An airborne campaign measuring wind signatures from the sea surface using an L-band polarimetric radiometer

A series of circle flights have been carried out over the sea surface, using the EMIRAD L-band polarimetric radiometer. Motion compensation is applied, and polarimetric azimuth signatures are generated. Single tracks show geophysical noise, typically about 2 K, but averaging decreases the noise, producing signatures with variations below 500 mK. A harmonic analysis of the results provides no clear signature, and for the 2^nd, 3^rd, and 4^th Stokes parameters it is shown, that a significant part of the signal must be due to Gaussian noise. The 1^st Stokes parameter is shown to have a 500 mK 2^nd harmonic, but a comparison of the signature to the downwelling galactic background radiation indicates, that the signature may not origin from the wind driven sea surface pattern.