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This work is part of the Soil Moisture Experiment 2002 (SMEX02) project. This data set provides data from various sensors on the Soil Climate Analysis Network (SCAN) station number 2031, located near Ames, Iowa, USA. The data include hourly and daily recordings of precipitation, air temperature, solar radiation, wind speed, relative humidity, soil moisture, and soil temperature.
The station houses numerous sensors that automatically record data. Sensors include global precipitation sensor, thermistor, thin film capacitance-type sensor, anemometer, pyranometer, pressure sensor, and a frequency-shift dielectric measuring device. Units of measurement vary, depending on the type of sensor. Data are uploaded by meteor burst telemetry to the Natural Resources Conservation Service (NRCS) Data Processing Center in Portland, Oregon.
The NRCS has been operating this SCAN station since 23 September 2001, but this data set covers only the time period of interest to the Soil Moisture Experiments 2002 (SMEX02) campaign, 1 June 2002 through 31 August 2002. Data are available in two text files, one for hourly data, the other for daily data.
These data were collected as part of a validation study for the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E). AMSR-E is a mission instrument launched aboard NASA's Aqua Satellite on 04 May 2002. AMSR-E validation studies linked to SMEX are designed to evaluate the accuracy of AMSR-E soil moisture data. Specific validation objectives include assessing and refining soil moisture algorithm performance; verifying soil moisture estimation accuracy; investigating the effects of vegetation, surface temperature, topography, and soil texture on soil moisture accuracy; and determining the regions that are useful for AMSR-E soil moisture measurements.
Jackson, T. 2003. SMEX02 Soil Climate Analysis Network (SCAN) Station 2031, Ames, Iowa. [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.
|Data format||Two ASCII text files, 381 KB and 4 KB|
|Spatial coverage|| 42.01° N
|Temporal coverage and resolution|| 1 June 2002 through 31 August 2002
Hourly and daily data are available.
|Tools for accessing data||View data using a browser or text editor.|
|File naming convention|| SCAN2031_Hourly.txt contains hourly data.
SCAN2031_Daily.txt contains daily data.
|File size|| SCAN2031_Hourly.txt size is 381 KB.
SCAN2031_Daily.txt size is 4 KB.
|Parameter(s)||Precipitation, air temperature, solar radiation, wind speed, relative humidity, soil moisture, and soil temperature|
|Procedures for obtaining data||Data are available via FTP.|
Thomas J. Jackson, Hydrologist, and Mike Cosh, General Physical Scientist, USDA ARS Hydrology Lab.
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United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) http://www.nrcs.usda.gov/
Data are in ASCII text format. The hourly data contain 32 columns; the daily data contain 8 columns. The following table is a key to the column headings and units of measure for the hourly data. The daily measurements (shown in the Label column) are a small subset of the hourly columns.
|PCPIN||CURRENT||Global Precipitation Sensor||inches|
| ATHX6 (hourly)
| ATHN6 (hourly)
| ATHA6 (hourly)
| WSPHA (hourly)
| WDHA (hourly)
|BPHGC||CURRENT||Barometric Pressure||inch of Hg|
|c1rdc||CURRENT||Real dielectric constant 2"||unitless|
|c1smv||CURRENT||Percent water by volume-2"||percentage|
|c1tmp||CURRENT||Soil temperature at depth of 2"||Celsius|
|c2rdc||CURRENT||Real dielectric constant at depth of 4"||unitless|
|c2smv||CURRENT||Percent water by volume at depth of 4"||percentage|
|c2tmp||CURRENT||Soil temperature at depth of 4"||Celsius|
|c3rdc||CURRENT||Real dielectric constant at depth of 8"||unitless|
|c3smv||CURRENT||Percent water by volume at depth of 8"||percentage|
|c3tmp||CURRENT||Soil temperature at depth of 8"||Celsius|
|c4rdc||CURRENT||Real dielectric constant at depth of 20"||unitless|
|c4smv||CURRENT||Percent water by volume at depth of 20"||percentage|
|c4tmp||CURRENT||Soil temperature at depth of 20"||Celsius|
|c5rdc||CURRENT||Real dielectric constant at depth of 40"||unitless|
|c5smv||CURRENT||Percent water by volume at depth of 40"||percentage|
|c5tmp||CURRENT||Soil temperature at depth of 40"||Celsius|
Files are named for the SCAN site and the frequency of data collection. The file names are "SCAN2031_daily.txt" and "SCAN2031_hourly.txt."
The file "SCAN2031_daily.txt" is 4 KB, "SCAN2031_hourly.txt" is 380 KB.
Measurements were taken at the SCAN site number 2031 in Ames, Iowa, USA. Latitude: 42.01° N, Longitude: 93.73° W.
Measurements were taken between 1 June 2003 and 31 August 2003.
Measurements are given daily and hourly.
The units of measurement for each parameter are given in the Format section.
The following table describes the parameters measured by each sensor:
|Global precipitation sensor||Precipitation||This instrument records daily cumulative inches of precipitation.|
|Shielded thermistor||Air temperature||Raised 6 feet off of the ground, this device reports the current temperature and the previous hourly maximum, hourly minimum, and hourly average.|
|Soil sensors||Soil moisture, soil temperature||The soil moisture and soil temperature data were recorded by sensors located at 5 depths, 2", 4", 8" , 20", and 40".|
|Thin film capacitance-type sensor||Relative humidity||This sensor is six feet above the surface. The value is a percentage, reported as current, previous hourly maximum, and previous hourly minimum.|
|Anemometer||Wind speed and direction||This sensor is 10 feet above the surface. It provides an hourly average from continuously sampled data.|
|Pyranometer||Solar radiation||This silicon cell sensor is 10 feet above the surface. It provides hourly average readings of total incoming solar energy in terms of Watts per square meter.|
|Silicon capacitive pressure sensor||Barometric pressure||This sensor measures hourly barometric pressure.|
The following is a sample from the hourly data:
Data are available via FTP.
Combined file size is 385 KB.
View the data in a Web browser or text editor.
For related data collections, please see AMSR-E Validation.
Please see Soil Climate Analysis (SCAN).
The following acronyms and abbreviations are used in this document.
|AMSR-E||Advanced Microwave Scanning Radiometer - Earth Observing System|
|SCAN||Soil Climate Analysis|
|SMEX||Soil Moisture Experiments|
|USDA||United States Department of Agriculture|
|NRCS||Natural Resources Conservation Service|
9 June 2003