Role of Stratospheric Sudden Warmings on the response to Central Pacific El Niño

The Northern Hemisphere (NH) polar stratospheric response to Central Pacific El Niño (CP-El Niño) events remains unclear. Contradictory results have been reported depending on the definition and events considered. We show that this is due to the prominent role of Stratospheric Sudden Warmings (SSWs)...

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Bibliographic Details
Authors: Iza, Maddalen; Calvo, Natalia
Format: Article
Publication date:2015
Country:España
Institution:TECNALIA Research & Innovation
Repository:TECNALIA Publications
Language:English
OAI Identifier:oai:dsp.tecnalia.com:11556/5284
Online Access:https://hdl.handle.net/11556/5284
Access Level:Open access
Keyword:Central Pacific ENSO
Eastern Pacific ENSO
flavors of ENSO
polar vortex
SSWs
stratospheric dynamics
Geophysics
General Earth and Planetary Sciences
Description
Summary:The Northern Hemisphere (NH) polar stratospheric response to Central Pacific El Niño (CP-El Niño) events remains unclear. Contradictory results have been reported depending on the definition and events considered. We show that this is due to the prominent role of Stratospheric Sudden Warmings (SSWs), whose signal dominates the NH winter polar stratospheric response to CP-El Niño. In fact, the CP-El Niño signal is robust when the events are classified according to the occurrence of SSWs and displays opposite response in winters with and without SSWs. In the absence of SSWs, polar stratospheric responses to Central Pacific and Eastern Pacific El Niño are clearly distinguishable in early winter, in relation to differences in the Pacific-North American pattern. Our results demonstrate that the occurrence of SSWs needs to be taken into account when studying the stratospheric response to CP-El Niño and explain why different responses to CP-El Niño have been reported previously.