Evaluation of wind vectors observed by QuikSCAT/SeaWinds using ocean buoy data

Wind vectors observed by QuikSCAT/SeaWinds are compared with wind and wave data from offshore moored buoys. Effects of oceanographic and atmospheric parameters on the scatterometry are also assessed by using the buoy data. The QuikSCAT/SeaWinds Standard Wind Data Products (Level 2B) were collocated with the Japan Meteorological Agency (JMA), National Data Buoy Center (NDBC), and Tropical Atmosphere Ocean (TAO) buoys. Only buoys located offshore and in deep water were selected. Temporal difference and spatial separation between the QuikSCAT/SeaWinds and buoy observations were limited to less than 30 min and 25 km. Wind speeds measured by the buoys at various height above the sea surface were corrected to equivalent neutral winds at a height of 10 m. Wind speeds and directions observed by QuikSCAT/SeaWinds agree well with the buoy data. Root-mean- squared differences of the wind speed and direction are 1.02 m/s and 22/spl deg/, respectively. Dependencies of wind speed residuals on oceanographic and atmospheric parameters observed by buoys are examined using the collocated data. Weak positive correlation of the wind speed residuals with the significant wave height is found, although no significant dependence on the sea surface temperature and atmospheric stability is discernible.