STUDIES OF FORMATION MECHANISM OF ACID SNOW PARTICLES ACOODING TO THEIR FORMATION PROCESSES

在日本札幌市郊区和中部进行了固体降水化学分析的个例研究，以探讨由于雪粒的生长机制不同而造成的降水化学的差异，即通过气相沉积或结冰。即使在蒸气沉积生长中，样品也被发现是酸性的。NO_3~-和NSS-Cl~-对酸化有贡献。在轮流生长的样品中，NSS-SO^2-浓度相当高。中心城区的雪样酸性较弱，这是由于降雪初期NSS-Ca^&2&gt；浓度较高所致。

Case studies of chemical analysis of solid precipitation were carried out at sites on the outskirts and central part of Sapporo City, Japan to investigate the difference in precipitation chemistry owing to the mechanism by which snow particles grow, i.e.by vapor deposition or by riming. Even in vapor depositional growth, the samples were found to be acidic. NO_3-and nss-Cl-contributed to the acidification. In the samples of riming growth, the nss-SO^2_-concentration was considerably high. Snow samples from the site in the central city area were less acidic due to the higher concentration of nss-Ca^<2+> in the early period of snowfalls.