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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Multiscale Atmosphere-Ocean Interactions and the Low-Frequency Variability in the Equatorial Region

Full text
Author(s):
Ramirez, Enver ; Dias, Pedro L. da Silva ; Raupp, Carlos F. M.
Total Authors: 3
Document type: Journal article
Source: JOURNAL OF THE ATMOSPHERIC SCIENCES; v. 74, n. 8, p. 2503-2523, AUG 2017.
Web of Science Citations: 2
Abstract

In the present study a simplified multiscale atmosphere-ocean coupled model for the tropical interactions among synoptic, intraseasonal, and interannual scales is developed. Two nonlinear equatorial beta-plane shallow-water equations are considered: one for the ocean and the other for the atmosphere. The nonlinear terms are the intrinsic advective nonlinearity and the air-sea coupling fluxes. To mimic the main differences between the fast atmosphere and the slow ocean, suitable anisotropic multispace/multitime scalings are applied, yielding a balanced synoptic-intraseasonal-interannual-El Nino (SInEN) regime. In this distinguished balanced regime, the synoptic scale is the fastest atmospheric time scale, the intraseasonal scale is the intermediate air-sea coupling time scale (common to both fluid flows), and El Nino refers to the slowest interannual ocean time scale. The asymptotic SInEN equations reveal that the slow wave amplitude evolution depends on both types of nonlinearities. Analytic solutions of the reduced SInEN equations for a single atmosphere-ocean resonant triad illustrate the potential of the model to understand slow-frequency variability in the tropics. The resonant nonlinear wind stress allows a mechanism for the synoptic-scale atmospheric waves to force intraseasonal variability in the ocean. The intraseasonal ocean temperature anomaly coupled with the atmosphere through evaporation forces synoptic and intraseasonal atmospheric variability. The wave-convection coupling provides another source for higher-order atmospheric variability. Nonlinear interactions of intraseasonal ocean perturbations may also force interannual oceanic variability. The constrains that determine the establishment of the atmosphere-ocean resonant coupling can be viewed as selection rules for the excitation of intraseasonal variability (MJO) or even slower interannual variability (El Nino). (AU)

FAPESP's process: 09/11643-4 - Multi-scale interactions in the atmosphere
Grantee:Carlos Frederico Mendonça Raupp
Support type: Research Grants - Young Investigators Grants
FAPESP's process: 06/60488-3 - Multiscale interaction between ocean and atmosphere and variability of low frequency
Grantee:Enver Manuel Amador Ramirez Gutierrez
Support type: Scholarships in Brazil - Doctorate