Abstract
The meaning of b-value in D=D1*Rb, which indicates the dependence of wetdepostion(D) of chemical species on precipitation amount(R) and constant(D1), was discussed for the precipitation collected on an event basis during rainy and snowy seasons in the suburbs of Niigata City, which is located on the Japan Sea coast. From the log(R)-log(D) plots, b-values were obtained as the slopes and were compared for the two seasons, among species and with the other reported values. Obtained b-values of all species, except C1-, for the snowy season were higher than those for the rainy season. Especially, remarkable differences were recognized for NO3-, nss-SO42-, NH4+ and nss-K+ In other words, the concentrations of these species hardly decrease with R in the snowy season. On the other hand, b-values of sea-salt components (Na+, Mg2+, C1-) were nearly equal in the both seasons. The differences of these b-values between two seasons may indicate that NO3-, nss-SO42-, NH4+ and nss-K+ are ingested into cloud-water by in-cloud scavenging process and are distributed rather homogeneously in snow-cloud which is convective in snowy season on Japan Sea coast, and that the effect of below-cloud scavenging of these species is not stronger than sea-salt components.
