中国西北地区大气气溶胶散射光学厚度分析

Analyses on Aerosol Scattering Optical Depth in the Arid Region of North-West China

提出一种利用地方气象台站测得的地表宽谱 ( 0 .3～ 4 μm)逐日太阳辐射日总量资料 (包括太阳总辐射和漫射太阳辐射 )来估算晴空无云天气条件下背景大气中大气气溶胶散射光学厚度的方法 ,这主要是基于地表的太阳总辐射和漫射太阳辐射对大气气溶胶散射光学特性的敏感性。该方法建立在观测数据和模式计算结果相互比较的基础上 ,而不需要知道某地相关的云、臭氧或水汽的探空资料。利用此方法 ,我们使用来自我国西北干旱地区 6个地方气象台站 (兰州、敦煌、民勤、格尔木、乌鲁木齐、喀什 ) 1986— 1992年的逐日太阳总辐射和漫射太阳辐射日总量资料 。

A method for estimating aerosol scattering optical depth in the atmospheric column in clear sky with the daily total of solar radiation (include global radiation and diffuse radiation) in operation whole\|spectral(0.3~4 μm) measured at meteorological stations is described, based on the sensitivity of global radiation and diffuse radiation to aerosol physical optical properties. The method is established based on the comparison between observed data and model calculation. The 550 nm aerosol scattering optical depth can be estimated with the method without consulting sounding data about water vapor, ozone and information of cloud condition. \ \ The seasonal and inter\|annual variations of aerosol scattering optical depth in the atmospheric column in clear sky are analyzed by using the data observed at 6 meteorological stations (Lanzhou, Dunhuang, Minqing, Geermu, Wulumuqi, Kashi) in the arid region of North\|West China during the period from 1986 to 1992 . Some interesting results will be revealed. The results are as flows: (1) Aerosol scattering optical depth have maximum values on the spring 1992, this may be the effects of Pinatubo volcanic eruption; (2) Aerosol scattering optical depth at other 5 stations have Minimum values in autumn or winter, whereas it happens in summer in Lanzhou; (3) Aerosol scattering optical depth are large in winter in Lanzhou, Wulumuqi and Kashi, these may be the effects of geography and city industrialization.