Validation of the CFOSAT Scatterometer Data With Buoy Observations and Tests of Operational Application to Extreme Weather Forecasts in Taiwan Strait.

The China‐France Oceanography Satellite (CFOSAT) launched in 2018 is equipped with the Chinese Scatterometer (CSCAT), which is designed to measure high‐precision sea surface wind fields in the global ocean. This study aims to validate the CFOSAT wind fields with moored buoy‐measured ground truth data from August 2019 to July 2021. The test area was chosen as the Taiwan Strait, which is an important navigation channel and rich fishery grounds in the East Asia. It is also a high wind speed area particularly during typhoons and cold air passages. Thus, the accurate wind forecasts are crucially needed to avoid capsizing and casualties. The validation results give the correlation coefficient (R2) of 0.92, the root mean square error (RMSE) of 1.75 m s−1, and the absolute deviation (AD) of 1.10 m s−1 for the wind speeds, and R2 of 0.96, the RMSE of 21.87°, and the AD of 1.17° for the wind directions. During cold air passages, the AD of wind speeds decreases to 1.03 m s−1, which is smaller than 1.17 m s−1 during typhoons. Using the CFOSAT wind as historical observation data for refining of forecast work was tested by model output statistics revised method. The test results show that the refined forecast results of wind fields are improved up to 4%–17%. Thus, the validation and test results obtained in this study indicate that updating satellite winds would have great contributions to refined forecasting of local sea surface winds. Plain Language Summary: The China‐France Oceanography Satellite (CFOSAT) is a China‐France joint mission launched in 2018, which aims to update satellite remote sensing technologies of the sea surface winds and waves. This paper reports the validation results of the CFOSAT winds with moored buoy measurements. The test area is chosen as the Taiwan Strait, which is an important navigation channel in the East Asia and a rich fishery ground. Total 467 satellite‐buoy spatiotemporal matching data pairs were collected during 8 typhoons and 8 cold air passage processes over the Taiwan Strait. Statistical calibration analyses give the correlation coefficients as high as 0.92 for the wind speeds and 0.96 for the wind directions, implying that the CFOSAT wind data are of high quality and satisfy the requirements for the operational applications. Furthermore, test results to use the CFOSAT winds for operational ocean forecasts in the Taiwan Strait and adjacent waters show that the accuracies of forecasting work are raised up to 4%–17% during the typhoon and cold air passage processes. Thus, the validation and test results provided by this study indicate that it is expectable that updating satellite winds would have great contributions to refined forecasting of local sea surface winds. Key Points: China‐France Oceanography Satellite (CFOSAT) scatterometer wind data are validated by buoy measurements deployed in the Taiwan StraitCalibration analyses of 467 spatiotemporal matching data pairs give correlation coefficients of 0.92 for wind speed and 0.96 for directionApplications of CFOSAT winds improve refined operational forecasts up to 4%–17% under the extreme weather conditions [ABSTRACT FROM AUTHOR]