A synoptic climatology of stream flow and acidity

Abstract

Prevlous investigations have suggested relationships among weather, stream flow and water chemistry. Presumably, acid rain liberates soil sulfates during periods of heavy precipitation. simultaneously raising stream levels and acidity. This paper expands on those works by reporting a synoptic climatology of stream flow and stream-sulfate concentrations. 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 2 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 concentrat~ons show sequences similar to those that transport acid rain and surface ozone into central Pennsylvania. Thus, this research suggests that because of the large-scale climatology of North Amenca, acidification of the streams of the northeastern United States and southwestern Canada IS likely to continue. It also paves the way for more-reflned directed case studies and modcling efforts linking the atmosphere to water quallty.

A nonparametric stochastic method for generating daily climate-adjusted streamflows

“…Monthly climate-streamflow states may be tied to temperature, geopotential heights, precipitation, humidity, or any number of climate indices. Classifying monthly climate into discrete states is common in synoptic atmospheric research and has been used to correlate global climate indicators with local weather cycles [Kalkstein et al, 1987;Yarnal and Draves, 1993; Figure 2. Example P-P (left) and Q-Q (right) plots for the increasing limb in the Potomac River during May.…”

Synoptic patterns associated with extreme dust events in the Mediterranean Basin

“…The environment-to-circulation approach is based on the identification of the atmospheric circulations associated with particular environmental conditions (Yarnal and Draves 1993), namely the development of an extreme dust event. The CT showing frequencies associated with dust events above 10 % are discussed.…”

Comparative study among different neural net learning algorithms applied to rainfall time series

“…Fox (1981) recommended the use of mean square error (MSE), but, Willmott (1982) described the limitations of the MSE, and alternatively proposed and used an 'index of agreement' (d) of the form: 1 (7) where, N is the number of observations. The index (d) is a descriptive measure, and it is both a relative and bounded measure, which can be widely applied in order to make cross-comparison between models (Willmott, 1982;Yarnal and Draves, 1993). Since a model intends to explain most of the major trends or patterns present in the observed data, it is important to know how much of the root mean square error (RMSE) is systematic in nature.…”