MODIS气溶胶光学厚度在临安大气颗粒物监测中的应用

Application of MODIS Aerosol Optical Depth in Monitoring PM_(10) Concentrations in Lin'an

基于大气辐射传输理论的研究表明,AOD(气溶胶光学厚度)与地面PM(颗粒物)浓度(以ρ计)呈正相关.利用2006—2010年MODIS晴空AOD数据产品与临安区域大气本底站监测的ρ(PM10)进行相关分析发现,二者的R(相关系数)为0.431,直接相关程度较低.根据AOD和气象能见度间的关系,获得了不同季节临安地区的气溶胶平均垂直标高,利用该垂直标高和RH(相对湿度)分别订正AOD和ρ(PM10)后,二者的相关性(R为0.576)明显提高.冬季AOD和ρ(PM10)的相关性最好,R为0.765;夏、春季次之,R分别为0.643和0.608;秋季最低,为0.442.经过对5年资料的对比分析,证实了MODIS气溶胶光学厚度经垂直标高和RH订正后,可用于临安地区地面空气污染的监测.

Theoretical analysis based on atmospheric radiative transfer has indicated a positive correlation between AOD（ aerosol optical depth） and surface-level PM （particulate matter） concentrations. This study was based on 5-year MODIS AOD product and PM10 concentration at Lin＇an Regional Background Station, for a total of 141 data pairs. A direct correlation analysis revealed a relatively low level of relationship between AOD and PMlo concentration （ R = 0. 431 ）. The seasonal average aerosol scalar heights were obtained by using a formula for visibility and AOD. After correcting by the seasonal average aerosol scalar heights and the influence of relative humidity （RH） , the correlation coefficient between AOD and PM10 concentration was significantly increased （ R = 0. 576 ）. The correlation between AOD and PMI0 concentration was also dependent on season; the highest correlation coefficient was found in winter （ R = 0. 765 after correction） , while the lowest was found in autumn （ R = 0. 442 after correction）. In summer and spring, The correlation was R = 0. 643 and R = 0. 608 respectively （after correction）. This study confirmed that, after taking aerosol vertical distribution and influence of RH into consideration, MODIS AOD can be used to evaluate the surface PM10 concentration in Lin＇an.