Glacier changes since the Last Glacial Maximum on two slopes of Mt Noijin Kang-Sang, Southern Tibetan Plateau

Abstract

In recent decades, most glaciers have been melting, thinning and retreating globally in response to continuously increasing temperatures. We simulated ice thicknesses and volumes on the east and west slopes of Mt Noijin Kang-Sang, Southern Tibetan Plateau (TP), since the Last Glacial Maximum (LGM), using a glacial flowline model. The simulated average ice thicknesses during the LGM and Lateglacial (LG), Early Holocene, Neoglacial and the Little Ice Age (LIA) periods were 1.4, 1.3, 1.1 and 1.2 times greater than those of modern glaciers in the Gangbu (eastern slope) and western valleys, respectively. In the Gangbu Valley, areas from the LGM-LG to LIA periods were 1.7, 1.5, 1.4 and 1.2 times greater than the modern glacier area, and the volume expansion indexes were 2.2, 1.9, 1.5 and 1.4. In the western valleys, the area expansion indexes were 2.2, 1.9, 1.5 and 1.4 times greater than the modern glacier, and volumes were 5.4, 4.4, 3.4 and 2.9 times greater, respectively. Glaciers in the western valleys retreated more extensively than those on the eastern slopes of Gangbu Valley after the LGM-LG, probably due to the smaller glaciers on the leeward western slopes with lower elevations. Equilibrium-line altitudes dropped ~425 m in Gangbu Valley and ~385 m in the western valleys during the LGM-LG, corresponding to a 3.8–4.1 °C temperature decrease in this region, which was consistent with cooling on the central Tibetan Plateau, but lower than cooling at the south-eastern edge of the Tibetan Plateau.