2006年春季青岛气溶胶光学厚度与气溶胶指数、能见度的关系分析

The Correlation Analysis of Aerosol Optical Depth,Aerosol Index and Visibility in Qingdao Spring 2006

由多波段天空辐射计观测的太阳直接辐射和散射辐射计算得到2006年春季22个晴天的大气气溶胶光学厚度(AOD),利用OMI(臭氧监测仪)的气溶胶指数(AI)线性插值得到相应22 d的气溶胶指数,说明AOD与AI具有较好的相关关系,并拟合出两者的线性关系式。分析AOD与实测水平能见度的关系,说明春季在少云或无云天气,大气中气溶胶含量高是导致能见度水平下降的主要原因。根据2个不同的能见度公式,分别由浑浊度系数和消光系数来计算22 d的水平能见度,并与实际观测值做相关,得到相关系数分别为0.764,0.760。当气溶胶标高取1.3 km时,由消光系数计算得到的水平能见度整体小于实测水平能见度;由浑浊度系数计算得到的能见度有11 d大于实测水平能见度,另外11 d小于s实测水平能见度。

Aerosol optical depth（AOD） was calculated by using the direct sun radiance and scatter data collected by a multi-wavelength sky radiometer during the 22 sunny days in spring 2006. The corresponding aerosol index（AI） was obtained by Linear Interpolation Algorithm from OMI aerosol index. A good linear relationship between AOD and AI was found, and the linear function was then explored. By analyzing AOD and horizontal visibility, a conclusion was given： the high concentration of aerosol was the dominant factor that caused the low visibility in a cloud-free or partly cloudy weather. The horizontal visibilities during the 22 days were calculated with the turbidity coefficient and extinction coefficient separately, based on two different visibility functions. The results showed that the horizontal visibilities were highly correlated with the observed data, and the correlation coefficients were 0. 764, 0. 760, respectively. When the aerosol scale height was given value 1.3 km, the visibility values calculated with extinction coefficient were smaller than the observed data during the whole sampling time; whereas the visibilities calculated with turbidity coefficient had higher values for 11 days compared with the observed data and lower values for the rest of the time.