The changes in concentration of nutrients and minerals in precipitation during 230 rain-events were studied at a prealpine location in Switzerland, using an automatic sequential precipitation sampler (SPS). The events were divided up in 3 groups: Thunderstorms, summer rain-events and snow-events. A mean deposition rate was calculated for each of these groups. The pH, the conductivity and the concentration of Ca, K, Na, Mg, Al, SO4, NO3 and Cl were analysed. A difference of 0.5 in the pH value, with a maximum up to 2.0, has been detected by comparing the real-time pH data with the laboratory analysis. As the particles in precipitation are composed of aerosols and gases in the atmosphere, they were fixed by raindrops or icecristals during cloud condensation (rainout) or scavenged during rain-events (washout). The washout during rain-events usually produced a strong acid reaction in the first collected samples. Based on 41 thunderstorms in the alptal-valley between 1989 to 1993, 28 % of the total input of nutrients and minerals were washed out in the first 5 mm of rain. The rainout during snow-events produced a maximum specific input of acid deposition, followed by summer rain-events and washouts of thunderstorms.
acidity, pH, rainfall chemistry, swquential sampling, deposition, washout, rainout, event, Saharian dust