Last Glacial Maximum glacier modelling in the Quemuqu Valley, southern Tibetan Plateau, and its climatic implications

A well-preserved Last Glacial Maximum (LGM) moraine set in the Quemuqu Valley on the eastern slope of the Qiongmu Gangri Peak offers great potential for reconstructing LGM glacier extent and examining LGM climate in the region. This study employed a coupled and physics-based mass balance and ice-flow model to investigate glacier sensitivities to climate in the valley. Based on the sensitivity tests and the well-preserved LGM moraines, the study also reconstructed the LGM glacier extent in the valley and assessed the magnitude of cooling for the LGM period. Model results suggest that the Quemuqu Valley sustained an ice volume of 6.80 +/- 0.16 km(3) in the LGM period. Temperature depression of 3.1-4.3 degrees C, combined with 30-70% modern precipitation, is likely to have supported the LGM glacier extent in the valley. The temperature inference for the LGM period is comparable with other independent palaeoclimate evidence in the region. However, there is a large difference in the reconstructed glacier volume (ice thickness) between previous research and the current study. The glacier model used here directly calculates the ice thickness and needs relatively less field evidence to constrain the model simulations. It is therefore advocated to use such a model to reconstruct past glaciers and their corresponding climates for other valleys of the Tibetan Plateau.