Abstract
We present the follow-up of our previously published work, where we
described a wavelet-based method to characterize the sea surface
backscatter structures in Synthetic Aperture Radar (SAR) images. The
method relies on the ability of the 2-D continuous wavelet technique to
detect the spatial structure of the Marine Atmospheric Boundary Layer
(MABL) and to isolate wind-related cells and features. The analysis of
the cells’ geometry, molded by the radiometric characteristics of the
sea surface, permits the identification of the wind direction inside the
cells, due to the along-wind asymmetry of backscatter structures, and
thus the computation of the wind speed through standard algorithms.
Twenty-one SAR images (ERS-2 and Envisat ASAR Wide Swath) over the
Mediterranean Sea have been analyzed, and the results are compared with
satellite wind fields. The images cover a range of meteorological
conditions from low to moderate winds. Comparison of the SAR-derived
wind fields with those provided by satellite scatterometers indicates a
good score of success (roughly 70%–80%). The developed methodology,
once tested over an adequate number of images to derive statistically
reliable results, could be routinely used to enrich SAR images with the
wind field as well as to characterize the MABL in terms of size,
distribution, and shape of the backscatter cells.