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

我们尝试建立一种新的方法来重建过去冰川（古冰川）的平衡线海拔（ELA），而不考虑累积比（AAR）的概念。这种新方法被称为冰川快照模型（GS模型），它结合了地貌解释和冰川流动模型，该模型基于每个网格的地表质量平衡和通量散度之间关系的概念。结果表明，GS模型可以较好地重建当前冰川的ELA，因此重建的ELA不依赖于流量参数值的选择。对过去冰川的结果表明，计算的古ela依赖于过去冰川的表面地形；即重建古ela的位置随地表地形重建方法的不同而变化。此外，一些冰厚变化较大的冰川的计算结果显示出多个古ela。这些结果表明，重建过去冰川表面地形的方法是古ela重建的关键。

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.