FOG AND PRECIPITATION CHEMISTRY AT MT. ROKKO IN KOBE, APRIL 1997-MARCH 1998

摘要

Fog water and precipitation were collected and analyzed to study fog and precipitation chemistry. The research was carried out through one year from April 1997 to March 1998 at Mt. Rokko in Kobe. Higher fog occurrence and larger volume of fog water were observed in summer, corresponding to the trend of seasonal variation in precipitation amount. The annual mean pH value of fog water (3.80) was lower by ca. one pH unit than that of precipitation (4.74). The concentration of chemical species in fog water was ca. 7 times that in precipitation. The highest anion and cation concentrations were SO_4~(2-) and NH_4~+ in fog water and Cl~- and Na~+ in precipitation, although the C1-/Na~+ equivalent ratio in both fog water and precipitation was almost the same value as that in sea water. It is considered that in the longest fog event, NH_4~+ and nss-SO_4~(2-) in fog water mainly scavenged as (NH_4)_2SO_4, mainly derived from (NH_4)_2SO_4 (aerosol) in the atmosphere, NH_3 was scavenged at the growing stage, and SO_2 was also scavenged after the mature stage. NO_3~- in this fog event was mainly absorbed as HNO_3.