Modeling mass balance and volume of Xiao Dongkemadi glacier in the Central Tibetan Plateau from 1989 to 2050

Abstract:

The Tibetan Plateau (TP) holds ten thousands of alpine glaciers in mid-latitude, which have shrunk with an accelerating retreat rate recently. Here, we applied a temperature-index distributed mass-balance model coupled with a volume-area scaling method to Xiao Dongkemadi Glacier (XDG) in the central TP, to assess its response to climate change. The result shows the simulated mass balance is in a good agreement with observations (R²=0.75, p<0.001) during the period of 1989-2012. The simulated mean annual mass balance (-213 mm w.e.) is close to the observation (-233 mm w.e.), indicating the model can be used to estimate the glacier variation in the future. Then the model was forced by the output of RegCM4 under the climate scenarios RCP4.5 and RCP8.5 from 2013 to 2050. The simulated terminus elevation of the glacier will rise from 5454m a.s.l. in 2013 to 5533m a.s.l. (RCP4.5) and 5543m a.s.l (RCP8.5) in 2050. XDG will lose its volume with an increasing rate of 600-700m³ a^-1 during the period of 1989-2050, indicating the melting water will enhance the river runoff. But for the long term, the contribution to the river runoff will decrease for shrinkage of glacier scale.