[A-CG44] 静止軌道衛星による陸面観測

[ACG44-02] High-Temporal-Resolution Land Surface Albedo Estimation Using Himawari-8/9 AHI: Evaluation with In-Situ and MODIS Observations

*李 偉¹、笹川 大河²、張 北辰¹、楊 偉¹、奈佐原 顕郎²、Ryu Youngryel³、村山 昌平⁴ (1.千葉大学、2.筑波大学、3.ソウル大学、4.産業技術総合研究所)

キーワード：BRDF、静止衛星、ひまわり８／９号

Himawari-8/9 are third-generation Japanese geostationary orbit (GEO) meteorological satellites that carry the Advanced Himawari Imager (AHI) sensor. The Himawari-8/9 AHI continuously observe the Earth's hemisphere in multiple spectral bands every 10 minutes. Therefore, compared with conventional earth observation satellites, land surface observation with higher temporal frequency became possible. Land Surface Albedo (LSA) plays a crucial role in the Earth's climate system, and its accurate estimates is expected to understand surface environmental and climate changes. Therefore, this study aims to estimate and evaluate LSA using Himawari-8/9 AHI data at eddy-covariance sites, and to understand changes in LSA. We applied a 10-minute AHI land surface reflectance dataset to the kernel-driven Bidirectional Reflectance Distribution Function (BRDF) model to estimate daily LSA. Two different in-situ measurements observed at eddy-covariance sites, shortwave radiation, and hyper-spectral observation, were used in this study. Our results show good agreement with in-situ observations and Moderate Resolution Imaging Spectroradiometer (MODIS) products (MCD43) temporally and spatially. Compared to MODIS, AHI LSA shows a more continuous time-series. Furthermore, changes in LSA at the cropland site due to rapid surface changes such as irrigation and harvesting were captured by AHI-based LSA. These results indicate a potential for large-scale surface change monitoring using Himawari-8/9 AHI data.