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This data set includes hourly precipitation data taken at 20 rain gauge locations as part of the Soil Moisture Experiment 2002 (SMEX02). This study was conducted during June, July, and August 2002 in the Walnut Creek watershed in south-central Iowa, USA. Data were recorded every hour from 1 June through 19 August 2002 and are available via FTP.
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.
Prueger, J. 2004. SMEX02 Rain Gauge Network, Walnut Creek, Iowa. [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.
|Data format||ASCII tab-delimited text files|
|Spatial coverage and resolution||42°N, 93°W|
|Temporal coverage and resolution||1 June 2002 to 19 August 2002
Data were gathered every hour
|File size||1.7 MB|
|Parameter(s)||Precipitation intensity in mm|
|Procedures for obtaining data||Data are available via FTP.|
John Prueger, Hydrologist
U.S. Department of Agriculture (USDA) Agriculture Research Service (ARS) National Soil Tilth Laboratory.
NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
Dr. Prueger would like to acknowledge the National Soil Tilth Laboratory in Ames, Iowa for support in maintaining this rain gauge network.
Data are ASCII tab-delimited text files.
File size is 1.7 MB.
Southernmost Latitude: 41.94°N
Northernmost Latitude: 41.99°N
Westernmost Longitude: 93.8°W
Easternmost Longitude: 93.4°W
Data were collected from 1 June 2002 to 19 August 2002.
Data were gathered every hour.
The following table describes the columns in the data file.
|Site_ID||Rain gauge identifier|
|UTM_Easting||meters (m)||WGS84, Zone 15|
|UTM_Northing||meters (m)||WGS84, Zone 15|
|Date||mm/dd/yyyy||Date measurement was taken|
|Hour||0 to 23||Hour measurement was taken (0 is midnight Central Standard Time)|
|Precip||millimeters (mm)||Amount of precipitation measured (missing data are represented by -99)|
The following table shows a small sample of the data file.
Data are available via FTP.
Total volume of combined files is 1.7 MB
Rain gauges are intended to provide continuous measurements of the precipitation at a single point, with many gauges distributed throughout the watershed.
The sources are twenty rain gauges placed in crop fields in the study area. A Texas Electronics model TE525 tipping bucket rain gauge measured precipitation. The device consists of small cones that fill up and tip when a specific amount of rain falls into the cone. The number of tips is converted to a calculated rainfall amount. These data are logged to a Campbell Scientific CR10 datalogger.
The following acronyms and abbreviations are used in this document.
|AMSR-E||Advanced Microwave Scanning Radiometer - Earth Observing System|
|FTP||File Transfer Protocol|
|SMEX||Soil Moisture Experiment|