Particle size distribution of insoluble mineral dust in snow from the East Rongbuk Glacier of Mt. Everest

초록

The dust in snow is insouluble mineral particles which are fractions of the atmospheric aerosol that have been deposited on the surface of the cold regions along with the dalling snow. The dust size distribution of the minneal particles interval 2 to 60 um radius has been measured in snow pit collected from the East Rongbuk Glacier (ERG) in the northeastern slope of Mt. Everest in the central Himalaya. A 2.1-mdepth snow pit was collected at 6576 m (28o01'N, 86o57'E) in September 2005. Particle size distributions of dust were determined using a Multisizer 3 Coulter Counter set up in a class 10 clean bench in a class 1000 clean laboratory in Korea Polar Research Institute (KOPRI). The instrument has been installed with a 100 um of aperture tube. The samples were made 2% conductive solution by adding a pre-filtered 4% NaCl electrolyte solution. At least three consecutive counts were performed on each volume of 500 uL. Statistical ahalyses were performed the volume size distribution considering from 2 um to 10 um. The mass was calculated from the measured volume assuming a particle density of 2.5 g cm-3. The dust concentrations of the ERG snow pit ranged from 131 to 4280 g mL-1 with the mean concentration of 757 ng mL-1. The correlations of dust concentration with the concentrations of Ca2+, SO42-, Al and Pb in snow pit were investigated. The dust record in snow pit showed the strong and positive correlation with the concentration of Ca2+, Al and Pb. The study of dust record in snow provide new information to investigate on the climate change.