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Modeling the backscattering and transmission properties of vegetation canopiesExperimental measurements of canopy attenuation at 10.2 GHz (X-band) for canopies of wheat and soybeans, experimental observations of the effect upon the microwave backscattering coefficient (sigma) of free water in a vegetation canopy, and experimental measurements of sigma (10.2 GHz, 50 deg, VV and VH polarization) of 30 agricultural fields over the growing season of each crop are discussed. The measurements of the canopy attenuation through wheat independently determined the attenuation resulting from the wheat heads and that from the stalks. An experiment conducted to simulate the effects of rain or dew on sigma showed that sigma increases by about 3 dB as a result of spraying a vegetation canopy with water. The temporal observations of sigma for the 30 agricultural fields (10 each of wheat, corn, and soybeans) indicated fields of the same crop type exhibits similar temporal patterns. Models previously reported were tested using these multitemporal sigma data, and a new model for each crop type was developed and tested. The new models proved to be superior to the previous ones.
Document ID
19850019009
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Allen, C. T. (Sandia National Lab. Albuquerque, N. Mex., United States)
Ulaby, F. T. (Michigan Univ. Ann Arbor, United States)
Date Acquired
September 5, 2013
Publication Date
February 1, 1984
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
NAS 1.26:171864
RSL-TR-360F
NASA-CR-171864
E85-10099
Accession Number
85N27320
Funding Number(s)
CONTRACT_GRANT: NAS9-15421
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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