Dependency analysis of normalized radar cross section of ocean surface on ocean winds using an airborne dual-frequency polarimetric SAR

The normalized radar cross section (NRCS) of ocean surface is measured from three directions of illumination by an airborne dual-frequency synthetic aperture radar(SAR) with L- and X-band, and the dependency of the NRCS and the polarimetric ratio on the relative wind direction is analyzed. In X-band, the NRCSs in parallel polarizations represent the dependency on the relative wind direction. The NRCS in HH polarization of X-band has difference between upwind and downwind condition, though that in VV polarization the NRCSs for upwind and down wind condition are almost same. The wind dependency of the NRCS in L-band is smaller than that of X-band. The polarimetric rate in X-band shows the wind dependency with small difference between upwind and downwind conditions, though that in L-band is not apparent. The results suggests the possibility of measurement of ocean winds only using the polarimetric SAR in X-band. Moreover, the small dependency of the NRCS in L-band suggests the possibility of the wind speed measurement over the ocean.