Validation of Hi-Resolution Sea Surface Temperature Algorithm Toward the Satellite-Borne Microwave Radiometer AMSR3 Mission

The Advanced Microwave Scanning Radiometer-3 (AMSR3), the successor to AMSR2, is currently under development for launch in 2023. One of the goals of the AMSR3 mission is to make the retrieval limit of sea surface temperature (SST) to the coast at least 30 km (ultimately 20 km) while mitigating the effects of weather. Since AMSR3 needs to maintain the same design as AMSR2 as much as possible in order to shorten the development period, this goal must be mainly achieved by a data processing approach. Therefore, we first developed a spatial resolution enhancement algorithm for the brightness temperature ( $T_{B}$ ) based on the Backus–Gilbert method. We aim to achieve the goal by retrieving SST using this resolution enhanced $T_{B}$ . At present, the standard SST product of AMSR2 retrieves SST in waters more than 80 km from the coast using the C-band $T_{B}$ . Therefore, we applied our spatial resolution enhancement algorithm to the C-band $T_{B}$ of AMSR2 to retrieve hi-resolution SST (HST), evaluated how close the retrieval limit is to the coast, and compared the retrieval accuracy with the standard SST product. As a result, it was confirmed that the retrieval limit of HST is less than 30 km to the coast, with retrieval accuracy as approximating that of the standard SST product.