Comparisons of SFMR and Satellite Microwave Remote Sensed Sea Surface Wind Speed in Hurricane Weather

The accuracy and consistency of sea surface wind speed measurements during hurricane conditions have garnered significant attention. Among the various techniques, the Stepping Frequency Microwave Radiometer (SFMR) provides crucial in-situ data on sea surface high wind speeds. This study aims to compare wind speed measurements obtained from SFMR with those from space-borne microwave scatterometers such as the C-band European MetOp series satellite Scatterometer ASCAT, the Ku-band China-France Oceanography Satellite (CFOSAT) Scatterometer CSCAT, and the Chinese HY-2 series satellite Scatterometer HSCAT, as well as microwave radiometers such as SMAP and SMOS. We establish the relationship between SFMR wind speed and spatial scale and propose a spatio-temporal matching method to align SFMR data with scatterometer and radiometer data. This method assumes that the spatial distribution of TC wind field is unchanged relative to the hurricane direction in a certain time range. According to the TC center path information of IBTrACS, the trajectory of SFMR is transformed into the relative coordinates of storm movement, which effectively extending the matching time difference between SFMR, scatterometer and radiometer sea surface wind speed data to 3 hours. Our findings indicate that radiometer measurements of high wind speeds (>15 m·s^–1) exhibit greater consistency with SFMR compared to scatterometer measurements, and Ku-band scatterometer measurements tend to saturate when wind speeds exceed 25 m·s^–1. The spatio-temporal matching results of SMAP and HSCAT also showed the same distribution characteristics. However, the ASCAT wind speed of C-band scatterometer still shows the overall increasing distribution characteristics. Additionally, Rainfall during high wind conditions significantly affects scatterometer wind speed error is still observed by us, although the error associated with wind speed is more pronounced. This study contributes to a better understanding of the error characteristics of sea surface wind speed measurements obtained from space-borne microwave scatterometers and radiometers, thereby offering valuable insights for the application of remote sensing data, subsequent research can analyze the contribution of different data sources in the physical meaning of wind speed to the consistency analysis results.