An analysis of spatial variability of the dominant ions in precipitation in the eastern United States

Data of the Multistate Atmospheric Power Production Pollution Study (MAP3S) and the National Atmospheric Deposition Program (NADP) were utilized to develop wet deposition spatial distribution patterns for the eastern United States for 1979. The ions of SO₄ ^?, NO₃ ^?, H⁺, and NH₄ ⁺ were selected for study since they are the most prominent ones found in precipitation. Total wet deposition for 1979 was normalized to one centimeter of precipitation and objectively analyzed using the Synagraphic Mapping System (SYMAP) technique. Gradients of SO₄ ^? and NO₃ ^? were found to be essentially uniform, both to the east and west of the major pollution regions. An increased gradient in normalized deposition for SO₄ ^?, NO₃ ^?, and H⁺ was found in the Appalachian Mountain region. Estimates of total wet deposition were obtained by using the normalized deposition values in conjunction with precipitation as reported by the National Climatic Center. SYMAP analyses of the estimated total wet deposition were localized in nature due to precipitation variations between sites.