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| Titel |
How well do coupled models replicate ocean energetics relevant to ENSO? |
| VerfasserIn |
Alexey Fedorov, Jaci Brown, Eric Guilyardi |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250049679
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| Zusammenfassung |
| Accurate replication of the processes associated with the energetics of the tropical ocean is
necessary if coupled GCMs are to simulate the physics of ENSO correctly, including the
transfer of energy from the winds to the ocean thermocline and energy dissipation during the
ENSO cycle. Here, we analyze ocean energetics in coupled GCMs in terms of two integral
parameters describing net energy loss in the system using the approach recently proposed by
Brown and Fedorov (2010) and Fedorov 2007. These parameters are (1) the efficiency γ of
the conversion of wind power into the buoyancy power that controls the rate of change of
the Available Potential Energy (APE) in the ocean and (2) the e-folding rate α
that characterizes the damping of APE by turbulent diffusion and other processes.
Estimating these two parameters for coupled models reveals potential deficiencies
(and large differences)Â in how state-of-the-art coupled GCMs reproduce the ocean
energetics as compared to ocean-only models and data assimilating models. The
majority of the coupled models we analyzed show a lower efficiency (values of γ
in the range of 10-50% versus 50-60% for ocean-only simulations or reanalysis)
and a relatively strong energy damping (values of α-1 in the range 0.4-1 years
versus 0.9-1.2 years). These differences in the model energetics appear to reflect
differences in the simulated thermal structure of the tropical ocean, the structure of ocean
equatorial currents, and deficiencies in the way coupled models simulate ENSO. |
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