华东地区气溶胶分布和变化特征研究

利用中分辨率光谱仪(MODIS)获得的气溶胶光学厚度(AOD)、细粒子比例(FMF)和臭氧检测仪(OMI)获得的气溶胶指数(AI)统计分析了2005—2014年我国华东地区气溶胶光学性质的时空分布特征,同时利用潜在源分析(PSCF)模型对我国华东地区AOD和AI的潜在源区进行分析。研究结果表明:华东地区的AOD、FMF和AI时空分布存在较大的差异,2005—2014年AOD和AI的平均值高值主要分布在华东地区北部,FMF的高值区则分布在华东南部地区;10 a间华东地区AOD呈现出先升高后降低的趋势,FMF波动幅度不明显,AI值有所上升;整个华东地区AOD的季节变化较为明显,春夏两季AOD明显高于秋冬两季。华东北部和中部地区夏季由于较高的相对湿度,AOD最大可达0.8以上。而在华东南部地区,夏季受到降水的影响,AOD维持在0.2~0.4之间。FMF季节变化趋势与AOD不同,夏季最大达到0.58,春季最小仅为0.26。AI平均值在冬季最大高达0.63,夏季最小,为0.27。PSCF分析显示华东地区AOD主要源区以局地排放为主,同时也存在由河南、湖北和湖南等周边省市近距离输送影响;AI以局地和北方远距离输送为主,同时也受到河南、湖北等周边省市近距离输送的影响。

A study of the characteristics of aerosol distribution and variation in eastern China

The characteristics of spatial and temporal distributions of aerosol optical depth (AOD), fine mode fraction (FMF) and aerosol index (AI) from 2005-2014 in Eastern China were analyzed based on the aerosol products of Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI). The method of potential source contribution function (PSCF) was applied to find the possible sources of AOD and AI in this region under different air mass conditions. The results showed that there was a relative large discrepancy existed in the spatial and temporal distributions of AOD, FMF and AI. The high value of the average AOD and AI from 2005-2014 distributed in the northern area of Eastern China. However, the high value of the average FMF spread across the southern part of Eastern China. AOD in this period firstly increased and then decreased, and the fluctuation of FMF was not obvious while AI presented a rising trend. There was a significant seasonal variation in AOD in eastern China. The average values of AOD in spring and summer were obviously higher than that in autumn and winter. In the northern and central regions of Eastern China, AOD reached the maximum of above 0.8 in summer due to the high relative humidity. However, AOD value of the southern region of Eastern China was between 0.2 and 0.4 because of the high-frequency precipitation in summer. Different from AOD seasonal variation, FMF of 0.58 was highest in summer, and its lowest value of 0.26 appeared in spring. While the average value of AI (0.63) was largest in winter, and the lowest value of 0.27 appeared in summer. The result of PSCF showed that local emission was the dominate source of AOD, and the short distance transport of aerosols from Henan, Hubei, Hunan and so on could also affect AOD in Eastern China. Local emission and long-range transport from north were the main sources of AI, and there was also influence coming from short distance transport of aerosols from Henan, Hubei and the surrounding provinces and cities.