Coastal Meteorology A Review of the State of the Science (1992) / Chapter Skim
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7. Air Quality
7. Air Quality
Pages 63-70
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From page 63... ...
An adequate understanding of coastal zone air pollution dispersion is required to license and control point sources of primary pollutants, design regional emission control strategies for secondary pollutants contributing to photochemical oxidants, develop and implement emergency responses to accidental releases of radiological and hazardous materials, assess dry and wet deposition of trace metals and other contaminants into sensitive coastal ecosystems, and, potentially, predict dispersion of militarily significant chemical and biological agents. DISPERSION IN THE COASTAL ZONE Substantial progress has been made in understanding the mechanisms involved with dispersion over distances ranging from tens of meters to circumglobal.
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From page 64... ...
hypothesized that mesoscale transport in sea breezes took the form of broad quasi-helical vortices extending parallel to the shore. Very finemesh mesoscale numerical dispersion modeling of complex wind fields at the Kennedy Space Center (Lyons et al., 1991a)
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From page 65... ...
This two-dimensional conceptual model has been extant since the mid-1970s (Lyons, 19751. Current efforts require verifying and quantifying many aspects of this model and expanding it to include the threedimensional structure of the land-sea breeze and its impacts on mesoscale transport and clouds in regions of irregular coastlines, islands, estuaries, and complex topography.
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From page 66... ...
Schematic showing that pollutants initially move inland in the Atlantic sea breeze inflow. They then rise rapidly in the strong updrafts in the sea breeze front over the Florida mainland.
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From page 67... ...
This results largely from these models' relatively modest computational requirements, easily available input data, conceptual simplicity, and widespread acceptance by regulatory agencies. While they achieve modest accuracy in idealized environments, the gradients of heat flux, mixing depth, and surface roughness, as well as intense shear, updrafts, and subsidence, severely limit their suitability in coastal zones.
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From page 68... ...
Dispersion modeling techniques currently in widespread use do not always account for even the known coastal zone dispersion mechanisms. Continued advances in affordable high-speed computing, prognostic mesoscale numerical modeling, and advanced dispersion simulation techniques promise to yield a more comprehensive understanding of coastal zone phenomena.
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From page 69... ...
· Comprehensive tracer programs should be conducted at increasingly less idealized coastal sites, which would allow for evaluation, validation, and eventual widespread use of improved dispersion models, as well as further quantification of the complex transport and diffusion processes affecting pollutants in the coastal zone. · Improved coordination should be required between air pollution and boundary layer field observation programs conducted on both sides of the littoral, which would advance knowledge of the underlying physical processes affecting dispersion over land, water, and the intervening transition zones.
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