Multidecadal variability in the transmission of ENSO signals to the Indian Ocean

Shi, G. and Ribbe, J. and Cai, W. and Cowan, T. (2007) Multidecadal variability in the transmission of ENSO signals to the Indian Ocean. Geophysical Research Letters, 34 (9). L09706. ISSN 0094-8276

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Since 1980, transmission of El Nino-Southern Oscillation (ENSO) signals into the Indian Ocean involves an equatorial, and a subtropical North Pacific (NP) Rossby wave pathway. We examine the robustness of the amount of energy that leaves the Pacific via each of the pathway using the Simple Ocean Data Assimilation with the Parallel Ocean Program (SODA-POP) reanalysis and a multi-century coupled model control experiment. We find that in the pre-1980 period, little ENSO signal is transmitted to the Indian Ocean and does not involve the subtropical NP pathway. Such multidecadal variability is periodically produced by the climate model. Examinations reveal that when ENSO is weak as determined by Nino3.4, their meridional extent is narrow, the associated discharge-recharge does not involve the subtropical NP pathway; further, weak ENSO events have a low signal-to-noise ratio, making the transmission hard to detect. The dynamics of multidecadal variability in ENSO strength awaits further investigation.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Draft version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 01:08
Last Modified: 02 Jul 2013 22:44
Uncontrolled Keywords: global climate change; climate variability; climate dynamics; atmospheric circulation; ocean circulation; El Nino Southern Oscillation; Indian Ocean; decadal ocean variability; Pacific Ocean; ocean model
Fields of Research : 04 Earth Sciences > 0401 Atmospheric Sciences > 040104 Climate Change Processes
04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040605 Palaeoclimatology
04 Earth Sciences > 0401 Atmospheric Sciences > 040105 Climatology (excl.Climate Change Processes)
Socio-Economic Objective: D Environment > 96 Environment > 9603 Climate and Climate Change > 960303 Climate Change Models
Identification Number or DOI: 10.1029/2007GL029528

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