Global Change Master Directory gsfc-gcmduso@mail.nasa.gov 50 2013-06-20T08:02:41Z nsidc Search: Parameters|BIOSPHERE http://mddemo.gsfc.nasa.gov/KeywordSearch/OpenSearch.do 86 0 http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0020 Coordinated Eastern Arctic Experiment (CEAREX) Data -30.0,60.0,30.0,90.0 1988-03-01T00:00:00Z 1989-05-31T00:00:00Z 2012-10-18T04:00:00Z CEAREX was a multi-platform field program conducted in the Norwegian Seas and Greenland north to Svalbard from September 1988 through May 1989. Canada, Denmark, France, Norway and the United States ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0181 CLPX-Model: Land Data Assimilation System (LDAS) Data -108.5,38.5,-104.0,42.0 2001-01-01T00:00:00Z 2003-08-01T00:00:00Z 2012-05-15T04:00:00Z The LDAS data set contains 43 model and observation-based fields produced by the LDAS uncoupled modeling system at the NASA Goddard Space Flight Center using the Mosaic Land Surface Model (LSM). ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0175 CLPX-Ground: ISA Snow Depth Transects and Related Measurements, Version 2.0 -108.5,38.5,-104.0,42.0 2002-02-19T00:00:00Z 2002-02-23T00:00:00Z 2012-05-14T04:00:00Z This data set consists of snow depth data from nine study areas, within three larger-scale areas in northern Colorado (Fraser, North Park, and Rabbit Ears Meso-cell Study Areas (MSAs)). The study ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0151 CLPX-Satellite: MODIS Radiances, Reflectances, Snow Cover and Related Grids -108.5,38.5,-104.0,42.0 2002-02-15T00:00:00Z 2002-05-15T00:00:00Z 2003-02-15T00:00:00Z 2003-05-15T00:00:00Z 2012-05-14T04:00:00Z This data set provides Moderate Resolution Imaging Spectroradiometer (MODIS) data from the Cold Land Processes Field Experiment (CLPX). These data are delivered in geographic (GEO) and Universal Tranverse ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0042 DMSP-F8 SSM/I Pathfinder Land Surface Products -180.0,-88.0,180.0,88.0 1987-08-01T00:00:00Z 1988-12-31T00:00:00Z 2012-05-14T04:00:00Z The Pathfinder Program, sponsored by the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA), is tasked to produce long-term data sets ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0184 SMEX02 Iowa Satellite Vegetation and Water Index (NDVI and NDWI) Data -93.827,41.694,-93.161,42.732 2002-06-06T00:00:00Z 2002-07-17T00:00:00Z 2012-05-14T04:00:00Z This data set is part of the Soil Moisture Experiment 2002 (SMEX02) project, which is associated with the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) validation project. ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0188 SMEX02 Regional Vegetation Sampling Data, Iowa -93.8,41.7,-93.2,42.7 2002-06-30T00:00:00Z 2002-07-28T00:00:00Z 2012-05-14T04:00:00Z This data set contains the vegetation parameters plant height, row spacing, stand density, and leaf area index (LAI) as part of the Soil Moisture Experiment 2002 (SMEX02). The SMEX studies are designed ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0189 SMEX02 Vegetation Water Content, Iowa Regional and Walnut Creek Watershed -93.841,41.694,-93.161,42.732 2003-06-25T00:00:00Z 2003-07-18T00:00:00Z 2012-05-14T04:00:00Z This data set is part of the Soil Moisture Experiment 2002 (SMEX02) project, which is associated with the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) validation project. ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0187 SMEX02 Watershed Vegetation Sampling Data, Walnut Creek, Iowa -93.8,41.7,-93.2,42.7 2002-06-15T00:00:00Z 2002-07-09T00:00:00Z 2012-05-14T04:00:00Z This data set contains the vegetation parameters stand density, plant height, phenological stage, ground cover, green and dry biomass, row spacing, stem and leaf water content, and leaf area index ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0297 SMEX03 Vegetation Data: Oklahoma -98.3,34.8,-97.6,35.9 2003-07-01T00:00:00Z 2003-07-18T00:00:00Z 2012-05-14T04:00:00Z This data set is part of the Soil Moisture Experiment 2003 (SMEX03). The parameters for this data set include Leaf Area Index (LAI), Multispectral Radiometer Reflectance (MSR), plant height, plant ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0401 SMEX04 Meteorological Network Data: Arizona -110.239,31.112,-109.718,31.422 2004-06-01T00:00:00Z 2004-09-30T00:00:00Z 2012-05-14T04:00:00Z Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS130 A Half-Century of Change in Arctic Alaskan Shrubs: A Photographic-Based Assessment -165.0,68.0,-145.0,70.0 1948-01-01T00:00:00Z 1951-12-31T00:00:00Z 1999-01-01T00:00:00Z 2003-12-31T00:00:00Z 2012-05-13T04:00:00Z In this study, the locations of 193 old aerial photographs of northern Alaskan landscapes were rephotographed and assessed for changes in vegetation. The original photographs were taken over northern ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS079 Chemical and Isotopic Tracers from the Arctic Ocean 2012-05-11T04:00:00Z These data are water column and sediment data tabulated in Microsoft Excel spreadsheets. They were largely collected in the Bering and Chukchi Seas, with some coverage for the Beaufort and East Siberian ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS904 Climate and Flux Data from Alaska Sites, 1998-2000 163.644,64.727,164.73,65.2 1998-06-27T00:00:00Z 2000-08-30T00:00:00Z 2012-05-11T04:00:00Z This data set contains climate, flux, and bulk density data from Ivotuk and Council (Seward Peninsula), Alaska, collected from 1998 through 2000. Surface energy and trace gas exchange measurements ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS143 Coring Data from Drained Thaw-Lake Basins of the Arctic Coastal Plain, Alaska -156.9804,70.4325,-153.8315,76.4379 2001-04-01T00:00:00Z 2003-08-31T00:00:00Z 2012-05-11T04:00:00Z This data set includes measurements and observations taken from drained thaw-lake basin (DTLB) cores retrieved from Barrow and Atqasuk, Alaska in April and August of 2001 through 2003. Investigators ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS073 Distribution of Zooplankton in the Northeast Water Polynya Project, Summer 1992 and 1993 -17.272,76.548,-7.2,80.807 1992-03-13T00:00:00Z 1992-07-18T00:00:00Z 1993-07-24T00:00:00Z 1993-08-12T00:00:00Z 2012-05-11T04:00:00Z These data represent quantitative taxonomic analyses of zooplankton samples collected while on board the USCGC Polar Sea, operating in the Northeast Water Polynya Project in July and August of 1992 ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS017 GIS Data from the Alaska North Slope -150.0,69.0,-150.0,69.0 2012-05-11T04:00:00Z This data set includes ArcInfo-formatted maps of the Kuparuk River Basin Region of the Alaskan North Slope (at 1:250,000 scale) and five subset study areas: the Upper Kuparuk River Basin Subregion ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS059 Global Land Use Data Sets -180.0,-90.0,180.0,90.0 2012-05-11T04:00:00Z Information on soils, vegetation types, cultivated areas, wetlands and inundated areal fraction at 1- x 1-degree resolution for the Earth are available. Global FAO soil units data distinguish 27 ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS051 LAII Alaska Landscape Flux Survey NOAA/ATDD Long-EZ Aircraft Data -148.0,69.0,152.0,70.0 1994-06-01T00:00:00Z 1996-08-31T00:00:00Z 2012-05-11T04:00:00Z The data in the aircraft portion of the Land Atmosphere Ice Interaction (LAII) Alaska Landscape Flux Survey (ALFS) were collected in June 1994, June 1995, August 1995, and June 1996. The object of ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS020 Land-Cover Map of the North Slope of Alaska -149.0,68.0,-149.0,68.0 2012-05-11T04:00:00Z This ARC/INFO map provides a spatially explicit representation of the nature and distribution of land cover and tundra types on the North Slope of Alaska. This was done in support of extrapolating ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS010 Long Term Ecological Research (LTER) Site Data, North Slope of Alaska -150.0,69.0,-150.0,69.0 1975-01-01T00:00:00Z T00:00:00Z 2012-05-11T04:00:00Z As part of the Arctic Long Term Ecological Research (ARC LTER) project, numerous investigators have collected diverse environmental data from sites in the northern foothills of Alaska's Brooks Range. ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS108 Methane Flux Measurements, Happy Valley, AK, 1994 -148.852,69.167,-148.852,69.167 1994-07-19T00:00:00Z 1994-07-24T00:00:00Z 2012-05-11T04:00:00Z This data set contains CH4 (methane) flux and related measurements taken at the Happy Valley Flux Study Site in northern Alaska during the summer of 1994. Sampling was conducted to test use of a laser ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS162 Model Output Assessing Net Carbon Exchange Across the Arctic Tundra-Boreal Forest Transition in Alaska, 1981-2000 -167.5,65.5,-141.5,69.0 1981-01-01T00:00:00Z 2000-12-31T00:00:00Z 2012-05-11T04:00:00Z In this study, investigators simulated the temporal and spatial patterns of net carbon exchange in Alaskan ecosystems that span the transition from Arctic tundra to boreal forest. They modeled net ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS052 Model Output from the Marine Biology Laboratory General Ecosystem Model (MBL-GEM) for Toolik Lake, 1921-2144, and the Kuparuk River Basin, 1995 -150.0,68.0,-148.0,69.0-149.0,69.0,-148.0,70.0 1921-01-01T00:00:00Z 2144-12-31T00:00:00Z 1995-05-01T00:00:00Z 1995-08-31T00:00:00Z 2012-05-11T04:00:00Z This data set contains model input and output data for four simulations of varying time periods and spatial coverage. The first two simulations are for acidic tussock tundra in the Toolik Lake region ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS089 Preliminary Investigation of Paleoenvironment, Processes, and Carbon Stocks of Drained Thaw-Lake Basins, Arctic Coastal Plain, Alaska -157.1418,70.9055,-155.5474,71.3136 2000-08-01T00:00:00Z 2001-12-31T00:00:00Z 2012-05-11T04:00:00Z This data set contains measurements taken from 78 drained thaw-lake basins on the Arctic Coastal Plain between Barrow and Atqasuk, Alaska. Investigators collected and analyzed sediment cores to determine ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS136 Radiocarbon Dates and Pollen Data, Peterson Erosional Remnant, Arctic Coastal Plain, Alaska -156.4,71.066666,-156.4,71.066666 2002-04-15T00:00:00Z 2003-08-15T00:00:00Z 2012-05-11T04:00:00Z This data set consists of pollen data and radiocarbon (<sup>14</sup>C) dates resulting from microscopic analysis and mass spectrometry of soil cores taken from the Peterson Erosional Remnant, located ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS164 Resource Allocation and Allometry of Plant Growth at Selected Sites in the Arctic: 2003-2005 Growing Seasons -149.5667,68.3,18.85,78.2167 2003-07-05T00:00:00Z 2005-08-05T00:00:00Z 2012-05-11T04:00:00Z This data set consists of seven data files containing measurements from Arctic field sites during the summer months from 5 July 2003 to 5 August 2005 as part of the Land-Atmosphere-Ice Interactions ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS119 Snow and Vegetation Measurements from Selected Sites Near Council, Alaska, USA, 2000-2002 -163.7378,64.5029,-163.6496,64.9354 2000-05-09T00:00:00Z 2002-10-03T00:00:00Z 2012-05-11T04:00:00Z A combination of snow depth, snow temperature, snow water equivalent (SWE), and albedo measurements were taken from the spring of 2000 to the fall of 2002 at five sites near Council, Alaska. The sites ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS103 Thaw Depth and Vegetation Radiance Measurements, Happy Valley, AK, 1994 -148.863,69.141,-148.84,69.149 1994-06-06T00:00:00Z 1994-07-17T00:00:00Z 2012-05-11T04:00:00Z This data set contains measurements for permafrost active layer thaw depth and vegetation reflectance (red and near-infrared bandwidths) at the Happy Valley Flux Study Site in northern Alaska during ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS131 West Siberian Lowland Peatland GIS Data Collection 60.0,50.0,93.0,75.0 1971-01-01T00:00:00Z 2001-12-31T00:00:00Z 2012-05-11T04:00:00Z This dataset contains the West Siberian Lowland (WSL) peatland GIS data collection. The collection covers the entire West Siberian lowland and was compiled from a wide array of data under the auspices ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]AE_Land3 AMSR-E/Aqua Daily L3 Surface Soil Moisture, Interpretive Parameters, & QC EASE-Grids -180.0,-89.24,180.0,89.24 2002-06-18T00:00:00Z T00:00:00Z 2012-05-03T04:00:00Z The Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) instrument on the NASA Earth Observing System (EOS) Aqua satellite provides global passive microwave measurements of terrestrial, ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]AE_Land AMSR-E/Aqua L2B Surface Soil Moisture, Ancillary Parms, & QC EASE-Grids -180.0,-89.24,180.0,89.24 2002-06-18T00:00:00Z T00:00:00Z 2012-05-03T04:00:00Z The Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) instrument on the NASA EOS Aqua satellite provides global passive microwave measurements of terrestrial, oceanic, and atmospheric ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]taylor_0739780 WAIS DIVIDE - High Temporal Resolution Black Carbon Record of Southern Hemisphere Biomass Burning -112.117,-79.666,-112.117,-79.666 2011-05-05T04:00:00Z This award supports a project to develop a 2,000-year high-temporal resolution record of biomass burning from the analysis of black carbon in the WAIS Divide bedrock ice core. Pilot data for the WAIS ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ARCSS091 Monitoring and Manipulation of Tundra Response to Climate Change, Arctic LTER, Toolik Lake, Alaska -149.717,68.628,-148.85,68.767 1995-01-01T00:00:00Z T00:00:00Z 2011-03-16T04:00:00Z The investigator has undertaken long-term field experiments and monitoring at the Arctic Long Term Ecological Research (LTER) station, Toolik Lake, Alaska, exploring the effects of climate change ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0419 SMEX04 Vegetation Data -110.67,29.94,-109.72,32.08 2004-07-20T00:00:00Z 2004-08-24T00:00:00Z 2011-03-08T05:00:00Z Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0455 SMEX05 Meteorological Network Data: Iowa -94.03,41.932,-93.48,41.99 2005-06-01T00:00:00Z 2005-07-17T00:00:00Z 2011-03-08T05:00:00Z Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0444 SMEX05 Vegetation Water Content Data: Iowa -94.0166,41.8666,-93.5166,42.0666 2005-06-06T00:00:00Z 2005-06-06T00:00:00Z 2005-07-17T00:00:00Z 2005-07-17T00:00:00Z 2011-03-08T05:00:00Z Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]NSIDC-0378 SMEX03 Soil Moisture, Meteorological, and Vegetation Data: Brazil -50.0,-17.0,-40.0,-7.0 2003-12-01T00:00:00Z 2003-12-31T00:00:00Z 2011-03-01T05:00:00Z Notice to Data Users: The documentation for this data set was provided solely by the Principal Investigator(s) and was not further developed, thoroughly reviewed, or edited by NSIDC. Thus, support ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd402 Borehole and environmental protection descriptive and numerical data, Yamal Peninsula, Russia 65.5,66.0,74.0,72.5 1977-01-01T00:00:00Z 1990-12-31T00:00:00Z 2011-01-24T05:00:00Z This database of selected borehole records from the Yamal Peninsula, Russia, contains environmental descriptions (textual and numerical) of the units on the index map, and relevant borehole data. ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd639 Circumpolar Arctic Vegetation Map -180.0,60.0,180.0,90.0 2011-01-24T05:00:00Z The Circumpolar Arctic Vegetation Map (CAVM) defines the spatial extent of dominant vegetation in terms of the dominant plant growth forms and physiognomy. Mapped vegetation extends south to the treeline, ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd613 Landscape Map of the Russian Arctic Coastal Zone 15.0,50.0,169.0,90.0 2011-01-24T05:00:00Z The map consists of ESRI Shapefiles of landscape polygons (in landscape unit types) for the Russian Arctic coastal zone (scale 1:4,000,000). The map is based on a digital circumpolar Lambert projection ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd193 Regionalization for geocryological conditions and forecast, Yamal Peninsula , Russia 66.5,66.5,73.5,73.5 1983-01-01T00:00:00Z 1989-12-31T00:00:00Z 2010-12-30T05:00:00Z This data set consists of a classification of the geological environment of Yamal, based on a map of natural complexes of North West Siberia. 52 separate regions were identified, distinguished by ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd277 Vegetation and soil classification at Barrow Environmental Observatory and Long Range Radar Site: Barrow Legacy Study, Alaska, USA -156.633,71.317,-156.55,71.333 1993-08-01T00:00:00Z 1994-08-31T00:00:00Z 2010-12-30T05:00:00Z Data from Barrow Environmental Observatory, Point Barrow and Barter Island Long Range Radar Sites (LRRS), taken during August 1993 and August 1994. Thaw depth data from: 1. 31 vegetation plots ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd240 Active Layer Measurements in Tanana Flats, Fairbanks, Alaska, USA -148.167,64.25,147.5,64.75 1989-01-01T00:00:00Z 1989-12-31T00:00:00Z 1992-01-01T00:00:00Z T00:00:00Z 2010-12-29T05:00:00Z This data set consists of active layer thickness from forested uplands (islands and benches) bordering the interconnected wetlands of Tanana Flats, near Fairbanks, Alaska. CRREL permafrost cores were ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd244 Hierarchic GIS: Process, Pattern and Scale for Analysis of Arctic Ecosystems (ITEX) -157.417,68.617,-148.567,71.333 2010-12-29T05:00:00Z This study is developing a GIS at multiple scales for the Kuparuk River Basin and other sites in Alaska. The project includes geobotanical sampling of 1 x 1 km grids at 100 m intervals for vegetation, ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd31 Upper soil temperatures in the Kolyma Highland 149.5,61.867,149.667,62.033 1977-10-01T00:00:00Z 1995-12-31T00:00:00Z 2010-12-29T05:00:00Z This data set contains soil temperature and meteorological data for various sampling locations near the Aborigen research station in the Kolyma Highland, Northeastern Russia. Data are averaged from ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd287 Rock glaciers, Fletschhorn Area, Valais, Switzerland 7.15,46.117,8.117,46.233 1995-01-01T00:00:00Z 1995-12-31T00:00:00Z 2010-12-28T05:00:00Z This data set contains a total amount of 74 rock glaciers which were investigated in the Fletschhorn Area in the southern Swiss Alps during the summer of 1995. The thorough investigation included ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd278 Seasonal frost penetration, Sleepers River Research Watershed, Vermont, USA -72.177,44.422,-72.039,44.53 1983-01-01T00:00:00Z 1992-12-31T00:00:00Z 2010-12-28T05:00:00Z The frost tube network is located within a 3.25-square-mile sub-watershed of the Sleepers River Research Watershed near Danville, Vermont, USA. Tubes were positioned in forested and non-forested cover ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd188 Slope Ecology and Active Layer in the Central Yamal Peninsula, West Siberia, Russia 68.9,70.283,68.9,70.283 1988-08-01T00:00:00Z 2002-09-30T00:00:00Z 2010-12-28T05:00:00Z This data set contains slope ecology parameters from Western Siberia, including morphology, lithology, soil-vegetation cover, depth of thaw, and chemical composition of landslide slopes. The study ... http://gcmd.gsfc.nasa.gov/getdif.htm?[GCMD]ggd195 Vegetation dynamics and geocryological conditions of the West Siberian Arctic, Russia 72.917,65.333,72.917,65.333 1972-01-01T00:00:00Z 2002-12-31T00:00:00Z 2010-12-28T05:00:00Z This data set includes soil temperature and ground temperature in 10 m boreholes, and active layer thickness, at 30 stations in both natural and disturbed conditions near gas pipelines, measured each ...