Comprehensive evaluation of black carbon effect on glacier melting on the Laohugou Glacier No. 12, Western Qilian Mountains

Abstract. Global warming and surface albedo reduction by black carbon (BC) in glacier jointly accelerated glacier melting, but their respective contributions remain unclear. This study developed a dynamic deposition model of light absorbing particles (LAPs), which coupled with a surface energy and mass balance model. Based on the coupled model, we further assessed atmospheric deposited BC effect on glacier melting for a period of September 2011–August 2012 on the Laohugou glacier No. 12 in the western Qilian Mountains. It was found that BC in glacier surface caused 13.1 % of annual glacier-wide melting, of which atmospheric direct deposited BC reduced albedo with 0.02 and accounted for 9.1 % of glacier melting. The air temperature during recent two decades has increased by 1.5 ℃ relative to that during 1950s, which accounted for 51.9 % of current glacier melt. Meanwhile, based on the BC emission increased by 4.6 times compared to the early Industrial Evolution recorded in an ice core, the increased BC accounted conservatively for 6.7 % of current glacier melting. Despite the importance of LAPs regarding glacier melting, their variation on the ice surface remains unclear, and relevant observations are urgently needed to improve simulation of the process.