极地冰雪环境地球化学指标及其指示意义

极地冰雪中可以反映气候环境的环境地球化学指标主要是可溶性杂质和不可溶性微粒。可溶性杂质主要包括H+、Na+、Mg2 +、Ca2 +、NH4+、Cl- 、NO3- 、SO42 - 、CH3SO3- 等。本文在概述冰雪中的这些化学杂质的来源影响因素和时空分布特征的基础上 ,概述了冰雪中NO3- 沉积的主要来源 (即闪电作用和高层大气光化学作用产生的含氮化合物等 )及其影响因素 (包括太阳活动、火山活动、超新星活动、核爆炸试验和沉积后的蒸发及迁移作用等 ) ,SO42 - 的主要来源 (即海洋生物释放和火山喷发等 )、影响因素 (包括源区温度、ENSO事件及海冰面积等 )和它们的时空变化特点 ;讨论了南、北极地区冰雪中微粒沉积的主要源区和变化特征。。

ENVIRONMENTAL GEOCHEMICAL INDEX IN POLAR SNOW AND ICE AND ITS SIGNIFICANCE

The geochemical impurities in polar snow and ice can provide information on local or global climate and environment (including human activities, biosphere, volcanic activities and so on) in the past, This paper discusses environmental geochemical indexes, such as, major ions, microparticles as well as the factors that influence their distribution with space and time. The chemical impurities deposited in polar snow mainly include Na + , K + , Ca 2+ , Mg 2+ , Cl - , NO 3 -, SO 4 2- and CH 3SO 3 - , as well as microparticles. There are three sources for the impurities, as, 1) dust emitted by continents under the action of weathering and wind (such as, some of Ca 2+ , SO 4 2- and Mg 2+ ); 2) sea salt (mainly Na + , Cl - and some of Mg 2+ , Ca 2+ , SO 4 2- and K + ); 3) gas-derived aerosol produced by the chemical transformation of atmospheric trace gases (some of Cl - , NO 3 -, SO 4 2- and CH 3SO 3 -). The impurity concentrations derived from continent and marine during the last glacial were higher than that at present in Arctic and Antarctic ice sheet. Human activities have lead to strong increases of sulfate and nitrate in Greenland ice sheet since the late 19 th Century