Journal article

The role of the SST-thermocline relationship in Indian Ocean Dipole skewness and its response to global warming

Benjamin Ng, Wenju Cai, Kevin Walsh

Scientific Reports | NATURE PUBLISHING GROUP | Published : 2014

Abstract

A positive Indian Ocean Dipole (IOD) tends to have stronger cold sea surface temperature anomalies (SSTAs) over the eastern Indian Ocean with greater impacts than warm SSTAs that occur during its negative phase. Two feedbacks have been suggested as the cause of positive IOD skewness, a positive Bjerknes feedback and a negative SST-cloud-radiation (SCR) feedback, but their relative importance is debated. Using inter-model statistics, we show that the most important process for IOD skewness is an asymmetry in the thermocline feedback, whereby SSTAs respond to thermocline depth anomalies more strongly during the positive phase than negative phase. This asymmetric thermocline feedback drives IOD..

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University of Melbourne Researchers

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Funding Acknowledgements

We thank the modelling groups for making their model output available. We also thank Evan Weller and Tim Cowan for their suggested improvements. This work is supported by the CSIRO Wealth from Oceans Flagship.