ELA reconstruction of the late Pleistocene glaciation in Japan by the coupling of geomorphological interpretation and glacier dynamics

点击翻译按钮获取中文摘要

We tried to develop a new method to reconstruct the equilibrium line altitude (ELA) of past glaciers (paleo-ELA) without the concept of accumulation are ratio (AAR). The new method, called glacier snapshot model (GS model), involves a combination of geomorphological interpretation and a glacier flow model that is based on the concept of the relationship between surface mass balance and flux divergence at each grid. The results obtained for the current glaciers indicate that the GS model can reconstruct the ELA well and that thus the reconstructed ELA does not depend on the selection of flow parameter values. The results obtained for past glaciers showed that calculated paleo-ELA depend on the surface topography of the past glacier; that is, the position of the reconstructed paleo-ELA varied with the method of reconstructing surface topography. Moreover, some of the calculation results for glaciers with large variations in ice thickness showed multiple paleo-ELA. These results indicate that method to reconstruct the surface topography of the past glacier is the key to paleo-ELA reconstruction.