雅鲁藏布江流域枯水期化学风化及CO2消耗

Study on chemical weathering and consumption of CO2 during dry season in the Yarlung Zangbo River Basin

基于雅鲁藏布江流域枯水期干支流地表径流、泉水、地下水以及降水样品,对主要离子、pH、TDS和CO2消耗进行分析,研究枯水期水化学特征及成因,并分析流域化学风化速率及CO2消耗通量。结果表明:流域水体总体呈现弱碱性,地表径流TDS均值约为世界河流的2.3倍,和长江流域相似,但远低于黄河流域。岩石风化是地表径流离子来源的主要影响因素。碳酸盐风化、硅酸盐风化和蒸发盐风化分别占离子来源的46.3%、28.6%和21.3%,碳酸盐风化速率和硅酸盐风化速率分别为1.43t/(km^2·a)和1.11t/(km^2·a),对应的CO2消耗速率为0.80×10^5mol/(km^2·a)和0.55×10^5 mol/(km^2·a),枯水期化学风化速率和CO2消耗速率较小。

Based on the surface runoff,spring water,groundwater,and precipitation samples obtained in the dry season from the main tributaries of Yarlung Zangbo River basin,the main ions,pH,TDS and CO2consumption were analyzed.The hydrochemical characteristics and causes were studied.The chemical weathering rate and CO2consumption flux in the basin were also analyzed.The results indicated that the basin water was mild alkaline as a whole.The mean TDS of surface runoff was approximately 2.3times compared to the world′s rivers.It was similar to the Yangtze River Basin but far below the Yellow River Basin.Rock weathering was the main factor affecting the ion source of surface runoff.Carbonate weathering,silicate weathering and evaporate weathering accounted for 46.3%,28.6%,and 21.3%of the ion sources,respectively.The carbonate weathering rate and silicate rates were 1.43t/(km^2.a),and 1.11t/(km^2.a),the corresponding CO2consumption rates were 0.80×10^5mol/(km^2.a)and 0.55×10^5 mol/(km^2.a),while the chemical weathering and CO2consumption rates were found lower in dry season.