SMEX03 Ancillary Soil Characteristics Data

Summary

The SMEX03 Ancillary Soil Characteristics data set contains data for the regional study areas of Alabama, Georgia, and Oklahoma, USA as part of the 2003 Soil Moisture Experiment (SMEX03). The original data were extracted from a multi-layer soil characteristics database for the conterminous United States and generated using Environmental Systems Research Institute (ESRI) ArcMap software for each regional study area. Parameters for this data set include available water capacity, bulk density, permeability, porosity, rock fragment class, rock fragment volume, percent sand, percent clay, and texture class. The temporal coverage is approximate, as these data are representative of the conditions present in each regional study area during the general timeline of the SMEX03 campaign. The total volume for these data sets is approximately 2.8 gigabytes. Data are provided in ASCII text files 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

The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.

Cosh, Michael H. and Joanna Birch. 2008. SMEX03 Ancillary Soil Characteristics Data. Boulder, Colorado USA: National Snow and Ice Data Center. Digital media.

Overview Table

Category	Description
Data format	ASCII Grid data files
Spatial coverage and resolution	Alabama: Southernmost Latitude: 34.66° N Northernmost Latitude: 35.19° N Westernmost Longitude: 87.77° W Easternmost Longitude: 87.08° W Georgia: Southernmost Latitude: 30.96° N Northernmost Latitude: 31.90° N Westernmost Longitude: 83.97° W Easternmost Longitude: 83.36° W Oklahoma North: Southernmost Latitude: 36.10 ° N Northernmost Latitude: 36.87 ° N Westernmost Longitude: 98.39 ° W Easternmost Longitude: 97.41 ° W Oklahoma South: Southernmost Latitude: 34.44 ° N Northernmost Latitude: 35.42 ° N Westernmost Longitude: 98.04° W Easternmost Longitude: 97.70 ° W
Temporal coverage and resolution	~June - July 2003
Tools for accessing data	No special tools are required to view these data.
File naming conventions	rg_ppd.txt
File size	10 - 26 MB
Parameters	Available Water Capacity Bulk Density Permeability Porosity Rock Fragment Class Rock Fragment Volume Percent Sand Percent Clay Texture Class
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

Investigator(s)

Michael H. Cosh
HydrologyRemote Sensing Laboratory
US Department of Agriculture (USDA) - Agricultural Research Service (ARS)
Bldg. 007, Rm. 104, BARC-West
Beltsville, MD 20705 USA

Joanna Birch
Hydrology/Remote Sensing Laboratory
US Department of Agriculture (USDA) - Agricultural Research Service (ARS)
Bldg. 007, Rm. 104, BARC-West
Beltsville, MD 20705 USA

Technical Contact

Acknowledgements

The investigators thank the Earth System Science Center at Pennsylvania State University for providing the data used in this data set through the Soil Information for Environmental Modeling and Ecosystem Management database.

2. Detailed Data Description

Format

Data are provided in ArcInfo ASCII Grid data files. The first six rows of each file contain header information, while the following rows contain the actual grid data. Refer to Table 2 for clarification of ASCII Grid header variables, or to the Sample Record section of this document to view the sample data record. Missing data are represented by -9999. The image dimensions for each regional study area are described in Table 1.

 

Table 1. Study Area Image Dimensions

Alabama	1920 rows by 4000 columns
Georgia	3432 rows by 1855 columns
Oklahoma	600 rows by 2080 columns

 

Table 2. ArcInfo ASCII Grid Header Values

Variable	Description
ncols	Number of columns in the grid
nrows	Number of rows in the grid
xllcorner	Western edge of the grid
yllcorner	Southern edge of the grid
cellsize	Spatial resolution of the grid
NODATA_value	Refers to value representing missing data, such as -9999

File and Directory Structure

The top directory level contains subdirectories for each SMEX03 study region and the readme.txt file, as shown in Figure 1.

Figure 1. Top Level Directory Structure of SMEX03 Ancillary Data

File Naming Conventions

The soil text files for each data set are named according to the following convention and as described in Table 3:

rg_ppd.txt

Where:

Table 3. Description of File Name Variables

Variable	Description
rg	Regional Study Areas (al: Alabama; ga: Georgia; on: Oklahoma North; os: Oklahoma South)
pp	Parameter Abbreviation Parameter Description awc Available Water Capacity bd Bulk Density poros Porosity perm Permeability sand Sand clay Clay rvol Rock Fragment Volume dtc Dominant Textural Code rfc Rock Fragment Class
d	Depth Code Depth from soil surface 1 0 - 5 cm 2 5 - 10 cm 3 10 - 20 cm 4 20 - 30 cm     Note: Files containing awc data do not include a depth code in the file name as in the file al_awc100.txt, for example, where 100 denotes cm rather than depth code value. There is only one awc file for each regional study area. AWC was computed for the top 100 cm from the surface.
.txt	Indicates that this is a text file.

Example: al_bd1.txt

 

File Size

File sizes for each region are described below:

Alabama

There are 33 ASCII text files containing Alabama soil data that range from 10 to 26 MB each, for a total of approximately 850 MB.

Georgia

There are 32 ASCII text files containing Georgia soil data that range from 10 to 26 MB each, for a total of 680 MB.

Oklahoma

There are 66 ASCII text files containing Oklahoma soil data that range from 10 to 26 MB each, for a total of 1380 MB.

 

Spatial Coverage

This data set covers the regional study areas as referenced by the following:

Alabama

Southernmost Latitude: 34.668845602° N
Northernmost Latitude: 35.194353404° N
Westernmost Longitude: 87.777562595° W
Easternmost Longitude: 87.087325703° W

Georgia

Southernmost Latitude: 30.961064855° N
Northernmost Latitude: 31.903257457° N
Westernmost Longitude: 83.970846870° W
Easternmost Longitude: 83.36425277° W

Oklahoma North

Southernmost Latitude: 36.107428397 ° N
Northernmost Latitude: 36.871048244 ° N
Westernmost Longitude: 98.394729898 ° W
Easternmost Longitude: 97.418165280 ° W

Oklahoma South

Southernmost Latitude: 34.443677450 ° N
Northernmost Latitude: 35.422765186 ° N
Westernmost Longitude: 98.046657639° W
Easternmost Longitude: 97.700276141 ° W

 

Spatial Resolution

The pixel size is 30 m by 30 m.

Projection

The projection is the Universal Transverse Mercator (UTM) with the World Geodetic System 1984 Datum (WGS 84) applied. The UTM zones for each regional study area are listed in Table 4.

Table 4. UTM Zones of Study Areas

Alabama	Zone 16
Georgia	Zone 17
Oklahoma	Zone 14

 

Temporal Coverage

While the United States SMEX03 campaign took place in Alabama, Georgia, and Oklahoma between June 23 and July 18, 2003, these Ancillary Soil Characteristics data are representative of the conditions to be expected in the US regional study areas during the approximate timeline of the SMEX03 campaign.

Parameters or Variables

Parameters for each data set include the following and are further described in Table 5:

• Available Water Capacity
• Bulk Density
• Permeability
• Porosity
• Rock Fragment Class
• Rock Fragment Volume
• Percent Sand
• Percent Clay
• Texture Class

Parameter Range

Parameters and respective parameter ranges for the Alabama, Georgia, and Oklahoma data files are described in Table 5.

Table 5. Parameter Description

Parameters	Values Given As
Available Water Capacity	Volumetric percent, computed for a column length of 100 cm, measured from the surface of the soil
Bulk Density	Mean bulk density (g/cm3) of soil
Permeability	Mean permeability rate (cm/hr) of soil
Porosity	Mean porosity (g/cm3) of soil
Rock Fragment Class	Rock Fragment Class Code Description 0 No Data 1 Bouldery 2 Cobbly 3 Channery 4 Cherty 5 Flaggy 6 Gravelly 7 Rubbly 8 Shaly 9 Stony 10 Slaty 11 Organic Materials 12 Water 13 Bedrock 14 No Rock Fragments 15 Other
Rock Fragment Volume	Percent of rock by volume in soil
Percent Sand	Percent of sand in soil
Percent Clay	Percent of clay in soil
Texture Class	Texture Class Code Description 0 No Data 1 Sand 2 Loamy Sand 3 Sandy Loam 4 Silt Loam 5 Silt 6 Loam 7 Sandy Clay Loam 8 Silty Clay Loam 9 Clay Loam 10 Sandy Clay 11 Silty clay 12 Clay 13 Organic Materials 14 Water 15 Bedrock 16 Other

Sample Data Record

Figure 2 displays a partial sample of the data file al_bd1.txt containing Alabama bulk density data. The first six rows display ArcInfo ASCII Grid header information, while the last six rows contain mean bulk density measurements, of which, only the first thirteen columns are shown in this sample. For clarification of ASCII Grid header variables, refer to Table 2 in the Format section.

Figure 2 . Sample Data Record

ncols			4000
nrows			1920
xllcorner			492000
yllcorner			3837000
cellsize			30
NODATA_value			-9999
1.5	1.5	1.5	1.5	1.5	1.5	1.5	1.5	1.5	1.5	1.5	1.5	1.5	...
1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	...
1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	...
1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	...
1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	...
1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	1.47	...

3. Data Access

Data are available via FTP.

Volume

Total volume is approximately 2.8 GB for all data. Volume by region is approximately:

Alabama: 850 MB

Georgia: 680 MB

Oklahoma: 1380 MB

Software and Tools

No special tools are required to view these data.

Related Data Collections

• AMSR-E Validation Data: Soil Moisture Data Web site: Data sets from SMEX campaigns available at NSIDC.
• AMSR-E/Aqua Data at NSIDC Web site: AMSR-E standard products available at NSIDC.

4. Data Acquisition and Processing

Data Source and Acquisition Methods

Alabama, Georgia, and Oklahoma ancillary soil characteristics data were retrieved from the Soil Information for Environmental Modeling and Ecosystem Management database hosted by the Earth System Science Center at Pennsylvania State University. The data for the regional study areas were retrieved from a multi-layer soil characteristics data set for the conterminous United States, called CONUS-SOIL. The data were then exported with ESRI ArcMap and exported as ASCII Grid data files.

5. References and Related Publicationss

Please visit the USDA SMEX03 Web site for in-depth information on the science mission and goal of the SMEX project.

6. Document Information

Acronyms and Abbreviations

Table 6 lists acronyms and abbreviations used in this document.

Table 6. Acronyms and Abbreviations

AL	Alabama
AMSR-E	Advanced Microwave Scanning Radiometer - Earth Observing System
ASCII	American Standard Code for Information Interchange
AWC	Available Water Capacity
BD	Bulk Density
CONUS-SOIL	Conterminous United States - Soil
DAAC	Distributed Active Archive Center
DTC	Dominant Textural Code
ESRI	Environmental Systems Research Institute
FTP	File Transfer Protocol
GA	Georgia
NASA	National Aeronautics and Space Administration
NSIDC	National Snow and Ice Data Center
OK	Oklahoma
ON	Oklahoma North
OS	Oklahoma South
PERM	Permeability
POROS	Porosity
RFC	Rock Fragment Class
RVOL	Rock Fragment Volume
SMEX03	Soil Moisture Experiment 2003
URL	Uniform Resource Locator
WGS 84	World Geodetic System 1984

Document Creation Date

May 2008

Document URL

http://nsidc.org/data/docs/daac/nsidc0339_smex03_ancillary_soils.gd.html