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SMEX02 Soil Climate Analysis Network (SCAN) Station 2031, Ames, Iowa

Summary

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.

Citing These Data:

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.

Overview Table

Category Description
Data format Two ASCII text files, 381 KB and 4 KB
Spatial coverage 42.01° N
93.73° W
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.

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. References and Related Publications
5. Document Information

1. Contacts and Acknowledgments:

Investigator(s) Name and Title:

Thomas J. Jackson, Hydrologist, and Mike Cosh, General Physical Scientist, USDA ARS Hydrology Lab.

Technical Contact:

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
e-mail: nsidc@nsidc.org

Acknowledgements:

United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) http://www.nrcs.usda.gov/

2. Detailed Data Description:

Format:

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.

Label Measurement Type Description Units
PCPIN CURRENT Global Precipitation Sensor inches
ATHC6 CURRENT Air temperature Celsius
ATHX6 (hourly)
ATX6 (daily)
MAXIMUM Air temperature Celsius
ATHN6 (hourly)
ATN6 (daily)
MINIMUM Air temperature Celsius
ATHA6 (hourly)
ATA6 (daily)
AVERAGE Air temperature Celsius
SRHA AVERAGE Solar radiation W/m2
WSPHA (hourly)
WSPDA (daily)
AVERAGE Wind speed m/h
WDHA (hourly)
WDDA (daily)
AVERAGE Wind direction degree
WSPHX MAXIMUM Wind speed m/h
RH1C1 CURRENT Relative humidity percentage
RH1N1 MINIMUM Relative humidity percentage
RH1X1 MAXIMUM Relative humidity percentage
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

File Naming Convention:

Files are named for the SCAN site and the frequency of data collection. The file names are "SCAN2031_daily.txt" and "SCAN2031_hourly.txt."

File Size:

The file "SCAN2031_daily.txt" is 4 KB, "SCAN2031_hourly.txt" is 380 KB.

Spatial Coverage:

Measurements were taken at the SCAN site number 2031 in Ames, Iowa, USA. Latitude: 42.01° N, Longitude: 93.73° W.

Temporal Coverage:

Measurements were taken between 1 June 2003 and 31 August 2003.

Temporal Resolution:

Measurements are given daily and hourly.

Parameter or Variable:

Unit of Measurement:

The units of measurement for each parameter are given in the Format section.

Parameter Source:

The following table describes the parameters measured by each sensor:

Sensor Parameter Description
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.

Sample Data Record:

The following is a sample from the hourly data:

Year Month Day ATX6 ATN6 ATA6 WSPDA WDDA
2002 6 1 32.43 17.07 25.32 5.16 280.26
2002 6 2 35.12 17.73 26.94 4.66 28.75
2002 6 3 26.18 15.68 20.34 9.99 108.66
2002 6 4 27.72 14.8 21.39 9.17 90.46

3. Data Access and Tools:

Data Access:

Data are available via FTP.

Volume:

Combined file size is 385 KB.

Software and Tools:

View the data in a Web browser or text editor.

Related Data Collections:

For related data collections, please see AMSR-E Validation.

4. References and Related Publications:

Please see Soil Climate Analysis (SCAN).

5. Document Information:

Acronyms and Abbreviations

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

Document Creation Date:

9 June 2003

Document URL:

http://nsidc.org/data/docs/daac/nsidc0142_smex_scan.gd.html