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Inter-decadal modulation of ENSO teleconnections to the Indian Ocean in a coupled model: Special emphasis on decay phase of El Niño

Chowdary, JS and Parekh, A and Gnanaseelan, C and Sreenivas, P (2014) Inter-decadal modulation of ENSO teleconnections to the Indian Ocean in a coupled model: Special emphasis on decay phase of El Niño. Global and Planetary Change, 112. pp. 33-40.

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Inter-decadal modulation of El Niño-Southern Oscillation (ENSO) teleconnections to tropical Indian Ocean (TIO) is investigated in the coupled general circulation model Climate Forecast System (CFS) using a hundred year integration. The model is able to capture the periodicity of El Niño variability, which is similar to that of the observations. The maximum TIO/north Indian Ocean (NIO) SST warming (during spring following the decay phase of El Niño) associated with El Niño is well captured by the model. Detailed analysis reveals that the surface heat flux variations mainly contribute to the El Niño forced TIO SST variations both in observations and model. However, spring warming is nearly stationary throughout the model integration period, indicating poor inter-decadal El Niño teleconnections. The observations on the other hand displayed maximum SST warming with strong seasonality from epoch to epoch. The model El Niño decay delayed by more than two seasons, results in persistent TIO/NIO SST warming through the following December unlike in the observations. The ocean wave adjustments and persistent westerly wind anomalies over the equatorial Pacific are responsible for late decay of El Niño in the model. Consistent late decay of El Niño, throughout the model integration period (low variance), is mainly responsible for the poor inter-decadal ENSO teleconnections to TIO/NIO. This study deciphers that the model needs to produce El Niño decay phase variability correctly to obtain decadal-modulations in ENSO teleconnection.

Item Type: Article
Additional Information: Copyright of the article belongs Elsevier.
Uncontrolled Keywords: Atmospheric pressure; Climatology; Decay (organic); Integration; Modulation; Water waves, Coupled general circulation models; ENSO; Equatorial Pacific; Model integration; Sea surface temperature (SST); Surface heat fluxes; Teleconnections; Tropical Indian ocean, Oceanography, decadal variation; El Nino-Southern Oscillation; oceanic general circulation model; periodicity; sea surface temperature; teleconnection, Indian Ocean; Indian Ocean (Tropical)
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 28 Nov 2014 09:55
Last Modified: 28 Nov 2014 09:55

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