Validation and Calibration of Nadir SWH Products From CFOSAT and HY‐2B With Satellites and In Situ Observations

The China France Oceanography Satellite (CFOSAT) and Haiyang‐2B (HY‐2B) satellites were successively launched in China on the 29th and 25th of October 2018, respectively. HY‐2 B carries the second Chinese radar altimeter along with three other microwave sensors, whereas CFOSAT contains the first Surface Waves Investigation and Monitoring (SWIM) instrument and a fan beam rotating scatterometer. As missions for measuring the dynamic marine environment, both satellites can measure the nadir significant wave height (SWH). For data obtained from a newly launched satellite to be utilized with confidence, the quality of SWH from the two satellites requires validation. In this study, the HY‐2B altimeter and CFOSAT nadir SWHs have been validated against the National Data Buoy Center (NDBC) buoys and the Jason‐3 altimeter SWH data, respectively, which resulted in CFOSAT nadir SWH having the best accuracy and HY‐2B having the best precision. The SWHs of the two missions are also calibrated by Jason‐3 and NDBC buoys. Following calibration, the root mean square error (RMSE) of CFOSAT and HY‐2B are 0.21 and 0.27 m, respectively, when compared to Jason‐3, and 0.23 and 0.30 m, respectively, compared to the buoys. Our results show that the two missions can provide good‐quality SWH and can be relied upon as a new data resource of global SWH. CFOSAT and HY‐2B are new satellites launched approximately one and a half years ago. Both have the capability to provide global ocean wave observations, the quality of which is critical, especially in climate change research. In this study, the SWH from both satellites are validated against the NDBC buoy and Jason‐3 altimeter SWH data. Lastly, a calibration method is used for the application of the new SWH data. Significant wave height from China France Oceanography Satellite (CFOSAT) and Haiyang‐2B (HY‐2B) satellites are validated against Jason‐3 and NDBC dataThe significant wave height from CFOSAT and HY‐2B have nearly the same performance, although there are small differences comparing to the two referencesLinear calibrations against Jason‐3 and NDBC buoy data are proposed Significant wave height from China France Oceanography Satellite (CFOSAT) and Haiyang‐2B (HY‐2B) satellites are validated against Jason‐3 and NDBC data The significant wave height from CFOSAT and HY‐2B have nearly the same performance, although there are small differences comparing to the two references Linear calibrations against Jason‐3 and NDBC buoy data are proposed