Document Type

Article

Publication Date

10-1-1993

Abstract

This feasibility study explores the potential benefits of polarization adjustment for spaceborne radar sensing of precipitation. More specifically, the role of the wave polarization in separating or “distinguishing” ocean surface return from the hydrometeor echoes of a “chirped” signal is examined.

To that end, experimental as well as computational data for the polarization scattering matrices of hydrometeors and ocean surfaces are obtained and used to calculate ocean and precipitation “response” to the transmitted pulse for various rain rates and incidence angles. The analysis is restricted to X and C bands, but simulations are performed for several signal-to-noise ratios, rain rates, and ocean surfaces. The problem is further restricted to the monostatic case (same polarizations for transmitter and receiver).

Even when the ocean and hydrometeor echoes are mixed throughout the entire radar resolution volume, the results appear promising. It is found that polarization, which provides the best contrast between rain and ocean returns, varies from almost circular near nadir to elliptical at large off-nadir look angles of incidence (ellipticity of 23° at a 40° incidence angle). Calculations show an order of magnitude improvement in the ratio of the returns when compared with the traditional choice of HH (horizontal transmit and receive polarization). The improvement is largest for the range of angles between 15° and 20° but depends on the assumed rain rate and, in particular, on the ocean surface roughness.

The general method described in this paper can be applied to many problems of radar and lidar meteorology, while the specific results reported here may have relevance for future precipitation measurement missions such as Tropical Rainfall Measuring Mission 2.

Publisher's Statement

Copyright 1993 American Meteorological Society. Publisher’s version of record: https://doi.org/10.1175/1520-0426(1993)010<0736:SRSOPA>2.0.CO;2

Publication Title

Journal of Atmospheric and Oceanic Technology

Version

Publisher's PDF

Included in

Physics Commons

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.