贵州龙里实验区酸性降水特征及变化趋势

Analysis of acid rain's characteristics and variation tendency in Longli experimental plot,Guizhou

以2007年4月～2008年12月贵州龙里实验区的降水监测数据为基础,运用统计学方法对该地区大气降水酸度和化学组成的特征及其季节变化趋势进行分析.结果表明,研究期内当地的降水pH均值为4.70,酸雨占降雨次数的70.1%和总降雨量的76.7%.酸雨的发生呈现一定的季节变化特征,其中春季为酸雨高发季节.降水中SO42-、NO3-、NH4+、Ca2+等含量较高.与相关研究进行对比,初步认为该地区大气降水所带来的S和N的湿沉降量尚未超过当地生态系统的酸沉降临界负荷.

From April 2007 to December 2008,the rainfalls had been collected and measured at Longli experimental plot in Guizhou Province.The acidity and chemical composition of rainwater were analyzed with statistical methods to reveal the characteristics and seasonal tendency of local acid rain.76.7% of the total capacity of rainwater were acidic with an average pH value of 4.70 and the frequency of acid rain accounted for 70.1% during the study period.Meanwhile,the concentrations of SO42-,NO3-,NH4＋,Ca2＋ of rainwater were higher in spring with much more occurrences of acid rain.As a conclusion,the wet depositions of sulfur and nitrogen did not exceed the critical loads estimated by the other studies.