A synoptic climatology of stream flow and acidity

Abstract

Separate manual analyses of high-discharge and high stream-sulfate events in central Pennsylvania, USA, demonstrate that nearly all are associated with lows forming in the lee of the Rocky Mountains, tracking from southwest to northeast, and passing to the northwest of the study area. These lows develop into two distinct circulation types: transient cyclonic storms in winter and spring, and stationary fronts in summer and fall. Objective analyses of composite daily pressure-patterns associated with elevated stream flow and stream-sulfate concentrations show sequences similar to those that transport acid rain and surface ozone into central Pennsylvania. This research suggests that because of the large-scale climatology of North America, acidification of the streams of the northeastern United States and southwestern Canada is likely to continue. -from Authors