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Intraseasonal variability of mixed layer depth in the tropical Indian Ocean

DRS at CSIR-National Institute of Oceanography

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Title Intraseasonal variability of mixed layer depth in the tropical Indian Ocean
 
Creator Keerthi, M.G.
Lengaigne, M.
Drushka, K.
Vialard, J.
de Boyer, M.C.
Pous, S.
Levy, M.
Muraleedharan, P.M.
 
Subject OCEANOGRAPHY AND LIMNOLOGY
OCEANOGRAPHY AND LIMNOLOGY
OCEANOGRAPHY AND LIMNOLOGY
METEOROLOGY AND CLIMATOLOGY
 
Description In this paper, we use an observational dataset built from Argo in situ profiles to describe the main large-scale patterns of intraseasonal mixed layer depth (MLD) variations in the Indian Ocean. An eddy permitting (0.25°) regional ocean model that generally agrees well with those observed estimates is then used to investigate the mechanisms that drive MLD intraseasonal variations and to assess their potential impact on the related SST response. During summer, intraseasonal MLD variations in the Bay of Bengal and eastern equatorial Indian Ocean primarily respond to active/break convective phases of the summer monsoon. In the southern Arabian Sea, summer MLD variations are largely driven by seemingly-independent intraseasonal fluctuations of the Findlater jet intensity. During winter, the Madden–Julian Oscillation drives most of the intraseasonal MLD variability in the eastern equatorial Indian Ocean. Large winter MLD signals in northern Arabian Sea can, on the other hand, be related to advection of continental temperature anomalies from the northern end of the basin. In all the aforementioned regions, peak-to-peak MLD variations usually reach 10 m, but can exceed 20 m for the largest events. Buoyancy flux and wind stirring contribute to intraseasonal MLD fluctuations in roughly equal proportions, except for the Northern Arabian Sea in winter, where buoyancy fluxes dominate. A simple slab ocean analysis finally suggests that the impact of these MLD fluctuations on intraseasonal sea surface temperature variability is probably rather weak, because of the compensating effects of thermal capacity and sunlight penetration: a thin mixed-layer is more efficiently warmed at the surface by heat fluxes but loses more solar flux through its lower base
 
Date 2016-04-11T08:17:45Z
2016-04-11T08:17:45Z
2016
 
Type Journal Article
 
Identifier Climate Dynamics, vol.46(7); 2016; 2633-2655
no
http://drs.nio.org/drs/handle/2264/4950
 
Language en
 
Relation Clim_Dyn_46_2633.jpg
 
Rights An edited version of this paper was published by Springer. This paper is for R & D purpose and Copyright [2016] Springer.
 
Publisher Springer