Impact of fine-dust air burden on the mass balance of a high mountain glacier: a case study of the Chongce ice cap, west Kunlun Shan, China

摘要

The coherent variations of annual snow accumulation rate and dust deposition over 60 years are recorded in an ice core drilled at 6530 ma.s.l. on the Chongce ice cap, located in the west Kunlun Shan, south of the Taklimakan desert in China. These records were investigated in the context both of the dust transport pathways from the source region and of climatic changes in this arid environment. The factors relating the dust transport from the source to sink area were taken into account to ascertain the integration of these factors on the precipitation-forming process at high elevations. Results indicate that: (1) dust is predominant among aerosols in precipitation at high altitude; (2) the dust aerosol population may be more instrumental than the vapor supply in the formation of precipitation at such altitudes; (3) compared to low-elevation glaciers, snow accumulation on high mountain glaciers seems to be more sensitive to changes in the concentration of air-burden dust particulates, which are closely related to the climatic variations around the desert region; and (4) under the current climate conditions surrounding the desert region, the decreasing trend in snow accumulation, in concert with the decrease in dust deposition that has occurred over the past several decades, might continue. This effect on snow accumulation at high altitudes may explain one of the elements potentially responsible for the longer-term glacial variation, i.e. the glacial retreat that has lasted for decades in central Asia.