The future monitoring capabilities of four network configurations in eastern Canada

The capability of deposition networks in eastern Canada to resolve regional trends has been examined by Blanchard et al. (1996, Atmospheric Environment 30, 2539–2549). This paper extends the earlier methods to permit evaluation of the need for specific individual sites, comparison of additional network configurations, and consideration of more regions. Parameter estimates for the statistical model are improved by using monthly instead of annual data. For the regions that we examined, eliminating all provincial sites in eastern Canada would cause an increase of 1 to 6 years in the time required for reaching a 90% probabiility of detecting the expected future trends. The elimination of certain key provincial sites may increase the uncertainties in the determination of deposition isopleths of particular interest, such as the 20 kg ha⁻¹ yr⁻¹ contours. The statistical techniques presented here are quite general and can be extended to statistical tests or estimators other than those illustrated here.