Examining the quality of CFOSAT-based surface winds over global oceans
with respect to 111 buoys
Abstract
The China-France Oceanography Satellite (CFOSAT), launched on 29 October
2018, is the world’s first satellite that carries both a real aperture
radar spectrometer and a fan-shaped beam rotary scanning scatterometer.
This study examined the retrieval results for the scatterometer onboard
the CFOSAT with respect to global buoys from NDBC, TAO/TRITON, PIRATA,
RAMA, PMEL, and MNR in 2019. For the scatterometer products in the range
of 4-24 ms-1, the root-mean-square error (RMSE) of the wind speed was
1.1 ms-1, and the wind direction RMSE was 20.4{degree sign} at the
global scale. In the tropics, the wind speed and wind direction RMSEs
were 1.1 ms-1 and 21.5{degree sign}, respectively, while the
corresponding RMSEs decreased to 1.1 ms-1 and 18.8{degree sign} in the
subtropics. The error statistics were larger in the range of 0-4 ms-1,
which is beyond the designed measurement accuracy, and the wind speed
was overestimated. Overall, the CFOSAT measurements are reliable in the
range of 4-24 ms-1, thus meeting the accuracy requirements of the
technical design. Finally, the influence of surface currents on the
CFOSAT measurements was analyzed. The results indicate that the
differences between the CFOSAT measurements and buoy observations in the
tropics were reduced by excluding the effect of the surface currents.