Joint Retrieval of Aerosols and Surface Properties from GCOM-C/SGLI Multispectral Observations

Several statistically optimized algorithms with a forward radiative transfer model have been developed to utilize satellite observation fully. This study presents new simultaneous retrieval results of aerosol and surface properties using the MWPM and the SIRAW algorithms applied to multi-spectral radiance data of the Second generation GLobal Imager (SGLI) on board the GCOM-C satellite. MWPM (Multi-Wavelength and multi-Pixel Method) [Hashimoto et al., 2017] is retrieved an aerosol and surface albedo using the multi-wavelength and multi-pixel information, adopted as the standard aerosol algorithm over land for GOSAT-2/CAI-2. SIRAW (SImultaneous Retrieval of Aerosol and Water-leaving radiance) [Shi and Nakajima 2018; Shi et al., 2019] is retrieved aerosols and ocean color simultaneously, adopted for the standard aerosol product of GOSAT-2/CAI-2 over ocean [Shi et al. 2020]. Satellite-retrieved parameters were validated with those of the AERONET observation in the coastal areas in East Asia. The present validation study shows that our product agreed better with in-situ data than the SGLI standard products derived from the conventional algorithms. We applied the present algorithms to 250 m radiance data of SGLI to obtain aerosol and ocean color distributions in the coastal areas and found that the current algorithm gave wider retrievable areas with larger AOTs than those of the standard algorithm. We also found the turbidity condition in the coastal regions was complicatedly various by two different aerosol and ocean spatial patterns, i.e., high contrast pattern between the coastline and off-shore areas and characteristic plume-type patterns of aerosol and ocean depending on the topographic structure of each region. It will be a promising future work to study spatial and temporal trends of these two characteristic patterns to understand the transportation of atmospheric and ocean color substances in the areas.