Atmospheric deposition to remote receptors II. Temporal and spatial variation of inorganic ion species in precipitation over the Ilwas-network

Abstract

Measurements of SO₄ ⁻, NO₃ ⁻, Cl⁻, NH₄ ⁺, Ca⁺⁺, Mg⁺⁺ Na⁺, K⁺, pH, and specific conductance, were made on a precipitation event basis (defined as daily collection) in a 4 to 7 site network which operated for 45 mo in the Adirondack Park of New York State. Three of the seven sites (one in each of three watersheds) operated for the entire study period to provide a temporal record which is spatially resolved over an intersite distance of 30 km (or less). Species concentrations received by the three watersheds were quite similar. The highest H⁺ and S0₄ ⁻ ion concentrations were observed during summer periods and N03 was found to be relatively invariant. Segregation by precipitation type indicated that the SO₄/NO₃ in winter rain was much larger than in snow. More than 50% of the total loading of major ions (H, NH₄, Ca, SO₄, NO₃) to these watersheds occurred during a 4 mo period, May–September. Loading to one of the watersheds, Sagamore, averaged approximately 20% less than to the two watersheds, Panther and Woods.