Great Lakes Atmospheric Deposition (GLAD) Network, 1982 and 1983: Data Analysis and Interpretation

This report was cited in "A Scientific Historical Review: the Atmospheric Sciences Program at the Illinois State Water Survey" (ISWS MP-171, http://hdl.handle.net/2142/49888) as Gatz, D.F., V.C. Bowersox, J. Su, and G.J. Stensland, 1988: Great Lakes Atmospheric Deposition (GLAD) Network, 1982 and 1983: Data Analysis and Interpretation. SWS Contract Report 448, Chicago, IL, 69 pp. However ISWS Contract Report no. 448 was apparently never officially issued as cited, and was not listed in the ISWS publications database nor available via the ISWS website.Under the Great Lakes Water Quality Agreement of 1972, the United States and Canada were provided a framework for the surveillance, monitoring, research, protection, and reclamation of the physical and chemical quality of the Great Lakes system. Within this framework, the monitoring of atmospheric deposition in the U.S. is coordinated by the Great Lakes National Program Office (GLNPO) of the U.S. Environmental Protection Agency (U.S. EPA, 1985). Research in the 1970's had shown that atmospheric deposition was an important source of certain organic and inorganic chemicals to lake watersheds. A network of stations to measure and characterize this deposition was established in 1976. In 1981 the GLNPO upgraded this earlier measurement network by establishing the Great Lakes Atmospheric Deposition (GLAD) network. Its purpose was to determine atmospheric loadings of metals, nutrients, and major inorganic species to the Great Lakes and to evaluate annual trends in the chemical loadings of these species to the Lakes. During 1981 and early 1982, 36 monitoring stations were installed along the U.S. shores of the 5 Lakes. The GLAD network was designed to collect wet-only deposition samples at these near-shore locations. The purpose of this study was to analyze and interpret atmospheric wet deposition data collected by the GLAD network, including: 1) an assessment of data quality, 2) a comparison of specific pairs of GLAD and National Atmospheric Deposition Program (NADP) sites, 3) estimation of atmospheric loadings of selected elements to the five Great Lakes, and 4) an analysis of the potential change in loading estimates caused by closing certain GLAD sampling sites.Ope