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1987 WET DEPOSITION TEMPORAL AND SPATIAL PATTERNS IN NORTH AMERICA
Citation:
Simpson, J. AND A. Olsen. 1987 WET DEPOSITION TEMPORAL AND SPATIAL PATTERNS IN NORTH AMERICA. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/4-90/019 (NTIS PB90251836), 1990.
Description:
The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. he report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. he data are from the Acid Deposition System for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network, the MAP3S precipitation chemistry network, the utility Acid Precipitation Study Program, the Canadian Precipitation Monitoring Network, and the daily and 4-weekly Acidic Precipitation in Ontario Study. osaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns for 1987 annual, winter, and summer periods. he temporal pattern analyses use a subset of 39 sites over a 9-year (1979-1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982-1987) period. nnual total precipitation and annual precipitation weighted ion concentrations exhibit substantial inter-annual variation during 1979-1987. ver 75% of the sites had decreasing trend estimates during this period for sulfate, calcium, chloride, sodium, potassium, and magnesium. itrate, ammonium and hydrogen ion show little or no indication of a trend.
