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A Comparison of Ground-Based and Satellite-Borne Microwave Radiometric Observations in the Great Plains

Authors :
Judge, Jasmeet
Galantowicz, John F.
England, Anthony W.
Source :
IEEE Transactions on Geoscience and Remote Sensing. August, 2001, Vol. 39 Issue 8, 1686
Publication Year :
2001

Abstract

We compare ground-based and the special sensor microwave/imager (SSM/I) brightness temperatures at 19 and 37 GHz in the Northern and the Southern Great Plains. The comparison was conducted to examine season-related differences in plot-scale and satellite footprint-scale brightness temperatures at these frequencies. The ground-based observations were from the three Radiobrightness Energy Balance Experiments (REBEXs), viz., REBEX-1, REBEX-4, and REBEX-5. REBEX-1 and REBEX-4 were conducted near Sioux Falls, SD, in fall and winter 1992--93, and in summer 1996, respectively. REBEX-5 was conducted near Lamont, OK, during summer 1997 as part of the Southern Great Plains Hydrology Experiment-1997 (SGP'97). The instantaneous fields of view (FOV) of the ground-based radiometers were only a few meters compared to those of the SSM/I, which were several tens of kilometers. The REBEX and the SSM/I brightness temperatures are moderately correlated at both the 19 and 37 GHz. They match well during winter when there was uniform snow cover over the SSM/I footprint. During spring, summer, and fall, REBEX brightness temperatures at the grass-site were on average 18 K higher than the SSM/I brightness temperatures because the SSM/I footprint included nearby agricultural fields in summer and predominantly bare soil in fall and spring. During summer, REBEX-4 brightness temperatures at the bare soil site were on average 10 K cooler than the SSM/I brightness temperatures. In effect, the REBEX grass and bare soil brightness temperatures bracket the SSM/I observations with the SSM/I brightness temperatures lying closest to those of the bare soil. Index Terms--Microwave radiometry, radiobrightness, scaling, soil moisture.

Details

ISSN :
01962892
Volume :
39
Issue :
8
Database :
Gale General OneFile
Journal :
IEEE Transactions on Geoscience and Remote Sensing
Publication Type :
Academic Journal
Accession number :
edsgcl.78258673