NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Estimating the path-average rainwater content and updraft speed along a microwave linkThere is a scarcity of methods for accurately estimating the mass of rainwater rather than its flux. A recently proposed technique uses the difference between the observed rates of attenuation A with increasing distance at 38 and 25 GHz, A(38-25), to estimate the rainwater content W. Unfortunately, this approach is still somewhat sensitive to the form of the drop-size distribution. An alternative proposed here uses the ratio A38/A25 to estimate the mass-weighted average raindrop size Dm. Rainwater content is then estimated from measurements of polarization propagation differential phase shift (Phi-DP) divided by (1-R), where R is the mass-weighted mean axis ratio of the raindrops computed from Dm. This paper investigates these two water-content estimators using results from a numerical simulation of observations along a microwave link. From these calculations, it appears that the combination (R, Phi-DP) produces more accurate estimates of W than does A38-25. In addition, by combining microwave estimates of W and the rate of rainfall in still air with the mass-weighted mean terminal fall speed derived using A38/A25, it is possible to detect the potential influence of vertical air motion on the raingage-microwave rainfall comparisons.
Document ID
19930067238
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Jameson, Arthur R.
(Applied Research Corp. Landover, MD, United States)
Date Acquired
August 16, 2013
Publication Date
August 1, 1993
Publication Information
Publication: Journal of Atmospheric and Oceanic Technology
Volume: 10
Issue: 4
ISSN: 0739-0572
Subject Category
Meteorology And Climatology
Accession Number
93A51235
Funding Number(s)
CONTRACT_GRANT: NAS5-30430
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available