[A-CG36_29PM2] 北極域の科学

[ACG36-12] 地上と衛星の統合観測による周北極域の植生フェノロジーの検出の高精度化

*永井 信¹、鄭 峻介²、小林 秀樹¹、伊川 浩樹³、中井 太郎⁴、金 龍元³、鈴木 力英¹、杉本 敦子² (1.海洋研究開発機構地球環境変動領域、2.北海道大学大学院地球環境科学研究院、3.アラスカ大学国際北極圏研究センター、4.名古屋大学地球水循環研究センター)

キーワード：フェノロジー, リモートセンシング, 陸域生態系, シベリア, アラスカ, 地上真値

To accurately evaluate the spatio-temporal variability of ecosystem functions and service in sub- and Arctic regions under rapid meteorological and climate changes, global, long-term, and comprehensive phenological observations are required. Towards this aim, satellite remote-sensing is useful to detect the spatio-temporal variability of plant phenology such as the timing of start (SGS) and end of growing season (EGS). However, from the in situ ecological research viewpoint, the satellite remote-sensing has not been sufficiently tested and validated by ground-truthing. Here, (1) we performed daily field observations with time-lapse digital cameras in boreal forests in Alaska and Siberia; (2) we examined the relationship between satellite-observed vegetation indices and plant phenology; and (3) we evaluated the spatio-temporal variability of the timing of SGS and EGS in sub- and Arctic regions by using MODIS Terra and Aqua-observed green-red vegetation index (GRVI). We found that (1) satellite-observed vegetation indices (i.e. NDVI, EVI, and GRVI) mainly detected the plant phenology of forest floor in sparse forests; (2) large year-to-year variability of the timing of SGS was detected in eastern Siberia and western Ural Mountains, while that of EGS was not clearly detected; and (3) in contrast, large year-to-year variability of the timing of EGS was detected in western Alaska, which is mainly covered by tundra vegetation, while that of SGS was not clearly detected.