AN ASSESSMENT OF VEERING WIND EFFECTS ON SCATTEROMETRY FROM THE SEA-SURFACE

To characterize scatterometer returns from the sea surface near meteor ological fronts, we investigated microwave scattering from seas in whi ch long waves are at oblique angles to short waves. We simulate the ef fects of veering winds on C- and K-u-band scatterometers by using mode ls in which the short waves align with the wind friction velocity u, but the long waves are at oblique angles to the u direction. The anal ysis reveals two main effects due to the rotation of the long wave slo pe probability density distribution. Azimuthally averaged normalized r adar cross-section a(0) decreases as the oblique angle increases. Addi tionally, two regimes exist. In the small angle regime, azimuthal scan s of normalized radar cross-section sigma degrees exhibit features sim ilar to the classic double-maxima pattern for non-veering wind conditi ons, but the axis of sigma degrees maxima is rotated toward the long-w ave axis. In the large angle regime, more than two maxima are apparent in azimuthal scans. Therefore it may be inappropriate to use standard three term Fourier cosine models for some veering wind conditions.