Conceptual
Model |
Site
Setting |
Aerosol
& Trends Analysis |
Backtrajectory
Analysis |
PMF
Analysis |
PMF Weighted
Backtrajectory Analysis |
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Swanquarter Wilderness Area |
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| The role of meteorology in the causes of haze |
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| January has peak transport frequency from
the northwest (post cold frontal airflow direction). January worst case days
have a relatively high concentration of nitrate which in shown in both the
high nitrate backtrajectory difference map and the PMF combustion mix 1
(high NO3) weighted backtrajectory map to be associated with northwesterly
flow. This flow is over areas of the Midwest high in ammonia emissions from
livestock.. In July flow is mostly from the southwest parallel to the
Atlantic Coast due to circulation around the Bermuda High. July has the
highest frequency of worst-case days and they are dominated by sulfate. The
PMF secondary sulfate factor weighted backtrajectories show most impact from
the southeastern US. In September peak frequency is from the north to
northeast due to clockwise rotation around high pressure areas typically to
the northwest of the site. |
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| Figure 5. Normalized residence time in January
(left) and July (right) (based on data from 2001-2004) |
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| Figure 6. Normalized residence time in
September (based on data from 2001-2004) |
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| For an in depth discussion on the role of meteorology
at Swanquarter see the Meteorological
Discussion section. HYSPLIT backtrajectories for Swanquarter can
be viewed in the
backtrajectory gallery page. |
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