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Dual frequency microwave radiometer measurements of soil moisture for bare and vegetated rough surfacesControlled ground-based passive microwave radiometric measurements on soil moisture were conducted to determine the effects of terrain surface roughness and vegetation on microwave emission. Theoretical predictions were compared with the experimental results and with some recent airborne radiometric measurements. The relationship of soil moisture to the permittivity for the soil was obtained in the laboratory. A dual frequency radiometer, 1.41356 GHz and 10.69 GHz, took measurements at angles between 0 and 50 degrees from an altitude of about fifty feet. Distinct surface roughnesses were studied. With the roughness undisturbed, oats were later planted and vegetated and bare field measurements were compared. The 1.4 GHz radiometer was less affected than the 10.6 GHz radiometer, which under vegetated conditions was incapable of detecting soil moisture. The bare surface theoretical model was inadequate, although the vegetation model appeared to be valid. Moisture parameters to correlate apparent temperature with soil moisture were compared.
Document ID
19740026660
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Lee, S. L. (Texas A&M Univ. College Station, TX, United States)
Date Acquired
September 3, 2013
Publication Date
August 1, 1974
Subject Category
Geophysics
Report/Patent Number
NASA-CR-140515
RSC-56
Accession Number
74N34773
Funding Number(s)
CONTRACT_GRANT: NGL-44-001-001
CONTRACT_GRANT: NAS9-13904
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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