SMEX03 Soil Climate Analysis Network (SCAN): Georgia

Summary

This data set contains measurements taken during the Soil Moisture Experiment 2003 (SMEX03) from 1 June 2003 to 31 July 2003 from sensors at the Soil Climate Analysis Network (SCAN) station located in Little River, GA, USA. Parameters measured include precipitation, air temperature, solar radiation, wind speed, wind direction, relative humidity, soil moisture, soil temperature, and soil salinity. Data are provided as tab-delimited ASCII text 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.

Citing These Data

Bosch, David D. and Garry Schaefer. 2006. SMEX03 Soil Climate Analysis Network (SCAN): Georgia. Boulder, CO USA: National Snow and Ice Data Center. Digital media.

Overview Table

Category	Description
Data format	Tab-delimited ASCII text.
Spatial coverage and resolution	Southernmost Latitude: 31.51º N Northernmost Latitude: 31.51º N Westernmost Longitude: 83.56º W Easternmost Longitude: 83.56º W
Temporal coverage and resolution	Data were collected hourly from 1 June 2003 through 31 July 2003. In addition, a daily file is available.
Tools for accessing data	View data using a browser or text editor.
File naming convention	Scan2027_Hourly.txt Scan2027_Daily.txt
File sizes	File sizes are 2.7 KB and 265 KB.
Parameters	Precipitation, air temperature, solar radiation, wind speed, wind direction, relative humidity, soil moisture, soil temperature, and soil salinity.
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. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments

Investigators

David D. Bosch
USDA Agricultural Research Service (ARS) Southeast Watershed Research Laboratory
Tifton, Georgia
USA

Garry Schaefer
USDA Natural Resources Conservation Service (NRCS)
Portland, Oregon
USA

Technical Contact

Acknowledgements

We would like to acknowledge the USDA Natural Resources Conservation Service (NRCS) http://www.nrcs.usda.gov/.

2. Detailed Data Description

Format

Data are provided as tab-delimited ASCII. Two types of files are available: hourly and daily. Table 1 displays the station identification number, the station name, and the station location of the SCAN station included in this data set. Please visit http://www.wcc.nrcs.usda.gov/scan for more information on SCAN stations.

Table 1: SMEX03 Georgia SCAN Station Specifications

SCAN Station No.	Station Name	Location	Coordinates (Latitude and Longitude)
2027	Little River	Tift County, GA	31.51º N, 83.56º W

Table 2 lists the column headings and definitions in the hourly file, and Table 3 lists the column headings and definitions in the daily file. Please visit http://www.wcc.nrcs.usda.gov/scan/sensors.html for more information on these parameters.

Note: In both files, missing data values are denoted by either -99.9 or -99.99.

Table 2: Column Headings and Definitions for the Hourly File

Column	Description	Units
ATHA6	Average air temperature	degrees Celsius
ATHC6	Current air temperature	degrees Celsius
ATHN6	Minimum air temperature	degrees Celsius
ATHX6	Maximum air temperature	degrees Celsius
c1rdc	Current soil dielectric constant an two inch depth	no units
c1sal	Current soil salinity at two inch depth	grams per liter
c1smv	Current soil moisture at two inch depth	percent water by volume
c1tmp	Current soil temperature at two inch depth	degrees Celsius
c2rdc	Current soil real dielectric constant at four inch depth	no units
c2sal	Current soil salinity at four inch depth	grams per liter
c2smv	Current soil moisture at four inch depth	percent water by volume
c2tmp	Current soil temperature at four inch depth	degrees Celsius
c3rdc	Current soil real dielectric constant at eight inch depth	no units
c3sal	Current soil salinity at eight inch depth	grams per liter
c3smv	Current soil moisture at eight inch depth	percent water by volume
c3tmp	Current soil temperature at eight inch depth	degrees Celsius
c4rdc	Current real dielectric constant at 20 inch depth	no units
c4sal	Current soil salinity at 20 inch depth	grams per liter
c4smv	Current soil moisture at 20 inch depth	percent water by volume
c4tmp	Current soil temperature at 20 inch depth	degrees Celsius
c5rdc	Current soil real dielectric constant at 40 inch depth	no units
c5sal	Current soil salinity at 40 inch depth	grams per liter
c5smv	Current soil moisture at 40 inch depth	percent water by volume
c5tmp	Current soil temperature at 40 inch depth	degrees Celsius
Day	Day of measurement
Hour	Hour of measurement	Eastern Standard Time (EST)
Month	Month of measurement
PCPIN	Cumulative total precipitation	inches
RH1C1	Current relative humidity	percent
RH1N1	Minimum relative humidity	percent
RH1X1	Maximum relative humidity	percent
SRHA	Average solar radiation	watts per square meter
WDHA	Average wind direction	degrees from true north
WSPHA	Average wind speed	meters per hour
WSPHX	Maximum wind speed	meters per hour
Year	Year of measurement

Table 3: Column Headings and Definitions for the Daily File

Column	Description	Units
ATA6	Average air temperature	degrees Celsius
ATN6	Minimum air temperature	degrees Celsius
ATX6	Maximum air temperature	degrees Celsius
Date	Date of measurement
ENHUM	Average relative humidity in enclosure	percent
Month	Month of measurement
WDDA	Average wind direction	degrees from true north
WSPDA	Average wind speed	meters per hour
Year	Year of measurement

File and Directory Structure

Table 4 lists the files contained in this data set.

Table 4: Files Contained In This Data Set

File Name	Description	File Size
Scan2027_Hourly.txt	This is a tab-delimited ASCII text file of the data in hourly measurements.	265 KB
Scan2027_Daily.txt	This is a tab-delimited ASCII text file of the data in daily averages.	2.7 KB

Spatial Coverage

Southernmost Latitude: 31.51º N
Northernmost Latitude: 31.51º N
Westernmost Longitude: 83.56º W
Easternmost Longitude: 83.56º W

Temporal Coverage

Data were collected between 1 June 2003 and 31 July 2003.

Temporal Resolution

Hourly measurements are averages computed as the sum of all measurements taken during an hour divided by the number of measurements taken during that hour. Daily values are averages computed as the sum of all hourly measurements taken during a day divided by the number of hourly measurements taken during that day.

Parameters

Parameter Descriptions

Table 5 describes the parameters in the hourly file.

Table 5: Parameters in Hourly File

Parameter	Description
Precipitation	Current value
Air temperature	Maximum, minimum, average, and current values
Relative humidity	Maximum, minimum, average, and current values
Wind speed	Maximum and average values
Wind direction	Averages
Solar radiation	Averages
Soil salinity	Current values at 2, 4, 8, 20, and 40 inch ground depths
Soil temperature	Current values at 2, 4, 8, 20, and 40 inch ground depths
Soil moisture as percent water by volume	Current values at 2, 4, 8, 20, and 40 inch ground depths
Soil r eal dielectric constant	Current values at 2, 4, 8, 20, and 40 inch ground depths

Table 6 describes the parameters in the daily file.

Table 6: Parameters in Daily File

Parameter	Description
Temperature	Daily maximum, minimum, and average values
Wind speed	Daily average
Wind direction	Daily average
Enclosure relative humidity	Current value

Sample Data Records

The following sample shows the first four records from the hourly file Scan2027_Hourly.txt. The first six and last six columns are displayed.

Year	Month	Day	Hour	PCPIN	ATHC6	...	c4sal	c4rdc	c5smv	c5tmp	c5sal	c5rdc
2003	6	1	0	33.29	25.81	...	0.1	7.1	26.6	23.92	0.13	14.81
2003	6	1	1	33.29	25.62	...	0.1	7.1	26.36	23.92	0.14	14.66
2003	6	1	2	33.29	25.15	...	0.09	7.24	26.36	23.92	0.14	14.66
2003	6	1	3	33.29	24.22	...	0.1	7.15	26.6	23.92	0.13	14.81

The following sample shows the first four records from the daily file Scan2027_Daily.txt. All nine columns are displayed.

Year	Month	Date	ATX6	ATN6	ATA6	WSPDA	WDDA	ENHUM
2003	6	1	33.14	18.44	26.67	5.1	233.85	59.37
2003	6	2	30.6	17.97	25.37	4.98	326.59	62.1
2003	6	3	32.19	15.73	24.86	2.64	101.36	61
2003	6	4	26.08	20.76	23.54	4.72	180.04	65.4

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The total data set volume is 268 KB.

Software and Tools

Data files are viewable with a browser or text editor.

Related Data Collections

Please visit the SMEX03 Web site for other data sets that are related to the SMEX03 experiment.

4. Data Acquisition and Processing

Sensor or Instrument Description

Each SCAN station houses multiple sensors that automatically record data. These data are uploaded at regular intervals to the NRCS Data Processing Center, Portland, Oregon, USA. Table 7 describes the sensors housed in the SCAN station and the parameters they measure.

Table 7: SCAN Station Sensors and Measured Parameters

Sensor Name	Parameters Measured	Method of Measurement
Tipping bucket rain gauge	Precipitation	Cumulative inches of precipitation are recorded.
Shielded thermistor	Air temperature	The instrument is raised six feet from the surface. Current temperature and the previous hour's maximum, minimum, and average temperatures are recorded.
Soil sensors	Soil moisture, soil temperature, soil salinity	Sensors are located at depths of 2, 4, 8, 20, and 40 inches below the surface. Current soil moisture, temperature, and salinity are recorded.
Thin film capacitance-type sensor	Relative humidity	The sensor is raised six feet from the surface. Current relative humidity and the previous hour's maximum and minimum relative humidities are recorded.
Anemometer	Wind speed, wind direction	The instrument is raised 10 feet from the surface. Hourly averages are computed from continuous measurements.
Pyranometer	Solar radiation	The sensor is raised 10 feet from the surface. Hourly average readings of total incoming solar energy are computed.

5. References and Related Publications

Please visit the SMEX03 Web site for more information, and see the NSIDC SMEX Web site to access data.

6. Document Information

Acronyms and Abbreviations

The following acronyms and abbreviations are used in this document.

AMSR-E	Advanced Microwave Scanning Radiometer - Earth Observing System
ASCII	American Standard Code for Information Interchange
FTP	File Transfer Protocol
NASA	National Aeronautics and Space Administration
NSIDC	National Snow and Ice Data Center
NRCS	Natural Resources Conservation Service
SCAN	Soil Climate Analysis Network
SMEX03	Soil Moisture Experiment 2003
URL	Uniform Resource Locator
USDA	United States Department of Agriculture

Document Creation Date

June 2006

Document URL

http://nsidc.org/data/docs/daac/nsidc0294_smex03_scan_ga.gd.html