| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Cyclogeostrophic balance in the Mozambique Channel
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| Autores: |
Penven, Pierrick
Halo, Issufo
Pous, Stephane
Marie, Louis
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| Data: |
2014-02
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| Ano: |
2014
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| Resumo: |
Three methods are proposed for the inclusion of inertia when deriving currents from sea surface height (SSH) in the Mozambique Channel: gradient wind, perturbation expansion, and an iterative method. They are tested in a model and applied to satellite altimetry. For an eddy of 25 cm amplitude and 100 km radius, typical of Mozambique Channel rings at 18°S, the error made with geostrophy is 40% for the anticyclones and 20% for the cyclones. Inertia could reach one third of the pressure gradient. Geostrophy underestimates subsurface currents by up to 50 cm s−1, resulting in errors of 30–40%. The iterative method results in errors of <5% for the most part of the structure. The error RMS in velocities based on 8 years of model SSH is in excess of 30 cm s−1 for geostrophy and reduces to about 10 cm s−1 for the gradient wind and iterative methods. The perturbation method is less accurate. Applied to satellite altimetry, the addition of inertia results in a significant increase in velocities for the anticyclones and a decrease for the cyclones. It induces a velocity increase of >50% in Mozambique Channel rings. Geostrophic EKE reaches 1400 cm2 s−2, while it attains 1800 cm2 s−2 when inertia is added. Applied to the Gulf Stream, these methods confirm the hypothesis of Maximenko and Niiler [2006] that centrifugal accelerations should be the main cause for the difference observed between geostrophic and drifter EKE. This methodology should result in a net improvement for operational surface ocean currents.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
http://archimer.ifremer.fr/doc/00175/28617/27045.pdf
DOI:10.1002/2013JC009528
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| Editor: |
Amer Geophysical Union
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| Relação: |
http://archimer.ifremer.fr/doc/00175/28617/
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| Formato: |
application/pdf
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| Fonte: |
Journal Of Geophysical Research-oceans (2169-9275) (Amer Geophysical Union), 2014-02 , Vol. 119 , N. 2 , P. 1054-1067
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| Direitos: |
2014. American Geophysical Union. All Rights Reserved.
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