Vol18 No.2: 367-376
【Title】Size distribution of PM20 observed to the north of the Tibetan Plateau
【Author】ZHOU Cheng-long1,2; YANG Fan1,2; HUO Wen1,2; MAMTIMIN Ali1,2; YANG Xing-hua1,2*
【Addresses】1 Institute of Desert Meteorology, China Meteorological Administration, Urumqi 830002, China; 2 Taklimakan Desert Meteorology Field Experiment Station, China Meteorological Administration, Urumqi 830002, China
【Corresponding author】YANG Xing-hua
【Citation】Zhou CL, Yang F, Huo W, et al. (2021) Size distribution of PM20 observed to the north of the Tibetan Plateau. Journal of Mountain Science 18(2). https://doi.org/10.1007/s11629-020-6086-3
【Abstract】The size distribution of airborne dust particles is an important parameter in the measurement of dust emissions due to wind erosion, and a quantitative and accurate description is necessary. Observations regarding the size distribution of airborne dust particles are currently lacking in Tibetan Plateau (TP). This study aims to obtain a dust particle size distribution and compare the difference in spatial distribution at a field site (FS) and two urban observation sites (Minfeng and Hetian), in the north of the TP, under the condition of the dust-days and clear-days. The observation data was collected from 5 July to 4 August, 2019. The mass concentration of dust (PM20) was measured with a 10-stage quartz crystal microbalance cascade impactor. The results suggested that 91.9% of the particles were less than 1.4 μm on clear-days, and particles of d≥ 1.4 μm increased to 27.2% with the occurrence of the dust events. More than 80% of the airborne dust particles were less than 1.4 μm for each friction velocity. The proportion of d < 0.7 μm was the greatest at 3.0 m (above the surface, similarly hereinafter) on dust-days, while the proportion of d > 0.7 μm was the greatest at 0.5 m on clear-days. During urban observation, with the occurrence of dust events, the concentration of a particle size greater than 2.5 μm increased most significantly in Minfeng, while the concentration of a particle size less than 0.7 μm increased most significantly in Hetian. Moreover, the proportion of particles with d < 0.7 μm had the smallest difference, while the proportion of particles with d > 1.4 μm had the most obvious difference among these three sites.
【Keywords】Dust day; Clear day; Friction velocity; Field; Urban; Coefficient variation