Influences of atmospheric circulation on the variability of wet sulfate deposition

Abstract

Precipitation chemistry data from the National Atmospheric Deposition Program were related to weather data from the Climate Diagnostics Center in order to reveal the influence of large-scale circulation patterns on the wet deposition of sulfate downwind of the Ohio River Valley, where SO 2 emissions were curtailed sharply in the mid-1990s. The chemistry data from five precipitation-sampling sites were combined to provide a regional average for each summer season over the 21-year period from 1984 to 2004. The long-term trend of sulfate concentration is associated to a statistically significant extent by composited flow patterns associated with the East Pacific-North Pacific index. The regional weather pattern for the sulfate-rich years is associated with an intensification of the Bermuda High over the southeastern United States at the surface in tandem with a weakening of the 500-hPa geopotential height (GPH) climatological trough located over the northeastern United States. The highest-sulfate concentration days for the Atmospheric Integrated Research Monitoring Network (AIRMoN) Pennsylvania site occurred during a similar synoptic pattern when intense convection over the eastern United States was favoured thermodynamically. This study suggests that temporal changes in the large-scale circulation pattern over North America need to be considered, in addition to changes in precursor emissions, as an explanation for the decreases in sulfate concentrations observed in summertime rains across the eastern United States.

Fluoride pollution of atmospheric precipitation and its relationship with air circulation and weather patterns (Wielkopolski National Park, Poland)

“…In general, the western and northern directions bring the most polluted precipitation to the study area. Similar results were seen in analyses of global and synoptic scale weather patterns causing high sulphate pollution (Dayan and Lamb 2005, 2008; Salvador et al 2010). It was shown that the greatest pollutant deposition occurs with intensified meridional flow over central Europe, indicating advection of cooler air from western Europe.…”

Atmospheric Research Over the Western North Atlantic Ocean Region and North American East Coast: A Review of Past Work and Challenges Ahead

“…An advantage of routinely collected data at stations associated with the Canadian Air and Precipitation Monitoring Network and National Atmospheric Deposition Program/National Trends Network along the U.S. and Canada coasts has been analysis of long‐term trends such as reductions in SO 4 2‐ (Driscoll et al, ). Although changes in precursor emissions have been documented as the root cause of SO 4 2‐ reductions, Dayan and Lamb () showed that temporal changes in large‐scale circulation patterns should be considered as well in driving trends in summertime concentrations along the East Coast. As SO 4 2‐ concentrations have decreased over the United States due to pollution regulations, a similar trend was observed in Bermuda based on data from 1989 to 1997 and from 2006 to 2009 (Keene et al, ).…”

Hydrobiogechemical interactions in the hyporheic zone of a sulfate-impacted, freshwater stream and riparian wetland ecosystem

“…140 At Second Creek, S recycling is likely fueled by high sulfate levels carried from the stream during downwelling hydrologic conditions and can have signicant impacts on water quality. While some environmental sulfate loading has decreased with efforts to mitigate acid rain, 142,143 high sulfate concentrations from industrial and agricultural waters 38 remains problematic for many sensitive ecosystems, especially as sulfate is not federally regulated in all waste streams. Constructed wetlands have been used for the remediation of sulfate by promoting sulfate reduction to sulde, and ultimately the precipitation of iron monosulde (e.g., FeS) and iron disulde phases (e.g., pyrite, chalcopyrite) that capture sulde as well as heavy metals.…”