拉萨市气溶胶光学厚度研究及MODIS产品检验

Analysis of the Aerosol Optical Depth in Lhasa and Evaluation of MODIS Aerosol Product

利用拉萨站及纳木错站地面观测数据分析了拉萨市气溶胶光学厚度(AOD)日变化、季节变化,并对MODIS产品的数据质量及适用性进行了初步检验。结果表明,拉萨市AOD在08~10时,17~20时存在明显波动,11~16时比较稳定。拉萨站与纳木错站AOD季节变化存在差异,拉萨站呈单峰型,峰值在春季,纳木错呈双峰型,主峰在春季,次峰出现在8月,季节变化极大值的出现可能与春季沙尘天气有关。拉萨站AOD整体高于纳木错站,Angstrom波长指数则相对较小,这可能与城市人类活动有关。MODIS气溶胶产品在拉萨不具适用性。

Using the ground-based observations at Lhasa and NamCo stations,the daily and seasonal variations of Aerosol Optical Depth(AO D)at Lhasa were investigated along with the preliminary validation of the quality and the adaptability of MODIS products.Results show that the AOD at Lhasa existed obvious fluctuation from 8 to 10 Am and 5 to 8 Pm while it^quite stable from 11 Am to 4 Pm.The seasonal variation exhibited different distribution at above two stations.The AOD at Lhasa indicated one peak and the AOD at NamCo presented double peaks variation with the maximum value in spring.The maximum value of seasonal variation might be related to the dust weather in spring.The AOD at Lhasa was larger than that at NamCo station as a whole with smaller angstrom wavelength index,this phenomenon probably connected with urban human activity and the aerosol product derived from MODIS was not suitable in Lhasa.