| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Ocean-Atmosphere Coupling in the Monsoon Intraseasonal Oscillation: A Simple Model Study
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| Autores: |
Bellon, Gilles
Sobel, Adam H.
Vialard, Jerome
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| Data: |
2008-10
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| Ano: |
2008
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| Palavras-chave: |
Madden julian oscillation
Tropical circulation model
Sea surface temperature
Asian summer monsoon
Convective perturbations
Walker circulation
Radiation budget
Indian ocean
Variability
Simulation
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| Resumo: |
A simple coupled model is used in a zonally symmetric aquaplanet configuration to investigate the effect of ocean-atmosphere coupling on the Asian monsoon intraseasonal oscillation. The model consists of a linear atmospheric model of intermediate complexity based on quasi-equilibrium theory coupled to a simple, linear model of the upper ocean. This model has one unstable eigenmode with a period in the 30-60-day range and a structure similar to the observed northward-propagating intraseasonal oscillation in the Bay of Bengal/west Pacific sector. The ocean-atmosphere coupling is shown to have little impact on either the growth rate or latitudinal structure of the atmospheric oscillation, but it reduces the oscillation's period by a quarter. At latitudes corresponding to the north of the Indian Ocean, the sea surface temperature (SST) anomalies lead the precipitation anomalies by a quarter of a period, similarly to what has been observed in the Bay of Bengal. The mixed layer depth is in phase opposition to the SST: a monsoon break corresponds to both a warming and a shoaling of the mixed layer. This behavior results from the similarity between the patterns of the predominant processes: wind-induced surface heat flux and wind stirring. The instability of the seasonal monsoon flow is sensitive to the seasonal mixed layer depth: the oscillation is damped when the oceanic mixed layer is thin (about 10 m deep or thinner), as in previous experiments with several models aimed at addressing the boreal winter Madden-Julian oscillation. This suggests that the weak thermal inertia of land might explain the minima of intraseasonal variance observed over the Asian continent.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
http://archimer.ifremer.fr/doc/00185/29637/27987.pdf
DOI:10.1175/2008JCLI2305.1
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| Editor: |
Amer Meteorological Soc
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| Relação: |
http://archimer.ifremer.fr/doc/00185/29637/
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| Formato: |
application/pdf
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| Fonte: |
Journal Of Climate (0894-8755) (Amer Meteorological Soc), 2008-10 , Vol. 21 , N. 20 , P. 5254-5270
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| Direitos: |
2008 American Meteorological Society
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