[A-CG44] 静止軌道衛星による陸面観測

[ACG44-03] A Hyper-temporal Monitoring of Terrestrial Evapotranspiration Using Himawari-8 Satellite

*張 北辰¹、市井 和仁¹、山本 雄平¹、李 偉¹、樋口 篤志¹、Minseok Kang²、Youngryel Ryu³、Su-Jin Kim⁴、村山 昌平⁵ (1.千葉大学、2.韓国国立農業気象センター、3.韓国ソウル大学校、4.韓国国立森林科学研究所、5.産業技術総合研究所)

キーワード：ひまわり8号、蒸発散量、日変化、PT-JPLモデル

Evapotranspiration (ET) is an important process whereby water loss from the Earth surface to the atmosphere, with energy transfer of the latent heat flux due to the water phase changes. The diurnal cycle of ET is affected by changes in stomatal conductance related to water or heat stress. The next-generation geostationary satellite can monitor surface changes with high-frequency observations every 10 minutes, supporting regional high-frequency ET estimation. In this study, we estimated diurnal ET over the Asia-Pacific region using the Japan’s geostationary satellite/sensor, Himawari-8/Advanced Himawari Imager (AHI). The Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model was used for ET estimation, with inputs including shortwave radiation, land surface temperature, and land surface reflectance from Himawari-8/AHI, as well as ancillary datasets from the European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA5) and the Moderate Resolution Imaging Spectroradiometer (MODIS). We validated the estimated ET using observations from 45 eddy covariance flux sites and compared the results with four available products. Hourly estimated ET accurately captured diurnal variation, with Kling-Gupta efficiency (KGE) values being positive at most of sites. Estimated ET showed comparable accuracy to other products and had an advantage in spatial resolution. Finally, a heatwave event in southeastern Australia in 2019 was used as a case study to preliminarily examine the capability of the estimated ET data in capturing environmental changes in regional and temporal distributions.