丽江-玉龙雪山不同区域大气降水化学特征

2008─2009年在丽江-玉龙雪山地区的丽江市区、玉龙雪山冰川公园索道下部站(索道地区)和白水1号冰川区(冰川区)3个采样点采集了113个降水样品,对其pH、电导率和主要离子(Cl-、SO42-、NO3-、Ca2+、Mg2+、Na+、K+和NH4+)质量浓度进行了分析.结果表明,所有样品实测pH均高于5.6.3个采样点ρ(总离子)平均值为丽江市区>索道地区>冰川区,其中ρ(SO4 2-)和ρ(Ca2+)均最高.丽江市区季风前后各离子质量浓度变化显著,其中海盐离子质量浓度〔ρ(Na+)和ρ(Cl-)〕从季风前期到季风期变化不大,在季风后期增加;ρ(NO3-)、ρ(SO42-)、ρ(NH4+)、ρ(Ca2+)、ρ(K+)和ρ(Mg2+)在季风前期显著高于季风期和季风后期.采用相关分析和主因子分析法对降水中离子来源进行研究,表明SO42-、NO3-和NH4+主要来自局地人类活动的贡献,Na+、K+和Cl-是海洋源贡献,Ca2+和Mg2+主要来源于地表粉尘. 

Chemical Characteristics of Rainwater in Different Regions of Lijiang-Yulong Snow Mountain

From 2008 to 2009,113 samples of rainwater were collected at Lijiang City,Yulong Snow Mountain glacial park cableway and the Baishui glacier No.1.The pH,electrical conductivity and the main ions(Cl-,SO42-,NO3-,Ca2+,Mg2+,Na+,K+ and NH4+) of the samples were analyzed.The results showed that the pH in all the samples was higher than 5.6.The mean of the total ionic concentration decreased in the following order: Lijiang City > cableway area > glacial area.SO42-and Ca2+ were the dominant cation and anion,respectively,in the three sampling areas.The concentrations of all the ions changed significantly with the monsoon.Among them,Na+ and Cl-increased only in the post-monsoon period,but did not change much in either the pre-monsoon or monsoon period.The mass concentrations of NO3-,SO42-,NH4+,Ca2+,K+ and Mg2+ were much higher in the pre-monsoon period than in the monsoon or post-monsoon period.Based on correlation and factor analysis of the ions in the rainwater,it was found that SO42-,NO3-and NH4+ were mainly from local human activity,Na+,K+ and Cl-were mostly from marine sources,and Ca2+ and Mg2+ were from dust.