从宽谱晴空大气透过率提取气溶胶光学信息

RETRIEVE AEROSOL OPTICAL INFORMATION FROM ATMOSPHERIC BROAD-BAND TRANSMITTANCE ON CLEAR SKY

大气气溶胶光学厚度是评价大气污染,研究气溶胶辐射效应的一个关键因子。结合五道梁地区MS-120太阳光度表观测及该地区宽谱太阳直接辐射观测资料,利用最小二乘法,拟合了晴空大气透射比与ngstr m浑浊度系数(1000nm波长气溶胶光学厚度)、1000nm波长气溶胶透射比回归方程。利用回归方程,从该地区晴空大气透射比中提取出了ngstr m浑浊度系数,利用ngstr m浑浊度系数与波长指数的关系,计算了五道梁地区波长指数的变化。计算了ngstr m浑浊度系数增大致使到达地表的太阳直接辐射的衰减量。

The atmospheric aerosol optical depth is the key factor for evaluating atmospheric pollution and studying aerosol radiative effect. In this paper, data observed by MS-120 phtosunmeter and by pyrheliometer on the ground were combined. The regressive equation between atmospheric transmittance on clear-sky (Ta) and Angstrom turbidity coefficient (β) and the regressive equation between the β and aerosol wavelength exponent (α) were obtained using least square method. The regressive equation between Ta and aerosol transmittance at 1000 nm wavelength (Tβ) was obtained as well with the same method. As a result, β is derived from Ta. And then, α can be calculated. At last, the decrease of direct solar radiation on clear sky could be got with Iob subtraction Itesti.