| Summary: | 碩士 === 國立臺灣大學 === 海洋研究所 === 89 === Daily precipitation including dry and wet precipitation, were collected at the center of metropolitan Taipei during 1998. Chemical analyse including pH, Na+, K+, Mg2+, Ca2+, Cl-, SO42-, NO3-, PO43-, SiO44- and Pb-210 were carried out on precipitation samples.
The atmospheric Pb-210 flux were highly variable on daily basis in Taipei. There was not evident correlation between Pb-210 fluxes and ionic concentrations in rainwater, however, a tight correlation between Pb-210 flux and precipitation rate was found during 1998. The mean annual flux of Pb-210 is about 1.5 dpm/cm2/yr in Taipei, Taiwan. Seasonal variation of Pb-210 flux is obvious with maximal fluxes in spring. Main factor controlling the flux of Pb-210 in spring is the Asia dust (KOSA). Acid rain caused by elevated sulfate concentration in the air which was originated from local sources was observed. Compositions of rainwater collected in metropolitan Taipei are mainly controlled by terrestrial input from Asia continent. However, marine contribution to the composition of rainwater during typhoon season is the most significant phenomenon in the area.
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