中文摘要：

利用太阳光度计CE-318对MODIS C5产品在西安地区的适用性进行了验证,结果表明,C5产品与太阳光度计CE-318反演的气溶胶光学厚度具有较好的一致性,相关系数为0.91,误差在预期范围内的样本占总数的74.5%,满足NASA设计要求,反演数值可用于区域气候变化和大气污染研究。同时利用2000—2010年MODIS C5气溶胶产品,分析了气溶胶光学厚度和小颗粒气溶胶对总光学厚度贡献的多年变化特征,得到：（1）沙尘粒子和人类活动产生的细粒子是关中盆地气溶胶的主要来源,气溶胶分布受地形影响显著,在特殊地形和盛行风向影响下,气溶胶粒子在边界层的水平扩散中受到抑制,并在其东部出现堆积,气溶胶光学厚度分布呈现出东高西低的趋势,高值中心主要分布在西安和渭南南部,是沙尘气溶胶和人类活动产生细粒子气溶胶的共同作用;关中西部多年处在气溶胶光学厚度的低值区,是由人类活动和工业排放产生的细粒子气溶胶所致。（2）关中不同地区气溶胶光学厚度的时间序列变化存在差异,其西部地区近10年呈波动下降趋势,中部和东部则呈波动增加趋势。（3）关中地区自西向东气溶胶光学厚度贡献中粗粒子的比重逐渐加大,近10年关中地区细粒子气溶胶污染有逐年加重的态势,其中中东部城市较为显著。

英文摘要：

Based on the CE318-sun photometer data in north part of Xi＇ an, the applicability of the aerosol optical thickness （AOD） products from MODIS Collection 5 over Guanzhong region of Shanxi Province is validated. The result shows that there is a good relationship between the AOD product of MO- DIS Collection cg data and CE31g-sun photometer data, and its correlation coefficient is about 0.91. Using the MODIS Collection 5 AOD product from 2000 to 2010, the long term variations of AOD and FMF （the fine--mode fraction） are analyzed. It is found that the main source of aerosol over Guanzhong region is dust storm and urban/industrial aerosols. At the east region of Guanzhong, due to the effect of special ter- rain and prevailing wind, the urban/industrial aerosol and dust aerosols are accumulated. While the main source of aerosol over the west part of Guanzhong is urban/industrial aerosol. Further more, it is found that the time series of AOD over the different parts of Guanzhong exist difference. Over the west part of Guanzhong there is a slightly decrease of AOD, and there is an obviously increase over the east part. After the analyzing the ten-year trend of FMF, it is also found that, although the ratio of fine-mode AOD is be- came smaller from west to east over Guanzhong region, the pollution of fine-mode aerosol over the whole region IS worsening.