辽宁省背景地区降水化学特征及其与大气传输的关系

为了解辽宁省背景地区降水化学特征及其与大气传输的关系，于2007年2月─2008年1月在辽中县水文监测站进行了降水化学特征观测，测量项目包括降水pH，电导率和离子浓度. 观测期间降水pH为3.4～7.3，降水量加权平均值为4.6，整体呈酸性. 降水中主要阴离子为SO₄2-和NO₃-，浓度分别为154.3和53.4 μeq/L,二者占阴离子总量的76.8%； 主要阳离子为NH₄+和Ca2+，浓度分别为124.6和89.2 μeq/L，占阳离子总量的70.6%. 利用后向气流轨迹分析了降水气团来源对降水化学的影响，结果表明:在辽宁省及周边地区的局地气团影响下，降水中离子浓度最高；而在起源于东亚地区，经朝鲜半岛到达的南-东南气团影响下，降水次数虽最多，但离子浓度最低. 

The Characteristics of Precipitation Chemistry and Its Relationship with Atmospheric Transport at a Background Site in Liaoning Province

To better understand the characteristics of precipitation chemistry and its relationship with atmospheric transport at a background site in Liaoning Province, pH, conductivities and ionic concentrations of rain samples were analyzed at Liaozhong hydrological site from February 2007 to January 2008. pH was found to range from 3.4 to 7.3, with a precipitation volume weighted average of 4.6, representing generally acidic acidity. The major anions, SO_4~(2-) and NO_3~-, were found to be 154.3 and 53.4 μeq/L respectively and occupied 76.8% of all anions. With concentrations of 124.6 and 89.2 μeq/L respectively, the NH_4~+ and Ca~(2+) occupied 70.6% of all cations. Backward trajectory analysis was conducted to gain further insights into the influence of the origination and travelling path of air masses on the chemical composition of the collected rain samples. The results suggest that the samples with high ion concentrations were found to be mainly influenced by locally originated air masses, while those with lower ion values were mainly caused by south-southeast air masses originating from Eastern Asia and then traveling across the Korean peninsula.