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| Titel |
Atmospheric transport of persistent semi-volatile organic chemicals to the Arctic and cold condensation in the mid-troposphere – Part 1: 2-D modeling in mean atmosphere |
| VerfasserIn |
J. Ma |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 15 ; Nr. 10, no. 15 (2010-08-09), S.7303-7314 |
| Datensatznummer |
250008687
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| Publikation (Nr.) |
 copernicus.org/acp-10-7303-2010.pdf |
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| Zusammenfassung |
| In the first part of this study for revisiting the cold
condensation effect on global distribution of semi-volatile organic
chemicals (SVOCs), the atmospheric transport of SVOCs to the Arctic in the
mid-troposphere in a mean meridional atmospheric circulation over the
Northern Hemisphere was simulated by a two-dimensional (2-D) atmospheric
transport model. Results show that under the mean meridional atmospheric
circulation the long-range atmospheric transport of SVOCs from warm
latitudes to the Arctic occurs primarily in the mid-troposphere. Although
major sources are in low and mid-latitude soils, the modeled air
concentration of SVOCs in the mid-troposphere is of the same order as or
higher than that near the surface, demonstrating that the mid-troposphere is
an important pathway and reservoir of SVOCs. The cold condensation of the
chemicals is also likely to take place in the mid-troposphere over a source
region of SVOCs in warm low latitudes through interacting with clouds. We
demonstrate that the temperature dependent vapour pressure and atmospheric
degradation rate of SVOCs exhibit similarities between lower atmosphere over
the Arctic and the mid-troposphere over a tropical region. Frequent
occurrence of atmospheric ascending motion and convection over warm
latitudes carry the chemicals to a higher altitude where some of these
chemicals may partition onto solid or aqueous phase through interaction with
atmospheric aerosols, cloud water droplets and ice particles, and become
more persistent at lower temperatures. Stronger winds in the mid-troposphere
then convey solid and aqueous phase chemicals to the Arctic where they sink
by large-scale descending motion and wet deposition. Using calculated water
droplet-air partitioning coefficient of several persistent organic
semi-volatile chemicals under a mean air temperature profile from the
equator to the North Pole we propose that clouds are likely important
sorbing media for SVOCs and pathway of the cold condensation effect and
poleward atmospheric transport. The role of deposition and atmospheric
descending motion in the cold condensation effect over the Arctic is also
discussed. |
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