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| Titel |
Toward a more physical representation of precipitation scavenging in global chemistry models: cloud overlap and ice physics and their impact on tropospheric ozone |
| VerfasserIn |
J. L. Neu, M. J. Prather |
| 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 ; 12, no. 7 ; Nr. 12, no. 7 (2012-04-05), S.3289-3310 |
| Datensatznummer |
250011013
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| Publikation (Nr.) |
 copernicus.org/acp-12-3289-2012.pdf |
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| Zusammenfassung |
| Uptake and removal of soluble trace gases and aerosols by precipitation
represents a major uncertainty in the processes that control the vertical
distribution of atmospheric trace species. Model representations of
precipitation scavenging vary greatly in their complexity, and most are
divorced from the physics of precipitation formation and transformation.
Here, we describe a new large-scale precipitation scavenging algorithm,
developed for the UCI chemistry-transport model (UCI-CTM), that represents a
step toward a more physical treatment of scavenging through improvements in
the formulation of the removal in sub-gridscale cloudy and ambient
environments and their overlap within the column as well as ice phase uptake
of soluble species. The UCI algorithm doubles the lifetime of HNO3 in
the upper troposphere relative to a scheme with commonly used fractional
cloud cover assumptions and ice uptake determined by Henry's Law and
provides better agreement with HNO3 observations. We find that the
process of ice phase scavenging of HNO3 is a critical component of the
tropospheric O3 budget, but that NOx and O3 mixing ratios are
relatively insensitive to large differences in the removal rate. Ozone
abundances are much more sensitive to the lifetime of HNO4,
highlighting the need for better understanding of its interactions with ice
and for additional observational constraints. |
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