Albedo reduction as an important driver for glacier melting in Tibetan Plateau and its surrounding areas

Abstract

Commonly known as the Asian Water Tower, glaciers in the Tibetan Plateau (TP) and its surrounding regions are vital to the regional water cycle and water resources in the downstream areas. Recently, these glaciers have been experiencing significant shrinkage mostly due to climate warming, which is also profoundly modulated by the surface snow albedos. In this study, we summarized the current status of the glaciers in the TP and its surrounding region, focusing on glacier retreat and mass balance. Furthermore, based on glacier surface snow albedo data retrieved from MODIS (moderate resolution imaging spectroradiometer, with resolution of 500 m × 500 m), we investigated the potential impact of glacier surface snow albedo changes on glacier melting. The results demonstrated that glacier shrinkage was pronounced over the Himalayas and the southeast TP. The regional distribution of the average albedos on the glacier surface (during summer) exhibited similar patterns to those of glacier retreat and mass balance changes, indicating a significant relationship between the annual glacier mass balance and glacier surface albedos during the past decades (2001–2018). This reflected that albedo reduction, in addition with rising temperatures and changing precipitation, was a significant driver of glacier melting in the TP. Estimations based on glacier surface summer albedos and snowmelt model further suggested that the effect of surface albedo reduction can drive about 30% to 60% of glacier melting. Due to its strong light absorption, black carbon (BC) in snow can be a substantial contributor to albedo reduction, which enhanced glacier melting in summer in the TP by approximately 15%. This study improved our insights into the causes of glacier melting in the Tibetan Plateau.