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| Titel |
Further examination of the thermodynamic modification of the inflow layer of tropical cyclones by vertical wind shear |
| VerfasserIn |
M. Riemer, M. T. Montgomery, M. E. Nicholls |
| 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 ; 13, no. 1 ; Nr. 13, no. 1 (2013-01-11), S.327-346 |
| Datensatznummer |
250017553
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| Publikation (Nr.) |
 copernicus.org/acp-13-327-2013.pdf |
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| Zusammenfassung |
Recent work has developed a new framework for the impact of
vertical wind shear on the intensity evolution of tropical
cyclones. A focus of this framework is on the frustration of
the tropical cyclone's power machine by shear-induced,
persistent downdrafts that flush relatively cool and dry
(lower equivalent potential temperature, θe) air into
the storm's inflow layer. These previous results have been
based on idealised numerical experiments for which we have
deliberately chosen a simple set of physical
parameterisations. Before efforts are undertaken to test the
proposed framework with real atmospheric data, we assess here
the robustness of our previous results in a more realistic and
representative experimental setup by surveying and diagnosing
five additional numerical experiments. The modifications of the
experimental setup comprise the values of the exchange
coefficients of surface heat and momentum fluxes, the inclusion
of experiments with ice microphysics, and the consideration of
weaker, but still mature tropical cyclones.
In all experiments, the depression of the inflow layer
θe values is significant and all tropical cyclones
exhibit the same general structural changes when interacting
with the imposed vertical wind shear. Tropical cyclones in which strong
downdrafts occur more frequently exhibit a more pronounced
depression of inflow layer θe outside of the
eyewall in our experiments. The magnitude of the θe
depression underneath the eyewall early after shear is
imposed in our experiments correlates well with the magnitude
of the ensuing weakening of the respective tropical cyclone.
Based on the evidence presented, it is concluded that the
newly proposed framework is a robust description of intensity
modification in our suite of experiments. |
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