“…While each precipitation event is unique, in general theoretical considerations and previous observations have indicated significant enrichment in the initial stages of precipitation events and in light precipitation events (e.g., Asman, Jonker, Slanina, & Baard, 1982;Burch, Waldner, & Fritschi, 1996;Claassen & Halm, 1995b;Kennedy, Zellweger, & Avanzino, 1979;Khare et al, 1996;Kins, 1982;Lim, Jickells, & Davies, 1991;Mizak et al, 2005;Pryor & Barthelmie, 2005;Radojevic & Lim, 1995;Seto et al, 2002;Seymour & Stout, 1983). Data collected during five precipitation events (all summertime liquid phase events) in the northeastern USA indicate up to 50% of the total sulfate (SO 4 2− ) and nitrate (NO 3 − ) deposition can occur during the first 15%-20% of the total rainfall and that after a precipitation depth of 4.6 mm ion concentrations tend to asymptote to a constant value for the remainder of the event (Seymour & Stout, 1983). Equally, data collected during 13 thunderstorms in the Altal-valley in Switzerland showed "28% of the total load of elements and nutrients was washed out in the first 5 mm of a rain-event" (Burch et al, 1996).…”