[A-CG57] 北極域の科学

[ACG57-12] Estimation of Greenland surface mass balance using positive degree-days method and energy balance model

*大石 龍太¹、齋藤 冬樹²、小長谷 貴志¹、阿部 彩子^1,2,3 (1.東京大学大気海洋研究所、2.海洋開発研究機構、3.国立極地研究所)

キーワード：古気候、氷床モデル、グリーンランド

A sea level rise is an important topic in a future climate projection. In the past warm period known as the Last Interglacial (LIG), paleoevidences indicate sea level rise of several meters. Paleoclimate modeling community applies past GCM results on ice sheet models and tries to reproduce past sea level rises. Typically, an empirical method called PDD (Positive Degree Days) is applied for the estimation of surface mass balance on the ice sheet as an upper boundary condition. The PDD only refers the surface atmosphere temperature and snowfall. In the present study, we use a process-based land surface model MATSIRO to estimate the Greenland surface mas balance forced not only by temperature and snowfall but also by other surface variables including shortwave and longwave radiation which are based on a regional climate model NHM-SMAP with 5km resolution. We compare the characteristics of resultant ice melt amount from PDD and MATSIRO to evaluate the inclusion of process-based heat and water balance instead of empirical equation. We also interpolated anomaly of two warming GCM experiments result from the presentday experiment and added them to the observed variables which are forcing of MATSIRO to predict the Greenland surface mass balance in the warm climate.