中国区域气溶胶对东亚夏季风的可能影响(Ⅱ)：黑碳气溶胶及其与硫酸盐气溶胶的综合影响

 利用NCAR的新一代GCM CAM3.0模式耦合一个气溶胶同化系统，研究了中国区域黑碳气溶胶的直接气候效应。结果显示，中国区域黑碳气溶胶引起全球平均辐射强迫为0.13 W/m2，导致除了青藏高原和广西以外的中国大部分地区降温，其中东北、四川和内蒙古中北部降温最显著。由此造成海陆温差缩小，气压差降低，从而总体上使东亚夏季风减弱。但与硫酸盐气溶胶的影响相比，黑碳气溶胶使季风减弱的程度较小，长江中下游地区的降水有所增加。黑碳气溶胶加强了中国东南部地区的对流活动，这与硫酸盐气溶胶的作用相反。同时，探讨了中国区域硫酸盐和黑碳气溶胶的综合直接气候效应。结果表明，硫酸盐和黑碳气溶胶的综合作用与仅有硫酸盐气溶胶的情形十分相似，降水变化的区域也和硫酸盐的保持一致。

Possible Effects of Aerosols over China on East Asian Summer Monsoon(Ⅱ):Black Carbon and Its Joint Effects with Sulfate Aerosols

The direct effects of black carbon (BC) aerosols over China on East Asian summer monsoon have been investigated using the latest version of general circulation model (GCM) CAM3.0 developed by NCAR/UCAR, which is coupled with an off-line aerosol assimilation system. The model results show that BC aerosols over China can bring about a global average radiative forcing of 0.13 W/m2, resulting in the decrease of land surface temperature in most of China except for Qinghai, Tibet and Guangxi provinces where the surface temperature increased. Therefore, the differences in surface temperature and pressure between land and sea reduce, which finally weakens East Asian summer monsoon. BC aerosols have less effect on weakening monsoon intensity compared with sulfate aerosols. However, it increases precipitation, especially convective precipitation in the middle and lower reaches of the Yangtze River. On the contrary to sulfate aerosols, BC aerosols enhance the convective activities in the southeast of China. Besides, the joint effect of BC and sulfate aerosols over China has also been studied. The model results indicate that the synthetic effect of sulfate and BC aerosols is similar to that of sulfate aerosols only, and precipitation changes induced by the joint effect are also consistent with those by the sulfate aerosols effect.