[A-CC26] 雪氷学

[ACC26-03] 消滅しつつあるヒマラヤの氷河のティッピングポイントの検出

*藤田 耕史¹、カヤスタ リジャン² (1.名古屋大学大学院環境学研究科、2.カトマンズ大学理学部)

キーワード：ヒマラヤ、氷河

Glacier AX010 in the Shorong region is an iconic glacier in the Nepal Himalaya, which has been intermittently observed since 1978. We conducted a drone photogrammetry survey in October 2023, and evaluated its volume change (~1.7 m yr^–1) since 2008, which is one of the fastest shrinking rates in the Himalayas. We reconstructed long-term mass balance over the past 45 years using the ERA5 reanalysis climate data and a glacier mass balance model, GLIMB. We first calibrated the ERA5 precipitation to get the observed geodetic mass balance. We then estimated the ideal temperature at which the glacier could maintain equilibrium states during every decade. We can determine the tipping point at which the glacier began irreversible shrinkage by comparing the ideal and actual temperatures. In addition, we conducted sensitivity analyses to quantify the effects of temperature warming, precipitation change, and surface lowering of the glacier on the observed shrinkage.