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Studies of snowpack properties by passive microwave radiometryResearch involving the microwave characteristics of snow was undertaken in order to expand the information content currently available from remote sensing, namely the measurement of snowcovered area. Microwave radiation emitted from beneath the snow surface can be sensed and thus permits information on internal snowpack properties to be inferred. The intensity of radiation received is a function of the average temperature and emissivity of the snow layers and is commonly referred to as the brightness temperature (T sub b). The T sub b varies with snow grain and crystal sizes, liquid water content and snowpack temperature. The T sub b of the 0.8 cm wavelength channel was found to decrease moreso with increasing snow depth than the 1.4 cm channel. More scattering of the shorter wavelength radiation occurs thus resulting in a lower T sub b for shorter wavelengths in a dry snowpack. The longer 21.0 cm wavelength was used to assess the condition of the underlying ground. Ultimately it may be possible to estimate snow volume over large areas using calibrated brightness temperatures and consequently improve snowmelt runoff predictions.
Document ID
19790008308
Acquisition Source
Legacy CDMS
Document Type
Preprint (Draft being sent to journal)
Authors
Chang, A. T. C.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hall, D. K.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Foster, J. L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Rango, A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Schmugge, T. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 3, 2013
Publication Date
November 1, 1978
Subject Category
Geophysics
Report/Patent Number
NASA-TM-79671
Report Number: NASA-TM-79671
Accession Number
79N16479
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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