青藏高原及毗邻山地利用冰川地貌重建古气候的研究综述

A review on the reconstruction of palaeoclimate by glacial landform in the Tibetan Plateau and adjacent mountains

利用冰川地貌定量重建冰期时的古气候特征是探讨冰川驱动机制的关键。利用冰川地貌反演古气候的模型主要有两类:基于物质平衡线高度变化和基于估算古冰川表面物质平衡的气候重建模型,因其原理、所需数据量的不同,适用性存在着差异,应用时需根据冰川区的具体特征选取多种模型重建古气候,提高模拟的精度。青藏高原及毗邻山地已有的基于古冰川的气候重建数据显示:MIS6以来冰川变化为气温变化驱动,冰川规模还受降水量增多的影响;MIS3中期冰川的规模较之末次冰盛期(Last Glacial Maximum,LGM)更大,主要是该较冷的亚阶段降水比LGM时期更为丰沛所致。

It is critical for understanding the relationships between glacier and climate change based on the palaeoclimate derived from glacial landform records. There are two approaches to reconstruct climate based on palaeoglacier. One is climatic reconstruction upon glacier equilibrium-line altitude(ELA)variation,and the other approach is climatic reconstruction based on glacier mass balance variation. With the difference between principle and required datasets of models,the applicability and accuracy of different models are variable. To improve the modeling accuracy,it is essential to apply a variety of models to reconstruct palaeoclimate based on the physical characteristics in the study area. Based on the previous palaeoclimate derived from glacial landform records in the Tibetan Plateau and adjacent mountains,the glaciations were driven by the drop of air temperature and the expansion of the extent of palaeoglaciers were also affected by the change in precipitation. Due to more abundant precipitation during mid-MIS3 than Last Glacial Maximum(LGM),the extent of palaeoglacier during mid-MIS3 was more extensive than that of LGM.