Spatial Resolution Enhancement of HY-2B Scanning Microwave Radiometer Low-Frequency Data

Microwave radiometers are widely used in Earth observation and ocean monitoring for their strong penetration ability. Nevertheless, their utilization is somewhat constrained by their intrinsic low-resolution capability, particularly in complex applications such as coastal zone monitoring and analysis of typhoons. To overcome this limitation, resolution enhancements are necessary. Here, we present a novel resolution enhancement technique, the alternating proximal gradient (APG) method, applied to Haiyang-2B (HY-2B) scanning microwave radiometer (SMR) data. This method is based on the decorrelation approach and incorporates total variation (TV) constraint. The APG method, along with the Backus–Gilbert (BG) method, is both applied to the 6.925-GHz data of HY-2B SMR. Both simulated and real HY-2B SMR data from two representative regions, including land-to-sea transition zones and cyclonic storms, are analyzed. Results show that both the BG method and the APG method can significantly enhance details obscured in the original SMR data. Furthermore, the enhanced brightness temperatures are compared to the AMSR-2 25-km product, revealing that the APG method provides more consistent results and contains more reliable information than the BG method in terms of resolution enhancement.