Accession Number : ADA331237

Title :   Effect of Surface Tilting on Altimeter Wind Measurements.

Descriptive Note : Final rept.,

Corporate Author : NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MESO- AND FINESCALE OCEAN PHYSICS SECTION

Personal Author(s) : Hwang, Paul A. ; Teague, William J. ; Jacobs, Gregg A. ; Wang, David W.

PDF Url : ADA331237

Report Date : 17 OCT 1997

Pagination or Media Count : 21

Abstract : A two-scale surface roughness model is presented to interpret the backscattering of satellite radar altimeters. It is found that the tilting effect of long waves produces an attenuation of the radar backscatter cross section. The calculated attenuation factor is in excellent agreement with TOPEX/POSEIDON (referred to as TOPEX for brevity) measurements. Two major contributors to the tilting mechanism are the wind-generated waves with the wavelengths much longer than the radar wavelength, and the ambient waves generated elsewhere that propagate into the measurement region. Using the information of the wavenumber spectra of short capillary-gravity waves measured in the ocean and an estimate of the ambient tilting wave components from ocean buoy measurements, computations of the tilting mechanism are carried out. The calculated attenuation factor is in excellent agreement with TOPEX measurements. With the tilting effect accounted, the agreement improves significantly between the wind speeds derived from the TOPEX Ku-band altimeter and those from the collocated ocean buoys.

Descriptors :   *BACKSCATTERING, *ALTIMETERS, *TILT, COMPUTATIONS, SURFACE WAVES, WIND, ATTENUATION, GRAVITY WAVES.

Subject Categories : Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE