Abstract:

Spaceborne microwave scatterometer is the most efficient instrument to measure the global ocean surface wind. The successfully launched HY-2B scatterometer is an important guarantee to continue the measurement of global ocean surface wind. In this paper, we use the European Center for Medium-Range Weather Forecasts (ECMWF) reanalysis wind data, Tropical Atmosphere Ocean Array (TAO) and National Data Buoy Center (NDBC) buoy wind data to estimate the accuracy of the HY-2B retrieved wind. Our statistical results show that at speed range from 4 to 24 m·s^-1, the retrieved wind speed root mean square error (RMSE) with respect to the ECMWF wind speed is 1.58 m·s^-1, and the direction RMSE is 15.34°, while the speed and direction RMSEs with respect to the TAO buoys located in the open ocean are 1.06 m·s^-1 and 15.98°, respectively. Thus, the retrieved wind well satisfies the operational precision requirement of the HY-2B scatterometer, that is, the speed and direction RMSEs should be better than 2 m·s^-1 and 20.00°, respectively, for the open ocean. Moreover, the NDBC buoys are mainly located in immediate offshore areas, HY-2B wind speed and direction RMSEs are 1.60 m·s^-1and 19.14°, respectively, which shows that HY-2B scatterometer has good ability to measure wind of offshore sea areas. We also reveal that the retrieved wind error varies with wind speed and cross track position of wind vector cell, which will provide the users with reference for the effective application of HY-2B wind product.

Key words: HY-2B satellite, microwave scatterometer, ocean surface wind, wind retrieval, accuracy analysis