中文摘要：

采用WRF／Chem模式对2004年4月6—8日发生在广东省一次典型冷锋酸雨过程的气象场和污染物分布进行数值模拟，分析此次酸雨过程中致酸污染物SO2、NOx、硫酸盐气溶胶和硝酸盐气溶胶的主要分布特征，进而探讨此次酸雨的成因．结果表明，冷锋过境前，边界层高度较低，不利于污染物扩散，主要是局地排放致酸；冷锋过境形成了逆温层，污染物在逆温层内成片状均匀分布，使广东省出现大范围的酸雨．污染物浓度分布的模拟结果表明：SO2以本地源为主；NOx扩散范围较S02广，分布更均匀；硫酸盐气溶胶和硝酸盐气溶胶6日主要分布在粤北，7日成大范围片状分布，与pH值的分布特征相似．

英文摘要：

The meteorological field and the distribution of air pollutants during a typical cold front acid rain event in Guangdong Province on April 6-8, 2004 were simulated by WRF/Chem model. The spatial distributions of ambient SO2 , NOx, and particulate sulfate and nitrate were investigated, and the formation processes of the acid rain event were then discussed. The results showed that the lowered boundary layer heights before cold front were the main reason for the unfavorable diffusion for air pollutants, and the acid rain was generally a local issue. Along with the advancing of cold front, an inversion layer was developed, in which the air pollutants homogeneously distributed in a large scale, resulting in acid rain episode covering most of Guangdong Province. The model results indicated that the ambient SO2 was mainly due to local emissions. NO~ showed larger scale transportation and hence more evenly distributed than SO2. Particulate sulfate and nitrate, with similar spatial pattern of pH values, showed a hotpot in the northern Guangdong on 6 April 2004, and expanded to cover a wider area on 7 April 2004.