STUDY OF POLARIZATION DIFFERENCES IN KU-BAND OCEAN RADAR IMAGERY

Radar returns from the sea surface can be represented as the sum of tw o contributions from Bragg scattering and from individual breaking eve nts. This representation is used to analyze polarimetric radar images of ocean areas obtained at grazing angles 6 degrees < psi < 18 degrees with the airborne K-u-band radar in the New York Bight. All images we re obtained for light and moderate winds and can be divided into three types according to texture differences. Images obtained confirm that there are differences between returns for horizontal/horizontal (HH) a nd vertical/vertical (VV) polarizations for the three types. The first type agrees qualitatively with predictions of the two-scale Bragg mod el, whereas the other two do not. The second and third types have a si gnificant spike contribution from breaking events at both polarization s. The last type reveals drastic differences between images obtained u sing HH and VV polarizations. The polarization dissimilarity is a resu lt of a low correlation between the spike clusters in HH-polarized ima ges and the variations of continuous background in VV-polarized images . The role of atmospheric stability in processes responsible for spati al decorrelation of the different scatterers is also examined.