Processes driving intraseasonal displacements of the eastern edge of the warm pool: the contribution of westerly wind events

Drushka, Kyla; Bellenger, Hugo; Guilyardi, Eric; Lengaigne, Matthieu; Vialard, Jérôme; Madec, Gurvan. 2015 Processes driving intraseasonal displacements of the eastern edge of the warm pool: the contribution of westerly wind events. Climate Dynamics, 44 (3-4). 735-755. 10.1007/s00382-014-2297-z

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Official URL: http://dx.doi.org/10.1007/s00382-014-2297-z

Abstract/Summary

We investigate the processes responsible for the intraseasonal displacements of the eastern edge of the western Pacific warm pool (WPEE), which appear to play a role in the onset and development of El Niño events. We use 25 years of output from an ocean general circulation model experiment that is able to accurately capture the observed displacements of the WPEE, sea level anomalies, and upper ocean zonal currents at intraseasonal time scales in the western and central Pacific Ocean. Our results confirm that WPEE displacements driven by westerly wind events (WWEs) are largely controlled by zonal advection. This paper has also two novel findings: first, the zonal current anomalies responsible for the WPEE advection are driven primarily by local wind stress anomalies and not by intraseasonal wind-forced Kelvin waves as has been shown in most previous studies. Second, we find that intraseasonal WPEE fluctuations that are not related to WWEs are generally caused by intraseasonal variations in net heat flux, in contrast to interannual WPEE displacements that are largely driven by zonal advection. This study hence raises an interesting question: can surface heat flux-induced zonal WPEE motions contribute to El Niño–Southern Oscillation evolution, as WWEs have been shown to be able to do?

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1007/s00382-014-2297-z
ISSN:	0930-7575
Additional Keywords:	Westerly wind events, Western Pacific warm pool, Air–sea interaction, El Niño, Intraseasonal variability
NORA Subject Terms:	Marine Sciences
Date made live:	18 Feb 2016 14:16 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/513014

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1007/s00382-014-2297-z

ISSN:

0930-7575

Additional Keywords:

Westerly wind events, Western Pacific warm pool, Air–sea interaction, El Niño, Intraseasonal variability

NORA Subject Terms:

Marine Sciences

Date made live:

18 Feb 2016 14:16 +0 (UTC)