High Resolution Ocean Surface Wind Fields Retrieved from Spaceborne Synthetic Aperture Radars Operating at C-band

This paper introduces algorithms designed to retrieve high-resolution ocean surface wind fields from satellite borne synthetic aperture radars (SARs) operating in C-band at either vertical (VV) or horizontal (HH) polarization in transmit and receive. Wind directions are extracted from wind induced streaks that are visible in SAR images at scales above 200 m and that are approximately in line with the mean surface wind direction. To extract the orientation of these streaks two algorithms are introduced, which are applied either in the spatial or spectral domain. Wind speeds are derived from the normalized radar cross section (NRCS) and image geometry of the calibrated SAR images, together with the local SARretrieved wind direction. Therefore several C-band models (CMOD4, CMOD IFR2, and CMOD5) are available which were developed for VV polarization and have been extended for HH polarization. To compare the different algorithms and C-band models and demonstrate their applicability, SAR retrieved wind fields are compared to numerical model results considering SAR data from the European satellite ERS-2 and ENVISAT.