舟山群岛降水中阴离子及pH值的特征分析

Characteristic Analysis on the Anions and pH Profiles of Rainwater of Zhoushan Archipelago

通过对舟山站点降水中的4种阴离子(F-、Cl-、NO3-和SO42-)及pH值近2a的连续观测,对阴离子和pH值的范围及变化趋势进行了描述;利用本征矢量投影技术对实验数据进行降维处理,并对造成异常样品点的影响因素进行了分析.进一步因子分析结果显示,舟山站点降水样本点在阴离子及pH值方面的分布特征可基本确定为2个因子,SO42--NO3-因子(FA1)及Cl-因子(FA2),可将其概括为“人类活动因子”与“海洋因子”,因子分析结果得到的主要因子FA1、FA2与本征矢量投影得到的主成分PC1、PC2基本对应,因子分析的结果对解释影响样品点差异的实际变量方面更具实际意义,即舟山站点样本点的异常值可归为2类,受SO42--NO3-因子(FA1)影响及受Cl-因子(FA2)影响.

Rainwater samples were collected at Zhoushan Archipelago in 2002 -2003, 4 main anion concentrations （F^- , Cl^- , NO^3- , SO4^2-） and pH value of rainwater sample were determined. The concentration variation range and character were depicted. Principal component analysis （PCA） and factor analysis （FA） were used to acquire a further knowledge on the characteristics of anions and pH value. Distribution character of samples was clearly depicted in the new PC1-PC2 ordinate generated by orthogonal projection and the reasons that caused the outliers in samples were discussed. In order to get the latent variables which most distinguishably effect the sample distribution, data profiles were investigated by factor analysis： two latent variables were responsible for the sample distribution within sufficient analysis accuracy, SO4^2--NO3^- factor （FA1）, called as “anthropogenic factor”, and Cl^- （FA2）, called as “marine factor”, which corresponding to PC1 and PC2 in orthogonal projection respectively. Results from factor analysis were more practical than from orthogonal projection, that is, the reasons attributed the outlier sample distribution at Zhoushan Archipelago were ascribed into two latent variables： anthropogenic factor （SO4^2--NO3^-） and marine factor （Cl^-）.