HYDROGEOCHEMICAL STUDY ON THE CHEMICAL COMPONENTS OF ACID SNOW AND THOSE ACCUMULATION AND MIGRATION PROCESS IN THE SNOWPACK

研究结果表明：1）北陆地区雪中主要的阳离子和阴离子为H^+、Na^+、K+、Ca^2+、Mg^2+、NH_4^+和Cl^-、SO_4 ^2、NO_3^-; 2）新雪的平均pH值为4.6，nss-SO_4^-<2->和NO_3^-是导致雪酸化的两种主要离子;当雪消融发生在融化季节的早期，离子浓度比整个雪包的平均浓度高2至4倍的融水从雪包流出，因为雪中的大部分离子在雪颗粒的表面附近排出。一个新的积雪模型的开发，考虑了四个主要的物理过程中发生的雪季，只需要定期提供的数据。通过对喜马拉雅山山脚下Siramine积雪的模拟，检验了模型的性能。Haku.5）通过融水的指数函数估计离子洗脱量。雪季模型结合融水与溶出离子量的指数关系，较好地模拟了包体中离子浓度随时间的变化。6）在日本北陆地区这样的暖雪地区，由于雪季降雪及其消融的重复性，不会发生强的酸冲击。

Research results are summarized as follows ;1) The major cations and anions in the snow in Hokuriku region are H^+, Na^+, K+, Ca^<2+>, Mg^<2+>, NH_4^+, and Cl^-, SO_4^2, NO_3^-.2) Mean pH value of the new snow is 4.6, and nss-SO_4^<2-> and NO_3^- are major two ions contribute to snow acidification.3) When snow ablation occurs in the early melt season, the melt water whose ion concentration is 2 to 4 times higher than the mean concentration of the whole pack flows out from the pack because most of ions in the snow exit near the surfaces of snow particles.4) A novel snow cover model is developed that considers the four main physical processes that occur during snow season and only requires the data routinely available. The model performance is tested through simulating the snow cover at Siramine, the foot of Mt. Haku.5) The amount of ion elution is estimated by the exponential function of melt water. The time variation of ion concentration profile in the pack is well simulated by using the snow cver model combined with the exponential relation between the melt water and the amount of eluted ion.6) Strong acid shock does not occur in the warm snow region like Hokuriku region, Japan because snowfall and its ablation are repeated in snow season.