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| Titel |
The energetics response to a warmer climate: relative contributions from the transient and stationary eddies |
| VerfasserIn |
D. Hernández-Deckers, J.-S. Storch |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 2, no. 1 ; Nr. 2, no. 1 (2011-06-21), S.105-120 |
| Datensatznummer |
250000463
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| Publikation (Nr.) |
 copernicus.org/esd-2-105-2011.pdf |
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| Zusammenfassung |
We use the Lorenz Energy Cycle (LEC) to evaluate changes in global
energetic activity due to CO2-doubling in the coupled
atmosphere-ocean ECHAM5/MPI-OM model. Globally, the energetic
activity – measured as the total conversion rate of available
potential energy into kinetic energy – decreases by about 4 %. This
weakening results from a dual response that consists of a
strengthening of the LEC in the upper-troposphere and a weakening in
the lower and middle troposphere. This is fully consistent with
results from a coarser resolution version of the same coupled model.
We further use our experiments to investigate the individual
contributions of the transient and stationary eddy components to the
main energetics response.
The transient eddy terms have a larger contribution to the total
energetic activity than the stationary ones. We find that this is also
true in terms of their 2 × CO2-response. Changes in the transient
eddy components determine the main energetics response, whereas the
stationary eddy components have very small contributions. Hence, the
dual response – strengthening in the upper troposphere and weakening
below – concerns mainly the transient eddy terms. We can relate
qualitatively this response to the two main features of the 2 × CO2
warming pattern: (a) the tropical upper-tropospheric warming increases
the pole-to-equator temperature gradient – strengthening the energetic
activity above – and enhances static stability – weakening the
energetic activity below; and (b) the high-latitude surface warming
decreases the pole-to-equator temperature gradient in the lower
troposphere – weakening the energetic activity below. Despite the
small contribution from the stationary eddies to the main energetics
response, changes in stationary eddy available potential energy
(Pse) reflect some features of the warming pattern: stronger
land-sea contrasts at the subtropics and weaker land-sea contrasts at
the high northern latitudes affect Pse regionally, but do not
affect the global energetics response. |
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