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Attenuation of soil microwave emissivity by corn and soybeans at 1.4 and 5 GHzTheory and experiments have shown that passive microwave radiometers can be used to measure soil moisture. However, the presence of a vegetative cover alters the measurement that might be obtained under bare conditions. Deterministically accounting for the effect of vegetation and developing algorithms for extracting soil moisture from observations of a vegetable-soil complex present significant obstacles to the practical use of this approach. The presence of a vegetation canopy reduces the sensitivity of passive microwave instruments to soil moisture variations. The reduction in sensitivity, as compared to a bare-soil relationship, increases as microwave frequency increases, implying that the longest wavelength sensors should provide the most information. Sensitivity also decreases as the amount of vegetative wet biomass increases for a given type of vegetation.
Document ID
19910031090
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Jackson, Thomas J.
(USDA, Hydrology Laboratory, Beltsville MD, United States)
O'Neill, Peggy E.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1989
Subject Category
Earth Resources And Remote Sensing
Accession Number
91A15713
Distribution Limits
Public
Copyright
Other

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