利用"兰州大学半干旱气候与环境观测站"2006年8月至2007年4月的CE-318全自动跟踪太阳光度计观测资料, 分析了黄土高原半干旱地区气溶胶光学厚度(AOD)的变化特征。结果表明, 黄土高原半干旱地区气溶胶光学厚度谱基本满足Angstrom关系; 在可见光和近红外波段, 随着波长的增大, 气溶胶光学厚度是减小的; 黄土高原半干旱地区AOD日变化类型主要有单峰型、稳定型、上升型3种。逐日变化特征显示, 降水对气溶胶粒子具有明显的湿清除作用, 霾的出现导致AOD明显增大; AOD日均值主要集中在0.1~0.4之间, 日极大值在08~11时(北京时, 下同)出现的频率最多, 日极小值在12~13时、14~17时出现的频率最多。气象条件对AOD有明显的影响, 在南风情况下AOD大, 东风情况下AOD小, 霾与晴天相比, AOD明显增大; 对同一波段, 风向差别引起的AOD的差异较晴天与霾相比引起的AOD的差异要小。

The AOD's variation characteristics in semi-arid region of Chinese Loess Plateau are analyzed by using the observed direct solar radiation data during August 2006 to April 2007 gained by the automatic sun tracking spectrophotometer CE-318 of SACOL. The results show that the AOD spectrum distributions in semi-arid region of Chinese Loess Plateau very nearly follow Angstrom's formula. In visible and near-infrared band AOD decreases while wavelength increases. There are three types of diurnal variations, and they are: Single peak type, steady type and rising type. Diurnal variation characteristics of AODshow that the precipitation has wet removal efficiency for aerosol particles and AOD obviously increases while haze appears. Diurnal average of AOD ranges from 0.1 to 0.4, the frequency of maximum AOD value is the highest at 08~11BST, and the frequency of minimum AOD value is the highest at 12~13BST, 14~17BST. The meteorological condition has obvouisly effect on AOD, under south wind AOD is big but under east wind AOD is small, Comparing with clear condition and haze AOD is obvouis big. For same band, the difference of AOD caused by wind direction is smaller than that caused by haze.