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Processes of interannual mixed layer temperature variability in the thermocline ridge of the Indian Ocean

DRS at CSIR-National Institute of Oceanography

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Title Processes of interannual mixed layer temperature variability in the thermocline ridge of the Indian Ocean
 
Creator PraveenKumar, B.
Vialard, J.
Lengaigne, M.
Murty, V.S.N.
Foltz, G.R.
McPhaden, M.J.
Pous, S.
Montegut , C.deB.
 
Subject surface temperature
thermocline ridge
interannual variability
ENSO
Indian Ocean Dipole
 
Description Sea-surface temperature interannual anomalies (SSTAs) in the thermocline ridge of the southwestern tropical Indian Ocean (TRIO) have several well-documented climate impacts. In this paper, we explore the physical processes responsible for SSTA evolution in the TRIO region using a combination of observational estimates and model-derived surface layer heat budget analyses. Vertical oceanic processes contribute most to SSTA variance from December to June, while lateral advection dominates from July to November. Atmospheric fluxes generally damp SSTA generation in the TRIO region. As a result of the phase opposition between the seasonal cycle of vertical processes and lateral advection, there is no obvious peak in SSTA amplitude in boreal winter, as previously noted for heat content anomalies. Positive Indian Ocean Dipole (IOD) events and the remote influence of El Niño induce comparable warming over the TRIO region, though IOD signals peak earlier (November–December) than those associated with El Niño (around March–May). Mechanisms controlling the SSTA growth in the TRIO region induced by these two climate modes differ strongly. While SSTA growth for the IOD mostly results from southward advection of warmer water, increased surface shortwave flux dominates the El Niño SSTA growth. In both cases, vertical oceanic processes do not contribute strongly to the initial SSTA growth, but rather maintain the SSTA by opposing the effect of atmospheric negative feedbacks during the decaying phase.
 
Date 2014-12-11T06:40:52Z
2014-12-11T06:40:52Z
2014
 
Type Journal Article
 
Identifier Climate Dynamics, vol.43(9-10); 2014; 2377-2397
http://drs.nio.org/drs/handle/2264/4660
 
Language en
 
Rights An edited version of this paper was published by Springer. This paper is for R & D purpose and Copyright [2014] Springer.
 
Publisher Springer