半干旱区沙尘天气对0.010～10μm沙尘气溶胶分布的影响

Characteristics of 0.010-10 μm Dust Aerosol Distribution in Dusty Weather in Semiarid Areas

利用WPS粒子谱仪对内蒙古朱日和背景天气及沙尘天气的气溶胶数浓度进行了观测,研究了不同天气背景下沙尘气溶胶数浓度及谱分布特征.结果表明：在背景天气和沙尘天气下,0.010-0.020,0.021-0.100,0.101-1.000,1.001-2.500μm等粒径段的气溶胶数浓度差别较大;沙尘天气对各粒径段,尤其是大于1.0μm的气溶胶数浓度影响较大,沙尘暴过程中1.001-2.500μm粒径段的气溶胶数浓度约为背景天气的35倍;各粒径段气溶胶数浓度在不同天气背景下的日变化规律有所不同,受气象要素的影响较大.对沙尘气溶胶谱分布的分析可知,沙尘暴发生前后1 h的沙尘气溶胶谱型均符合Lorentz分布,背景天气下同时段的沙尘气溶胶谱型也符合Lorentz分布;沙尘天气下沙尘气溶胶谱型在沙尘暴发生前1 h的主峰值比背景天气高1个数量级,沙尘暴发生后1 h的峰值半径明显移向大粒子.

Using a WPS particle spectrometer, this study observed the concentration of 0.010-10μm aerosols in different weather conditions in spring in Zhurihe, Inner Mongolia, and researched the concentration and spectral distribution characteristics of sand dust aerosols under different weather backgrounds. The research results show that dust aerosol number concentrations of 0.010-0.020, 0. 021-0. 100 0. 101-1. 000 and 1. 001-2. 500μm particles are largely different in dusty weather and in the background weather, especially for aerosols with diameter larger than 1.0 μm. The mean concentration of 1.001-2.500 μm aerosols in dusty weather is 35 times that of the background weather. In addition, the daily change characteristics of 0.010-0.020, 0.021-0.100, 0.101-1.000 and 1.001-2.500 μm particles have larger varieties under different weather conditions. Meteorological factors have obvious effects on the daily distribution characteristics of dust aerosols. At the same time, the dust aerosol size distribution in background and dusty weather was analyzed. It was discovered through spectral pattern fitting of the number concentration of sand dust aerosol that the distributions within 1 h before and after a sandstorm in two different weather backgrounds accord with a Lorentz distribution. The peak of sand dust aerosol distribution 1 h before a sandstorm in dusty weather is an order of magnitude higher than that in the background weather, and the peak radius 1 h after a sandstorm shifts obviously to bigger particles.