decomposition of the restricted visibility graph into 2-connected components and trees is considered. Performance for the 2-robot team is expressed in terms of sizes of 2-connected components, and the sizes and diameters of the trees. The proposed algorithm and analysis can be applied to the methods based on Voronoi diagram and trapezoidal decomposition.

  9. Palaeolimnological evidence of vulnerability of Lake Neusiedl (Austria) toward climate related changes since the last "vanished-lake" stage.

    Science.gov (United States)

    Tolotti, Monica; Milan, Manuela; Boscaini, Adriano; Soja, Gerhard; Herzig, Alois

    2013-04-01

    The palaeolimnological reconstruction of secular evolution of Euroepan Lakes with key socio-economical relevance respect to large (climate change) and local scale (land use, tourism) environmental changes, represents one of the objectives of the project EuLakes (European Lakes Under Environmental Stressors, Supporting lake governance to mitigate the impact of climate change, Reg. N. 2CE243P3), launched in 2010 within the Central European Inititiative. The project consortium comprises lakes of different morphology and prevalent human uses, including the meso-eutrophic Lake Neusiedl, the largest Austrian lake (total area 315 km2), and the westernmost shallow (mean depth 1.2 m) steppe lake of the Euro-Asiatic continent. The volume of Lake Neusiedl can potentially change over the years, in relation with changing balance between atmospheric precipitation and lake water evapotranspiration. Changing water budget, together with high lake salinity and turbidity, have important implications over the lake ecosystem. This contribution illustrates results of the multi-proxi palaeolimnological reconstruction of ecologial changes occurred in Lake Neusiedl during the last ca. 140 years, i.e. since the end of the last "vanished-lake" stage (1865-1871). Geochemical and biological proxies anticipate the increase in lake productivity of ca. 10 years (1950s) respect to what reported in the literature. Diatom species composition indicate a biological lake recovery in the late 1980s, and suggest a second increment in lake productivity since the late 1990s, possibly in relation with the progressive increase in the nitrogen input from agriculture. Abundance of diatoms typical of brackish waters indicated no significant long-term change in lake salinity, while variations in species toleranting dessiccation confirm the vulnerability of Lake Neusiedl toward climate-driven changes in the lake water balance. This fragility is aggravated by the the semi-arid climate conditions of the catchemnt

  10. Are all temperate lakes eutrophying in a warmer world?

    Science.gov (United States)

    Paltsev, A.; Creed, I. F.

    2017-12-01

    Freshwater lakes are at risk of eutrophication due to climate change and intensification of human activities on the planet. In relatively undisturbed areas of the temperate forest biome, lakes are "sentinels" of the effects of rising temperatures. We hypothesise that rising temperatures are driving a shift from nutrient-poor oligotrophic states to nutrient-rich eutrophic states. To test this hypothesis, we examined a time series of satellite based chlorophyll-a (a proxy of algal biomass) of 12,000+ lakes over 30 years in the Canadian portion of the Laurentian Great Lakes basin. From the time series, non-stationary trends (detected by Mann-Kendall analysis) and stationary cycles (revealed through Morlet wavelet analysis) were removed, and the standard deviation (SD) of the remaining residuals was used as an indicator of lake stability. Four classes of lake stability were identified: (1) stable (SD is consistently low); (2) destabilizing (SD increases over time); (3) unstable (SD is consistently high); and (4) stabilizing lakes (SD decreases over time). Stable lakes were either oligotrophic or eutrophic indicating the presence of two stable states in the region. Destabilizing lakes were shifting from oligotrophic to lakes with a higher trophic status (indicating eutrophication), unstable lakes were mostly mesotrophic, and stabilizing lakes were shifting from eutrophic to the lakes with lower trophic status (indicating oligotrophication). In contrast to common expectations, while many lakes (2142) were shifting from oligotrophic to eutrophic states, more lakes (3199) were showing the opposite trend and shifting from eutrophic to oligotrophic states. This finding reveals a complexity of lake responses to rising temperatures and the need to improve understanding of why some lakes shift while others do not. Future work is focused on exploring the interactive effects of global, regional, and local drivers of lake trophic states.

  11. Microplastics in Taihu Lake, China.

    Science.gov (United States)

    Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-09-01

    In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Australian Acid Playa Lake as a Mars Analog: Results from Sediment Lipid Analysis

    Science.gov (United States)

    Graham, H.; Baldridge, A. M.; Stern, J. C.

    2015-12-01

    The ephemeral saline acidic lakes on the Yilgarn Craton of Western Australia have been suggested as geochemical analogues to martian terrains. Both are characterized by interbedded phyllosilicates and hydrated sulfates. On Mars, these areas indicate shifting environmental conditions, from the neutral/alkaline and wet conditions that dominated during the Noachian era to the more familiar dry, acidic conditions that began in the Hesperian. The habitability of such a dynamic environment can be informed by investigation of the Yilgarn Lake system. Previous work has found phospholipid fatty acids (PLFA) evidence of microbial communities in sections of sediment cores taken from Lake Gilmore. These communities include both Gram-positive and -negative bacteria, Actinomycetes, and even methanotrophs. Given recurring detection of methane on the martian surface, evidence of a methane cycling community in an analogous environment is of particular interest. In this study we analyze the carbon isotope composition of bulk organic material as well as extracted lipids from the Lake Gilmore sediment cores at both a near-shore and mid-lake location. These analyses reveal very low accumulations of organic carbon, concentrated primarily in the gypsum-rich near-shore core. The near-shore sediments show a down-core decrease in abundance of organic carbon as well as depletion in the carbon isotope composition (δ13C) with depth. Bulk carbon did not exhibit the unique, highly depleted, diagnostic signature associated with methanotrophic biomass. Compound-specific isotope analysis (CSIA) of carbon in extracted methanotroph PFLAs can confirm the presence of a methane cycling metabolism at depth. Also, additional extractions have isolated lipids associated with lake-edge grasses. These analyses consider both the chain-length distribution and carbon CSIA of these lipids in order to understand the effect of terrestrial detritus on any preserved methanotroph carbon signal, given the very low

  13. Morphological modeling of terrains and volume data

    CERN Document Server

    Comic, Lidija; Magillo, Paola; Iuricich, Federico

    2014-01-01

    This book describes the mathematical background behind discrete approaches to morphological analysis of scalar fields, with a focus on Morse theory and on the discrete theories due to Banchoff and Forman. The algorithms and data structures presented are used for terrain modeling and analysis, molecular shape analysis, and for analysis or visualization of sensor and simulation 3D data sets. It covers a variety of application domains including geography, geology, environmental sciences, medicine and biology. The authors classify the different approaches to morphological analysis which are all ba

  14. Designated Wildlife Lakes - points

    Data.gov (United States)

    Minnesota Department of Natural Resources — This is a point shapefile of Designated Wildlife Lakes in Minnesota. This shapefile was created by converting lake polygons from the Designated Wildlife Lakes...

  15. Great Lakes Bathymetry

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lakes Michigan, Erie, Saint Clair, Ontario and Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and...

  16. Bathymetry of Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Superior has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  17. Bathymetry of Lake Ontario

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Ontario has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  18. Bathymetry of Lake Michigan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Michigan has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  19. Bathymetry of Lake Huron

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  20. Stability Index for Biped Robot Moving on Rough Terrain

    Science.gov (United States)

    Sato, Tomoya; Sakaino, Sho; Ohnishi, Kouhei

    In this paper, a stability index based on the ZMP (zero-moment point) for biped robots moving on rough terrain is proposed. The proposed method projects a support polygon on to a virtual plane and sets a virtual ZMP on it. In rough terrain, using the proposed method, stability check and trajectory planning are able to be treated as the case of flat terrain. The validity of the proposed method was confirmed by some simulations and experiments.

  1. Survivor shielding. Part C. Improvements in terrain shielding

    International Nuclear Information System (INIS)

    Egbert, Stephen D.; Kaul, Dean C.; Roberts, James A.; Kerr, George D.

    2005-01-01

    A number of atomic-bomb survivors were affected by shielding provided by terrain features. These terrain features can be a small hill, affecting one or two houses, or a high mountain that shields large neighborhoods. In the survivor dosimetry system, terrain shielding can be described by a transmission factor (TF), which is the ratio between the dose with and without the terrain present. The terrain TF typically ranges between 0.1 and 1.0. After DS86 was implemented at RERF, the terrain shielding categories were examined and found to either have a bias or an excessive uncertainty that could readily be removed. In 1989, an improvement in the terrain model was implemented at RERF in the revised DS86 code, but the documentation was not published. It is now presented in this section. The solution to the terrain shielding in front of a house is described in this section. The problem of terrain shielding of survivors behind Hijiyama mountain at Hiroshima and Konpirasan mountain at Nagasaki has also been recognized, and a solution to this problem has been included in DS02. (author)

  2. LUNAR TERRAIN AND ALBEDO RECONSTRUCTION FROM APOLLO IMAGERY

    Data.gov (United States)

    National Aeronautics and Space Administration — LUNAR TERRAIN AND ALBEDO RECONSTRUCTION FROM APOLLO IMAGERY ARA V NEFIAN*, TAEMIN KIM, MICHAEL BROXTON, AND ZACH MORATTO Abstract. Generating accurate three...

  3. Estimation of soil salt content (SSC) in the Ebinur Lake Wetland National Nature Reserve (ELWNNR), Northwest China, based on a Bootstrap-BP neural network model and optimal spectral indices.

    Science.gov (United States)

    Wang, Xiaoping; Zhang, Fei; Ding, Jianli; Kung, Hsiang-Te; Latif, Aamir; Johnson, Verner C

    2018-02-15

    Soil salinity is recognized worldwide as a major threat to agriculture, particularly in arid regions. Producers and decision-makers thus require updated and accurate maps of salinity in agronomical and environmentally relevant regions. The goals of this study were to test various regression models for estimating soil salt content based on hyperspectral data, HJ-CCD images, and Landsat OLI data using; develop optimal band Difference Index (DI), Ratio Index (RI), and Normalization Index (NDI) algorithms for monitoring soil salt content using image and spectral data; and to compare the performances of the proposed models using a Bootstrap-BP neural network model (Bootstrap-BPNN) from different data sources. The results showed that previously published optimal remote sensing parameters can be applied to estimate the soil salt content in the Ebinur Lake Wetland National Nature Reserve (ELWNNR). Optimal band combination indices based on DI, RI, and NDI were developed for different data sources. Then, the Bootstrap-BP neural network model was built using 1000 groups of Bootstrap samples of remote sensing indices (DI, RI and NDI) and soil salt content. When verifying the accuracy of hyperspectral data, the model yields an R 2 value of 0.95, a root mean square error (RMSE) of 4.38g/kg, and a residual predictive deviation (RPD) of 3.36. The optimal model for remote sensing images was the first derivative model of Landsat OLI, which yielded R 2 value of 0.91, RMSE of 4.82g/kg, and RPD of 3.32; these data indicated that this model has a high predictive ability. When comparing the salinization monitoring accuracy of satellite images to that of ground hyperspectral data, the accuracy of the first derivative of the Landsat OLI model was close to that of the hyperspectral parameter model. Soil salt content was inverted using the first derivative of the Landsat OLI model in the study area. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Evaluating the Implications of Climate Phenomenon Indices in Supporting Reservoir Operation Using the Artificial Neural Network and Decision-Tree Methods: A Case Study on Trinity Lake in Northern California

    Science.gov (United States)

    Yang, T.; Akbari Asanjan, A.; Gao, X.; Sorooshian, S.

    2016-12-01

    Reservoirs are fundamental human-built infrastructures that collect, store, and deliver fresh surface water in a timely manner for all kinds of purposes, including residential and industrial water supply, flood control, hydropower, and irrigation, etc. Efficient reservoir operation requires that policy makers and operators understand how reservoir inflows, available storage, and discharges are changing under different climatic conditions. Over the last decade, the uses of Artificial Intelligence and Data Mining (AI & DM) techniques in assisting reservoir management and seasonal forecasts have been increasing. Therefore, in this study, two distinct AI & DM methods, Artificial Neural Network (ANN) and Random Forest (RF), are employed and compared with respect to their capabilities of predicting monthly reservoir inflow, managing storage, and scheduling reservoir releases. A case study on Trinity Lake in northern California is conducted using long-term (over 50 years) reservoir operation records and 17 known climate phenomenon indices, i.e. PDO and ENSO, etc., as predictors. Results show that (1) both ANN and RF are capable of providing reasonable monthly reservoir storage, inflow, and outflow prediction with satisfactory statistics, and (2) climate phenomenon indices are useful in assisting monthly or seasonal forecasts of reservoir inflow and outflow. It is also found that reservoir storage has a consistent high autocorrelation effect, while inflow and outflow are more likely to be influenced by climate conditions. Using a Gini diversity index, RF method identifies that the reservoir discharges are associated with Southern Oscillation Index (SOI) and reservoir inflows are influenced by multiple climate phenomenon indices during different seasons. Furthermore, results also show that, during the winter season, reservoir discharges are controlled by the storage level for flood-control purposes, while, during the summer season, the flood-control operation is not as

  5. Conically scanning lidar error in complex terrain

    DEFF Research Database (Denmark)

    Bingöl, Ferhat; Mann, Jakob; Foussekis, Dimitri

    2009-01-01

    Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However, in mountainous or complex terrain this assumption is not valid implying a risk that the lidar will derive an erroneous wind speed. The magnitude of this error ismeasured by collocati.......0. The measurement data are compared with the model predictions with good results for the hilly site, but with less success at the mountainous site. This is a deficiency of the flow model, but the methods presented in this paper can be used with any flow model......Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However, in mountainous or complex terrain this assumption is not valid implying a risk that the lidar will derive an erroneous wind speed. The magnitude of this error ismeasured by collocating...... a meteorological mast and a lidar at two Greek sites, one hilly and one mountainous. The maximum error for the sites investigated is of the order of 10 %. In order to predict the error for various wind directions the flows at both sites are simulated with the linearized flow model, WAsP Engineering 2...

  6. Addressing terrain masking in orbital reconnaissance

    Science.gov (United States)

    Mehta, Sharad; Cico, Luke

    2012-06-01

    During aerial orbital reconnaissance, a sensor system is mounted on an airborne platform for imaging a region on the ground. The latency between the image acquisition and delivery of information to the end-user is critical and must be minimized. Due to fine ground pixel resolution and a large field-of-view for wide-area surveillance applications, a massive volume of data is gathered and imagery products are formed using a real-time multi-processor system. The images are taken at oblique angles, stabilized and ortho-rectified. The line-of-sight of the sensor to the ground is often interrupted by terrain features such as mountains or tall structures as depicted in Figure1. The ortho-rectification process renders the areas hidden from the line-of sight of the sensor with spurious information. This paper discusses an approach for addressing terrain masking in size, weight, and power (SWaP) and memory-restricted onboard processing systems.

  7. Great Lakes Science Center

    Data.gov (United States)

    Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

  8. Influence of terrain and highway construction on thermokarst distribution, North Slave region, NWT, Canada

    Science.gov (United States)

    Morse, Peter; Wolfe, Stephen; McWade, Taylor

    2017-04-01

    Permafrost degradation has been observed throughout the north and is expected to have broad reaching effects on the land and its people. Nevertheless, for much of Northern Canada little quantified information about thermokarst exists. For example, in the southern North Slave region, NWT, thermokarst distribution has never been assessed though permafrost is in thermal disequilibrium and modelling suggests permafrost extent will decline. Additionally, differential subsidence has been observed in the subarctic city of Yellowknife and along highway infrastructure connecting it to the south. To better understand present and future permafrost conditions, we mapped the location and size of thermokarst ponding (a change from forest cover to water) in the study area by comparing historic and modern remotely sensed data sets available from 1945, 1961, and 2005. These data were used to evaluate the dominant terrain controls on the distribution of thermokarst in the region, and the potential influence that highway construction may have had on thermokarst development. Historically, discontinuous permafrost developed in a time-transgressive manner during the Holocene as lake-level receded from glacial Lake McConnell to present-day Great Slave Lake (5 mmṡa-1 over the last 8000 years). As a consequence of inundation the upland areas are characterized by extensive wave-washed bedrock outcrops with glaciolacustrine (GL) sediments and glaciofluvial materials occurring between them, whereas the lowland areas feature prominent GL deposits that cover nearly 70 % of the exposed surface. Throughout much of the region ground ice accumulation likely accompanied permafrost aggradation into fine-grained sediments, as is evident by lithalsa growth in particular. Highway 3, constructed during the mid-1960s, was preferentially aligned to crossed terrain underlain by fine-grained sediments to avoid bedrock and waterbodies. Local silt and clay used for highway embankment construction was sourced

  9. Single-Frame Terrain Mapping Software for Robotic Vehicles

    Science.gov (United States)

    Rankin, Arturo L.

    2011-01-01

    This software is a component in an unmanned ground vehicle (UGV) perception system that builds compact, single-frame terrain maps for distribution to other systems, such as a world model or an operator control unit, over a local area network (LAN). Each cell in the map encodes an elevation value, terrain classification, object classification, terrain traversability, terrain roughness, and a confidence value into four bytes of memory. The input to this software component is a range image (from a lidar or stereo vision system), and optionally a terrain classification image and an object classification image, both registered to the range image. The single-frame terrain map generates estimates of the support surface elevation, ground cover elevation, and minimum canopy elevation; generates terrain traversability cost; detects low overhangs and high-density obstacles; and can perform geometry-based terrain classification (ground, ground cover, unknown). A new origin is automatically selected for each single-frame terrain map in global coordinates such that it coincides with the corner of a world map cell. That way, single-frame terrain maps correctly line up with the world map, facilitating the merging of map data into the world map. Instead of using 32 bits to store the floating-point elevation for a map cell, the vehicle elevation is assigned to the map origin elevation and reports the change in elevation (from the origin elevation) in terms of the number of discrete steps. The single-frame terrain map elevation resolution is 2 cm. At that resolution, terrain elevation from 20.5 to 20.5 m (with respect to the vehicle's elevation) is encoded into 11 bits. For each four-byte map cell, bits are assigned to encode elevation, terrain roughness, terrain classification, object classification, terrain traversability cost, and a confidence value. The vehicle s current position and orientation, the map origin, and the map cell resolution are all included in a header for each

  10. A late Pliocene to middle Pleistocene pluvial lake in Fish Lake Valley, Nevada and California

    Science.gov (United States)

    Reheis, M.C.; Slate, J.L.; Sarna-Wojcicki, A. M.; Meyer, C.E.

    1993-01-01

    The question of whether a pluvial lake existed in Fish Lake Valley, Nevada and California, has been debated for more than 100 yr. New stratigraphic evidence indicates that a lake did exist in this valley at intervals during late Pliocene to middle Pleistocene time. This lake may have drained northward, or it may have been periodically contiguous with a pluvial lake to the north in Columbus Salt Marsh. Proof of the existence of this lake, informally named Pluvial Lake Rennie, is derived from three principal outcrops of shallow-water deposits, two outcrops of deep-water deposits, and several drilling logs. The deposits contain beds of silicic tephra, which provide age control. Pluvial Lake Rennie fluctuated in size and depth beginning prior to 2 Ma and continuing until sometime after 0.77 Ma. At about 0.77 Ma, the lake had a highstand at an elevation of ~1460 m, covered an area of 400-500 km2, and had a maximum depth of ~250 m. The lake level dropped just after the eruption of the Bishop ash, but the lake may have persisted at a lower level until ~0.5 Ma. -from Authors

  11. A terrain-based site characterization map of California with implications for the contiguous United States

    Science.gov (United States)

    Yong, Alan K.; Hough, Susan E.; Iwahashi, Junko; Braverman, Amy

    2012-01-01

    We present an approach based on geomorphometry to predict material properties and characterize site conditions using the VS30 parameter (time‐averaged shear‐wave velocity to a depth of 30 m). Our framework consists of an automated terrain classification scheme based on taxonomic criteria (slope gradient, local convexity, and surface texture) that systematically identifies 16 terrain types from 1‐km spatial resolution (30 arcsec) Shuttle Radar Topography Mission digital elevation models (SRTM DEMs). Using 853 VS30 values from California, we apply a simulation‐based statistical method to determine the mean VS30 for each terrain type in California. We then compare the VS30 values with models based on individual proxies, such as mapped surface geology and topographic slope, and show that our systematic terrain‐based approach consistently performs better than semiempirical estimates based on individual proxies. To further evaluate our model, we apply our California‐based estimates to terrains of the contiguous United States. Comparisons of our estimates with 325 VS30 measurements outside of California, as well as estimates based on the topographic slope model, indicate our method to be statistically robust and more accurate. Our approach thus provides an objective and robust method for extending estimates of VS30 for regions where in situ measurements are sparse or not readily available.

  12. Pacing during an ultramarathon running event in hilly terrain

    Directory of Open Access Journals (Sweden)

    Hugo A. Kerhervé

    2016-10-01

    Full Text Available Purpose The dynamics of speed selection as a function of distance, or pacing, are used in recreational, competitive, and scientific research situations as an indirect measure of the psycho-physiological status of an individual. The purpose of this study was to determine pacing on level, uphill and downhill sections of participants in a long (>80 km ultramarathon performed on trails in hilly terrain. Methods Fifteen ultramarathon runners competed in a  173 km event (five finished at  103 km carrying a Global-Positioning System (GPS device. Using the GPS data, we determined the speed, relative to average total speed, in level (LEV, uphill (UH and downhill (DH gradient categories as a function of total distance, as well as the correlation between overall performance and speed variability, speed loss, and total time stopped. Results There were no significant differences in normality, variances or means in the relative speed in 173-km and 103-km participants. Relative speed decreased in LEV, UH and DH. The main component of speed loss occurred between 5% and 50% of the event distance in LEV, and between 5% and 95% in UH and DH. There were no significant correlations between overall performance and speed loss, the variability of speed, or total time stopped. Conclusions Positive pacing was observed at all gradients, with the main component of speed loss occurring earlier (mixed pacing in LEV compared to UH and DH. A speed reserve (increased speed in the last section was observed in LEV and UH. The decrease in speed and variability of speed were more important in LEV and DH than in UH. The absence of a significant correlation between overall performance and descriptors of pacing is novel and indicates that pacing in ultramarathons in trails and hilly terrain differs to other types of running events.

  13. Stability Impact on Wake Development in Moderately Complex Terrain

    Science.gov (United States)

    Infield, D.; Zorzi, G.

    2017-05-01

    This paper uses a year of SCADA data from Whitelee Wind Farm near Glasgow to investigate wind turbine wake development in moderately complex terrain. Atmospheric stability measurements in terms of Richardson number from a met mast at an adjoining site have been obtained and used to assess the impact of stability on wake development. Considerable filtering of these data has been undertaken to ensure that all turbines are working normally and are well aligned with the wind direction. A group of six wind turbines, more or less in a line, have been selected for analysis, and winds within a 2 degree direction sector about this line are used to ensure, as far as possible, that all the turbines investigated are fully immersed in the wake/s of the upstream turbine/s. Results show how the terrain effects combine with the wake effects, with both being of comparable importance for the site in question. Comparison has been made with results from two commercial CFD codes for neutral stability, and reasonable agreement is demonstrated. Richardson number has been plotted against wind shear and turbulence intensity at a met mast on the wind farm that for the selected wind direction is not in the wake of any turbines. Good correlations are found indicating that the Richardson numbers obtained are reliable. The filtered data used for wake analysis were split according to Richardson number into two groups representing slightly stable to neutral, and unstable conditions. Very little difference in wake development is apparent. A greater difference can be observed when the data are separated simply by turbulence intensity, suggesting that, although turbulence intensity is correlated with stability, of the two it is the parameter that most directly impacts on wake development through mixing of ambient and wake flows.

  14. Ribbon terrain formation and implications for lithosphere evolution, Venus

    Science.gov (United States)

    Hansen, V. L.; Willis, J. J.

    1997-03-01

    Venus terrain ribbons comprise a fabric of alternating, parallel, closely-spaced, radar-dark/bright lineaments showing a distinct dark-bright pairing. It is presently argued that the opening of tensile fractures within a brittle layer above a sharp brittle ductile transition over a ductile substrate can account for the formation of the observed geometric characteristics of ribbon terrain.

  15. Synthetic SAR Image Generation using Sensor, Terrain and Target Models

    DEFF Research Database (Denmark)

    Kusk, Anders; Abulaitijiang, Adili; Dall, Jørgen

    2016-01-01

    of the object using a CAD-model. The raw measurements are input to a SAR system and terrain model, which models thermal noise, terrain clutter, and SAR focusing to produce synthetic SAR images. Examples of SAR images at 0.3m and 0.1m resolution, and a comparison with real SAR imagery from the MSTAR dataset...

  16. Terrain Perception in a Shape Shifting Rolling-Crawling Robot

    Directory of Open Access Journals (Sweden)

    Fuchida Masataka

    2016-09-01

    Full Text Available Terrain perception greatly enhances the performance of robots, providing them with essential information on the nature of terrain being traversed. Several living beings in nature offer interesting inspirations which adopt different gait patterns according to nature of terrain. In this paper, we present a novel terrain perception system for our bioinspired robot, Scorpio, to classify the terrain based on visual features and autonomously choose appropriate locomotion mode. Our Scorpio robot is capable of crawling and rolling locomotion modes, mimicking Cebrenus Rechenburgi, a member of the huntsman spider family. Our terrain perception system uses Speeded Up Robust Feature (SURF description method along with color information. Feature extraction is followed by Bag of Word method (BoW and Support Vector Machine (SVM for terrain classification. Experiments were conducted with our Scorpio robot to establish the efficacy and validity of the proposed approach. In our experiments, we achieved a recognition accuracy of over 90% across four terrain types namely grass, gravel, wooden deck, and concrete.

  17. Evaluation of topographic index in relation to terrain roughness and ...

    Indian Academy of Sciences (India)

    comparing the topographic index surface with respect to reference data (10 m grid spacing topographic index surface). The RMSE and mean error of topographic index surface increases in larger grid spacing and the effect is more in rugged terrain. 1. Introduction. Terrain relief is the first order control on the vari- ous natural ...

  18. 1 Integrating land cover and terrain characteristics to explain plague ...

    African Journals Online (AJOL)

    Information System (GIS) can provide greater possibility to refine the analysis of land cover and terrain characteristics for ... Regression Tree (BRT) statistical method was used to clarify the relationships between land cover and terrain variables .... shapefile. The training dataset is defined as multiple polygons for each class.

  19. Conically scanning lidar error in complex terrain

    Directory of Open Access Journals (Sweden)

    Ferhat Bingöl

    2009-05-01

    Full Text Available Conically scanning lidars assume the flow to be homogeneous in order to deduce the horizontal wind speed. However, in mountainous or complex terrain this assumption is not valid implying a risk that the lidar will derive an erroneous wind speed. The magnitude of this error is measured by collocating a meteorological mast and a lidar at two Greek sites, one hilly and one mountainous. The maximum error for the sites investigated is of the order of 10 %. In order to predict the error for various wind directions the flows at both sites are simulated with the linearized flow model, WAsP Engineering 2.0. The measurement data are compared with the model predictions with good results for the hilly site, but with less success at the mountainous site. This is a deficiency of the flow model, but the methods presented in this paper can be used with any flow model.

  20. Experiment S-5: Synoptic Terrain Photography

    Science.gov (United States)

    Lowman, Paul D., Jr.

    1966-01-01

    The Synoptic Terrain Photography Experiment (S-5) was successfully conducted during the Gemini V mission, the second of the Gemini flights on which it was carried. This report summarizes briefly the methods and results of the experiment. Interpretation of the many excellent pictures obtained is in progress, and a full report is not possible at this time; instead, representative pictures will be presented and described. The purpose of the experiment was to obtain a large number of high-quality color photographs of selected land areas from geologic and geographic study. Southern Mexico, eastern Africa, and Australia were given high priority, but it was stressed that good pictures of any cloud-free land area would be useful. The same camera (Hasselblad 500 C) and film (Ektachrome MS) used on the Gemini III and IV missions were carried on the Gemini V flight.

  1. Predicting future glacial lakes in Austria using different modelling approaches

    Science.gov (United States)

    Otto, Jan-Christoph; Helfricht, Kay; Prasicek, Günther; Buckel, Johannes; Keuschnig, Markus

    2017-04-01

    Glacier retreat is one of the most apparent consequences of temperature rise in the 20th and 21th centuries in the European Alps. In Austria, more than 240 new lakes have formed in glacier forefields since the Little Ice Age. A similar signal is reported from many mountain areas worldwide. Glacial lakes can constitute important environmental and socio-economic impacts on high mountain systems including water resource management, sediment delivery, natural hazards, energy production and tourism. Their development significantly modifies the landscape configuration and visual appearance of high mountain areas. Knowledge on the location, number and extent of these future lakes can be used to assess potential impacts on high mountain geo-ecosystems and upland-lowland interactions. Information on new lakes is critical to appraise emerging threads and potentials for society. The recent development of regional ice thickness models and their combination with high resolution glacier surface data allows predicting the topography below current glaciers by subtracting ice thickness from glacier surface. Analyzing these modelled glacier bed surfaces reveals overdeepenings that represent potential locations for future lakes. In order to predict the location of future glacial lakes below recent glaciers in the Austrian Alps we apply different ice thickness models using high resolution terrain data and glacier outlines. The results are compared and validated with ice thickness data from geophysical surveys. Additionally, we run the models on three different glacier extents provided by the Austrian Glacier Inventories from 1969, 1998 and 2006. Results of this historical glacier extent modelling are compared to existing glacier lakes and discussed focusing on geomorphological impacts on lake evolution. We discuss model performance and observed differences in the results in order to assess the approach for a realistic prediction of future lake locations. The presentation delivers

  2. The study of Lake Urmia desiccation: morphometry impress

    Science.gov (United States)

    Moradi, Ayoub; Rasouli, Ali Akbar; Roostaei, Shahram

    2017-04-01

    Located in northwestern Iran, the hypersaline Lake Urmia has started a serious uninterrupted desiccation since 1995. The lake has lost about eight meters of water level and about 75% of water surface area during past 20 years. In particular, the lake water volume decrement has been accelerated in recent years. The importance of the Lake Urmia for human life in northwestern Iran, and its destructive effects on a vast region if totally dry up, demands comprehensive studies of the lake level fluctuations mechanism. According to literature review, the water volume of the lake behaves sometimes differently from the water storage of the whole basin. Our time series analysis using Land Data Assimilation Systems also confirms those differences within last decades. In other hand, many studies addressed the lake desiccation to climatic changes and/or anthropogenic influences such as excessive dam constructions in the watershed during last decades. As water leaves the lake only through evaporation, the fluctuation of evaporation has a distinctive role in the lake level variations. Dramatic decreament in the lake extent indicates of a special morphometry. The lake's morphometry has made it vulnerable to temperature and salinity changes. It strongly controls the lake's water heat capacity and water density. And, it therefore controls the rate of evaporation from water surface. We study the role of lake's morphometry on the lake desiccation. Although, the global climatic change is known as the primary reason for current droughts in the Middle East generally, our preliminary results show that the lake's morphometry is the main cause for the accelerating of water volume lost in Lake Urmia. In particular, after 2007, lake's water temperature and density show significant variations. Water heat capacity and evaporation rate are consistent with information of lake's hypsometry.

  3. The individual response of saline lakes to a severe drought.

    Science.gov (United States)

    Tweed, Sarah; Grace, Mike; Leblanc, Marc; Cartwright, Ian; Smithyman, Donna

    2011-09-01

    A severe protracted drought between 1997 and 2009 has altered the physical and chemical hydrology of a series of lakes in the Corangamite Basin of southeast Australia. Leading up to the drying out of most lakes (many for the first time on record), we document the changes in lakes' water quantity (water levels and inundation), salinity (Cl concentrations), salinity processes (Cl/Br ratios), nutrient concentrations and ratios (ammonia, phosphate and NOx (nitrate and nitrite)) and algae (as chlorophyll-a) for six lakes. All lakes show record declines in inundated areas and increases in salinity from pre-drought (drought conditions. However, the magnitude of change in salinity varies for different lakes, and there is no systematic change in the controls on lake salinity processes. Four lakes show no change in salinity processes, one lake shows the beginnings of change; where halite dissolution reactions increased closer to the time of the lake drying up, and another lake shows a marked shift from predominantly evaporation to the cyclic dissolution and precipitation of halite. Changes in filterable reactive phosphorus (FRP) values and lake N and P limitation predictions also showed little systematic correlation with changes in lake salinity, and nutrient values varied between lakes and over time. The decline in NO(x) concentrations in lakes where electrical conductivity (EC) values were above 100 mS/cm indicates some correlation with changes in salinity. Largely, these lakes exhibit individual changes in water quality parameters and salinity processes in response to the drought, indicating that while the stress of drought is regional, the hydrochemical response is local. In future changing climates, these results suggest that the catchment adaption strategies will require comprehensive plans for individual lake systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Slip estimation methods for proprioceptive terrain classification using tracked mobile robots

    CSIR Research Space (South Africa)

    Masha, Ditebogo F

    2017-11-01

    Full Text Available Recent work has shown that proprioceptive measurements such as terrain slip can be used for terrain classification. This paper investigates the suitability of four simple slip estimation methods for differentiating between indoor and outdoor terrain...

  5. Mixing heights over hilly terrain - a case study in northern austria

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, K. [Central Inst. for Meteorology and Geodynamics, ZAMG, Vienna (Austria)

    1997-10-01

    Simultaneous Sodar measurements (Remtech PA2) were conducted from 10 October 1996 to 24 January 1997 at two sites in northern Austria, near the village Allensteig on top of a hill (590 m.s.l.) and in the village Lenzing (460 m.s.l.) near the lake Attersee. The two sites are 145 km apart from each other and differ much according to the complexity of the surrounding terrain, land use and altitude. Mixing height and inversions height estimations from the Sodar measurements are compared with mixing heights derived from radiosonde potential temperature profiles at the next stations Linz and Vienna using the parcel method of Stull (1991) explained by M. Piringer (this volume). The information about the static stability at different Sodar heights, which is provided by the new Sodar software in terms of vertical temperature gradients, is discussed. (au)

  6. A benthic quality index for European alpine lakes

    Directory of Open Access Journals (Sweden)

    Bruno Rossaro

    2012-10-01

    Full Text Available The development of benthic quality indices for European lakes is hindered by the lack of information concerning many national lake types and pressures. Most information is from north European lakes stressed by acidification and from deep lakes subjected to eutrophication; for other lake types (the ones included in the Mediterranean areas for example and for other pressures (hydro-morphological alteration, toxic stress there is practically no information about the response of benthic macro-invertebrates; this hinders the possibility of an intercalibration of the indices among the member states (MS in the EU. In the present communication three benthic quality indices are proposed considering the littoral, sublittoral and profundal zone in 5 reference and 7 non reference lakes from the Alpine region in response to eutrophication. The sensitivity values of the 177 species found in these lakes were calculated taking a weighted average of the values of environmental variables from lakes in which the species were present. The indicator taxa which prevailed in these lakes were Chironomids and Oligochaetes. A coinertia analysis emphasized the importance of trophic variables (transparency, nitrates, total phosphorous in explaining the species distribution, but geographic (altitude and morphometric (depth, volume variables were also important. The indices enabeled a separation of reference from non-reference lakes and to assign the non-reference lakes to different quality classes in agreement with the Water Framework Directive.doi: 10.5324/fn.v31i0.1364.Published online: 17 October 2012. 

  7. Indicators: Phytoplankton

    Science.gov (United States)

    Phytoplankton are free-floating, microscopic algae that inhabit the sunlit, upper layer of most freshwater and marine environments. They are usually responsible for the color and clarity of lakes, wetlands, rivers, streams and estuaries.

  8. Potential flood volume of Himalayan glacial lakes

    Directory of Open Access Journals (Sweden)

    K. Fujita

    2013-07-01

    Full Text Available Glacial lakes are potentially dangerous sources of glacial lake outburst floods (GLOFs, and represent a serious natural hazard in Himalayan countries. Despite the development of various indices aimed at determining the outburst probability, an objective evaluation of the thousands of Himalayan glacial lakes has yet to be completed. In this study we propose a single index, based on the depression angle from the lakeshore, which allows the lakes to be assessed using remotely sensed digital elevation models (DEMs. We test our approach on five lakes in Nepal, Bhutan, and Tibet using images taken by the declassified Hexagon KH-9 satellite before these lakes experienced an outburst flood. All five lakes had a steep lakefront area (SLA, on which a depression angle was steeper than our proposed threshold of 10° before the GLOF event, but the SLA was no longer evident after the events. We further calculated the potential flood volume (PFV; i.e., the maximum volume of floodwater that could be released if the lake surface was lowered sufficiently to eradicate the SLA. This approach guarantees repeatability to assess the possibility of GLOF hazards because it requires no particular expertise to carry out, though the PFV does not quantify the GLOF risk. We calculated PFVs for more than 2000 Himalayan glacial lakes using visible band images and DEMs of ASTER data. The PFV distribution follows a power-law function. We found that 794 lakes did not have an SLA, and consequently had a PFV of zero, while we also identified 49 lakes with PFVs of over 10 million m3, which is a comparable volume to that of recorded major GLOFs. This PFV approach allows us to preliminarily identify and prioritize those Himalayan glacial lakes that require further detailed investigation on GLOF hazards and risk.

  9. BASALT A: Basaltic Terrains in Idaho and Hawaii as Planetary Analogs for Mars Geology and Astrobiology

    Science.gov (United States)

    Hughes, Scott S.; Haberle, Christopher W.; Nawotniak, Shannon E. Kobs; Sehlke, Alexander; Garry, W. Brent; Elphic, Richard C.; Payler, Sam J.; Stevens, Adam H.; Cockell, Charles S.; Brady, Allyson L.; hide

    2018-01-01

    Assessments of field research target regions are described within two notably basaltic geologic provinces as Earth analogs to Mars. Regions within the eastern Snake River Plain of Idaho and the Big Island of Hawaii, USA, provinces that represent analogs of present-day and early Mars, respectively, were evaluated on the basis of geologic settings, rock lithology and geochemistry, rock alteration, and climate. Each of these factors provide rationale for the selection of specific targets for field research in five analog target regions: (1) Big Craters and (2) Highway lava flows at Craters of the Moon National Monument and Preserve, Idaho; and (3) Mauna Ulu low shield, (4) Kilauea Iki lava lake and (5) Kilauea caldera in the Kilauea Volcano summit region and the East Rift Zone of Hawaii. Our evaluation of compositional and textural differences, as well as the effects of syn- and post-eruptive rock alteration, shows that the basaltic terrains in Idaho and Hawaii provide a way to characterize the geology and major geologic substrates that host biological activity of relevance to Mars exploration. This work provides the foundation to better understand the scientific questions related to the habitability of basaltic terrains, the rationale behind selecting analog field targets, and their applicability as analogs to Mars.

  10. Limnology of Eifel maar lakes

    National Research Council Canada - National Science Library

    Scharf, Burkhard W; Björk, Sven

    1992-01-01

    ... & morphometry - Physical & chemical characteristics - Calcite precipitation & solution in Lake Laacher See - Investigations using sediment traps in Lake Gemundener Maar - Phytoplankton of Lake Weinfelder Maar...

  11. Terrain aided navigation for autonomous underwater vehicles with coarse maps

    International Nuclear Information System (INIS)

    Zhou, Ling; Cheng, Xianghong; Zhu, Yixian

    2016-01-01

    Terrain aided navigation (TAN) is a form of geophysical localization technique for autonomous underwater vehicles (AUVs) operating in GPS-denied environments. TAN performance on sensor-rich AUVs has been evaluated in sea trials. However, many challenges remain before TAN can be successfully implemented on sensor-limited AUVs, especially with coarse maps. To improve TAN performance over coarse maps, a Gaussian process (GP) is proposed for the modeling of bathymetric terrain and integrated into the particle filter (GP-PF). GP is applied to provide not only the bathymetric value prediction through learning a set of bathymetric data from coarse maps but also the variance of the prediction. As a measurement update, calculated on bathymetric deviation is performed through the PF to obtain absolute and bounded positioning accuracy. Through the analysis of TAN performance on experimental data for two different terrains with map resolutions of 10–50 m, both the ability of the proposed model to represent the actual bathymetric terrain with accuracy and the effect of the GP-PF for TAN on sensor-limited systems in suited terrain are demonstrated. The experiment results further verify that there is an inverse relationship between the coarseness of the map and the overall TAN accuracy in rough terrains, but there is hardly any relationship between them in relatively flat terrains. (paper)

  12. Environmental Impacts of Forest Road Construction on Mountainous Terrain

    Directory of Open Access Journals (Sweden)

    Erhan Caliskan

    2013-03-01

    Full Text Available Forest roads are the base infrastructure foundation of forestry operations. These roads entail a complex engineering effort because they can cause substantial environmental damage to forests and include a high-cost construction. This study was carried out in four sample sites of Giresun, Trabzon(2 and Artvin Forest Directorate, which is in the Black Sea region of Turkey. The areas have both steep terrain (30-50% gradient and very steep terrain (51-80% gradient. Bulldozers and hydraulic excavators were determined to be the main machines for forest road construction, causing environmental damage and cross sections in mountainous areas.As a result of this study, the percent damage to forests was determined as follows: on steep terrain, 21% of trees were damaged by excavators and 33% of trees were damaged by bulldozers during forest road construction, and on very steep terrain, 27% of trees were damaged by excavators and 44% of trees were damaged by bulldozers during forest road construction. It was also determined that on steep terrain, when excavators were used, 12.23% less forest area was destroyed compared with when bulldozers were used and 16.13% less area was destroyed by excavators on very steep terrain. In order to reduce the environmental damage on the forest ecosystem, especially in steep terrains, hydraulic excavators should replace bulldozers in forest road construction activities.

  13. Bathymetry of Lake Erie and Lake Saint Clair

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Erie and Lake Saint Clair has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and...

  14. Self-Supervised Learning of Terrain Traversability from Proprioceptive Sensors

    Science.gov (United States)

    Bajracharya, Max; Howard, Andrew B.; Matthies, Larry H.

    2009-01-01

    Robust and reliable autonomous navigation in unstructured, off-road terrain is a critical element in making unmanned ground vehicles a reality. Existing approaches tend to rely on evaluating the traversability of terrain based on fixed parameters obtained via testing in specific environments. This results in a system that handles the terrain well that it trained in, but is unable to process terrain outside its test parameters. An adaptive system does not take the place of training, but supplements it. Whereas training imprints certain environments, an adaptive system would imprint terrain elements and the interactions amongst them, and allow the vehicle to build a map of local elements using proprioceptive sensors. Such sensors can include velocity, wheel slippage, bumper hits, and accelerometers. Data obtained by the sensors can be compared to observations from ranging sensors such as cameras and LADAR (laser detection and ranging) in order to adapt to any kind of terrain. In this way, it could sample its surroundings not only to create a map of clear space, but also of what kind of space it is and its composition. By having a set of building blocks consisting of terrain features, a vehicle can adapt to terrain that it has never seen before, and thus be robust to a changing environment. New observations could be added to its library, enabling it to infer terrain types that it wasn't trained on. This would be very useful in alien environments, where many of the physical features are known, but some are not. For example, a seemingly flat, hard plain could actually be soft sand, and the vehicle would sense the sand and avoid it automatically.

  15. Hybrid RANS/LES applied to complex terrain

    DEFF Research Database (Denmark)

    Bechmann, Andreas; Sørensen, Niels N.

    2011-01-01

    Large Eddy Simulation (LES) of the wind in complex terrain is limited by computational cost. The number of computational grid points required to resolve the near-ground turbulent structures (eddies) are very high. The traditional solution to the problem has been to apply a wall function...... aspect ratio in the RANS layer and thereby resolve the mean near-wall velocity profile. The method is applicable to complex terrain and the benefits of traditional LES are kept intact. Using the hybrid method, simulations of the wind over a natural complex terrain near Wellington in New Zealand...

  16. An Integrated Approach To Offshore Wind Energy Assessment: Great Lakes 3D Wind Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Barthelmie, R. J. [Cornell Univ., Ithaca, NY (United States). Sibley School of Mechanical & Aerospace Engineering; Pryor, S. C. [Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences

    2017-09-18

    This grant supported fundamental research into the characterization of flow parameters of relevance to the wind energy industry focused on offshore and the coastal zone. A major focus of the project was application of the latest generation of remote sensing instrumentation and also integration of measurements and numerical modeling to optimize characterization of time-evolving atmospheric flow parameters in 3-D. Our research developed a new data-constrained Wind Atlas for the Great Lakes, and developed new insights into flow parameters in heterogeneous environments. Four experiments were conducted during the project: At a large operating onshore wind farm in May 2012; At the National Renewable Energy Laboratory National Wind Technology Center (NREL NWTC) during February 2013; At the shoreline of Lake Erie in May 2013; and At the Wind Energy Institute of Canada on Prince Edward Island in May 2015. The experiment we conducted in the coastal zone of Lake Erie indicated very complex flow fields and the frequent presence of upward momentum fluxes and resulting distortion of the wind speed profile at turbine relevant heights due to swells in the Great Lakes. Additionally, our data (and modeling) indicate the frequent presence of low level jets at 600 m height over the Lake and occasions when the wind speed profile across the rotor plane may be impacted by this phenomenon. Experimental data and modeling of the fourth experiment on Prince Edward Island showed that at 10-14 m escarpment adjacent to long-overseas fetch the zone of wind speed decrease before the terrain feature and the increase at (and slightly downwind of) the escarpment is ~3–5% at turbine hub-heights. Additionally, our measurements were used to improve methods to compute the uncertainty in lidar-derived flow properties and to optimize lidar-scanning strategies. For example, on the basis of the experimental data we collected plus those from one of our research partners we advanced a new methodology to

  17. Sea lamprey mark type, marking rate, and parasite-host relationships for lake trout and other species in Lake Ontario

    Science.gov (United States)

    Lantry, Brian F.; Adams, Jean V.; Christie, Gavin; Schaner, Teodore; Bowlby, James; Keir, Michael; Lantry, Jana; Sullivan, Paul; Bishop, Daniel; Treska, Ted; Morrison, Bruce

    2015-01-01

    We examined how attack frequency by sea lampreys on fishes in Lake Ontario varied in response to sea lamprey abundance and preferred host abundance (lake trout > 433 mm). For this analysis we used two gill net assessment surveys, one angler creel survey, three salmonid spawning run datasets, one adult sea lamprey assessment, and a bottom trawl assessment of dead lake trout. The frequency of fresh sea lamprey marks observed on lake trout from assessment surveys was strongly related to the frequency of sea lamprey attacks observed on salmon and trout from the creel survey and spawning migrations. Attack frequencies on all salmonids examined were related to the ratio between the abundances of adult sea lampreys and lake trout. Reanalysis of the susceptibility to sea lamprey attack for lake trout strains stocked into Lake Ontario reaffirmed that Lake Superior strain lake trout were among the most and Seneca Lake strain among the least susceptible and that Lewis Lake strain lake trout were even more susceptible than the Superior strain. Seasonal attack frequencies indicated that as the number of observed sea lamprey attacks decreased during June–September, the ratio of healing to fresh marks also decreased. Simulation of the ratios of healing to fresh marks indicated that increased lethality of attacks by growing sea lampreys contributed to the decline in the ratios and supported laboratory studies about wound healing duration.

  18. An open source high-performance solution to extract surface water drainage networks from diverse terrain conditions

    Science.gov (United States)

    Stanislawski, Larry V.; Survila, Kornelijus; Wendel, Jeffrey; Liu, Yan; Buttenfield, Barbara P.

    2018-01-01

    This paper describes a workflow for automating the extraction of elevation-derived stream lines using open source tools with parallel computing support and testing the effectiveness of procedures in various terrain conditions within the conterminous United States. Drainage networks are extracted from the US Geological Survey 1/3 arc-second 3D Elevation Program elevation data having a nominal cell size of 10 m. This research demonstrates the utility of open source tools with parallel computing support for extracting connected drainage network patterns and handling depressions in 30 subbasins distributed across humid, dry, and transitional climate regions and in terrain conditions exhibiting a range of slopes. Special attention is given to low-slope terrain, where network connectivity is preserved by generating synthetic stream channels through lake and waterbody polygons. Conflation analysis compares the extracted streams with a 1:24,000-scale National Hydrography Dataset flowline network and shows that similarities are greatest for second- and higher-order tributaries.

  19. Geophysical investigation of sentinel lakes in Lake, Seminole, Orange, and Volusia Counties, Florida

    Science.gov (United States)

    Reich, Christopher; Flocks, James; Davis, Jeffrey

    2012-01-01

    This study was initiated in cooperation with the St. Johns River Water Management District (SJRWMD) to investigate groundwater and surface-water interaction in designated sentinel lakes in central Florida. Sentinel lakes are a SJRWMD established set of priority water bodies (lakes) for which minimum flows and levels (MFLs) are determined. Understanding both the structure and lithology beneath these lakes can ultimately lead to a better understanding of the MFLs and why water levels fluctuate in certain lakes more so than in other lakes. These sentinel lakes have become important water bodies to use as water-fluctuation indicators in the SJRWMD Minimum Flows and Levels program and will be used to define long-term hydrologic and ecologic performance measures. Geologic control on lake hydrology remains poorly understood in this study area. Therefore, the U.S. Geological Survey investigated 16 of the 21 water bodies on the SJRWMD priority list. Geologic information was obtained by the tandem use of high-resolution seismic profiling (HRSP) and direct-current (DC) resistivity profiling to isolate both the geologic framework (structure) and composition (lithology). Previous HRSP surveys from various lakes in the study area have been successful in identifying karst features, such as subsidence sinkholes. However, by using this method only, it is difficult to image highly irregular or chaotic surfaces, such as collapse sinkholes. Resistivity profiling was used to complement HRSP by detecting porosity change within fractured or collapsed structures and increase the ability to fully characterize the subsurface. Lake Saunders (Lake County) is an example of a lake composed of a series of north-south-trending sinkholes that have joined to form one lake body. HRSP shows surface depressions and deformation in the substrate. Resistivity data likewise show areas in the southern part of the lake where resistivity shifts abruptly from approximately 400 ohm meters (ohm-m) along the

  20. Lake metabolism scales with lake morphometry and catchment conditions

    DEFF Research Database (Denmark)

    Stæhr, Peter Anton; Båstrup-Spohr, Lars; Jensen, Kaj Sand

    2012-01-01

    We used a comparative data set for 25 lakes in Denmark sampled during summer to explore the influence of lake morphometry, catchment conditions, light availability and nutrient input on lake metabolism. We found that (1) gross primary production (GPP) and community respiration (R) decline with lake...... in lake morphometry and catchment conditions when comparing metabolic responses of lakes to human impacts....

  1. Changing values of lake ecosystem services as a result of bacteriological contamination on Lake Trzesiecko and Lake Wielimie, Poland

    Directory of Open Access Journals (Sweden)

    Cichoń Małgorzata

    2017-12-01

    Full Text Available Lake ecosystems, on the one hand, are affected by tourism, and on the other by development for tourism. Lake ecosystem services include: water with its self-cleaning processes, air with climate control processes, as well as flora and fauna. Utilisation of services leads to interventions in the structure of ecosystems and their processes. Only to a certain extent, this is specific to each type of environmental interference, remains within the limits of ecosystem resilience and does not lead to its degradation. One of the threats is bacteriological contamination, for which the most reliable sanitation indicator is Escherichia coli. In lake water quality studies it is assumed that the lakeshore cannot be a source of bacteria. It has been hypothesised that the problem of bacterial contamination can be serious for the places that do not have any infrastructure, especially sanitation. Consequently, the purpose of the study was to determine the extent to which lakeshore sanitation, in particular the level of bacteriological contamination, has an impact on the value of services provided by the selected lake ecosystems (Lake Trzesiecko and Lake Wielimie – Szczecinek Lake District. Five selected services related to lake ecosystems are: water, control over the spread of contagious diseases, aesthetic values, tourism and recreation, as well as the hydrological cycle with its self-cleaning function. Services, as well as the criteria adopted for evaluation, allow us to conclude that the services provided by the lake ecosystems are suitable to fulfill a recreation function. However, the inclusion of quality criteria for sanitary status has shown that the value of system services has dropped by as much as 50%. Value changes are visible primarily for water and aesthetic qualities. Such a significant decrease in the value of services clearly indicates the importance of the sanitary conditions of lakes and their appropriate infrastructure. In view of the

  2. Searching for Terrain Softening near Mercury's North Pole

    Science.gov (United States)

    Cobian, P. S.; Vilas, F.; Lederer, S. M.; Barlow, N. G.

    2004-01-01

    In 1999, following the initial discovery of radar bright craters near both poles of Mercury measured the depth-todiameter (d/D) ratios of 170 impact craters in Mariner 10 images covering four different regions on Mercury s surface. Rapid softening of crater structure, indicated by lower d/D ratios, could indicate the possibility of subsurface water ice in Mercury's terrain originating from an internal source in the planet. Their study included 3 specific radar bright craters suggested to contain ice. They concluded that no terrain softening was apparent, and a rapidly emplaced exogenic water source was the most likely source for the proposed ice in these craters. Recent radar observations of the Mercurian North pole have pinpointed many additional radar bright areas with a resolution 10x better than previous radar measurements, and which correlate with craters imaged by Mariner 10. These craters are correlated with regions that are permanently shaded from direct sunlight, and are consistent with observations of clean water ice. We have expanded the initial study by Barlow et al. to include d/D measurements of 12 craters newly identified as radar bright at latitudes poleward of +80o. The radar reflectivity resemblances to Mars south polar cap and echoes from three icy Galilean satellites suggest that these craters too may have polar ice on Mercury. The effect of subsurface H20 on impact craters is a decrease in its d/D ratio, and softening of crater rims over a period of time. The study of Barlow et al., focused on determining the d/D ratios of 170 impact craters in the Borealis (north polar), Tolstoj (equatorial), Kuiper (equatorial), and Bach (south polar) quadrangles. This work focuses on the newly discovered radar bright craters, investigating their d/D ratios as an expansion of the earlier work..We compare our results to the statistical results from Barlow et al. here. With the upcoming Messenger spacecraft mission to Mercury, this is an especially timely study

  3. Lake Charles CCS Project

    Energy Technology Data Exchange (ETDEWEB)

    Leib, Thomas [Leucadia Energy, LLC, Salt Lake City, UT (United States); Cole, Dan [Denbury Onshore, LLC, Plano, TX (United States)

    2015-06-30

    , construction labor, engineering, and other costs. The CCS Project Final Technical Report is based on a Front End Engineering and Design (FEED) study prepared by SK E&C, completed in [June] 2014. Subsequently, Fluor Enterprises completed a FEED validation study in mid-September 2014. The design analyses indicated that the FEED package was sufficient and as expected. However, Fluor considered the construction risk based on a stick-build approach to be unacceptable, but construction risk would be substantially mitigated through utilization of modular construction where site labor and schedule uncertainty is minimized. Fluor’s estimate of the overall EPC project cost utilizing the revised construction plan was comparable to SKE&C’s value after reflecting Fluor’s assessment of project scope and risk characteristic. Development was halted upon conclusion of Phase 2A FEED and the project was not constructed.Transport and Sequestration – The overall objective of the pipeline project was to construct a pipeline to transport captured CO2 from the Lake Charles Clean Energy project to the existing Denbury Green Line and then to the Hastings Field in Southeast Texas to demonstrate effective geologic sequestration of captured CO2 through commercial EOR operations. The overall objective of the MVA portion of the project was to demonstrate effective geologic sequestration of captured CO2 through commercial Enhanced Oil Recovery (EOR) operations in order to evaluate costs, operational processes and technical performance. The DOE target for the project was to capture and implement a research MVA program to demonstrate the sequestration through EOR of approximately one million tons of CO2 per year as an integral component of commercial operations.

  4. A post-Calumet shoreline along southern Lake Michigan

    Science.gov (United States)

    Capps, D.K.; Thompson, T.A.; Booth, R.K.

    2007-01-01

    The southern shore of Lake Michigan is the type area for many of ancestral Lake Michigan's late Pleistocene lake phases, but coastal deposits and features of the Algonquin phase of northern Lake Michigan, Lake Huron, and Lake Superior are not recognized in the area. Isostatic rebound models suggest that Algonquin phase deposits should be 100 m or more below modern lake level. A relict shoreline, however, exists along the lakeward margin of the Calumet Beach that was erosional west of Deep River and depositional east of the river. For this post-Calumet shoreline, the elevation of basal foreshore deposits east of Deep River and the base of the scarp west of Deep River indicate a slightly westward dipping water plane that is centered at ???184 m above mean sea level. Basal foreshore elevations also indicate that lake level fell ???2 m during the development of the shoreline. The pooled mean of radiocarbon dates from the surface of the peat below post-Calumet shoreline foreshore deposits indicate that the lake transgressed over the peat at 10,560 ?? 70 years B.P. Pollen assemblages from the peat are consistent with this age. The elevation and age of the post-Calumet shoreline are similar to the Main Algonquin phase of Lake Huron. Recent isostatic rebound models do not adequately address a high-elevation Algonquin-age shoreline along the southern shore of Lake Michigan, but the Goldthwait (1908) hinge-line model does. ?? 2006 Springer Science+Business Media B.V.

  5. Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

    Science.gov (United States)

    Lin, Chen; Ma, Ronghua; He, Bin

    2015-12-24

    Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

  6. Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication—A Case Study in the Taihu Lake Basin (China)

    Science.gov (United States)

    Lin, Chen; Ma, Ronghua; He, Bin

    2015-01-01

    Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

  7. Prototyping Tensegrity Lander Systems for Icy Terrain (Year 2)

    Data.gov (United States)

    National Aeronautics and Space Administration — Demonstrate that a tensegrity lander is a low-cost and revolutionary landing concept for exploring icy terrain where landing forces, payload protection and mobility...

  8. VTAC: virtual terrain assisted impact assessment for cyber attacks

    Science.gov (United States)

    Argauer, Brian J.; Yang, Shanchieh J.

    2008-03-01

    Overwhelming intrusion alerts have made timely response to network security breaches a difficult task. Correlating alerts to produce a higher level view of intrusion state of a network, thus, becomes an essential element in network defense. This work proposes to analyze correlated or grouped alerts and determine their 'impact' to services and users of the network. A network is modeled as 'virtual terrain' where cyber attacks maneuver. Overlaying correlated attack tracks on virtual terrain exhibits the vulnerabilities exploited by each track and the relationships between them and different network entities. The proposed impact assessment algorithm utilizes the graph-based virtual terrain model and combines assessments of damages caused by the attacks. The combined impact scores allow to identify severely damaged network services and affected users. Several scenarios are examined to demonstrate the uses of the proposed Virtual Terrain Assisted Impact Assessment for Cyber Attacks (VTAC).

  9. CITY OF RADFORD TERRAIN, CITY OF RADFORD, VA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data includes digital elevation models, LIDAR derived contours, LIDAR three-dimensional spot elevations and breaklines, field surveyed ground elevations and...

  10. Classification of Mars Terrain Using Multiple Data Sources

    Data.gov (United States)

    National Aeronautics and Space Administration — Classification of Mars Terrain Using Multiple Data Sources Alan Kraut1, David Wettergreen1 ABSTRACT. Images of Mars are being collected faster than they can be...

  11. Laser altimetry and terrain analysis: A revolution in geomorphology

    NARCIS (Netherlands)

    Anders, N.; Seijmonsbergen, H.

    2008-01-01

    Terrain analysis in geomorphology has undergone a serious quantitative revolution over recent decades. Lidar information has been efficiently used to automatically classify discrete landforms, map forest structures, and provide input for models simulating landscape development, e.g. channel incision

  12. TERRAIN, CITY OF SEWARD, KENAI PENINSULA BOROUGH, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. LandingNav: Terrain Guided Automated Precision Landing, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase I effort successfully demonstrated the feasibility of a terrain guided automated precision landing sensor using an innovative multi-field-of-view stereo...

  14. DCS Terrain for Bacon County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  15. DCS Terrain Submission for Jefferson Davis Parish, LA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. Optimization of Wind Farm Layout in Complex Terrain

    DEFF Research Database (Denmark)

    Xu, Chang; Yang, Jianchuan; Li, Chenqi

    2013-01-01

    Microscopic site selection for wind farms in complex terrain is a technological difficulty in the development of onshore wind farms. This paper presented a method for optimizing wind farm layout in complex terrain. This method employed Lissaman and Jensen wake models, took wind velocity distribut......Microscopic site selection for wind farms in complex terrain is a technological difficulty in the development of onshore wind farms. This paper presented a method for optimizing wind farm layout in complex terrain. This method employed Lissaman and Jensen wake models, took wind velocity...... are subject to boundary conditions and minimum distance conditions. The improved genetic algorithm (GA) for real number coding was used to search the optimal result. Then the optimized result was compared to the result from the experienced layout method. Results show the advantages of the present method...

  17. DCS Terrain Submission for Los Angeles County, CA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. DCS Terrain for Appling County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  19. DCS Terrain for Evans County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  20. DCS Terrain for Treutlen County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  1. DCS Terrain for Johnson County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  2. DCS Terrain for Wheeler County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  3. DCS Terrain for Tattnall County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  4. DCS Terrain for Tift County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  5. DCS Terrain Submission for Gold Star Canyon Study

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  6. DIGITAL DCS Terrain Submission for WHATCOM COUNTY, WASHINGTON

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describe the digital topographic data that were used to create...

  7. DCS Terrain Submission for La Paz County, AZ

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  8. DCS Terrain Submittal for Spalding County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. TERRAIN submission for Rock River RiskMap DFIRM

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. TERRAIN submission for Rock River Risk Map, Dane County Portion

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  11. DCS Terrain Submittal for Washita County, Oklahoma, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  12. DCS Terrain Submittal for Dougherty County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  13. DCS Terrain Submission for Lewis and Clark County, Montana

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  14. DCS Terrain for Bullcoh County GA MAPMOD04-08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  15. DCS Terrain Submission for Mercer County New Jersey

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. DCS Terrain Submittal for Thomas County, Georgia, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  17. DCS Terrain Submission for Clay County, AR, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  18. DIGITAL TERRAIN DCS DATABASE for ALLEN PARISH, LA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  19. DCS Terrain Submission for Chippewa County, MI (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  20. DCS Terrain for Roscommon County, MI (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  1. Terrain, BIG BLUE RIVER TRIBUTARY NO 44, GAGE COUNTY, NE

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. TERRAIN, CITY OF ANSONIA, NEW HAVEN COUNTY, CONNECTICUT - Levee PMR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  3. Terrain Submission for Dickinson County, MI (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  4. Cross-coupled control for all-terrain rovers.

    Science.gov (United States)

    Reina, Giulio

    2013-01-08

    Mobile robots are increasingly being used in challenging outdoor environments for applications that include construction, mining, agriculture, military and planetary exploration. In order to accomplish the planned task, it is critical that the motion control system ensure accuracy and robustness. The achievement of high performance on rough terrain is tightly connected with the minimization of vehicle-terrain dynamics effects such as slipping and skidding. This paper presents a cross-coupled controller for a 4-wheel-drive/4-wheel-steer robot, which optimizes the wheel motors' control algorithm to reduce synchronization errors that would otherwise result in wheel slip with conventional controllers. Experimental results, obtained with an all-terrain rover operating on agricultural terrain, are presented to validate the system. It is shown that the proposed approach is effective in reducing slippage and vehicle posture errors.

  5. Cross-Coupled Control for All-Terrain Rovers

    Directory of Open Access Journals (Sweden)

    Giulio Reina

    2013-01-01

    Full Text Available Mobile robots are increasingly being used in challenging outdoor environments for applications that include construction, mining, agriculture, military and planetary exploration. In order to accomplish the planned task, it is critical that the motion control system ensure accuracy and robustness. The achievement of high performance on rough terrain is tightly connected with the minimization of vehicle-terrain dynamics effects such as slipping and skidding. This paper presents a cross-coupled controller for a 4-wheel-drive/4-wheel-steer robot, which optimizes the wheel motors’ control algorithm to reduce synchronization errors that would otherwise result in wheel slip with conventional controllers. Experimental results, obtained with an all-terrain rover operating on agricultural terrain, are presented to validate the system. It is shown that the proposed approach is effective in reducing slippage and vehicle posture errors.

  6. DCS Terrain Submission for Pine County, MN (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  7. DCS Terrain for Dodge County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  8. DCS Terrain Submission for Santa Cruz,CA - CW (NAVD)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  9. DCS Terrain Submittal for Crenshaw County, Alabama, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  10. Terrain Submission for Pottawattamie County, IA (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describe the digital topographic data that were used to create...

  11. DCS Terrain Submission for Wilkin County, MN (Countywide DFIRM)

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  12. DCS Terrain for Montgomery County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  13. TERRAIN, CITY OF GRAND PRAIRIE, DALLAS COUNTY, TEXAS

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  14. DCS Terrain for Laurens County GA MAPMOD04-08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  15. DCS Terrain Submission for Bear Creek in Clear Creek County

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  16. DCS Terrain for Jenkins County GA MapMod08

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that was used to create...

  17. Lunar All-Terrain Utility Vehicle for EVA, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ProtoInnovations, LLC proposes to develop a new type of planetary rover called a Lunar All-terrain Utility Vehicle ("Lunar ATV") to assist extra-vehicular activities...

  18. TERRAIN DATA CAPTURE STANDARDS, LUZERNE COUNTY, PA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data includes digital elevation models, LIDAR derived contours, LIDAR three-dimensional spot elevations and breaklines, field surveyed ground elevations and...

  19. DCS Terrain Submittal for Bernalillo County, New Mexico, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  20. Lunar All-Terrain Utility Vehicle for EVA, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — ProtoInnovations, LLC proposes to develop a new type of planetary rover called a Lunar All-terrain Utility Vehicle ("LATUV") to assist extra-vehicular activities in...

  1. DCS Terrain Submission for Monmouth County, New Jersey

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  2. Exploration of Extreme Terrain Using a Polyhedral Rover

    Data.gov (United States)

    National Aeronautics and Space Administration — Exploring celestial bodies with extreme terrains in our solar system, like Mars, Europa, Enceladus, and asteroids, are of great importance to NASA because these...

  3. DCS Terrain Submission for McCook County, SD

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix M: Data Capture Standards, describes the digital topographic data that were used to create...

  4. DCS Terrain submission for Washoe County NV PMR

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Terrain data, as defined in FEMA Guidelines and Specifications, Appendix N: Data Capture Standards, describes the digital topographic data that was used to create...

  5. Deciphering dynamical proxy responses from lake sediments

    Science.gov (United States)

    Ramisch, Arne; Tjallingii, Rik; Hartmann, Kai; Brauer, Achim; Diekmann, Bernhard; Haberzettl, Torsten; Kasper, Thomas; Ahlborn, Marieke

    2017-04-01

    Lakes form a reliable archive of paleoenvironmental change in the terrestrial realm. Non-destructive XRF scans provide high-resolution records of element concentrations that are commonly related to past environmental change. However, XRF records of lake sediments enclose paleoenvironmental information that originates from multiple lake external and internal forcing. The variety of environmental forcing factors can complicate a direct identification of single mechanisms like climatic change from XRF or other proxy records. Here we present XRF records from several Asian lake archives, which indicate asynchronous variations of similar geochemical records since the late glacial/early Holocene. All XRF time series are characterized by damped harmonic oscillations of relative element concentrations through time. The asynchronous variations can be expressed by the frequency and the rate of damping of theses oscillations that differ between the lakes. We argue that the oscillatory behavior is a result of a feedback between the physical removal and dissolution of mineral phases in catchment soils and their subsequent enrichment and deposition within the lake. We present a numerical model, which accurately simulates major Holocene variations in the element concentration of lake records and discuss implications for the reconstruction of environmental signals from lake sediments.

  6. Object Georeferencing in UAV-Based SAR Terrain Images

    OpenAIRE

    Łabowski Michał; Kaniewski Piotr; Serafin Piotr; Wajszczyk Bronisław

    2016-01-01

    Synthetic aperture radars (SAR) allow to obtain high resolution terrain images comparable with the resolution of optical methods. Radar imaging is independent on the weather conditions and the daylight. The process of analysis of the SAR images consists primarily of identifying of interesting objects. The ability to determine their geographical coordinates can increase usability of the solution from a user point of view. The paper presents a georeferencing method of the radar terrain images. ...

  7. Calibrated L-Band Terrain Measurements and Analysis Program.

    Science.gov (United States)

    1986-02-01

    space of these three parameters, points corresponding to samples from different terrain types will be well separated. And not only will points for...different terrain types be quite distinct, but also dif- ferent regions of the three-parameter space will characterize differ- ent surface types. The...planned to examine goodness of fit of both the IG and log- 4-4 normal distributions to histograms based on various samples, using 86 the Kolmogoroff -Smirnov

  8. National Lakes Assessment Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Lakes Assessment (NLA) is a first-ever statistically-valid survey of the biological condition of lakes and reservoirs throughout the U.S. The U.S....

  9. Structural Analysis and Geodynamic Implications of Tessera Terrain, Venus

    Science.gov (United States)

    Hansen, V. L.; Willis, J. J.

    1996-03-01

    Understanding processes of tessera formation is fundamental to Venus tectonic and geodynamic models. We examined tessera terrain in Ishtar Terra, crustal plateaus, and as inliers within the plains using high-resolution Magellan SAR imagery. We describe several major types of tesseraeeach found in specific geologic or geomorphic regions. Fold and S-C tessera terrain are found only in Ishtar Terra; lava flow and basin-and-dome terrains reside within the interior of crustal plateaus, whereas folded ribbon terrain and extended folded terrain comprise margins of crustal plateaus; and star terrain lies within central Phoebe. Inliers are divisible into fracture-dominated and graben-dominated tesserae, which may represent ancient flooded coronae-chasmata and crustal plateaus, respectively. Thus tesserae might form in several tectonic environments, including as a result of (1) subsurface flow in Ishtar Terra, (2) as sequences of surface-layer extension and contraction in crustal plateaus, (3) as highly-extended, previously-deformed crustal plateaus which have deflated or sunken, and become flooded and thus preserved as large plains inliers, and (4) as densely-fractured surface layersfractured as a result of corona and chasma formationwhich have since sunken and become flooded, and thus preserved as isolated, scattered, highly-fractured inliers. If these models of formation are correct, tesserae would not form a global onion skin; they would not represent a globally synchronous unit; they would not record a single period of deformation; and it would not infer a single mechanism for tesserae formation.

  10. terrain analysis in the course curricula of the south african army

    African Journals Online (AJOL)

    a_lodi

    ensuring that terrain is utilised and employed to the benefit of the South African. Army.5 Military terrain analysis ... terrain to determine the manoeuvre potential, ways to reduce natural and enemy obstacles, and how they ... working relationship with the military intelligence staff and the engineer terrain warrant officer. For the ...

  11. Lake Erie and Lake Michigan zebra mussel settlement monitoring and implications for chlorination treatment

    International Nuclear Information System (INIS)

    Demoss, D.; Mendelsberg, J.I.

    1992-01-01

    This paper reports on the 1991 zebra mussel veliger settlement monitoring program undertaken to record and evaluate zebra mussel veliger settlement in Lake Erie and Lake Michigan. Studies by Dr. Gerald Mackie of Canada in 1990 indicated veliger settlement may be occurring primarily during short time periods every season corresponding with warmer water temperatures. Veliger settlement monitoring was performed using a plexiglass sampler apparatus. The samplers were simple in design and consisted of a 20-inch-square plexiglass base panel with thirty-six 1 inch x 3 inch clear plexiglass microscope slides attached. The results of the monitoring program indicate the existence of preferential settlement periods for veligers correlating with sustained lake water temperatures above 70 degrees F. Veliger settlement concentrations in the south basin of Lake Michigan appear to be similar to those in western Lake Erie

  12. 77 FR 41686 - Safety Zone; Sheffield Lake Fireworks, Lake Erie, Sheffield Lake, OH

    Science.gov (United States)

    2012-07-16

    ...-AA00 Safety Zone; Sheffield Lake Fireworks, Lake Erie, Sheffield Lake, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on Lake Erie, Sheffield Lake, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie...

  13. Remotely Sensing Lake Water Volumes on the Inner Arctic Coastal Plain of Northern Alaska

    Science.gov (United States)

    Simpson, C. E.; Arp, C. D.; Jones, B. M.; Hinkel, K. M.; Carroll, M.; Smith, L. C.

    2017-12-01

    Thermokarst lake depth is controlled by the amount of excess ice in near-surface permafrost, with lake depths of about 1 - 3 m in areas of epigenetic permafrost and over 10 m in areas of syngenetic permafrost. An important exception to these general patterns is found on the inner Arctic Coastal Plain (ACP) of northern Alaska, where deep lakes occur in Pleistocene-aged, ground-ice poor sandy terrain. These lakes cover 20% of the currently inactive sand sheet and dune deposit (referred to as the Pleistocene Sand Sea) that comprises approximately 7000 km2 of the ACP. Surrounded by high and eroding bluffs, sand sea lakes lie in natural depressions and are characterized by wide, shallow littoral shelves and central troughs that are typically oriented NNW to SSE and can reach depths greater than 20 m. Despite their unique form and extensive coverage, these lakes have received little prior study and a literature gap remains regarding regional water storage. This research classifies sand sea lakes, estimates individual lake volume, and provides a first quantification of water storage in a region of the lake-dominated ACP. We measured bathymetric profiles in 19 sand sea lakes using a sonar recorder to capture various lake depth gradients. Bathymetric surveys collected by oil industry consultants, lake monitoring programs, and habitat studies serve as additional datasets. These field measured lake depth data points were used to classify Color Infrared Photography, WorldView-2 satellite imagery, and Landsat-OLI satellite imagery to develop a spectral depth-classification algorithm and facilitate the interpolation of the bathymetry for study lakes in the inner ACP. Finally, we integrate the remotely sensed bathymetry and imagery-derived lake surface area to estimate individual and regional-scale lake volume. In addition to the natural function of these lakes in water storage, energy balance, and habitat provision, the need for winter water supply to build ice roads for oil

  14. Hydrological and solute budgets of Lake Qinghai, the largest lake on the Tibetan Plateau

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Zhangdong [Chinese Academy of Sciences (CAS), Beijing (China); National Cheng Kung Univ., Tainan City (Taiwan); You, Chen-Feng [National Cheng Kung Univ., Tainan City (Taiwan); Wang, Yi [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shi, Yuewei [Bureau of Hydrology and Water Resources of Qinghai Province, Xining (China)

    2009-12-04

    Water level and chemistry of Lake Qinghai are sensitive to climate changes and are important for paleoclimatic implications. An accurate understanding of hydrological and chemical budgets is crucial for quantifying geochemical proxies and carbon cycle. Published results of water budget are firstly reviewed in this paper. Chemical budget and residence time of major dissolved constituents in the lake are estimated using reliable water budget and newly obtained data for seasonal water chemistry. The results indicate that carbonate weathering is the most important riverine process, resulting in dominance of Ca 2+ and DIC for river waters and groundwater. Groundwater contribution to major dissolved constituents is relatively small (4.2 ± 0.5%). Wet atmospheric deposition contributes annually 7.4–44.0% soluble flux to the lake, resulting from eolian dust throughout the seasons. Estimates of chemical budget further suggest that (1) the Buha-type water dominates the chemical components of the lake water, (2) Na+, Cl-, Mg 2+ , and K+ in lake water are enriched owing to their conservative behaviors, and (3) precipitation of authigenic carbonates (low-Mg calcite, aragonite, and dolomite) transits quickly dissolved Ca 2+ into the bottom sediments of the lake, resulting in very low Ca 2+ in the lake water. Therefore, authigenic carbonates in the sediments hold potential information on the relative contribution of different solute inputs to the lake and the lake chemistry in the past.

  15. Mid Holocene lake level and shoreline behavior during the Nipissing phase of the upper Great Lakes at Alpena, Michigan, USA

    Science.gov (United States)

    Thompson, T.A.; Lepper, K.; Endres, A.L.; Johnston, J.W.; Baedke, S.J.; Argyilan, E.P.; Booth, R.K.; Wilcox, D.A.

    2011-01-01

    The Nipissing phase was the last pre-modern high-water stage of the upper Great Lakes. Represented as either a one- or two-peak highstand, the Nipissing occurred following a long-term lake-level rise. This transgression was primarily an erosional event with only the final stage of the transgression preserved as barriers, spits, and strandplains of beach ridges. South of Alpena, Michigan, mid to late Holocene coastal deposits occur as a strandplain between Devils Lake and Lake Huron. The landward part of this strandplain is a higher elevation platform that formed during the final stage of lake-level rise to the Nipissing peak. The pre-Nipissing shoreline transgressed over Devils Lake lagoonal deposits from 6.4 to 6.1. ka. The first beach ridge formed ~ 6. ka, and then the shoreline advanced toward Lake Huron, producing beach ridges about every 70. years. This depositional regression produced a slightly thickening wedge of sediment during a lake-level rise that formed 20 beach ridges. The rise ended at 4.5. ka at the Nipissing peak. This peak was short-lived, as lake level fell > 4. m during the following 500. years. During this lake-level rise and subsequent fall, the shoreline underwent several forms of shoreline behavior, including erosional transgression, aggradation, depositional transgression, depositional regression, and forced regression. Other upper Great Lakes Nipissing platforms indicate that the lake-level change observed at Alpena of a rapid pre-Nipissing lake-level rise followed by a slower rise to the Nipissing peak, and a post-Nipissing rapid lake-level fall is representative of mid Holocene lake level in the upper Great Lakes. ?? 2011 Elsevier B.V.

  16. Antibiotics and Antibiotic Resistance Genes in Sediment of Honghu Lake and East Dongting Lake, China.

    Science.gov (United States)

    Yang, Yuyi; Cao, Xinhua; Lin, Hui; Wang, Jun

    2016-11-01

    Sediment is an ideal medium for the aggregation and dissemination of antibiotics and antibiotic resistance genes (ARGs). The levels of antibiotics and ARGs in Honghu Lake and East Dongting Lake of central China were investigated in this study. The concentrations of eight antibiotics (four sulfonamides and four tetracyclines) in Honghu Lake were in the range 90.00-437.43 μg kg -1 (dry weight (dw)) with mean value of 278.21 μg kg -1 dw, which was significantly higher than those in East Dongting Lake (60.02-321.04 μg kg -1 dw, mean value of 195.70 μg kg -1 dw). Among the tested three sulfonamide resistance genes (sul) and eight tetracycline resistance genes (tet), sul1, sul2, tetA, tetC, and tetM had 100 % detection frequency in sediment samples of East Dongting Lake, while only sul1, sul2, and tetC were observed in all samples of Honghu Lake. The relative abundance of sul2 was higher than that of sul1 at p  tetB > tetC > tetA. The relative abundance of sul1, sul2, and tetC in East Dongting Lake was significantly higher than those in Honghu Lake. The abundance of background bacteria may play an important role in the horizontal spread of sul2 and tetC genes in Honghu Lake and sul1 in East Dongting Lake, respectively. Redundancy analysis indicated that tetracyclines may play a more important role than sulfonamides in the abundance of sul1, sul2, and tetC gens in Honghu Lake and East Dongting Lake.

  17. Anaglyph, Salt Lake City, Utah

    Science.gov (United States)

    2002-01-01

    The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This anaglyph image provides a stereoscopic map view of north central Utah that includes all of these Olympic sites. In the south, next to Utah Lake, Provo hosts the ice hockey competition. In the north, northeast of the Great Salt Lake, Ogden hosts curling and the nearby Snowbasin ski area hosts the downhill events. In between, southeast of the Great Salt Lake, Salt Lake City hosts the Olympic Village and the various skating events. Further east, across the Wasatch Mountains, the Park City ski resort hosts the bobsled, ski jumping, and snowboarding events. The Winter Olympics are always hosted in mountainous terrain. This view shows the dramatic landscape that makes the Salt Lake City region a world-class center for winter sports.The stereoscopic effect of this anaglyph was created by first draping a Landsat satellite image over a Shuttle Radar Topography Mission digital elevation model and then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed

  18. HYDRAULICS, LAKE COUNTY, MONTANA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Recent developments in digital terrain and geospatial database management technology make it possible to protect this investment for existing and future projects to...

  19. HYDRAULICS, LAKE COUNTY, FL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Recent developments in digital terrain and geospatial database management technology make it possible to protect this investment for existing and future projects to...

  20. HYDROLOGY, LAKE COUNTY, CA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — Recent developments in digital terrain and geospatial database management technology make it possible to protect this investment for existing and future projects to...

  1. Integrated terrain mapping with digital Landsat images in Queensland, Australia

    Science.gov (United States)

    Robinove, Charles Joseph

    1979-01-01

    Mapping with Landsat images usually is done by selecting single types of features, such as soils, vegetation, or rocks, and creating visually interpreted or digitally classified maps of each feature. Individual maps can then be overlaid on or combined with other maps to characterize the terrain. Integrated terrain mapping combines several terrain features into each map unit which, in many cases, is more directly related to uses of the land and to methods of land management than the single features alone. Terrain brightness, as measured by the multispectral scanners in Landsat 1 and 2, represents an integration of reflectance from the terrain features within the scanner's instantaneous field of view and is therefore more correlatable with integrated terrain units than with differentiated ones, such as rocks, soils, and vegetation. A test of the feasibilty of the technique of mapping integrated terrain units was conducted in a part of southwestern Queensland, Australia, in cooperation with scientists of the Queensland Department of Primary Industries. The primary purpose was to test the use of digital classification techniques to create a 'land systems map' usable for grazing land management. A recently published map of 'land systems' in the area (made by aerial photograph interpretation and ground surveys), which are integrated terrain units composed of vegetation, soil, topography, and geomorphic features, was used as a basis for comparison with digitally classified Landsat multispectral images. The land systems, in turn, each have a specific grazing capacity for cattle (expressed in beasts per km 2 ) which is estimated following analysis of both research results and property carrying capacities. Landsat images, in computer-compatible tape form, were first contrast-stretched to increase their visual interpretability, and digitally classified by the parallelepiped method into distinct spectral classes to determine their correspondence to the land systems classes and

  2. Heritage strain and diet of wild young of year and yearling lake trout in the main basin of Lake Huron

    Science.gov (United States)

    Roseman, E.F.; Stott, W.; O'Brien, T. P.; Riley, S.C.; Schaeffer, J.S.

    2009-01-01

    Restoration of lake trout Salvelinus namaycush stocks in Lake Huron is a fish community objective developed to promote sustainable fish communities in the lake. Between 1985 and 2004, 12.65 million lake trout were stocked into Lake Huron representing eight different genetic strains. Collections of bona fide wild fish in USGS surveys have increased in recent years and this study examined the ancestry and diet of fish collected between 2004 and 2006 to explore the ecological role they occupy in Lake Huron. Analysis of microsatellite DNA revealed that both pure strain and inter-strain hybrids were observed, and the majority of fish were classified as Seneca Lake strain or Seneca Lake hybrids. Diets of 50 wild age-0 lake trout were examined. Mysis, chironomids, and zooplankton were common prey items of wild age-0 lake trout. These results indicate that stocked fish are successfully reproducing in Lake Huron indicating a level of restoration success. However, continued changes to the benthic macroinvertebrate community, particularly declines of Mysis, may limit growth and survival of wild fish and hinder restoration efforts.

  3. Geomorphic response to sea level and climate changes during Late Quaternary in a humid tropical coastline: Terrain evolution model from Southwest India.

    Science.gov (United States)

    K, Maya; S, Vishnu Mohan; Limaye, Ruta B; Padmalal, Damodaran; Kumaran, Navnith K P

    2017-01-01

    The coastal lands of southern Kerala, SW India in the vicinity of Achankovil and Thenmala Shear Zones reveal a unique set of geomorphic features like beach ridges, runnels, chain of wetlands, lakes, estuaries, etc. The chain of wetlands and water bodies that are seen in the eastern periphery of the coastal lands indicates the remnants of the upper drainage channels of the previously existed coastal plain rivers of Late Pleistocene age that are later broadened due to coastal erosion under the transgressive phase. The terrain evolutionary model developed from the results of the study shows that the Late Pleistocene transgressive events might have carved out a major portion of the land areas drained by the coastal plain rivers and as a result the coastal cliff has been retreated several kilometers landwards. The NNE-SSW trending beach ridges located close to the inland wetlands indicate the extent of shoreline shift towards eastwards during Late Pleistocene period. The present beach parallel ridges in the younger coastal plain indicate the limit of the Mid Holocene shoreline as the transgression was not so severe compared to Late Pleistocene event. The zone of convergence of the two sets of beach ridges coincides with the areas of economically viable heavy mineral placers that resulted from the size and density based sorting under the repeated transgressive events to which the coast had subjected to. The chain of wetlands in the eastern side of the study area has been evolved from a mega lagoon existed during Late Pleistocene. The Pallikkal River that links discrete eastern wetland bodies has been evolved into its present form during Early Holocene.

  4. Complex terrain influences ecosystem carbon responses to temperature and precipitation

    Science.gov (United States)

    Reyes, W. M.; Epstein, H. E.; Li, X.; McGlynn, B. L.; Riveros-Iregui, D. A.; Emanuel, R. E.

    2017-08-01

    Terrestrial ecosystem responses to temperature and precipitation have major implications for the global carbon cycle. Case studies demonstrate that complex terrain, which accounts for more than 50% of Earth's land surface, can affect ecological processes associated with land-atmosphere carbon fluxes. However, no studies have addressed the role of complex terrain in mediating ecophysiological responses of land-atmosphere carbon fluxes to climate variables. We synthesized data from AmeriFlux towers and found that for sites in complex terrain, responses of ecosystem CO2 fluxes to temperature and precipitation are organized according to terrain slope and drainage area, variables associated with water and energy availability. Specifically, we found that for tower sites in complex terrain, mean topographic slope and drainage area surrounding the tower explained between 51% and 78% of site-to-site variation in the response of CO2 fluxes to temperature and precipitation depending on the time scale. We found no such organization among sites in flat terrain, even though their flux responses exhibited similar ranges. These results challenge prevailing conceptual framework in terrestrial ecosystem modeling that assumes that CO2 fluxes derive from vertical soil-plant-climate interactions. We conclude that the terrain in which ecosystems are situated can also have important influences on CO2 responses to temperature and precipitation. This work has implications for about 14% of the total land area of the conterminous U.S. This area is considered topographically complex and contributes to approximately 15% of gross ecosystem carbon production in the conterminous U.S.

  5. Impact of terrain heterogeneity on near-surface turbulence structure

    Science.gov (United States)

    Fesquet, Clément; Drobinski, Philippe; Barthlott, Christian; Dubos, Thomas

    2009-10-01

    This study investigates the impact of terrain heterogeneity on local turbulence measurements using 18 months of turbulence data taken on a 30 m tower at the SIRTA mixed land-use observatory under varying stability conditions and fetch configurations. These measurements show that turbulence variables such as the turbulent kinetic energy or momentum fluxes are strongly dependent on the upstream complexity of the terrain (presence of trees or buildings, open field). However, using a detection technique based on wavelet transforms which permits the isolation of the large-scale coherent structures from small-scale background fluctuations, the study shows that, for all stability conditions, whatever the upstream complexity of the terrain, the coherent structures display universal properties which are independent of the terrain nature: the frequency of occurrence, time duration of the coherent structures, the time separation between coherent structures and the relative contribution of the coherent structures to the total fluxes (momentum and heat) appear to be independent of the upstream roughness. This is an important result since coherent structures are known to transport a large portion of the total energy. This study extends to all stability conditions a numerical study by Fesquet et al. [Fesquet, C., Dupont, S., Drobinski, P., Barthlott, C., Dubos, T., 2008. Impact of terrain heterogeneities on coherent structures properties: experimental and numerical approaches. In: 18th Symposium on Boundary Layers and Turbulence. No. 11B.1. Stockholm, Sweden., Fesquet, C., Dupont, S., Drobinski, P., Dubos, T., Barthlott, C., in press. Impact of terrain heterogeneity on coherent structure properties: numerical approach. Bound.-Layer Meteorol.] conducted in neutral conditions which shows that a reason for such behavior is that the production of local active turbulence in an internal boundary layer associated with coherent structure originating from the outer layer and impinging

  6. An Inter-Comparison Study of Multi- and DBS Lidar Measurements in Complex Terrain

    Directory of Open Access Journals (Sweden)

    Lukas Pauscher

    2016-09-01

    Full Text Available Wind measurements using classical profiling lidars suffer from systematic measurement errors in complex terrain. Moreover, their ability to measure turbulence quantities is unsatisfactory for wind-energy applications. This paper presents results from a measurement campaign during which multiple WindScanners were focused on one point next to a reference mast in complex terrain. This multi-lidar (ML technique is also compared to a profiling lidar using the Doppler beam swinging (DBS method. First- and second-order statistics of the radial wind velocities from the individual instruments and the horizontal wind components of several ML combinations are analysed in comparison to sonic anemometry and DBS measurements. The results for the wind speed show significantly reduced scatter and directional error for the ML method in comparison to the DBS lidar. The analysis of the second-order statistics also reveals a significantly better correlation for the ML technique than for the DBS lidar, when compared to the sonic. However, the probe volume averaging of the lidars leads to an attenuation of the turbulence at high wave numbers. Also the configuration (i.e., angles of the WindScanners in the ML method seems to be more important for turbulence measurements. In summary, the results clearly show the advantages of the ML technique in complex terrain and indicate that it has the potential to achieve significantly higher accuracy in measuring turbulence quantities for wind-energy applications than classical profiling lidars.

  7. Stream, Lake, and Reservoir Management.

    Science.gov (United States)

    Dai, Jingjing; Mei, Ying; Chang, Chein-Chi

    2017-10-01

    This review on stream, lake, and reservoir management covers selected 2016 publications on the focus of the following sections: Stream, lake, and reservoir management • Water quality of stream, lake, and reservoir • Reservoir operations • Models of stream, lake, and reservoir • Remediation and restoration of stream, lake, and reservoir • Biota of stream, lake, and reservoir • Climate effect of stream, lake, and reservoir.

  8. The effects of synoptical weather pattern and complex terrain on the formation of aerosol events in the Greater Taipei area.

    Science.gov (United States)

    Chuang, Ming-Tung; Chiang, Pen-Chi; Chan, Chang-Chuan; Wang, Chu-Fang; Chang, E-E; Lee, Chung-Te

    2008-07-25

    The aerosol in the Taipei basin is difficult to transport outward under specific weather patterns owing to complex terrain blocking. In this study, seven weather patterns are identified from synoptic weather maps for aerosol events, which occurred from March 2002 to February 2005. Among the identified weather patterns, High Pressure Peripheral Circulation (HPPC), Warm area Ahead of a cold Front (WAF), TYPhoon (TYP), Pacific High Pressure system stretching westerly (PHP), Weak High Pressure system (WHP), and Weak Southern Wind (WSW) are related to terrain blocking. The remaining pattern is High Pressure system Pushing (HPP). The classification of the pollution origin of the air masses shows that 15% of event days were contributed by long-range transport (LRT), 20% by local pollution (LP), and 65% by LRT/LP mix. Terrain blocking causes aerosol accumulation from high atmospheric stability and weak winds occurring under HPPC, TYP, and PHP weather patterns when the Taipei basin is situated on the lee side of the Snow Mountains Chain (SMC). Terrain blocking also occurs when the Taipei basin is situated on the upwind of SMC and Mt. Da-Twen under WAF and WSW patterns. To study the variation of aerosol properties under the mixed influence of terrain and pollution origin, we conducted a field observation simultaneously at the urban, suburban, and background sites in the Greater Taipei area from April 14 to 23, 2004. Terrain blocking plays an important role in aerosol accumulation in the stagnant environment when the Taipei basin is on the lee side of SMC. On the other hand, the PM(2.5) sulfate level is stable with a fraction of 30% in PM(2.5) during the observation period at the urban (25%-33%) and background (25%-41%) sites. It indicates that background PM(2.5) sulfate is high on the West Pacific in winter.

  9. Volcanic lake systems as terrestrial analogue for sulphate-rich terrains on Mars

    NARCIS (Netherlands)

    Rodríguez, A.

    2016-01-01

    Remote-sensing observations and rover missions have documented the abundant presence of sulphate-rich mineral associations on the surface of Mars. Together with widespread occurrences of silica and frequent enrichments of chlorine and bromine in soils and rocks, the sulphate associations are

  10. THE WATER QUALITY FROM SAINT ANA LAKE

    OpenAIRE

    M.VIGH; Z.MAKFALVI

    2013-01-01

    Inside the Ciomad Massive appears a unique lake in Romania, with an exclusive precipitations alimentation regime. The lake’s origin and the morphometric elements, together with the touristic activity, determine the water’s quality and characteristics. Water status evaluation was realized using random samples taken between the years 2005 and 2010. Qualitative parameters indicate the existence of a clear water lake, belonging to ultra-oligotrophic faze. This is because the crater is covered wit...

  11. Mechanisms influencing changes in lake area in Alaskan boreal forest

    Science.gov (United States)

    Roach, Jennifer K.; Griffith, Brad; Verbyla, David; Jones, Jeremy B.

    2011-01-01

    During the past ∼50 years, the number and area of lakes have declined in several regions in boreal forests. However, there has been substantial finer-scale heterogeneity; some lakes decreased in area, some showed no trend, and others increased. The objective of this study was to identify the primary mechanisms underlying heterogeneous trends in closed-basin lake area. Eight lake characteristics (δ18O, electrical conductivity, surface : volume index, bank slope, floating mat width, peat depth, thaw depth at shoreline, and thaw depth at the forest boundary) were compared for 15 lake pairs in Alaskan boreal forest where one lake had decreased in area since ∼1950, and the other had not. Mean differences in characteristics between paired lakes were used to identify the most likely of nine mechanistic scenarios that combined three potential mechanisms for decreasing lake area (talik drainage, surface water evaporation, and terrestrialization) with three potential mechanisms for nondecreasing lake area (subpermafrost groundwater recharge through an open talik, stable permafrost, and thermokarst). A priori expectations of the direction of mean differences between decreasing and nondecreasing paired lakes were generated for each scenario. Decreasing lakes had significantly greater electrical conductivity, greater surface : volume indices, shallower bank slopes, wider floating mats, greater peat depths, and shallower thaw depths at the forest boundary. These results indicated that the most likely scenario was terrestrialization as the mechanism for lake area reduction combined with thermokarst as the mechanism for nondecreasing lake area. Terrestrialization and thermokarst may have been enhanced by recent warming which has both accelerated permafrost thawing and lengthened the growing season, thereby increasing plant growth, floating mat encroachment, transpiration rates, and the accumulation of organic matter in lake basins. The transition to peatlands associated

  12. Integration of Bayesian analysis for eutrophication prediction and assessment in a landscape lake.

    Science.gov (United States)

    Yang, Likun; Zhao, Xinhua; Peng, Sen; Zhou, Guangyu

    2015-01-01

    Eutrophication models have been widely used to assess water quality in landscape lakes. Because flow rate in landscape lakes is relatively low and similar to that of natural lakes, eutrophication is more dominant in landscape lakes. To assess the risk of eutrophication in landscape lakes, a set of dynamic equations was developed to simulate lake water quality for total nitrogen (TN), total phosphorous (TP), dissolve oxygen (DO) and chlorophyll a (Chl a). Firstly, the Bayesian calibration results were described. Moreover, the ability of the model to reproduce adequately the observed mean patterns and major cause-effect relationships for water quality conditions in landscape lakes were presented. Two loading scenarios were used. A Monte Carlo algorithm was applied to calculate the predicated water quality distributions, which were used in the established hierarchical assessment system for lake water quality risk. The important factors affecting the lake water quality risk were defined using linear regression analysis. The results indicated that the variations in the landscape lake receiving recharge water quality caused considerable landscape lake water quality risk in the surrounding area. Moreover, the Chl a concentration in lake water was significantly affected by TP and TN concentrations; the lake TP concentration was the limiting factor for growth of plankton in lake water. The lake water TN concentration provided the basic nutritional requirements. Lastly, lower TN and TP concentrations in the receiving recharge water caused increased lake water quality risk.

  13. Generating color terrain images in an emergency response system

    International Nuclear Information System (INIS)

    Belles, R.D.

    1985-08-01

    The Atmospheric Release Advisory Capability (ARAC) provides real-time assessments of the consequences resulting from an atmospheric release of radioactive material. In support of this operation, a system has been created which integrates numerical models, data acquisition systems, data analysis techniques, and professional staff. Of particular importance is the rapid generation of graphical images of the terrain surface in the vicinity of the accident site. A terrain data base and an associated acquisition system have been developed that provide the required terrain data. This data is then used as input to a collection of graphics programs which create and display realistic color images of the terrain. The graphics system currently has the capability of generating color shaded relief images from both overhead and perspective viewpoints within minutes. These images serve to quickly familiarize ARAC assessors with the terrain near the release location, and thus permit them to make better informed decisions in modeling the behavior of the released material. 7 refs., 8 figs

  14. A bibliography of terrain modeling (geomorphometry), the quantitative representation of topography: supplement 4.0

    Science.gov (United States)

    Pike, Richard J.

    2002-01-01

    . Coverage is representative from about 1800 through early–mid 2002. Papers increasingly are published exclusively or in duplicate on the Internet's World Wide Web; the dates given here for Web addresses (URLs) that lack a print publication indicate a Web site's last update or my last access of it. The bibliography is arranged alphabetically and thus is not readily summarized. This introduction cites about 500 entries, a third of them grouped under 24 morphometric topics, as a guide to the listing's contents. Continuing the practice of previous bibliographies in the series to provide more information on a few applications (see summary of past topics in Pike, 2000a), this report elaborates further on topographic data, putative new parameters, tectonic geomorphology/neo-orometry, biogeography, ice-cap morphometry, results from the Mars Global DEM, landslide-hazard mapping, terrain modeling as physics, Hack's law, and broad-scale computer visualization. The literature of some of these subjects is large, and none of the summaries is intended to more than introduce the topic and comment on some of the current contributions of terrain modeling. Closing the essay is a discussion of pre-1900 papers that trace the evolution of ridge-line and watercourse quantification by descriptive geometry, as well as comments on some new books and an on-line bulletin board.

  15. A Synoptic Climatology of Heavy Rain Events in the Lake Eyre and Lake Frome Catchments

    Directory of Open Access Journals (Sweden)

    Michael John Pook

    2014-11-01

    Full Text Available The rare occasions when Lake Eyre in central, southern Australia fills with water excite great interest and produce major ecological responses. The filling of other smaller lakes such as Lake Frome, have less impact but can contribute important information about the current and past climates of these arid regions. Here, the dominant synoptic systems responsible for heavy rainfall over the catchments of Lake Eyre and Lake Frome since 1950 are identified and compared. Heavy rain events are defined as those where the mean catchment rainfall for 24 hours reaches a prescribed threshold. There were 25 such daily events at Lake Eyre and 28 in the Lake Frome catchment. The combination of a monsoon trough at mean sea level and a geopotential trough in the mid-troposphere was found to be the synoptic system responsible for the majority of the heavy rain events affecting Lake Eyre and one in five of the events at Lake Frome. Complex fronts where subtropical interactions occurred with Southern Ocean fronts also contributed over 20% of the heavy rainfall events in the Frome catchment. Surface troughs without upper air support were found to be associated with 10% or fewer of events in each catchment, indicating that mean sea level pressure analyses alone do not adequately capture the complexity of the heavy rainfall events. At least 80% of the heavy rain events across both catchments occurred when the Southern Oscillation Index (SOI was in its positive phase, and for Lake Frome, the SOI exceeded +10 on 60% of occasions, suggesting that the background atmospheric state in the Pacific Ocean was tilted towards La Niña. Hydrological modeling of the catchments suggests that the 12-month running mean of the soil moisture in a sub-surface layer provides a low frequency filter of the precipitation and matches measured lake levels relatively well.

  16. Survey and assessment of post volcanic activities of a young caldera lake, Lake Cuicocha, Ecuador

    Directory of Open Access Journals (Sweden)

    G. Gunkel

    2009-05-01

    Full Text Available Cuicocha is a young volcano adjacent to the inactive Pleistocene Cotacachi volcano complex, located in the western cordilleras of the Ecuadorian Andes. A series of eruptions with intensive ash emission and collapse of the caldera occurred around 4500–3000 y BP. A crater 3.2 km in diameter and a maximum depth of 450 m was formed. Further eruptions of the volcano occurred 1300 y BP and formed four smaller domes within the caldera. Over the last few hundred years, a caldera lake has developed, with a maximum depth of 148 m. The lake water is characterized by sodium carbonate with elevated concentrations of manganese, calcium and chloride. Nowadays, an emission of gases, mainly CO2, and an input of warm spring water occur in Lake Cuicocha. The zone of high activity is in the western basin of the lake at a depth of 78 m, and continuous gas emissions with sediment resuspension were observed using sonar. In the hypolimnion of the lake, CO2 accumulation occurs up to 0.2% saturation, but the risk of a limnic eruption can be excluded at present. The lake possesses monomictic stratification behaviour, and during overturn an intensive gas exchange with the atmosphere occurs. Investigations concerning the sedimentation processes of the lake suggest only a thin sediment layer of up to 10–20 cm in the deeper lake basin; in the western bay, in the area of gas emissions, the lake bottom is partly depleted of sediment in the form of holes, and no lake colmation exists. Decreases in the lake water level of about 30 cm y−1 indicate a percolation of water into fractures and fissures of the volcano, triggered by a nearby earthquake in 1987.

  17. Ecobiological assessment of a freshwater lake at Schirmacher Oasis, East Antarctica, with reference to human activities

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Dhargalkar, V.K.

    of certain lake environmental aspects over a decadal period indicate that the lake environment is in a healthy condition. However, intensive human activities in the catchment area may deteriorate the ecosystem and hence regular monitoring and stringent...

  18. Salting our freshwater lakes

    Science.gov (United States)

    Bartlett, Sarah L.; Burke, Samantha M.; Doubek, Jonathan P.; Krivak-Tetley, Flora E.; Skaff, Nicholas K.; Summers, Jamie C.; Farrell, Kaitlin J.; McCullough, Ian M.; Morales-Williams, Ana M.; Roberts, Derek C.; Ouyang, Zutao; Scordo, Facundo; Hanson, Paul C.; Weathers, Kathleen C.

    2017-01-01

    The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L−1), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue. PMID:28396392

  19. Estimation of the Pollution Level in El Timsah Lake, Egypt

    International Nuclear Information System (INIS)

    Abd El Samie, S.G.; Hassan, H.B.; Hamza, M.S.

    2008-01-01

    The wide range of activities surrounding El Timsah Lake and the discharge effluent at the north and eastern parts of the lake led to high level of anthropogenic pollution in lake water more than the navigation activities. Heavy metals concentration increases in low salinity water toward the land from the discharging effluent. Whereas, oil hydrocarbon and water salinity increase toward Suez Canal current water. This indicates some dispersion of oil ballast water of shipping tankers or from petroleum companies during transportation in the Suez Canal. Chemical and isotopic results indicate lake water stratification, low mixing rate due to slow current of lake water. This led to long residence time of the pollution load enhancing accumulation and precipitation of the heavy metals to the bottom sediment near the boundaries of the lake

  20. The Improved Kriging Interpolation Algorithm for Local Underwater Terrain Based on Fractal Compensation

    Directory of Open Access Journals (Sweden)

    Pengyun Chen

    2014-01-01

    Full Text Available The interpolation-reconstruction of local underwater terrain using the underwater digital terrain map (UDTM is an important step for building an underwater terrain matching unit and directly affects the accuracy of underwater terrain matching navigation. The Kriging method is often used in terrain interpolation, but, with this method, the local terrain features are often lost. Therefore, the accuracy cannot meet the requirements of practical application. Analysis of the geographical features is performed on the basis of the randomness and self-similarity of underwater terrain. We extract the fractal features of local underwater terrain with the fractal Brownian motion model, compensating for the possible errors of the Kriging method with fractal theory. We then put forward an improved Kriging interpolation method based on this fractal compensation. Interpolation-reconstruction tests show that the method can simulate the real underwater terrain features well and that it has good usability.

  1. Observations of the Temperature and Humidity Structure Parameter Over Heterogeneous Terrain by Airborne Measurements During the LITFASS-2003 Campaign

    Science.gov (United States)

    Platis, Andreas; Moene, Arnold F.; Villagrasa, Daniel Martínez; Beyrich, Frank; Tupman, David; Bange, Jens

    2017-12-01

    The turbulent structure parameters of temperature (C_T^2) and humidity (C_Q^2), and their cross-structure parameter (C_{QT}), are investigated using data collected with the airborne-measurement platform Helipod during the LITFASS-2003 campaign. The flights took place within the atmospheric surface layer over heterogeneous terrain including forests, a lake and farmland. We find variability in C_T^2 along such flight legs, with values of C_T^2 over forested surfaces one order of magnitude larger than over farmland, and two orders of magnitude larger than over the lake. However, a quantitative relationship between the magnitude of C_Q^2 and the surface type is not found, most likely due to a similar surface latent heat flux between the land-use types. However, when the different flight legs are taken together and data grouped by land-use type, values of C_Q^2 are significantly lower over the lake than over the other surfaces. A classification of C_{QT} is only possible between water and land surfaces, with lower values over water. We find the correlation coefficient R_{QT} in the range of 0.4-1.0, which is less than unity, and thus violates the assumption of unity in Monin-Obukhov similarity theory.

  2. The role of climatic and terrain attributes in estimating baseflow recession in tropical catchments

    Directory of Open Access Journals (Sweden)

    J. L. Peña-Arancibia

    2010-11-01

    Full Text Available The understanding of low flows in rivers is paramount more than ever as demand for water increases on a global scale. At the same time, limited streamflow data to investigate this phenomenon, particularly in the tropics, makes the provision of accurate estimations in ungauged areas an ongoing research need. This paper analysed the potential of climatic and terrain attributes of 167 tropical and sub-tropical unregulated catchments to predict baseflow recession rates. Daily streamflow data (m3 s–1 from the Global River Discharge Center (GRDC and a linear reservoir model were used to obtain baseflow recession coefficients (kbf for these catchments. Climatic attributes included annual and seasonal indicators of rainfall and potential evapotranspiration. Terrain attributes included indicators of catchment shape, morphology, land cover, soils and geology. Stepwise regression was used to identify the best predictors for baseflow recession coefficients. Mean annual rainfall (MAR and aridity index (AI were found to explain 49% of the spatial variation of kbf. The rest of climatic indices and the terrain indices average catchment slope (SLO and tree cover were also good predictors, but co-correlated with MAR. Catchment elongation (CE, a measure of catchment shape, was also found to be statistically significant, although weakly correlated. An analysis of clusters of catchments of smaller size, showed that in these areas, presumably with some similarity of soils and geology due to proximity, residuals of the regression could be explained by SLO and CE. The approach used provides a potential alternative for kbf parameterisation in ungauged catchments.

  3. Western Alaska ESI: LAKES (Lake Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing lakes and land masses used in the creation of the Environmental Sensitivity Index (ESI) for Western Alaska. The...

  4. Patterns of Local Circulation in the Itaipu Lake Area: Numerical Simulations of Lake Breeze.

    Science.gov (United States)

    Stivari, Sônia M. S.; de Oliveira, Amauri P.; Karam, Hugo A.; Soares, Jacyra

    2003-01-01

    The lake-breeze circulation in the Itaipu region was investigated numerically using a nonhydrostatic version of the Topographic Vorticity Model. The area of study corresponds to a 100 km × 180 km rectangle, located on the Brazil-Paraguay border, with Itaipu Lake in its center. The characteristics of the lake breeze generated by the numerical experiments were consistent with the observations available in the area. The numerical experiments have shown that the land use effect is important in the spatial distribution of the lake-breeze circulation and that the topography contributes to modulating the breeze intensity, with the daytime valley-mountain circulation intensifying the lake breeze. However, the circulation pattern observed during daytime over the region is mainly due to the Itaipu Lake presence. The numerical results indicated that Itaipu Lake is able to generate and sustain a lake breeze, with 3.5 m s1 of maximum intensity and 1500-m depth, that propagates inland at 5.1 km h1 under typical undisturbed and calm-wind summer conditions.

  5. A Systematic Study of Zerbar Lake Restoration

    Science.gov (United States)

    Hosseini, Reza; Oveis Torabi, Seyed; Forman Asgharzadeh, Deonna

    2017-04-01

    The beautiful lake of Zerbar, located near Marivan City at the west of Iran, is a freshwater lake with an area of 20 km2 and average depth of 5 meters. The lake is created by regional tectonic activities and is mainly fed with natural spring water from bottom. During the past three decades, regional development has caused much disturbance to the natural environment of the lake and its watershed. Rescuing the lake is crucial to the sustainability of the whole region. The study of Zerbar Restoration was performed with the aim to restore its health indicators. Variety of human activities in the watershed, as well as the multidisciplinary nature of lake restoration studies, made it necessary to develop a systematic approach to conduct the study. In Step I of restoration studies, satellite images were investigated to identify the historical changes of watershed during the past 30 years. Meanwhile, documents since 50 years ago were studied. Results indicate that farmland and graze land areas have been relatively constant during the past 50 years. Also, the area of lake, its riparian canes and floating plants have not changed much. In fact, the only significant land use change observed was the significant spread of Marivan City that has stretched toward the lake. The main physical variation to the lake has been elevating the southern edge of the lake by a constructing a landfill dam which was done to control the lake's overflow discharge for irrigation of downstream farmland development. Step II consists of studies performed by disciplines of water resources, hydrogeology, water quality, wetland and watershed ecology, agriculture, animal farming and fishery. Study results indicate that eutrophication (TSL>100), mainly caused by sewage from Marivan City and the surrounding rural areas has been the main reason for lake ecosystem degradation. DPSIR framework, as a novel approach in lake restoration, was applied to synthesize the study results of different disciplines in a

  6. ISOSTATICALLY DISTURBED TERRAIN OF NORTHWESTERN ANDES MOUNTAINS FROM SPECTRALLY CORRELATED FREE-AIR AND GRAVITY TERRAIN DATA

    Directory of Open Access Journals (Sweden)

    Hernández P Orlando

    2006-12-01

    Full Text Available Recently revised models on global tectonics describe the convergence of the North Andes, Nazca, Caribbean and South American Plates and their seismicity, volcanism, active faulting and extreme
    topography. The current plate boundaries of the area are mainly interpreted from volcanic and seismic datasets with variable confidence levels. New insights on the isostatic state and plate boundaries of
    the northwestern Andes Mountains can be obtained from the spectral analysis of recently available gravity and topography data.
    Isostatically disturbed terrain produces free-air anomalies that are highly correlated with the gravity effects of the terrain. The terrain gravity effects (TGE and free air gravity anomalies (FAGA of the
    Andes mountains spectral correlation data confirms that these mountains are isostatically disturbed. Strong negative terrain-correlated FAGA along western South America and the Greater and Lesser Antilles are consistent with anomalously deepened mantle displaced by subducting oceanic plates.

    Inversion of the compensated terrain gravity effects (CTGE reveals plate subduction systems with alternating shallower and steeper subduction angles. The gravity modeling highlights crustal
    deformation from plate collision and subduction and other constraints on the tectonism of the plate boundary zones for the region.

  7. Rehabilitation of Mohawk Lake: Brantford's crown jewel

    International Nuclear Information System (INIS)

    Farrell, C.W.; Kube, D.J.

    1994-01-01

    Mohawk Lake in Brantford, Ontario had been receiving contaminants from various industrial and municipal sources since the late 1800s. The lake suffered a slow death with the absence of any watershed management plan. A citizen committee was established in 1990 to rehabilitate the lake so that its recreational and resource potential could be fully realized. In 1993, the committee obtained government funding to carry out a detailed baseline environmental study of the lake. Lake sediments were found to consist of an upper horizon of poorly consolidated, organic-rich, odoriferous material overlying a more compact sandy layer. Lake water was characterized by high concentrations of nutrients and metals, and high biological oxygen demand. Sediments also had high concentrations of heavy metals and low concentrations of such organic contaminants as pyrene, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. The most distinct contaminant appeared to be petroleum hydrocarbons at 0.5-1% concentration. It was determined that lake rehabilitation would require removal of these sediments. Tests indicated that the sediments were non-hazardous non-registrable solid waste, and the preferred removal option was hydraulic dredging into settlement ponds along the undeveloped south shore of the lake. A sediment trap was recommended to be installed at the entrance of the lake, along with a constructed wetland to remove a variety of water pollutants. The sediment dredging, dewatering, trap and wetland installation, and land remediation of the sediment disposal area are estimated to cost ca $3.75 million, and the work will require at least 18 months to complete. 1 fig

  8. Irregular Morphing for Real-Time Rendering of Large Terrain

    Directory of Open Access Journals (Sweden)

    S. Kalem

    2016-06-01

    Full Text Available The following paper proposes an alternative approach to the real-time adaptive triangulation problem. A new region-based multi-resolution approach for terrain rendering is described which improves on-the-fly the distribution of the density of triangles inside the tile after selecting appropriate Level-Of-Detail by an adaptive sampling. This proposed approach organizes the heightmap into a QuadTree of tiles that are processed independently. This technique combines the benefits of both Triangular Irregular Network approach and region-based multi-resolution approach by improving the distribution of the density of triangles inside the tile. Our technique morphs the initial regular grid of the tile to deformed grid in order to minimize approximation error. The proposed technique strives to combine large tile size and real-time processing while guaranteeing an upper bound on the screen space error. Thus, this approach adapts terrain rendering process to local surface characteristics and enables on-the-fly handling of large amount of terrain data. Morphing is based-on the multi-resolution wavelet analysis. The use of the D2WT multi-resolution analysis of the terrain height-map speeds up processing and permits to satisfy an interactive terrain rendering. Tests and experiments demonstrate that Haar B-Spline wavelet, well known for its properties of localization and its compact support, is suitable for fast and accurate redistribution. Such technique could be exploited in client-server architecture for supporting interactive high-quality remote visualization of very large terrain.

  9. An improved active contour model for glacial lake extraction

    Science.gov (United States)

    Zhao, H.; Chen, F.; Zhang, M.

    2017-12-01

    Active contour model is a widely used method in visual tracking and image segmentation. Under the driven of objective function, the initial curve defined in active contour model will evolve to a stable condition - a desired result in given image. As a typical region-based active contour model, C-V model has a good effect on weak boundaries detection and anti noise ability which shows great potential in glacial lake extraction. Glacial lake is a sensitive indicator for reflecting global climate change, therefore accurate delineate glacial lake boundaries is essential to evaluate hydrologic environment and living environment. However, the current method in glacial lake extraction mainly contains water index method and recognition classification method are diffcult to directly applied in large scale glacial lake extraction due to the diversity of glacial lakes and masses impacted factors in the image, such as image noise, shadows, snow and ice, etc. Regarding the abovementioned advantanges of C-V model and diffcults in glacial lake extraction, we introduce the signed pressure force function to improve the C-V model for adapting to processing of glacial lake extraction. To inspect the effect of glacial lake extraction results, three typical glacial lake development sites were selected, include Altai mountains, Centre Himalayas, South-eastern Tibet, and Landsat8 OLI imagery was conducted as experiment data source, Google earth imagery as reference data for varifying the results. The experiment consequence suggests that improved active contour model we proposed can effectively discriminate the glacial lakes from complex backgound with a higher Kappa Coefficient - 0.895, especially in some small glacial lakes which belongs to weak information in the image. Our finding provide a new approach to improved accuracy under the condition of large proportion of small glacial lakes and the possibility for automated glacial lake mapping in large-scale area.

  10. Tectonized Terrains of Enceladus: The Same but Different

    Science.gov (United States)

    Pappalardo, R. T.; Crow-Willard, E.

    2010-12-01

    The Cassini spacecraft has now imaged Enceladus sufficiently well to recognize details of the satellite’s three distinct large-scale quasi-circular regions of tectonic deformation. In addition to the well-known “south polar terrain” (SPT), Enceladus also displays tectonically deformed terrains that we refer to as “trailing hemisphere terrain” (THT) and “leading hemisphere terrain” (LHT). Global geological mapping shows that each of the three terrains has a central region of tectonic deformation that is framed by units of curvilinear ridges and troughs, and all have comparable areal extent (the SPT being the smallest). Initial mapping by Porco et al. (Science 311, 1393, 2006) shows that the SPT has a central region which contains the distinctive subparallel “tiger stripes” and is wrapped by curvilinear terrain displaying outward-pointed Y-shaped zones of deformation that transition into radiating fracture zones. In its central region, the THT contains relatively old striated plains (Diyar and Sarandib Planitiae). These striated units are transected by ridged terrain, characterized by large ridges (the unusual “dorsa”), which are inferred to have formed by contraction and thrust faulting. The THT contains a unit consisting of smooth materials and long shallow troughs that is nearly identical to materials of the central SPT and with similar orientation. The LHT also contains a disorganized network of troughs similar to the central terrain of the SPT. The LHT contains polygons of sub-parallel troughs, suggestive of shearing. Neither the THT nor the LHT displays long individual and subparallel tectonic fractures that resemble the tiger stripes, and neither displays radiating fracture zones like those of the SPT. The gross similarities in shape and dimension of the tectonized terrains of Enceladus suggest similar formational processes, plausibly representing deformation above large-scale regions of warm ice. However, differences in morphological

  11. Synthetic SAR Image Generation using Sensor, Terrain and Target Models

    DEFF Research Database (Denmark)

    Kusk, Anders; Abulaitijiang, Adili; Dall, Jørgen

    2016-01-01

    A tool to generate synthetic SAR images of objects set on a clutter background is described. The purpose is to generate images for training Automatic Target Recognition and Identification algorithms. The tool employs a commercial electromagnetic simulation program to calculate radar cross sections...... of the object using a CAD-model. The raw measurements are input to a SAR system and terrain model, which models thermal noise, terrain clutter, and SAR focusing to produce synthetic SAR images. Examples of SAR images at 0.3m and 0.1m resolution, and a comparison with real SAR imagery from the MSTAR dataset...

  12. Terrain dependant hop count selection for transparent relay transmissions

    Directory of Open Access Journals (Sweden)

    Cibile K. Kanjirathumkal

    2013-12-01

    Full Text Available In this Letter, the selection of the best hop count for a particular topography, in the context of enhanced connectivity using multi-hop transparent relay communication is addressed. Based on the coefficient of variation and the terrain specific fading severity factor of the distribution, it is possible to estimate the optimal hop count that can provide the required performance at detector. Two distribution models, which can adequately characterise the terrain fading effects on empirical data are considered for performance comparison. The results are useful in selecting branches, with low variability and optimal hop count for connectivity, in multi-stream switched diversity combining systems.

  13. Terrain Mapping and Obstacle Detection Using Gaussian Processes

    DEFF Research Database (Denmark)

    Kjærgaard, Morten; Massaro, Alessandro Salvatore; Bayramoglu, Enis

    2011-01-01

    In this paper we consider a probabilistic method for extracting terrain maps from a scene and use the information to detect potential navigation obstacles within it. The method uses Gaussian process regression (GPR) to predict an estimate function and its relative uncertainty. To test the new...... methods, we have arranged two setups: an artificial flat surface with an object in front of the sensors and an outdoor unstructured terrain. Two sensor types have been used to determine the point cloud fed to the system: a 3D laser scanner and a stereo camera pair. The results from both sensor systems...

  14. Are Titan's radial Labyrinth terrains surface expressions of large laccoliths?

    Science.gov (United States)

    Schurmeier, L.; Dombard, A. J.; Malaska, M.; Radebaugh, J.

    2017-12-01

    The Labyrinth terrain unit may be the one of the best examples of the surface expression of Titan's complicated history. They are characterized as highly eroded, dissected, and elevated plateaus and remnant ridges, with an assumed composition that is likely organic-rich based on radar emissivity. How these features accumulated organic-rich sediments and formed topographic highs by either locally uplifting or surviving pervasive regional deflation or erosion is an important question for understanding the history of Titan. There are several subsets of Labyrinth terrains, presumably with differing evolutionary histories and formation processes. We aim to explain the formation of a subset of Labyrinth terrain units informally referred to as "radial Labyrinth terrains." They are elevated and appear dome-like, circular in planform, have a strong radial dissection pattern, are bordered by Undifferentiated Plains units, and are found in the mid-latitudes. Based on their shape, clustering, and dimensions, we suggest that they may be the surface expression of large subsurface laccoliths. A recent study by Manga and Michaut (Icarus, 2017) explained Europa's lenticulae (pits, domes, spots) with the formation of saucer-shaped sills that form laccoliths around the brittle-ductile transition depth within the ice shell (1-5 km). Here, we apply the same scaling relationships and find that the larger size of radial labyrinth terrains with Titan's higher gravity implies deeper intrusion depths of around 20-40 km. This intrusion depth matches the expected brittle-ductile transition on Titan based on our finite element simulations and yield strength envelope analyses. We hypothesize that Titan's radial labyrinth terrains formed as cryovolcanic (water) intrusions that rose to the brittle-ductile transition within the ice shell where they spread horizontally, and uplifted the overlying ice. The organic-rich sedimentary cover also uplifted, becoming more susceptible to pluvial and fluvial

  15. Geologic Map of Mount Mazama and Crater Lake Caldera, Oregon

    Science.gov (United States)

    Bacon, Charles R.

    2008-01-01

    Crater Lake partly fills one of the most spectacular calderas of the world, an 8-by-10-km basin more than 1 km deep formed by collapse of the volcano known as Mount Mazama (fig. 1) during a rapid series of explosive eruptions about 7,700 years ago. Having a maximum depth of 594 m, Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 km2 of pristine forested and alpine terrain, including the lake itself, virtually all of Mount Mazama, and most of the area of the geologic map. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama's climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, greatly enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. Lastly, the many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama are a source of information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive

  16. Pollution at Lake Mariut

    International Nuclear Information System (INIS)

    Nour ElDin, H.; Halim, S. N.; Shalby, E.

    2004-01-01

    Lake Mariut, south Alexandria, Egypt suffered in the recent decades from intensive pollution as a result of a continuous discharge of huge amounts of agriculture wastewater that contains a large concentration of the washed pesticides and fertilizers in addition to domestic and industrial untreated wastewater. The over flow from the lake is discharged directly to the sea through El-Max pumping station via EI-Umum drain. Lake Mariout is surrounded by a huge number of different industrial activities and also the desert road is cutting the lake, this means that a huge number of various pollutants cycle through the air and settle down in the lake, by the time and during different seasons these pollutants after accumulation and different chemical interactions will release again from the lake to the surrounding area affecting the surrounding zone

  17. Aluminum substitution in goethite in lake ore

    Directory of Open Access Journals (Sweden)

    Carlson, L.

    1995-06-01

    Full Text Available The extent of substitution of Fe by Al in goethite in 32 lake ore samples collected from 11 lakes in Finland varied between 0 and 23 mol-%. The data indicated a negative relationship between Al-substitution and the particle size of lake ore. Differences in the Al-substitution were apparent between sampling sites, suggesting that kinetic and environmental variation in lake ore formation influences the substitution. Non-substituted goethite is formed in coarse-grained sediments with locally high concentrations of Fe due to iron-rich springs. Unit cell edge lengths and volumes of goethite varied as function of Al-subsitution but deviated from the Vegard relationship towards higher values.

  18. Diatoms of the Mystery Lake, Taiwan (III

    Directory of Open Access Journals (Sweden)

    Jiunn-Tzong Wu

    2009-09-01

    Full Text Available This is the last part of study about the diatom flora found in the Mystery Lake, a slightly acidic lake situated within a hardwood nature preserve in northeastern Taiwan. In this article, we reported 17 species, belonging to 4 genera, 4 families, and 2 orders, based on scanning electron microscopic observations. The species described here, 9 are newly recorded in Taiwan. They are: Navicula cryptotenella, Navicula ingrata, Navicula subfasciata, Pinnularia borealis var. rectangularis, Pinnularia interrupta, Pinnularia maior, Sellaphora laevissima, S. vitabunda, and Nitzschia perminuta. In total, we found 76 diatom species in the surface sediments of this lake. Among them, 33 (43% are newly recorded to Taiwan. The present study indicates that this lake is characterized by high species diversity and high species richness, which are related to the oligotrophic and non-polluted environmental conditions.

  19. 2016 Lake Michigan Lake Trout Working Group Report

    Science.gov (United States)

    Madenjian, Charles P.; Breidert, Brian; Boyarski, David; Bronte, Charles R.; Dickinson, Ben; Donner, Kevin; Ebener, Mark P.; Gordon, Roger; Hanson, Dale; Holey, Mark; Janssen, John; Jonas, Jory; Kornis, Matthew; Olsen, Erik; Robillard, Steve; Treska, Ted; Weldon, Barry; Wright, Greg D.

    2017-01-01

    This report provides a review on the progression of lake trout rehabilitation towards meeting the Salmonine Fish Community Objectives (FCOs) for Lake Michigan (Eshenroder et. al. 1995) and the interim goal and evaluation objectives articulated in A Fisheries Management Implementation Strategy for the Rehabilitation of Lake Trout in Lake Michigan (Dexter et al. 2011); we also include data describing lake trout stocking and mortality to portray the present state of progress towards lake trout rehabilitation.

  20. Effects of introduced fish on macroinvertebrate communities in historically fishless headwater and kettle lakes

    Science.gov (United States)

    Schilling, Emily Gaenzle; Loftin, Cynthia S.; Huryn, Alexander D.

    2009-01-01

    Widespread fish introductions have led to a worldwide decline in the number of fishless lakes and their associated communities. Studies assessing effects of fish stocking on native communities in historically fishless lakes have been limited to high-elevation headwater lakes stocked with non-native trout. Little is known about the effect of fish stocking in historically fishless and hydrologically isolated lowland kettle lakes. We compared the effects of introduced fish on macroinvertebrate communities in kettle lakes stocked with centrarchids, salmonids, and cyprinids, and headwater lakes stocked with brook trout (Salvelinus fontinalis) in Maine, USA. Fish had significant effects on macroinvertebrate community structure in both lake types, with reduced species richness and abundances of taxa characteristic of fishless lakes. The effects of introduced fish were more pronounced in headwater lakes despite a less diverse fish assemblage than in kettle lakes. We attribute this to abundant submerged vegetation providing refuge from fish predation and reduced stocking frequency in kettle lakes. We assessed effects of stocking duration on macroinvertebrates in a subset of headwater lakes with known dates of trout introduction. Species richness and abundance of most taxa declined within 3 years following trout introduction; however, richness and abundance were least in lakes with long stocking histories (≥40 years). Macroinvertebrates previously identified as fishless bioindicators were absent from all stocked lakes, indicating that trout rapidly eliminate these sensitive taxa. Conservation of this historically undervalued ecosystem requires protecting remaining fishless lakes and recovering those that have been stocked.

  1. Recent lake ice-out phenology within and among lake districts of Alaska, U.S.A.

    Science.gov (United States)

    Arp, Christopher D.; Jones, Benjamin M.; Grosse, Guido

    2013-01-01

    The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. In lake-rich regions, the loss of ice cover also plays a key role in landscape and climatic processes. Thus, there is a need to understand lake ice phenology at multiple scales. In this study, we observed ice-out timing on 55 large lakes in 11 lake districts across Alaska from 2007 to 2012 using satellite imagery. Sensor networks in two lake districts validated satellite observations and provided comparison with smaller lakes. Over this 6 yr period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low inter-annual variability. Approximately 80% of the variation in ice-out timing was explained by the date of 0°C air temperature isotherm and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Coherence in ice-out timing within the lakes of each district was consistently strong over this 6 yr period, ranging from r-values of 0.5 to 0.9. Inter-district analysis of coherence also showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June–July) and climatology is sea-ice influenced. These patterns of lake ice phenology provide a spatially extensive baseline describing short-term temporal variability, which will help decipher longer term trends in ice phenology and aid in representing the role of lake ice in land and climate models in northern landscapes.

  2. Great Lakes Literacy Principles

    Science.gov (United States)

    Fortner, Rosanne W.; Manzo, Lyndsey

    2011-03-01

    Lakes Superior, Huron, Michigan, Ontario, and Erie together form North America's Great Lakes, a region that contains 20% of the world's fresh surface water and is home to roughly one quarter of the U.S. population (Figure 1). Supporting a $4 billion sport fishing industry, plus $16 billion annually in boating, 1.5 million U.S. jobs, and $62 billion in annual wages directly, the Great Lakes form the backbone of a regional economy that is vital to the United States as a whole (see http://www.miseagrant.umich.edu/downloads/economy/11-708-Great-Lakes-Jobs.pdf). Yet the grandeur and importance of this freshwater resource are little understood, not only by people in the rest of the country but also by many in the region itself. To help address this lack of knowledge, the Centers for Ocean Sciences Education Excellence (COSEE) Great Lakes, supported by the U.S. National Science Foundation and the National Oceanic and Atmospheric Administration, developed literacy principles for the Great Lakes to serve as a guide for education of students and the public. These “Great Lakes Literacy Principles” represent an understanding of the Great Lakes' influences on society and society's influences on the Great Lakes.

  3. The Key Lake project

    International Nuclear Information System (INIS)

    1991-01-01

    Key Lake is located in the Athabasca sand stone basin, 640 kilometers north of Saskatoon, Saskatchewan, Canada. The three sources of ore at Key Lake contain 70 100 tonnes of uranium. Features of the Key Lake Project were described under the key headings: work force, mining, mill process, tailings storage, permanent camp, environmental features, worker health and safety, and economic benefits. Appendices covering the historical background, construction projects, comparisons of western world mines, mining statistics, Northern Saskatchewan surface lease, and Key Lake development and regulatory agencies were included

  4. Wind Tunnel Modeling Of Wind Flow Over Complex Terrain

    Science.gov (United States)

    Banks, D.; Cochran, B.

    2010-12-01

    , vortex shedding, and local turbulence intensity and wind shear values. To achieve accurate results, attention must of course be paid to issues such as ensuring Reynolds number independence, avoiding blockage issues, and properly matching the velocity power spectrum, but once this is done, the laws of fluid mechanics take care of the rest. There will not be an overproduction of turbulent kinetic energy at the top of escarpments, or unacceptable dissipation of inlet turbulence levels. Modern atmospheric boundary layer wind tunnels are also often used to provide validation data for evaluating the performance of CFD model in complex flow environments. Present day computers have further increased the quality and quantity of data that can be economically obtained in a timely manner, for example through wind speed measurement using a computer controlled 3-D measurement positioning system Given this accuracy and widespread acceptance, it is perhaps surprising that ours was the only wind tunnel model in the Bolund blind experiment, an indication of how seldom physical modelling is used when estimating terrain effect for wind farms. In demonstrating how the Bolund test was modeled, this presentation will provide background on wind tunnel testing, including the governing scaling parameters. And we’ll see how our results compared to the full scale tests.

  5. Early recognition of glacial lake hazards in the Himalaya using remote sensing datasets

    Science.gov (United States)

    Quincey, D. J.; Richardson, S. D.; Luckman, A.; Lucas, R. M.; Reynolds, J. M.; Hambrey, M. J.; Glasser, N. F.

    2007-03-01

    Glacier recession in high-Himalayan catchments leads to the formation of moraine-dammed lakes on many debris-covered glacier tongues. Such lakes are hazardous to communities and infrastructure downstream because of their potential to breach catastrophically, and their early recognition is required if remedial efforts are to be timely and cost-effective. Whilst the development of supraglacial lakes is known to begin as a series of ponds that subsequently coalesce into a larger lake, the relationship between glacier dynamics and lake formation is not well understood. Using ERS-1 and ERS-2 Synthetic Aperture Radar (SAR) data, SPOT-5 optical imagery and historical aerial photography, information is presented on the dynamics and structure of glaciers in Tibet (China) and Nepal that drain the southern side of the Himalaya. Glacier velocity data derived from interferometry show that where lakes are developing on debris-covered tongues the ice is virtually stagnant (displacements photography and SPOT-5 HRS data reveal that supraglacial lake formation is prevalent where glacier surface gradients are less than 2° from the glacier terminus, supporting empirical observations from previous work. The resolution offered by the DEMs and SAR data allows variations in transverse glacier elevations and velocities to be detected, such that the pattern of lake development on an individual glacier can be identified. Whilst the glacier surface gradient provides the boundary conditions favourable for lake formation, local variations in glacier velocity and surface morphology between flow units control the precise location of lake growth. Integrating the surface gradient and velocity information into a single analysis highlights those glaciers that are particularly vulnerable to lake development over an expected decadal timescale. The wider application of these techniques, based on remote sensing data, is particularly suitable for 'first-pass' hazard assessments and for regions where

  6. Recently surveyed lakes in northern Manitoba and Saskatchewan, Canada: characteristics and critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Isaac WONG

    2010-08-01

    Full Text Available Based on minimal information, lakes in the western Canadian provinces of Manitoba (MB and Saskatchewan (SK have long been considered unaffected by acid rain. However, emissions of acidifying pollutants from MB smelters and oil sand processing in Alberta (AB may pose a developing threat. Surveys of 347 lakes located on geologically sensitive terrain in northern MB and SK were conducted to assess their acidification sensitivity and status. The survey domain (~193,000 km2 contained 81,494 lakes ≥1 ha in area. Small lakes dominated the inventory in terms of numbers, and large lakes dominated in terms of area. Survey lakes were selected using a stratified-random sampling design in 10 sampling blocks within the overall survey domain. Few lakes had pH <6, and only three (all in SK were acidic, i.e., Gran Alkalinity (Alk <0 μeq L–1. A broad range in lake sensitivity was apparent, and very sensitive lakes (low specific conductance, base cations and Alk were present in all sampling blocks. Dissolved organic carbon (DOC was an important constituent of many lakes. Critical loads (CL of acidity calculated using the Steady-State Water Chemistry model (SSWC revealed extremely low 5th percentile values for every block (range 1.9 to 52.7 eq ha–1 y–1. Block CL exceedances calculated using estimated S and N deposition for 2002 ranged from 54.5 to 909 eq ha–1 y–1. The largest exceedances were for sampling blocks located near smelter sources or downwind of the oil sands. Lake chemistry revealed by our surveys was compared to others conducted both nearby and outside Canada.

  7. Invertebrates as indicators for chemical stress in sewage-influenced stream systems: toxic and endocrine effects in gammarids and reactions at the community level in two tributaries of Lake Constance, Schussen and Argen.

    Science.gov (United States)

    Peschke, Katharina; Geburzi, Jonas; Köhler, Heinz-R; Wurm, Karl; Triebskorn, Rita

    2014-08-01

    The present study investigates the impact of releases from waste water treatment plants and storm water overflow basins on gammarids and other macrozoobenthos. The study relates to a recent upgrading of a waste water treatment plant (Langwiese) at the Schussen river, an important tributary to Lake Constance. Samples were taken at different sites at the Schussen river upstream and downstream of a storm water overflow basin and the waste water treatment plant Langwiese and, in parallel, at the Argen river, a less polluted reference stream. We assessed the influence of water quality on the distribution of macrozoobenthos and on the health of gammarid populations by a variety of ecotoxicological methods including biomarkers prior to the expansion of the waste water treatment plant. Through histopathological studies, the impact of parasites on host tissue health was evaluated. Analyses of heat shock protein (hsp70) levels allowed us to draw conclusions about the proteotoxicity-related stress status of the organisms. Furthermore, gammarid populations from all sites were investigated in respect to sex ratio, parasitism rate, and fecundity. Macrozoobenthos community integrity was determined by means of the saprobic index and the abundance as well as by the number of taxa. In gammarids, the sex ratio was significantly shifted towards females, fecundity was significantly decreased, and the hsp70 level was significantly increased downstream of the waste water treatment plant Langwiese, compared to the upstream sampling site. Similarly, these effects could be detected downstream of three small storm water overflow basins. In the macrozoobenthos communities, the abundance of taxa, the number of taxa, the number of ephemeroptera, plecoptera, and trichoptera taxa (EPT-taxa), and the number of sensitive taxa decreased downstream of the storm water overflow basin Mariatal as well as downstream of the waste water treatment plant Langwiese. Our study showed, that waste water

  8. Discourse-Centric Learning Analytics: Mapping the Terrain

    Science.gov (United States)

    Knight, Simon; Littleton, Karen

    2015-01-01

    There is an increasing interest in developing learning analytic techniques for the analysis, and support of, high-quality learning discourse. This paper maps the terrain of discourse-centric learning analytics (DCLA), outlining the distinctive contribution of DCLA and outlining a definition for the field moving forwards. It is our claim that DCLA…

  9. Effects of All-Terrain Vehicles on Stream Dynamics

    Science.gov (United States)

    Anne Chin; Deven M. Rohrer; Daniel A. Marion; J. Alan Clingenpeel

    2004-01-01

    Abstract - This paper reports preliminary results from research conducted in the Ouachita National Forest to assess the effects of all-terrain vehicle (ATV) trails on stream characteristics. The study focuses on the Wolf Pen Gap Trail that has been in use since 1991. We examine whether that the trail system has caused increased sediment input to and...

  10. How fine is fine enough when doing CFD terrain simulations

    DEFF Research Database (Denmark)

    Sørensen, Niels N.; Bechmann, Andreas; Réthoré, Pierre-Elouan

    The present work addresses the problem of establishing the necessary grid resolution to obtain a given level of numerical accuracy using a CFD model for prediction of flow over terrain. It is illustrated, that a very high resolution may be needed if the numerical difference between consecutive...

  11. How fine is fine enough when doing CFD terrain simulations

    DEFF Research Database (Denmark)

    Sørensen, Niels N.; Bechmann, Andreas; Réthoré, Pierre-Elouan

    2012-01-01

    The present work addresses the problemof establishing the necessary grid resolution to obtain a given level of numerical accuracy using a CFD model for prediction of flow over terrain. It is illustrated, that a very high resolution may be needed if the numerical difference between consecutive...

  12. Simulation of Wind Farms in Flat & Complex terrain using CFD

    DEFF Research Database (Denmark)

    Prospathopoulos, John; Cabezon, D.; Politis, E.S.

    2010-01-01

    Use of computational fluid dynamic (CFD) methods to predict the power production from wind entire wind farms in flat and complex terrain is presented in this paper. Two full 3D Navier–Stokes solvers for incompressible flow are employed that incorporate the k–ε and k–ω turbulence models respectively...

  13. Prediction of wind energy distribution in complex terrain using CFD

    DEFF Research Database (Denmark)

    Xu, Chang; Li, Chenqi; Yang, Jianchuan

    2013-01-01

    Based on linear models, WAsP software predicts wind energy distribution, with a good accuracy for flat terrain, but with a large error under complicated topography. In this paper, numerical simulations are carried out using the FLUENT software on a mesh generated by the GAMBIT and ARGIS software...

  14. Profile derived fluxes above inhomogeneous terrain : a numerical approach

    NARCIS (Netherlands)

    Kroon, L.J.M.

    1985-01-01

    In Chapter 1 the goals of the present study were presented. These goals are (i) the estimation and analysis of the errors introduced in the standard flux determination methods when they are applied above non-homogeneous terrain
    (ii) providing simple techniques for estimating these errors,

  15. The retrieval of land surface albedo in rugged terrain

    NARCIS (Netherlands)

    Gao, B.; Jia, L.; Menenti, M.

    2012-01-01

    Land surface albedo may be derived from the satellite data through the estimation of a bidirectional reflectance distribution function (BRDF) model and angular integration. However many BRDF models do not consider explicitly the topography. In rugged terrain, the topography influences the observed

  16. CALCULATION OF CHEMICAL ATMOSPHERE ESTIMATION GIVEN THE COMPLEX TERRAIN

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2010-06-01

    Full Text Available The 3D numerical model was used to simulate the toxic gas dispersion over a complex terrain after an accident spillage. The model is based on the K-gradient transport model and the model of potential flow. The results of numerical experiment are presented.

  17. Sculpting Mountains: Interactive Terrain Modeling Based on Subsurface Geology.

    Science.gov (United States)

    Cordonnier, Guillaume; Cani, Marie-Paule; Benes, Bedrich; Braun, Jean; Galin, Eric

    2018-05-01

    Most mountain ranges are formed by the compression and folding of colliding tectonic plates. Subduction of one plate causes large-scale asymmetry while their layered composition (or stratigraphy) explains the multi-scale folded strata observed on real terrains. We introduce a novel interactive modeling technique to generate visually plausible, large scale terrains that capture these phenomena. Our method draws on both geological knowledge for consistency and on sculpting systems for user interaction. The user is provided hands-on control on the shape and motion of tectonic plates, represented using a new geologically-inspired model for the Earth crust. The model captures their volume preserving and complex folding behaviors under collision, causing mountains to grow. It generates a volumetric uplift map representing the growth rate of subsurface layers. Erosion and uplift movement are jointly simulated to generate the terrain. The stratigraphy allows us to render folded strata on eroded cliffs. We validated the usability of our sculpting interface through a user study, and compare the visual consistency of the earth crust model with geological simulation results and real terrains.

  18. Modeling air-quality in complex terrain using mesoscale and ...

    African Journals Online (AJOL)

    Air-quality in a complex terrain (Colorado-River-Valley/Grand-Canyon Area, Southwest U.S.) is modeled using a higher-order closure mesoscale model and a higher-order closure dispersion model. Non-reactive tracers have been released in the Colorado-River valley, during winter and summer 1992, to study the ...

  19. Integrating land cover and terrain characteristics to explain plague ...

    African Journals Online (AJOL)

    Literature suggests that higher resolution remote sensing data integrated in Geographic Information System (GIS) can provide greater possibility to refine the analysis of land cover and terrain characteristics for explanation of abundance and distribution of plague hosts and vectors and hence of health risk hazards to ...

  20. Planning Routes Across Economic Terrains: Maximizing Utility, Following Heuristics

    Science.gov (United States)

    Zhang, Hang; Maddula, Soumya V.; Maloney, Laurence T.

    2010-01-01

    We designed an economic task to investigate human planning of routes in landscapes where travel in different kinds of terrain incurs different costs. Participants moved their finger across a touch screen from a starting point to a destination. The screen was divided into distinct kinds of terrain and travel within each kind of terrain imposed a cost proportional to distance traveled. We varied costs and spatial configurations of terrains and participants received fixed bonuses minus the total cost of the routes they chose. We first compared performance to a model maximizing gain. All but one of 12 participants failed to adopt least-cost routes and their failure to do so reduced their winnings by about 30% (median value). We tested in detail whether participants’ choices of routes satisfied three necessary conditions (heuristics) for a route to maximize gain. We report failures of one heuristic for 7 out of 12 participants. Last of all, we modeled human performance with the assumption that participants assign subjective utilities to costs and maximize utility. For 7 out 12 participants, the fitted utility function was an accelerating power function of actual cost and for the remaining 5, a decelerating power function. We discuss connections between utility aggregation in route planning and decision under risk. Our task could be adapted to investigate human strategy and optimality of route planning in full-scale landscapes. PMID:21833269