Multipass High-Resolution Scatterometer Image Reconstruction and Validation for FY-3E WindRAD

Abstract

Fengyun-3E wind radar (FY-3E WindRAD), as the world’s first global dual-frequency rotating fan-beam scatterometer, provides observations in both C-band and Ku-band. The original footprint scales of approximately 25 and 10 km, respectively, are similar to those of most spaceborne scatterometers and are insufficient for Earth observation applications requiring finer spatial detail. Although the conventional scatterometer image reconstruction (SIR) framework provides a well-established technical foundation for numerous scatterometer reconstructions, its application to FY-3E WindRAD, with its rotating fan-beam geometry and dense sampling characteristics, requires careful consideration of residual noise amplification and reconstruction artifacts under complex viewing conditions. This study investigates the combination of SIR with different filtering methods and further explores multipass high-resolution reconstruction of FY-3E WindRAD observations. Comparative experiments identify adaptive bilateral filtering (ABF) as an effective postprocessing approach for balancing noise suppression and structural preservation. By applying the SIR with adaptive bilateral filtering (SIR-ABF)-based reconstruction framework, single-pass C-band and Ku-band WindRAD observations are reconstructed on a 3.125-km grid. Furthermore, with the implementation of the designed multipass joint reconstruction strategy, the effective sampling density is increased, enabling high-resolution reconstruction on a grid with an approximate spacing of 1.5625 km. Based on the reconstruction performance evaluation metrics within the designed validation framework, experimental results demonstrate that the SIR-ABF achieves an optimal balance between noise suppression and structural feature preservation. The multipass reconstruction strategy further enables the generation of finely gridded backscatter products, providing a practical basis for high-resolution applications of scatterometer observations.