Processes driving intraseasonal displacements of the eastern edge of the warm pool: the contribution of westerly wind events
Processes driving intraseasonal displacements of the eastern edge of the warm pool: the contribution of westerly wind events
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?
Westerly wind events, Western Pacific warm pool, Air–sea interaction, El Niño, Intraseasonal variability
735-755
Drushka, Kyla
8dec5bba-01cf-475b-8dee-cb211d63b3ec
Bellenger, Hugo
f4ba092a-3e2e-4886-bf26-c98d0a404ba3
Guilyardi, Eric
7a596a3f-7c16-4d5b-8fa8-13848959694d
Lengaigne, Matthieu
3f78eafe-bcd2-41c4-9e0e-3b8bb3c55aa4
Vialard, Jérôme
165dd2c7-d5ec-4bd6-9f20-02e182e38f36
Madec, Gurvan
ffb28deb-4bbd-4a4c-914f-492f813e4864
February 2015
Drushka, Kyla
8dec5bba-01cf-475b-8dee-cb211d63b3ec
Bellenger, Hugo
f4ba092a-3e2e-4886-bf26-c98d0a404ba3
Guilyardi, Eric
7a596a3f-7c16-4d5b-8fa8-13848959694d
Lengaigne, Matthieu
3f78eafe-bcd2-41c4-9e0e-3b8bb3c55aa4
Vialard, Jérôme
165dd2c7-d5ec-4bd6-9f20-02e182e38f36
Madec, Gurvan
ffb28deb-4bbd-4a4c-914f-492f813e4864
Drushka, Kyla, Bellenger, Hugo, Guilyardi, Eric, Lengaigne, Matthieu, Vialard, Jérôme and 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), .
(doi:10.1007/s00382-014-2297-z).
Abstract
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?
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Published date: February 2015
Keywords:
Westerly wind events, Western Pacific warm pool, Air–sea interaction, El Niño, Intraseasonal variability
Organisations:
Marine Systems Modelling
Identifiers
Local EPrints ID: 388128
URI: http://eprints.soton.ac.uk/id/eprint/388128
ISSN: 0930-7575
PURE UUID: 1d931d21-c57b-4244-93a6-30ebea48b725
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Date deposited: 18 Feb 2016 14:11
Last modified: 14 Mar 2024 22:52
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Contributors
Author:
Kyla Drushka
Author:
Hugo Bellenger
Author:
Eric Guilyardi
Author:
Matthieu Lengaigne
Author:
Jérôme Vialard
Author:
Gurvan Madec
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