华北地区沙尘天气垂直气溶胶直接辐射强迫

利用CALIOP数据和SBDART（Santa Barbara DISORT Atmospheric Radiative Transfer）辐射传输模式研究了2013~2016年华北地区8d沙尘天气气溶胶及其直接辐射强迫垂直分布特征，分析了气溶胶垂直分布和光学特性对直接辐射强迫的影响.结果表明，气溶胶集中分布在地表及以上3km范围，其中纯净沙尘型和污染沙尘型气溶胶位于上层，污染大陆型气溶胶和烟雾位于下层.大气层顶、地表和大气层的日均气溶胶直接辐射强迫分别是-38.41~-88.44，-74.03~-225.86，9.06~137.42W/m².0~8km高度范围气溶胶直接辐射强迫是负值，且随着高度的增加绝对值逐渐减小.气溶胶垂直分布对大气层顶、地表和大气层的直接辐射强迫影响较小，但对直接辐射强迫垂直分布影响较大，由气溶胶廓线差异造成的同一高度层气溶胶直接辐射强迫最大差值能达到31.18W/m².气溶胶光学厚度和单次散射反照率对直接辐射强迫影响明显.消光能力相同时，吸收性气溶胶对短波太阳光的衰减作用大于散射性气溶胶，后向散射比例大的气溶胶大于后向散射比例小的气溶胶.

Vertical distribution of aerosol direct radiative forcing in dust events over north China

Using CALIOP data and SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer) model, the vertical distribution of aerosols and their direct radiative forcing in 8 dusty days between 2013 and 2016 in north China were studied. The effects of vertical distribution and optical properties on aerosol direct radiative forcing were also analyzed. The results showed that, the aerosols are concentrated from the surface to 3km, in which the dust particles are in the upper layer, while polluted continental aerosols and smoke are in the lower layer. The daily mean of aerosol direct radiative forcing is in -38.41~-88.44 W/m² at the top of the atmosphere, and -74.03~-225.86W/m² at the surface and 9.06~137.42W/m² in the atmosphere, respectively. The aerosol direct radiative forcing is negative at 0~8km, and the magnitude gradually decreases as altitude. Vertical distribution has little effect on the magnitude of direct aerosol radiative forcing, but exhibits great influence on its vertical characteristics. The maximum difference of aerosol direct radiative forcing at the same altitude caused by the difference of aerosol profile can reach 31.18W/m². The influence of aerosol optical depth and single scattering albedo on aerosol direct radiative forcing is obvious. When the extinction ability is the same, the attenuation effect of absorbing aerosols or with large backscattering ratio on short-wave sunlight is greater than that of scattering aerosols or with small backscattering ratio.