Characteristics of atmospheric dust deposition in snow on Glacier No. 4, Mt Bogeda, China

摘要

Wind-blown mineral dust derived from the crustal surface is an important atmospheric component affecting the Earth's radiation budget. Deposition of dust particles was measured in snow on the Glacier No. 4, Mt Bogeda, in the eastern Tian Shan, China. The mean number concentration of dust particles with 0.57 ＜ d ＜ 26 urn in the snowpack is 279 x 10~3 mL~(-1), with a mean mass concentration of 1,480 μg kg~(-1). Dust number size distribution showed the dominant particles with d ＜ 2 μm, while volume size distribution showed single-modal structures having volume median diameters from 3 to 25 μm. Results were compared with the data from other sites in the Tian Shan and various northern hemisphere sites. A backward trajectory model was also employed to examine the transport process of dust particles in this region. Most of the air mass originated from the southern and northwestern regions, e.g., the Taklimakan and Gur-bantunggut deserts in springtime, during the Asian dust period, which may bring plentiful aerosol dust particles from the sandy deserts. Transport of dust from western Chinese deserts to adjacent mountains is in agreement with a growing body of evidence on the importance of dust inputs to alpine regions.