川南城市群大气灰霾时空分布特征及成因分析

Analyses on the spatial-temporal distribution features and causing factors of atmospheric haze in the southerncity-group of Sichuan

以2006~2015年四川南部的MODIS 3km AOD日产品及地面观测数据为基础,利用本地CE318数据对MODIS AOD产品进行校验,确保AOD产品的可用性;建立了AOD与PM_(2.5/10)之间的关系模型,并重点分析了川南城市群的大气灰霾时空分布特征及其成因.结果表明:CE318AOD与MODIS AOD的相关性为0.779,PM_(2.5)、PM_(10)与MODIS AOD的最优相关性为0.894、0.83;在空间上,川南AOD均值呈现出北高南低的格局,其中内江市和自贡市AOD值最大;在时间上,2006~2013年AOD均值变化不明显,2013年后明显下降;季节上表现为春冬季高、夏秋季低,其中春季AOD高值占比最大;月变化特征表现为2~4、9月AOD值高,其他月AOD值低;川南AOD的时空分布受地形、工业、风向风速、流场、边界层高度等因素影响,其中地形和流场对川南AOD的空间分布影响最为突出.

This study checked the quality of MODIS3km AOD daily data using the local CE318data in southern Sichuan.After ensuring the availability of MODIS AOD product,the relationship model of MODIS AOD and PM2.5/10was set up.And the temporal-spatial characteristics of atmospheric haze in the city group of Southern Sichuan were analyzed.Thecorrelation coefficient between CE318AOD data and MODIS AOD product was0.779,and the optimal correlationcoefficient between PM2.5,PM10and MODIS AOD was0.894,0.83respectively.Spatially,the value of average AOD inthe northern region was higher than the southern region of southern Sichuan,and the cities with highest AOD wereNeijiang and Zigong.Temporally,the averaged AOD had no significant change from2006to2013,but decreasedobviously after2013.Also the averaged AOD was higher in spring and winter,but lower in summer and autumn,and thelargest proportion of high value was in spring.The monthly variation features showed that the AOD value was high fromFebruary to April and September and low in other months.The temporal and spatial distribution of AOD in SouthernSichuan were affected by terrain,industrial,wind speed and direction,flow field,PBL and other factors,among which,theterrain and flow field were the most prominent factors.