Atmospheric Environment 36 (2002) 1051–1062 Spatial patterns of precipitation quantity and chemistry and air temperature in the Adirondack region of New York Mari Ito a, *, Myron J. Mitchell a , Charles T. Driscoll b a State University of New York, College of Environmental Science and Forestry, Syracuse, NY 13210-2877, USA b Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244, USA Received 23 February 2001; accepted 11 September 2001 Abstract Regional assessments are critical to evaluate resources at risk from disturbances, such as acidic deposition, which occur in large spatial extent. It is imperative to accurately quantify atmospheric deposition to the regions like the Adirondack Mountains of New York where soils and surface waters are highly sensitive to inputs of strong acids. Spatial patterns in precipitation quantity and concentrations of major ions in precipitation in the Adirondack region were estimated based on the locations of monitoring sites using the data from 1988 to 1999. Mean monthly minimum and maximum daily air temperatures were also predicted to characterize site conditions. The trends in precipitation quantity, temperature, and most ion concentrations during the period examined were not significant or minimally significant, suggesting that the mean values over the period could be used for the regression models to describe spatial patterns. The spatial variations in the mean annual and monthly precipitation amounts, monthly mean minimum and maximum daily temperatures, and annual and quarterly sulfate and nitrate concentrations were generally explained by the regression models. Comparisons with the regression models of Ollinger et al. (US Ecological Applications 3(3) (1993) 459; US Department of Agriculture, Forest Service, Radnor, PA., 1995, 30p.) for the northeastern US suggest local variations in climate variables for the smaller Adirondack region. Further, precipitation quantity, minimum and maximum temperatures, and concentrations and deposition of ions in precipitation were predicted for the entire Adirondack region, using digital elevation models among others. Precipitation quantity and the sulfate and nitrate concentrations generally increased from the northeast to the southwest. Precipitation quantity and sulfate concentrations also generally increased with elevation. Minimum and maximum temperatures decreased from the southeast to the northwest and with elevation. r 2002 Elsevier Science Ltd. All rights reserved. Keywords: Atmospheric deposition; Acidic deposition; Acid rain; Precipitation chemistry; Temperature; Spatial variation; Adirondack region 1. Introduction Surface waters in the northeastern United States are sensitive to inputs of strong acid as defined by an acid neutralizing capacity (ANC) o 50 meql 1 (Driscoll et al., 2001). A synoptic survey of lakes in the Adirondack region of New York State, conducted in the mid 1980s, showed that 26% of the 1469 lakes surveyed with the surface area >0.5 ha had negative ANC values (Kretser et al., 1989), suggesting high sensitivity to acidic deposition. Atmospheric emissions of chemicals have changed over the past 30yr as a result of air pollution control legislation. The emissions of sulfur dioxide (SO 2 ) have decreased since 1973 after the 1970 Amendments to the Clean Air Act, while emissions of nitrogen oxide (NO x ) have remained essentially unchanged since 1980 (Driscoll et al., 2001). Acidic deposition to sensitive ecosystems may result in the acidification of soils, *Corresponding author. Fax: +1-315-470-6996. E-mail address: mito@mailbox.syr.edu (M. Ito). 1352-2310/02/$-see front matter r 2002 Elsevier Science Ltd. All rights reserved. PII:S1352-2310(01)00484-8