The ability of wet deposition networks to detect temporal trends

We use the spatial/temporal model developed in Oehlert (1993) to estimate the detectability of trends in wet‐deposition sulphate. Precipitation volume adjustments of sulphate concentration dramatically improve the detectability and quantifiability of trends. Anticipated decreases in sulphate of about 30 per cent in the Eastern U.S. by 2005 predicted by models should be detectable much earlier, say, 1997, but accurate quantification of the true decrease will require several additional years of monitoring. It is possible to delete a few stations from the East without materially affecting the detectability or quantifiability of trends. Careful siting of new stations can provide substantial improvement to regional trend estimation.