The following data collections are not available due to unplanned system maintenance: AMSR-E, Aquarius, High Mountain Asia, IceBridge, ICESat/GLAS, MEaSUREs, MODIS, NISE, SMAP, and VIIRS. We apologize for any inconvenience. Please contact User Services with any questions.

Get Data


To learn more about Earthdata Login and to register for an account, please see How to Register with Earthdata Login. Once you have logged in, data can be downloaded via a Web browser, command line, or client. For help with downloading data, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.


Data Set ID:

SMEX02 Soil Climate Analysis Network (SCAN) Station 2031, Ames, Iowa, Version 1

This data set provides data from various sensors on the Soil Climate Analysis Network (SCAN) station number 2031, located near Ames, Iowa, USA.

Geographic Coverage

  • Atmospheric Temperature > Air Temperature
  • Atmospheric Winds
  • Atmospheric Water Vapor > Humidity
  • Land Temperature > Land Surface Temperature
  • Precipitation
  • Precipitation > Precipitation Amount
  • Soils > Soil Moisture/Water Content
  • Soils > Soil Temperature
  • Frozen Ground > Soil Temperature
Spatial Coverage:
  • N: 42.1, S: 42.1, E: -93.85, W: -93.85

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 June 2002 to 31 August 2002
Temporal Resolution: Not specified
Data Format(s):
  • ASCII Text
Version: V1
Data Contributor(s): Thomas Jackson, Michael Cosh

Data Citation

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Jackson, T. 2003. SMEX02 Soil Climate Analysis Network (SCAN) Station 2031, Ames, Iowa, Version 1. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: [Date Accessed].

Back to Top

Collapse All / Open All

Detailed Data Description


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
Background color on
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."

Background color on
File Size

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

Background color on

Combined file size is 385 KB.

Background color on
Spatial Coverage

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

Background color on
Temporal Coverage

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

Temporal Resolution

Measurements are given daily and hourly

Background color on
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:

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
Background color on

Software and Tools

View the data in a Web browser or text editor.

Background color on

References and Related Publications

Contacts and Acknowledgments

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


United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS)

Document Information


9 June 2003

No technical references available for this data set.
No FAQs or How Tos available for this data set.

Access complete Knowledge Base

Questions? Please contact:
NSIDC User Services
Phone: 1 303 492-6199