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Microwave remote sensing of soil moisture content over bare and vegetated fields
Author(s) -
Wang J. R.,
Shiue J. C.,
McMurtrey J. E.
Publication year - 1980
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl007i010p00801
Subject(s) - water content , environmental science , brightness temperature , radiometer , microwave , soil science , remote sensing , vegetation (pathology) , radiative transfer , radiometry , moisture , atmospheric radiative transfer codes , grassland , soil water , atmospheric sciences , geology , meteorology , agronomy , physics , optics , geotechnical engineering , quantum mechanics , medicine , pathology , biology
Remote measurements of soil moisture contents over bare fields and fields covered with orchard grass, corn, and soybean were made during October 1979 with 1.4 GHz and 5 GHz microwave radiometers mounted on a truck. Ground truth of soil moisture content, ambient air and soil temperatures was acquired concurrently with the radiometric measurements. The biomass of the vegetation was sampled about once a week. The measured brightness temperatures over bare fields were compared with those of radiative transfer model calculations using as inputs the acquired soil moisture and temperature data with appropriate values of dielectric constants for soil‐water mixtures. Good agreement was found between the calculated and the measured results over 10°‐70° incident angles. The presence of vegetation was found to reduce the sensitivity of soil moisture sensing. At 1.4 GHz the sensitivity reduction ranged from ∼20% for 10‐cm tall grassland to over 60% for the dense soybean field. At 5 GHz the corresponding reduction in sensitivity ranged from ∼70% to ∼90%.