中文摘要：

本文应用WRF-Chem（Weather Research and Forecasting—Chemistry）模式研究中国东部地区气溶胶及其部分组分（硫酸盐、硝酸盐和黑碳气溶胶）在天气尺度下的辐射强迫和对地面气温的影响.5个无明显降水时间段（2006年8月23～25日、2008年11月10～12日、2008年12月16～18日、2009年1月15～17日和2009年4月27～29日）的模拟显示,气溶胶浓度呈现显著的白天低,夜间高的日变化特征,且北方区域（29.8°～42.6°N,110.2°～120.3°E）平均PM2.5近地面浓度（40～80μg m-3）高于南方区域（22.3°～29.9°N,109.7°～120.2°E,30～47 μg m-3）.气溶胶对地面2m温度（地面气温）有明显的降温效果,在早上08：00（北京时,下同）和下午17：00左右最为显著,最高可降低约0.2～1 K,同时气溶胶的参与改善了模式对地面气温的模拟.本文还通过对2006年8月23～25日一次个例的模拟,定量分析了气溶胶及其部分组分（硫酸盐、硝酸盐和黑碳气溶胶）的总天气效应（直接效应＋间接效应）、直接效应和间接效应分别对到达地面的短波辐射和地面气温的影响.北方区域平均气溶胶直接效应所造成的短波辐射强迫要高于南方区域,分别为-11.3 Wm^-2和-5.8Wm^-2,导致地面气温分别降低了0.074 K和0.039 K.南方区域平均气溶胶间接效应所产的短波辐射强迫高于北方区域,分别为-14.4 W m^-2和-12.4W m^-2,引起的地面气温的改变分别为-0.094K和-0.035K.对于气溶胶组分,硫酸盐气溶胶的直接效应和间接效应的作用相当,其总效应在北方和南方区域平均短波辐射强迫分别为-7.0 Wm^-2和-10.5 Wm^-2,对地面气温的影响为-0.062 K和-0.074 K,而硝酸盐气溶胶的作用略小.黑碳气溶胶使得北方和南方区域平均到达地表的太阳短波辐射分别减少了6.5 Wm^-2和5.8 W m^-2,而地表气温则分别增加了0.053 K和0.017 K,相比于间接效应,黑碳气溶胶的直接效应的影响更加显著.

英文摘要：

Using the WRF-Chem （Weather Research and Forecasting—Chemistry） model,we investigate aerosol radiative forcing and its impacts on surface air temperature in Eastern China on the synoptic scale.Simulations of five selected periods without precipitation （August 23-25,2006; November 10-12,2008; December 16-18,2008; January 15-17,2009; and April 27-29,2009） indicate that aerosol concentrations are generally lower in the daytime and higher at night.Simulated surface-layer concentrations of PM2.5 averaged over Northern China （29.8°-42.6°N,110.2°-120.3°E,）are 40-80 tg m-3,higher than the simulated values of 30-47 μg m3 in Southern China （22.3°-29.9°N,109.7°-120.2°E）.Aerosols exerted a large cooling effect on surface air temperature （SAT,2 m above ground level）,and the effect is the strongest at 08：00 and 17：00 with decreases in temperature by 0.2-1 K.We also find that including aerosols in simulations improves the simulation of SAT.Based on the simulation of a weather event during August 23 to 25 in 2006,we quantitatively analyze the total （direct ＋ indirect）,direct,and indirect radiative effects of aerosols on SAT.Shortwave radiative forcing at the surface induced by direct effects of aerosols is stronger in Northern China than that in Southern China,with average forcings of-11.3 W m^-2 and-5.8 W m^-2,respectively,and corresponding coolings of SAT by 0.074 K and 0.039 K.However,shortwave radiative forcing induced by indirect effects of aerosols is weaker in Northern China than that in Southern China,with average forcings of-12.4 W/m2 and-14.4 W m^-2,respectively,and corresponding coolings of SAT by 0.035 K and 0.094 K.The direct and indirect effects of sulfate are of similar magnitude.The total effect of sulfate on shortwave radiative forcing in Northern and Southern China is-7.0 W m^-2 and-10.5 W m^-2,respectively,causing a cooling of SAT by 0.062 K and 0.074 K,while the effect of nitrate is relative weak.Due to black carbon aerosols,the solar shortwave radiation reaching the s