Characteristics of atmospheric dust deposition in snow on the glaciers of the eastern Tien Shan, China

Wind-blown mineral aerosol dust derived from the crustal surface is an important atmospheric component affecting the Earth's radiation budget. Deposition of water-insoluble dust was determined in snow deposited on Urumqi glacier No. 1, Haxilegen glacier No. 51 and Miaoergou glacier, eastern Tien Shan, China. Analysis of the horizontal distribution of snow depth and concentration, and flux of dust particles in the snow cover suggests that dust deposition differs on each of these glaciers as the atmospheric environment changes from west to east. Mean mass concentrations of micro-particles in the size range 0.57-26 mu m diameter at the three locations are respectively 969, 1442 and 3690 mu g kg(-1), with an increasing trend from west to east. Dust layers in the snow cover contain Na- and Ca-rich materials typically found in central Asian dust particles. Volume size distributions of dust particles in the snow showed single-modal structures having volume median diameters of 3-22 mu m. Dust profiles in the snow cover over the past 4 years reveal frequent, sporadic high dust concentrations with a large year-to-year variability, implying that dust deposition in the eastern Tien Shan is very sensitive to atmospheric environment change.