The Polarimetric Scanning Radiometer (PSR) is an airborne microwave imaging radiometer developed and operated by the National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory. This data set includes brightness temperature data for the C-band and X-band. Measurements were taken 25 June through 17 July 2003 in regional areas of Alabama, Georgia, and Oklahoma, USA and the Little Washita Watershed of Oklahoma, USA during the Soil Moisture Experiment 2003 (SMEX03). The PSR/CX band radiometer is similar to the low-frequency channels of the Advanced Microwave Scanning Radiometers (AMSR-E) on the NASA Aqua satellite. The radiometer operates at vertical (V) and horizontal (H) polarizations. Data are provided in ASCII text files and available from 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.
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., R. Bindlish, A. J. Gasiewski, M. Klein, and B. Stankov. 2007. SMEX03 Aircraft Polarimetric Scanning Radiometer (PSR) Data. [indicate subset used]. Boulder, Colorado USA: NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: 10.5067/MK0BQ0W0O973.
|Data format||ASCII text files|
|Spatial coverage and resolution||
Southernmost Latitude: 34.66º N
Northernmost Latitude: 35.19º N
Westernmost Longitude: 87.09º W
Easternmost Longitude: 85.77º W
Southernmost Latitude: 30.96º N
Northernmost Latitude: 31.89º N
Westernmost Longitude: 83.97º W
Easternmost Longitude: 83.36º W
Southernmost Latitude: 34.42º N
Northernmost Latitude: 36.87º N
Westernmost Longitude: 98.34º W
Easternmost Longitude: 97.42º W
|Temporal coverage and resolution||25 June through 17 July 2003|
|File naming convention||Processed data: SSMDD.txt
Raw data: PPPPMDD##.txt
|File size||File sizes range 107 KB to 4.6 MB|
|Procedures for obtaining data||Data are available via FTP.|
Thomas J. Jackson and Rajat Bindlish
US Department of Agriculture (USDA) - Agricultural Research Service (ARS)
Hydrology and Remote Sensing Lab
Beltsville, MD 20705
Albin J. Gasiewski and Marian Klein
University of Colorado at Boulder - National Oceanic & Atmospheric Administration (NOAA)
Center for Environmental Technology (CET)
Boulder, CO 80305
National Oceanic & Atmospheric Administration (NOAA)
Environment Technology Laboratory (ETL)
Boulder, CO 80305
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
Data are provided as ASCII text files. Table 1 describes the format of the processed data files. Table 2 describes the format of the raw data files.
|Column 1||UTM - Northing|
|Column 2||UTM - Easting|
|Column 3||C-band (7.32 GHz) V|
|Column 4||C-band (7.32 GHz) H|
|Column 5||X-band (10.7 GHz) H|
|Column 1||UTM - Northing|
|Column 2||UTM - Easting|
|Column 5||C-band (7.32 GHz) V|
|Column 6||C-band (7.32 GHz) H|
|Column 7||X-band (10.7 GHz) H|
Data are organized in directories based on study area (AL = Alabama, GA = Georgia, LW = Little Washita, ON = Oklahoma North, OS = Oklahoma South). Within each study area directory are a processed and a raw directory. The processed directories contain gridded brightness temperatures. The raw directories contain the raw brightness temperature observations.
The processed files are named according to the following convention.
|SS||= study area (AL=Alabama, GA=Georgia,LW = Little Washita, ON = Oklahoma North, OS = Oklahoma South)|
The raw files are named according to the following convention.
|PPPP||= processing level (L23i)|
|##||= 2 digit number|
File sizes range from 107 KB to 4.6 MB.
Table 3 lists the spatial coverage of each study area. All locations are UTM zone 14 in NAD83/WGS84 datum.
Alabama Regional Area
Georgia Regional Area
Oklahoma Little Washita Watershed
Oklahoma North Regional Area
Oklahoma South Regional Area
Measurements were collected from 25 June through 17 July 2003 in the study areas. Table 4 lists the collection dates for each area.
|Alabama||25, 27, 29, 30 June
|Georgia||25, 29, 30 June|
|Little Washita||3, 5, 7, 10, 17 July|
|Oklahoma North||3, 5, 7, 10, 11, 12, 13, 14, 15, 17 July|
|Oklahoma South||2, 3, 5, 7, 10, 12, 13, 14, 15, 17 July|
Data collection was timed to coincide with a 3 hour window centered on the Aqua equatorial overpass time of 13:30 LST.
Parameters in this data set are brightness temperatures for the C-band (7.32 GHz) V and H and for the X-band (10.7 GHz) H. Observations at the X-band (10.7 GHz) V are not available due to calibration problems.
The following sample shows the first 5 rows from the AL processed file AL625.txt:
The following sample shows the first 5 rows from the ON raw file L23i70309.txt:
Data are available via FTP.
Total volume of the data is approximately 530 MB.
The PSR/CX band instrument was integrated onto the NASA Wallops Flight Facility (WFF) P3B aircraft in the aft portion of the bomb bay and flown over the regional and watershed areas. The PSR scans at a constant incidence angle of 55° with a swath width of 19 km. The flight line has a spacing of 11 km and a length of 80 km. Four regional flight lines at an altitude of ~8000 m were flown over AL, GA, ON, and OS. Two watershed flight lines at an altitude of ~3000 m covered the LW watershed area. The P3 was deployed out of Huntsville, Alabama from 25 June to 2 July 2003 and out of Oklahoma City, Oklahoma from 2 July to 17 July 2003.
PSR/CX raw data goes through several processing steps. Quality control, time synchronization, calibration, rasterization, and georegistration are considered preprocessing. Following this are removing of Radio Frequency Interference (RFI), adjusting for temporal variations inherent in mapping a large region with an aircraft sensor, and resampling the data to a standard grid that facilitates multitemporal analysis and integration with ancillary data bases for algorithm applications (Jackson et al. 2005).
The PSR/CX data consist of beam positions for sequential conical scans. Each beam position footprint is about 3 km in size. Due to sampling rates, the spacing between these footprints is 300 m, which results in over sampling. In addition, each line of data overlaps other lines. In order to produce a data set that can be integrated in further analyses, all the footprint data were used in a kriging-based grid resampling procedure. The output grid selected was 800 m, which matched the nominal field scale in the regions as well as the resolution of other databases. Each channel of data was resampled independently (Jackson et al. 2005).
Jackson, T. J., R. Bindlish, A. J. Gasiewski, B. Stankov, M. Klein, E. G. Njoku, D. Bosch, T. L. Coleman, C. Laymon, and P. Starks. 2005. Polarimetric Scanning Radiometer C and X-band microwave observations during SMEX03. IEEE Transactions on Geosciences and Remote Sensing 43:2418-2430.
Please see the USDA SMEX03 Web site for in depth information on the science mission and goal of the SMEX project.
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|
|NAD83||North American Datum of 1983|
|NASA||National Aeronautics and Space Administration|
|NOAA||National Oceanic and Atmospheric Administration|
|NSIDC||National Snow and Ice Data Center|
|PSR||Polarimetric Scanning Radiometer|
|RFI||Radio Frequency Interference|
|SMEX||Soil Moisture Experiment|
|URL||Uniform Resource Locator|
|UTM||Universal Transverse Mercator|
|WFF||Wallops Flight Facility|
|WGS84||World Geodetic System 1984|