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Interannual variability of the South Indian Countercurrent

Citation

Menezes, VV and Phillips, HE and Vianna, ML and Bindoff, NL, Interannual variability of the South Indian Countercurrent, Journal of Geophysical Research: Oceans, 121, (5) pp. 3465-3487. ISSN 2169-9275 (2016) [Refereed Article]


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Copyright Statement

Copyright 2016 American Geophysical Union

DOI: doi:10.1002/2015JC011417

Abstract

In the present work, we investigate the interannual variability of the South Indian Countercurrent (SICC), a major and still understudied current of the Indian Ocean circulation. To characterize the interannual variability of the SICC, four different datasets (altimetry, GLORYS, OFAM3 and SODA) are analysed using multiple tools, which include Singular Spectrum Analysis and wavelet methods. The quasibiennial band dominates the SICC low frequency variance, with the main peak in the 1.51.8 yr interval. A secondary peak (2.12.5 yr) is only found in the western basin. Interannual and decadal-type modulations of the quasi-biennial signal are also identified. In addition, limitations of SODA before the 1960ís in the SICC region are revealed. Within the quasi-biennial band the SICC system presents two main patterns with a multiple jet structure. One pattern is characterized by a robust northern jet, while in the other the central jet is well developed and northern jet is weaker. In both patterns, the southern jet has always a strong signature. When the northern SICC jet is stronger, the northern cell of the subtropical gyre has a triangular shape, with its southern limb having a strong equatorward slant. The quasi-biennial variability of the SICC is probably related to the Indian Ocean tropical climate modes that are known to have a strong biennial characteristic.

Item Details

Item Type:Refereed Article
Keywords:Indian Ocean, South Indian Countercurrent, jets, fronts, subtropical gyre, quasi-biennial variability, wavelet
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Physical Oceanography
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Variability (excl. Social Impacts)
Author:Menezes, VV (Ms Viviane Menezes)
Author:Phillips, HE (Dr Helen Phillips)
Author:Bindoff, NL (Professor Nathan Bindoff)
ID Code:109039
Year Published:2016
Funding Support:Australian Research Council (DP130102088)
Deposited By:Centre for Ecology and Biodiversity
Deposited On:2016-05-18
Last Modified:2016-12-07
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