In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions...In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions （Na＋, K＋, Ca2＋, Mg2＋, NH4＋, SO4^2-, NO3- and Cl-） were combined with tritium （^3H or T） concentration （T specific activity） in both precipitation and snow, and transformation patterns of polluted air mass in Niigata region were revealed. The low level tritium in precipitation was measured by a distillation process and an electrolytic enrichment process. Each tritium concentration in the precipitation sample thus obtained was measured by liquid scintillation counter. On the basis of the above measurement and analysis, it was found that the tritium and nss （non-sea-salt） calcium concentrations showed a seasonal variation with a highest value in spring over one year.展开更多
文摘In order to evaluate seasonal and regional variations in precipitation in Niigata City, 65 hourly precipitation samples were collected from October 2009 to June 2011 including two snow events. In this work, major ions （Na＋, K＋, Ca2＋, Mg2＋, NH4＋, SO4^2-, NO3- and Cl-） were combined with tritium （^3H or T） concentration （T specific activity） in both precipitation and snow, and transformation patterns of polluted air mass in Niigata region were revealed. The low level tritium in precipitation was measured by a distillation process and an electrolytic enrichment process. Each tritium concentration in the precipitation sample thus obtained was measured by liquid scintillation counter. On the basis of the above measurement and analysis, it was found that the tritium and nss （non-sea-salt） calcium concentrations showed a seasonal variation with a highest value in spring over one year.
