LAUSR

This letter preliminarily assesses the accuracy of ocean wind products from the Ku-band scatterometer (HSCAT) onboard the recently launched Chinese satellite HY-2B. The wind vectors derived from HSCAT during the period from November 15, 2018 to April 30, 2019 are evaluated. The reference wind data include in situ measurements from the offshore meteorological buoys of the National Data Buoy Center, USA, and westerlies mooring of the National Ocean Technology Center, China, and scatterometer winds from the European Advanced Scatterometer (ASCAT) and Indian SCATSAT-1 Oceansat Scatterometer (OSCAT). The spatial difference is limited to $25/\surd 2$ km, while the HSCAT winds are temporally collocated with buoys and other scatterometers by less than 0.5 and 1.5 h, respectively. The comparison results show that the HSCAT data have a root-mean-square error (RMSE) of 0.95–1.20 m/s (14.7°–25.7°) regarding the wind speed and direction, respectively, indicating consistency between the HSCAT winds and the reference. Furthermore, better agreement is found for the HY-2B HSCAT winds processed using the Pencil-beam Wind Processor (PWP) algorithm, regarding wind speed (RMSE of 0.95–1.07 m/s) and particularly with respective to the wind direction (RMSE of 14.7°–19.6°), both satisfying the mission specification (< 2 m/s and < 20 for wind speed and direction, respectively). The encouraging validation results over the first 5 months demonstrate that the HY-2B HSCAT wind products will be useful for the scientific community.