Srivastava, S and Chakraborty, A and Murtugudde, R (2024) Decadal preference of seasonal ENSO transition through a southern hemisphere climate mode. In: Environmental Research Letters, 19 (6).
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Abstract
El Niño Southern Oscillation (ENSO) is the leading interannual coupled climate mode in the tropical Pacific. The seasonal transition of ENSO from boreal winter to the following summer can significantly affect the global climate. One of the major hurdles in understanding the seasonal transition of ENSO is the spring predictability barrier. Here, we show that ENSO�s seasonal transition is modulated by a multidecadal climate mode of boreal spring sea-level pressure (SLP) in the extratropical Southern Hemisphere. This ENSO transition mode (ETM), when characterised by a decrease in SLP and associated clockwise circulation of the surface winds centred over the southeastern subtropical Pacific Ocean, produces westerly anomalies at the equator. These wind anomalies in the equatorial eastern Pacific aid the seasonal warming of Niño3.4 sea surface temperature anomalies (N34SST) from boreal winter to the following summer. The ETM time series shows prominent multidecadal variations at around 50 years. This creates a conducive environment for alternate cold and warm seasonal transitions leading to multidecadal variations in boreal summer N34SST. Thus, ETM provides a physical insight into the seasonal transition of ENSO and leads to a new paradigm for ENSO evolution beyond its peak. This has implications for seasonal ENSO forecasts and decadal climate predictions. © 2024 The Author(s). Published by IOP Publishing Ltd.
| Item Type: | Journal Article |
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| Publication: | Environmental Research Letters |
| Publisher: | Institute of Physics |
| Additional Information: | The copyright for this article belongs to authors. |
| Keywords: | Climatology; Sea level; Surface waters; Tropics, Boreal winters; Decadal climate variability; El Nino southern oscillation; Multidecadal variations; Sea level pressure; Sea surface temperature anomalies; Seasonal transition; Southern Hemisphere; Transition modes; Tropical-extratropical interactions, Atmospheric pressure |
| Department/Centre: | Division of Mechanical Sciences > Divecha Centre for Climate Change Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences |
| Date Deposited: | 07 Jun 2024 05:48 |
| Last Modified: | 07 Jun 2024 05:48 |
| URI: | http://eprints.iisc.ac.in/id/eprint/85247 |
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