中国南极长城站1998年大气降水化学特征的初步研究
THE PRELIMINARY ANALYSIS ON THE PRECIPITATION CHEMISTRY AT THE CHINA GREAT WALL STATION,ANTARCTIC IN 1998
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摘要: 文中报告了1998年1~12月,在中国南极长城站(62°13'S,58°58'W,海拔10.0m)采集的115个有效降水样品的pH值、电导率和化学组分分析结果.长城站地区降水的年平均pH值为5.62,电导率年平均值为85.16μS/cm.秋季期间降水的pH值和电导率较高,其它季节较低.降水中最主要的离子为Cl-,Na+,其他离子按平均浓度值依次排列为SO42-,Mg2+,Ca2+,K+,NO3-,NH4+.除NO3-,NH4+外,各主要离子浓度间呈显著正相关,表明其来源具有同一性.降水样品的离子组成比例与周围海区的海水接近,显示了海盐是降水中可溶性离子的主要来源,而其它源只对Ca2+有一定贡献.该地区的降水具有较典型的海洋性降水的化学特征.Abstract: This paper reports the analysis results(including pH,conductivity and ion concentrations)of the precipitation samples colected at the Great Wall Station of Antarctic(62°13'S,58°58'W,ASL 10.0m)in 1998.The average pH value and conductivity are 5.62 and 85.16 μS/cm,respectively.The pH value and conductivity of precipitation were higher during autumn,but lower during other seasons.The majorions in the precipitation are Cl- and Na+,fol owed by SO42-,Mg2+,Ca2+,K+,NO3-,NH4+ with the lower concentrations in order.The positive correlation significantly existing between the majorions except NO3-and NH4+ indicated that those majorions might come from the same sources.The fact that the proportions of ions in precipitation are extremely close to that of seawater of Antarctic Ocean may show that sea-salt originated aerosol is the dominant source of dissolvedions in precipitation.However,there is yet other sources which may contribute to Ca2+ ion in the precipitation.The precipitation at the area is characterized by marine type chemically.