Tropical Cyclone Wind Field Reconstruction from SAR and Analytical Model

Abstract

Sea surface wind field retrieval from Synthetic Aperture Radar (SAR) imagery is based on geophysical model functions (GMFs), which describe the relationship between the near surface winds and the normalized radar backscatter cross section. However, existing GMFs will saturate under tropical cyclone conditions, and cause huge wind retrieval errors. This study develops an approach to estimate tropical cyclone parameters and wind fields based on an improved Holland model and the SAR images. To evaluate its accuracy, three case studies of Typhoon Aere, Typhoon Khanun and Hurricane Ophelia are presented. Estimated results are validated by the best track data of the Joint Typhoon Warning Center (JTWC) and reanalyzed H*wind fields from the Hurricane Research Division (HRD). These results indicate that the tropical cyclone center, maximum wind speed and central pressure are generally consistent with the best track data, and wind fields agree well with reanalyzed data.