利用2000年3月-2017年3月Terra卫星反演的MODIS气溶胶光学厚度(Aerosol Optical Depth,AOD)资料、NCEP的fnl全球业务分析数据、CMAP降水资料、 CERES SYN1deg Ed 4月平均资料以及NCEP /NCAR再分析资料等,依据中国东部冬季区域平均AOD距平具有显著的年际变化特征,将历年冬季AOD划分为5个不同的污染等级,并探讨了不同污染等级的局地成因及其与冬季风环流的联系。结果表明,中国东部冬季AOD区域平均值与气候要素场有很好的相关关系,即AOD异常偏高(低)时,入射到地面的太阳短波辐射通量减小(增加),地面气温降低(增加),地气系统冷却(加热),地面降水呈现华北与江淮内陆少、江淮东南多(华北与江淮西南部多、江淮地区东部少)的分布特征。中国东部AOD值异常偏高与风速异常偏小有关,且这种负相关关系在华北表现最明显:即AOD异常偏高(低)时,华北地面风速偏小(大),江淮地面风速偏大(小)。个例分析表明,纬向风速异常偏小、东风异常及阿留申低压偏弱是2013年AOD异常偏高的主要原因。
英文摘要:
In the present paper,using the latest aerosol optical thickness(AOD) data(Collection 6) derived from the Moderate Resolution Imaging Spectroradiometer(MODIS) on board the Terra spacecraft,the National Centers for Environmental Prediction Final(NCEP FNL) Operational Global Analysis data,Climate Prediction Center(CPC) Merged Analysis of Precipitation ( CMAP) data,CERES syn1deg Ed4 monthly average data,NCEP /National Center for Atmospheric Research ( NCAR) reanalysis data from March 2000 to February 2017,the possible relation of AOD variations with winter monsoon is investigated.According to the AOD values,five different pollution levels are defined.The results show that the abnormally high AOD value in eastern China is related to the anomaly of wind speed.The negative correlation is most obvious in northern China.In winter,the averaged AOD over eastern China has a high negative correlation with the climatic variables.When the AOD is abnormally high (low),the short-wave solar radiation reaching the ground reduces( increases);the surface temperature declines (rises);the atmosphere is cooling ( heating);the surface precipitation displays characteristics of lower inland, and higher in the southeast(higher inland,lower in the southeast); and the influence of wind speed anomalies on the regional distribution of AOD anomalies is significantly different.When the AOD anomaly is high (low),the surface wind speed in northern China is small(large) and large(small) in the Jianghuai region.The case analysis shows that the anomalously high AOD in 2013 is due to the weak zonal wind and the weak Aleutian low pressure.These results have scientific significance for deepening our understanding of the relationship between the changes in winter monsoon and aerosol pollution.