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Microwave brightness spectra of layered media

A. W. England and G. R. Johnson
Microwave brightness spectra of layered media
Geophysics (April 1977) 42 (3): 514-521


Many natural media are layered at the scale of microwaves. Examples include frozen soil over moist soil, ice over water, and snow over soil. The microwave brightness spectra of such media may exhibit interference patterns. Such patterns have been observed for emission from fresh-water ice but not for emission from snow or from seasonally frozen soil. Three factors which determine whether interference is detectable are the spectral resolution of the radiometer, the uniformity of layer thickness, and the distinctness of interfaces between layers. Analyses of these factors show that: (1) The radiobrightnesses of layered media vary sufficiently slowly with wavelength that radiometers designed for the radio-astronomy bands provide adequate spectral resolution; (2) a variability of layer thickness greater than 15 percent of the free-space wavelength in the area viewed by the radiometer will effectively eliminate an interference pattern; and (3) a diffuse interface, whose thickness is 15 percent of the free-space wavelength, is transparent to microwaves so that effects of the interface will not appear in the radiobrightness spectrum.

ISSN: 0016-8033
EISSN: 1942-2156
Coden: GPYSA7
Serial Title: Geophysics
Serial Volume: 42
Serial Issue: 3
Serial Info: Special issue on remote sensing
Title: Microwave brightness spectra of layered media
Affiliation: U. S. Geol. Surv., Reston, Va., United States
Pages: 514-521
Published: 197704
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 14
Accession Number: 1977-037990
Categories: Applied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by Society of Exploration Geophysicists, Tulsa, OK, United States
Update Code: 1977
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