东北吉林地区云水化学航测研究

利用飞机航测于2007年夏季在东北吉林地区采集了24个云水样品,对云水的pH值与主要无机水溶性离子成分进行分析.结果表明,该地区云水呈酸性,平均pH值为4.93;主要离子成分依次为SO42-109.7μeq/L,NH4+74.8μeq/L,Ca2+71.9μeq/L,和NO3-51.4μeq/L;SO42-/NO3-的当量比为2.1,与龙凤山降水样品比值相当.云水离子浓度主要受天气形势及气团输送特征影响.集合后推气流轨迹分析表明离子浓度最高的云水样品主要受到华北地区污染输送的影响.对比同步采集的高空云水与地面降水样品,发现云下冲刷过程可对降水酸度起到一定的中和作用.

Aircraft study of cloud water chemistry over Jilin Province in Northeast China

24 cloud water samples were collected aboard an aircraft over Jilin province during June-July 2007. The pH values and concentrations of major water-soluble ions were analyzed. The results showed that the cloud water was obviously acidified, with a mean pH value of 4.93. The dominant ions were SO42-, NH4+, Ca2+, and NO3-, with mean concentrations of 109.7, 74.8, 71.9, and 51.4meq/L, respectively. The equivalent ratio of SO42-/NO3- was 2.1, which is comparable to that of the precipitation at Longfengshan. The concentrations of ions in cloud water were mainly affected by synoptic weather condition and long-range transport patterns. Ensemble trajectory analysis revealed that the cloud water with the highest ion concentrations was affected by the regional transport of air pollution from the North China Plains. Comparison of cloud water with rain water samples at ground level suggests that the acidity of rainfalls can be neutralized during the washout process.