17:15 〜 18:30
[ACG33-P02] Himawari-8 AHI NDVI Temporal Signature Variability of Broadleaf Deciduous Forests Along Temperature, Elevation, and Latitudinal Gradients in Northern Japan
キーワード：Advanced Himawari Imager、NDVI、Phenology
Himawari-8 Advanced Himawari Imager (AHI), one of new-generation geostationary satellite sensors, is equipped with a red and near-infrared bands and has been imaging an Earth’s hemisphere at 10 min intervals since July 2015. This new-generation geostationary satellite sensor provides the potential to generate higher-temporal resolution vegetation index (VI) time series data than the conventional polar-orbiting satellite sensors even in cloud-prone areas and seasons. In this study, we assessed how AHI NDVI higher-temporal signatures varied for deciduous broadleaf forests (DBFs) along temperature, elevation, and latitudinal gradients in the northern Japan. AHI 10-min data were obtained for a three-year period of 2016-2018 and reduced into daily NDVI time series. Two temperature-driven indices, the warmth and coldness indices (WI and CI, respectively), were obtained from mean monthly temperature. A land cover map derived from Advanced Land Observing Satellite (ALOS) data was used to identify DBF areas along three transects drawn from Japan Sea to Pacific Ocean. AHI NDVI temporal signatures had one growth cycle/season per year, but were different along temperature, elevation, and latitudinal gradients. The start of growth season (SGS) metric derived from AHI NDVI was positively, but weakly correlated with the latitude (r = .47) and elevation (r = .47). In contrast, the AHI NDVI-derived end of growth season (EGS) metric significantly correlated to the latitude (r = .73), but extremely weakly to the elevation (r = .07). The highest correlations were obtained with the WI and CI for these metrices (r = .86 between the SGS and WI, and r = .75 between the EGS and CI). It was found that AHI-derived NDVI temporal data were useful for regional-scale analysis of DBF phenology.