河南省气溶胶光学特性的时空变化特征

利用2001～2018年的Terra MODIS C6.1气溶胶产品对河南省大气气溶胶光学特性进行研究,分析气溶胶光学厚度(AOD)、气溶胶垂直柱质量浓度(AMC)和细粒子比(FMF)的时空分布特征,并针对代表性区域研究了气溶胶光学参数的时间变化特征.结果表明,河南省年均AOD和AMC及其在各个季节的空间分布均为东高西低、北高南低,与河南省特殊地势、人口分布及各地区企业数量有关,而FMF的空间分布与AOD和AMC分布相反.春季AMC值最高,而FMF值最低,表明春季主要是受到沙尘气溶胶的影响.夏季AOD和FMF值最高,而AMC值较低,主要是夏季气溶胶吸湿增长作用增强导致AOD高值出现,雨水冲刷与二次气溶胶生成量增加使夏季以细模态气溶胶为主.秋、冬季河南省AOD和AMC值相对较低,FMF值略高于春季.河南省AOD和AMC呈现逐年下降趋势;而FMF呈现上升趋势,而且2011年之后AOD、AMC和FMF的月平均峰谷差值均有所减少.

Spatio-Temporal Distribution and Variation Characteristics of Aerosol Optical Properties in Henan Province

The temporal variation and spatial distribution characteristics of aerosol optical depth (AOD), aerosol column mass concentration (AMC), and fine mode fraction (FMF) were analyzed based on the aerosol product information obtained from MODIS/Terra C6.1 from 2001 to 2018 in the Henan province. The spatial distribution of AOD and AMC in all seasons are high in the east and low in the west, and high in the north and low in the south, which was related to the special topography, population distribution, and number of enterprises in each region. Meanwhile, the spatial distribution of FMF is opposite to that of AOD and AMC. In spring, AMC was the highest, while FMF was the lowest, indicating that it was mainly affected by dust aerosol in spring. AOD and FMF were the highest in summer, while the AMC was lower, mainly because the high values of AOD in summer were caused by the hygroscopic growth of aerosol. The increase of rainwater scouring and secondary aerosol generation led to the domination of fine-mode aerosols in summer. In autumn and winter, the AOD and AMC were relatively low, and the FMF was slightly higher than in spring. The AOD and AMC in the Henan Province showed a decreasing annual trend, while the FMF exhibited an increasing trend. The average monthly peak-valley difference of AOD, AMC, and FMF decreased after 2011.