Electronically Scanned Thinned Array Radiometer (ESTAR) Retrieved Soil Moisture:
J. Jacobs

Overview

The electronically scanned thin array radiometer (ESTAR) has provided L-band passive microwave measurements during field experiments like Walnut Gulch, Washita'92 and SGP97 in the Southern Great Plains and other regions of the United States. (refer to SGP99 Electronically Scanned Thinned Array Radiometer (ESTAR) Brightness Temperature Data for more sensor information). This airborne L-band passive microwave remote sensing investigation is aimed to support algorithm development.

The ESTAR instrument was flown on a P-3B aircraft operated by NASA Wallops Flight Facility. Flights were conducted at an altitude of 7.6 km. As in the case of SGP97 the planned 4 parallel lines were modified to compensate for strong RFI in the vicinity of Oklahoma City. During the SGP period, six good days of data were collected by ESTAR-July 8, 9, 14, 15, 19 and 20. More details about the SGP99 ESTAR dataset are available in Le Vine et al. (2001). The soil conditions during SGP99 were extremely dry with mean soil moisture content less than 15% for the majority of the experiment. The only significant rainfall event during the study period occurred on the evening of July 9th and the morning of July 10th.

The soil moisture retrieval algorithm applied here uses ESTAR brightness temperatures along with surface temperature measured on the ground and land surface characteristics of roughness and vegetation. This retrieval algorithm is identical to that from previous ESTAR studies and is described by Jackson et al. (1993,1999).

The files and data format

All files are contained in five subdirectories of the path and are described in the table below. For brightness temperature, soil moisture, and soil temperature MMDD refers to the month and day of the observations.

All data are in ascii flat files, consisting of 218 pixels wide by 379 rows with no headers. Following shows the Format and Georeferencing for all the files.

Data access and contact

FTP Site

The ESTAR data files from SGP99 reside on DAAC anonymous FTP. You may access them from this document

ESTAR Data Online (ASCII)

Or directly via FTP at

ftp disc.gsfc.nasa.gov
login: anonymous
password: < your email address >
cd /data/sgp99/air_remote_sensing/estar/estar_retrieved_sm/estar_jacobs

Points of Contact

Jennifer Jacobs
Department of Civil Engineering
University of New Hampshire
Durham, NH 03824
Phone: 603 862-0635
Fax: 603 862-3957
Email: Jennifer.Jacobs@unh.edu

For Information about SGP99 data at the Goddard DAAC, contact

Hydrology Data Support Team
Goddard DAAC, Code 902
NASA Goddard Space Flight Center
Greenbelt, MD 20771
phone: 301-614-5165
fax: 301-614-5268
Email: hydrology@eosdata.gsfc.nasa.gov

References

Guha, A., J.M. Jacobs, T.J. Jackson, M. Cosh, E. Hsu, and J. Judge. 2003. Soil moisture mapping using ESTAR from the Southern Great Plains experiment (SGP99). IEEE Transactions on Geoscience and Remote Sensing Letters. 41(10), 2392-2397.

Le Vine, D.M., Jackson, T. J., Swift, C. T., Haken, M., and Bidwell, S. ESTAR measurements during the Southern Great Plains experiments. IEEE Trans. on Geoscience and Remote Sensing, 39:1680-1685. 2001.

Jackson, T.J., Le Vine, D.M., Griffis, A., Goodrich, D.C., Schmugge, T.J., Swift, C., and O'Neill, P.E., 1993.  Soil Moisture and Rainfall Estimation over a Semiarid Environment with the ESTAR Microwave Radiometer.  IEEE Tran Geosci Remote Sensing, GE-31, pp 836-841.

Jackson, T. J., Le Vine, D. M., Hsu, A. Y., Oldak, A., Starks, P. J., Swift, C. T., Isham, J. D., and Haken, M. Soil moisture mapping at regional scales using microwave radiometry: the Southern Great Plains hydrology experiment. IEEE Trans. on Geoscience and Remote Sensing, 37(5): 2136-2151. 1999.