分位数回归法在离子浓度对酸雨pH影响分析中的应用

APPLICATION OF QUANTILE REGRESSION ON ANALYSIS OF THE IMPACT OF ION CONCENTRATION ON PH OF ACID PRECIPITATION

综述了目前国内外对酸雨pH值与离子浓度之间关系的研究现状,并针对环境学科的特殊性,将分位数回归思想与逐步回归方法结合起来,以四川省宜宾市的历年酸雨数据为实例,运用R软件进行分析,得出了降水在不同pH水平下H+与SO24-、NO-3、NH+4、Ca2+浓度之间的关系。由回归结果可以看出,当pH值较低和较高时,H+浓度主要受NO-3和Ca2+的影响;当pH值处于中等水平时,H+浓度主要受SO24-、NO-3和Ca2+的影响。与传统的多元回归方法对比,该方法的优越性在于,其结果不仅能反映出H+浓度均值与其他离子浓度均值之间的关系,还能反映出H+处于不同浓度梯度水平下与各离子之间的变量关系。从而可以根据当地酸雨的pH水平分析出主要的制约因子,在此基础上制定出更高效的酸雨治理措施。

Researches of the relationship between ion concentration and pH value of acid precipitation in domestic and overseas were summarized.Due to the particularity of environment subject,quantile regression idea and stepwise regression method were combined to analyze the monitoring data of acid precipitation covering recent years in Yibin,one city in Sichuan province.The regression result obtained in the software R finally provided the different concentration relationships between H+ and SO2-4,NO-3,NH+4,Ca2+ under different quantile levels of pH value,which suggested that when pH value was at the lower and upper level,concentration of H+ was mainly impacted by concentration of NO-3 and Ca2+,and when pH value was at the mean level,concentration of H+ is mainly impacted by concentration of SO2-4,NO-3 and Ca2+.Compared with conventional multiple regression,the superiority of this method is that its result can not only show the relationship between average concentration of H+ and SO2-4,NO-3,NH+4,Ca2+,but also represent the different concentration relationships between H+ and SO2-4,NO-3,NH+4,Ca2+ under different quantile levels.Then we can obtain the main constricting factors of H+,and make higher effective measures according to the local pH level.