SMEX03 Soil Climate Analysis Network (SCAN): Alabama

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 10 Soil Climate Analysis Network (SCAN) stations located in northern Alabama and southern Tennessee, USA. Parameters measured include precipitation, air temperature, solar radiation, wind speed, wind direction, relative humidity, soil moisture, soil temperature, soil salinity, and soil dielectric constant. 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

We kindly request that you cite the use of this data set in a publication using the following citation. For more information, see our Use and Copyright Web page.

Jackson, T., M. Cosh, T. Coleman, C. Laymon, and W. Crosson. 2006. SMEX03 Soil Climate Analysis Network (SCAN): Alabama. [indicate subset used]. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.

Overview Table

Category Description
Data format Tab-delimited ASCII text.
Spatial coverage and resolution

Southernmost Latitude: 34.43º N
Northernmost Latitude: 35.13º N
Westernmost Longitude: 87.00º W
Easternmost Longitude: 86.10º W

Temporal coverage and resolution Data were collected hourly from 1 June 2003 through 31 July 2003. In addition, daily files are available.
Tools for accessing data View data using a browser or text editor.
File naming convention SCANxxxx_Hourly.txt
SCANxxxx_Daily.txt
File sizes File sizes are: 3.1 KB, 5.0 KB, 273 KB, and 389 KB.
Parameters Precipitation, air temperature, solar radiation, wind speed, wind direction, relative humidity, soil moisture, soil temperature, soil salinity, and soil dielectric constant.
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

Thomas J. Jackson
USDA Agricultural Research Service (ARS) Hydrology and Remote Sensing Laboratory
Beltsville, Maryland
USA

Michael H. Cosh
USDA ARS Hydrology and Remote Sensing Laboratory
Beltsville, Maryland
USA

Tommy Coleman
Alabama A&M University
Huntsville, Alabama
USA

Charles Laymon
Universities Space Research Association, Global Hydrology and Climate Center
NASA Marshall Space Flight Center
Huntsville, Alabama
USA

William Crosson
Universities Space Research Association, Global Hydrology and Climate Center
NASA Marshall Space Flight Center
Huntsville, Alabama
USA

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

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 text. Two types of files are available for each station: hourly and daily. Table 1 displays the station identification number, the station name, and the station location for the SCAN stations whose data are part of this data set. More information on SCAN stations is posted at http://www.wcc.nrcs.usda.gov/scan.

Table 1: SMEX03 Alabama SCAN Stations
SCAN Station No. Station Name Location Coordinates (Latitude and Longitude)
2053
WTARS
Madison County, AL
34.90º N, 86.53º W
2054
Hytop
Jackson County, AL
34.87º N, 86.10º W
2055
Hodges
Marshall County, AL
34.45º N, 86.15º W
2056
Stanley Farm
Morgan County, AL
34.43º N, 86.68º W
2057
AAMU
Madison County, AL
34.78º N, 86.55º W
2058
Hartselle USDA
Morgan County, AL
34.43º N, 87.00º W
2059
Newby Farm
Limestone County, AL
34.85º N, 86.88º W
2075
McAlister Farm
Lincoln County, TN
35.07º N, 86.58º W
2076
Allen Farms
Giles County, TN
35.07º N, 86.90º W
2077
Eastview Farm
Franklin County, TN
35.13º N, 86.18º W


Table 2 lists the column headings and definitions in the hourly files, and Table 3 lists the column headings and definitions in the daily files. More information on these parameters can be found at http://www.wcc.nrcs.usda.gov/scan/sensors.html.

Note 1: In both files, missing data values are denoted by either -99.9 or -99.99.

Note 2: Not all parameters listed are measured at every station.

Table 2: Column Headings and Definitions for the Hourly Files
Column
Description
Units
SCAN Station No.
2053 2054 2055 2056 2057 2058 2059 2075 2076 2077
#
Number of measurements
no units
x
x
x
x
x
x
x
x
x
x
ATEA
Average air temperature, sampled at 10 minute intervals
degrees Celsius
 
 
 
 
 
 
 
x
x
x
ATEC
Current air temperature, sampled at 10 minute intervals
degrees Celsius
 
 
 
 
 
 
 
x
x
x
ATEN
Minimum air temperature, sampled at 10 minute intervals
degrees Celsius
 
 
 
 
 
 
 
x
x
x
ATEX
Maximum air temperature, sampled at 10 minute intervals
degrees Celsius
 
 
 
 
 
 
 
x
x
x
ATHA6
Average air temperature, hourly
degrees Celsius
x
x
x
x
x
x
x
 
 
 
ATHC6
Current air temperature, hourly
degrees Celsius
x
x
x
x
x
x
x
 
 
 
ATHN6
Minimum air temperature, hourly
degrees Celsius
x
x
x
x
x
x
x
 
 
 
ATHX6
Maximum air temperature, hourly
degrees Celsius
x
x
x
x
x
x
x
 
 
 
BAT1
System battery
volts
x
x
x
x
x
x
x
 
 
 
BATCR
Data logger battery
volts
 
 
 
 
 
 
 
x
x
x
BPC
Current barometric pressure
inches Hg
 
 
 
 
 
 
 
x
x
x
BPHGC
Current barometric pressure Hg (Mercury)
inches Hg
x
x
 
 
 
 
 
 
 
 
c1rdc
Real dielectric constant, 2-inch depth
no units
x
x
x
x
x
x
x
x
x
x
c1sal
Soil salinity, 2-inch depth
grams per liter
x
x
x
x
x
x
x
x
x
x
c1smv
Percent water by volume, 2-inch depth
percent
x
x
x
x
x
x
x
x
x
x
c1tmp
Soil temperature, 2-inch depth
degrees Celsius
x
x
x
x
x
x
x
x
x
x
c2rdc
Real dielectric constant, 4-inch depth
no units
x
x
x
x
x
x
x
x
x
x
c2sal
Soil salinity, 4-inch depth
grams per liter
x
x
x
x
x
x
x
x
x
x
c2smv
Percent water by volume, four-inch depth
percent
x
x
x
x
x
x
x
x
x
x
c2tmp
Soil temperature, 4-inch depth
degrees Celsius
x
x
x
x
x
x
x
x
x
x
c3rdc
Real dielectric constant, 8-inch depth
no units
x
x
x
x
x
x
x
x
x
x
c3sal
Soil salinity, 8-inch depth
grams per liter
x
x
x
x
x
x
x
x
x
x
c3smv
Percent water by volume, 8-inch depth
percent
x
x
x
x
x
x
x
x
x
x
c3tmp
Soil temperature, 8-inch depth
degrees Celsius
x
x
x
x
x
x
x
x
x
x
c4rdc
Real dielectric constant, 20-inch depth
no units
x
x
x
x
x
x
x
x
x
x
c4sal
Soil salinity, 20-inch depth
grams per liter
x
x
x
x
x
x
x
x
x
x
c4smv
Percent water by volume, 20-inch depth
percent
x
x
x
x
x
x
x
x
x
x
c4tmp
Soil temperature, 20-inch depth
degrees Celsius
x
x
x
x
x
x
x
x
x
x
c5rdc
Real dielectric constant, 40-inch depth
No units
x
x
x
x
x
x
x
x
x
x
c5sal
Soil salinity, 40-inch depth
grams per liter
x
x
x
x
x
x
x
x
x
x
c5smv
Percent water by volume, 40-inch depth
percent
x
x
x
x
x
x
x
x
x
x
c5tmp
Soil temperature, 40-inch depth
degrees Celsius
x
x
x
x
x
x
x
x
x
x
Date
Date of measurement
 
x
x
x
x
x
x
x
x
x
x
HFT1A
Average heat flux
watts per square meter
 
 
x
x
x
x
x
 
 
 
HFT2A
Average heat flux
watts per square meter
 
 
x
x
x
x
x
 
 
 
HFT3A
Average heat flux
watts per square meter
 
 
x
x
x
x
x
 
 
 
Hour
Hour of measurement
Central Standard Time (CST)
x
x
x
x
x
x
x
x
x
x
ML2A1
Average ML2 soil moisture theta probe #1
percent
 
 
x
x
x
x
x
 
 
 
ML2A2
Average ML2 soil moisture theta probe #2
percent
 
 
x
x
x
x
x
 
 
 
ML2V1
Average ML2 soil moisture theta probe #1
volt
 
 
x
x
x
x
x
 
 
 
ML2V2
Average ML2 soil moisture theta probe #2
volt
 
 
x
x
x
x
x
 
 
 
Month
Month of measurement
 
x
x
x
x
x
x
x
x
x
x
PCCTB
Current precipitation-tipping bucket,USVI
inches
 
 
 
 
 
 
 
 
 
x
PCPIN
Current global precipitation sensor
inches
x
x
x
x
x
x
x
 
 
 
PPCT1
No description available
no units given
 
 
 
 
 
 
 
 
x
 
PPCTB
No description available
no units given
 
 
 
 
 
 
 
x
 
 
RH1C1
Current relative humidity-SM/ST, previous hour
percent
x
x
x
x
x
x
x
 
 
 
RH1N1
Minimum relative humidity-SM/ST, previous hour
percent
x
x
x
x
x
x
x
 
 
 
RH1X1
Maximum relative humidity-SM/ST, previous hour
percent
x
x
x
x
x
x
x
 
 
 
RHC
Current relative humidity
percent
 
 
 
 
 
 
 
x
x
x
RHN
Minimum relative humidity
percent
 
 
 
 
 
 
 
x
x
x
RHX
Maximum relative humidity
percent
 
 
 
 
 
 
 
x
x
x
SLRHA
Average hourly solar radiation
watts per square meter
 
 
x
x
x
x
x
 
 
 
SOLAR
Current solar radiation
watts per square meter
 
 
 
 
 
 
 
x
x
x
SRHA
Average hourly solar radiation
watts per square meter
x
x
 
 
 
 
 
 
 
 
STM1A
Average TM10 soil temperature, probe #1
degrees Celsius
 
 
x
x
x
x
x
 
 
 
STM2A
Average TM10 soil temperature, probe #2
degrees Celsius
 
 
x
x
x
x
x
 
 
 
STM3A
Average TM10 soil temperature, probe #3
degrees Celsius
 
 
x
x
x
x
x
 
 
 
WDHA
Average wind direction, hourly
degrees from true north
x
x
 
 
 
 
 
 
 
 
WDUVM
Unit vector mean wind direction
degrees
 
 
x
x
x
x
x
 
 
 
WNDDA
Average vector wind direction
meters per hour
 
 
 
 
 
 
 
x
x
x
WNDSA
Average wind speed, previous hour
meters per hour
 
 
 
 
 
 
 
x
x
x
WSHX
Maximum wind speed
miles per hour
 
 
 
 
 
 
 
x
x
x
WSPHA
Average wind speed hourly
meters per hour
x
x
x
x
x
x
x
 
 
 
WSPHX
Maximum wind speed, hourly
meters per hour
x
x
x
x
x
x
x
 
 
 


Table 3: Column Headings and Definitions for the Daily Files
Column
Description
Units
SCAN Station No.
2053 2054 2055 2056 2057 2058 2059 2075 2076 2077
#
Number of measurements no units
x
x
x
x
x
x
x
 
 
x
AT24A
Average air temperature, 24 hours degrees Celsius
 
 
 
 
 
 
 
x
x
x
AT24N
Minimum air temperature, 24 hours degrees Celsius
 
 
 
 
 
 
 
x
x
x
AT24X
Maximum air temperature, 24 hours degrees Celsius
 
 
 
 
 
 
 
x
x
x
ATA6
Average air temperature daily degrees Celsius
x
x
x
x
x
x
x
 
 
 
ATN6
Minimum air temperature daily degrees Celsius
x
x
x
x
x
x
x
 
 
 
ATX6
Maximum air temperature daily degrees Celsius
x
x
x
x
x
x
x
 
 
 
Date
Date of measurement  
x
x
x
x
x
x
x
x
x
x
ENHUM
Current relative humidity in enclosure percent
x
x
 
 
 
 
 
 
 
 
EPCRN
Minimum hourly CR10X Internal Temperature degrees Celsius
 
 
x
x
x
x
x
 
 
 
EPCRX
Maximum hourly CR10X Internal Temperature degrees Celsius
 
 
x
x
x
x
x
 
 
 
Hour
Hour of measurement CST
x
x
x
x
x
x
x
 
 
x
LBAT
Current lithium battery for data logger backup volts
x
x
x
x
x
x
x
x
x
x
Month
Month of measurement  
x
x
x
x
x
x
x
x
x
x
PCPDY

Total precipitation, previous day

inches
 
 
 
 
 
 
 
x
x
x
PCPYR
Total precipitation, year-to-date inches
 
 
 
 
 
 
 
x
x
x
RHENC
Current internal relative humidity percent
 
 
 
 
 
 
 
x
x
x
RHN24
Relative humidity, 24 hour minimum percent
 
 
x
x
x
x
x
 
 
 
RHX24
Relative humidity, 24 hour maximum percent
 
 
x
x
x
x
x
 
 
 
SLRDA
Average solar radiation watts per square meter
 
 
x
x
x
x
x
 
 
 
WD24A
Average wind direction,previous 24 hours degree
 
 
 
 
 
 
 
x
x
x
WDDA
Average wind direction daily degree
x
x
x
x
x
x
x
 
 
 
WS24A
Average wind speed, 24 hours meters per hour
 
 
 
 
 
 
 
x
x
x
WSPDA
Average wind speed daily meters per hour
x
x
x
x
x
x
x
 
 
 

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
SCANxxxx_Hourly.txt These are tab-delimited ASCII text files of the data in hourly measurements, where xxxx is the SCAN station identification number.
273 KB to 389 KB
SCANxxxx_Daily.txt These are tab-delimited ASCII text files of the data in daily averages, where xxxx is the SCAN station identification number.
3.1 KB to 5.0 KB

Spatial Coverage

Southernmost Latitude: 34.43º N
Northernmost Latitude: 35.13º N
Westernmost Longitude: 87.00º W
Easternmost Longitude: 86.10º 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.

Parameter or Variable

Parameter Descriptions

Table 5 describes the parameters in the hourly files.

Table 5: Parameters in Hourly Files
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 temperature Current values at 2, 4, 8, 20, and 40 inch ground depths
Percent water by volume Current values at 2, 4, 8, 20, and 40 inch ground depths
Real dielectric constant Current values at 2, 4, 8, 20, and 40 inch ground depths

Table 6 describes the parameters in the daily files.

Table 6: Parameters in Daily Files
Parameter Description
Temperature Daily maximum, minimum, and average values
Wind speed Daily average
Wind direction Daily average
Battery voltage Current value
Enclosure relative humidity Current value

Sample Data Records

The following sample shows the first four records from the hourly file Scan2057_Hourly.txt. The first six and last six columns are shown.

Year
Month
Date
Hour
#
BAT1
...
STM1A
STM2A
STM3A
HFT1A
HFT2A
HFT3A
3
6
1
0
1
13
...
60.24
60.56
59.32
-10.45
-4.98
-3.42
3
6
1
1
2
12.97
...
60.05
60.44
59.34
-11.62
-6.15
-4.2
3
6
1
2
3
12.95
...
59.8
60.32
59.34
-14.16
-7.91
-5.57
3
6
1
3
4
12.92
...
59.56
60.2
59.39
-17.88
-10.26
-7.33

The following sample shows the first four records from the daily file Scan2057_Daily.txt. The first six and last six columns are shown.

Year
Month
Date
Hour
#
ATX6
...
WDDA
RHX24
RHN24
EPCRX
EPCRN
LBAT
3
6
1
0
1
28.38
...
308.22
77.09
46.3
31.4
18.75
3.18
3
6
2
0
1
24.25
...
37.01
97.07
42.91
28.38
12.6
3.18
3
6
3
0
1
23.96
...
89.14
98.44
50.38
28.18
11.01
3.18
3
6
4
0
1
27.79
...
244.13
96.75
53.92
31.31
18.56
3.17

3. Data Access and Tools

Data Access

Data are available via FTP.

Volume

The total data set volume is 3.4 MB.

Software and Tools

Data files are viewable using 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 each SCAN station and the parameters they measure.

Table 7: SCAN Station Sensors and Measured Parameters
Sensor Name
Parameters Measured
Method of Measurement
Global Precipitation Sensor
Precipitation
Daily 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
Sensors are located at depths of 2, 4, 8, 20, and 40 inches below the surface. Current soil moisture and temperature 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.
Silicon Capacitive Pressure Sensor
Barometric pressure
Hourly barometric pressure is recorded.

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
ARS Agricultural Research Service (ARS)
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/nsidc0293_smex03_scan_al.gd.html