Extension of Kirchhoff method under stationary phase approximation to determination of polarimetric thermal emission of the sea

Wind direction over the sea can be determined from radiometric measurements of the third Stokes parameter (T/sub U/). The Kirchhoff method is extended under the stationary phase approximation to compute the dependence of T/sub U/ on frequency, wind speed and incidence angle. Numerical predictions, in agreement with experimental measurements, are presented.