Variability of El Niño-Southern Oscillation-related noise in the equatorial Pacific Ocean

Renguang Wu, Benjamin Kirtman

Research output: Contribution to journalArticle

Abstract

This study documents the variability of noise in the equatorial Pacific associated with the El Niño and La Niña events based on the ensemble retrospective forecasts of the Climate Forecast System, It is found that the noise (measured by the ensemble spread) in the western equatorial Pacific zonal wind stress is enhanced around and before the peak of El Niño events and weakened around 2-3 months after the peak of El Niño events. The change in the wind stress noise is communicated to the thermocline depth in the eastern equatorial Pacific with about 1 month time lag. The eastern equatorial Pacific SST noise, however, decreases during the decay stages of El Niño events while the corresponding noise in the surface zonal wind and heat flux increases. This decrease in the SST noise is related to the weakening of the SST front and the suppression of the tropical instability waves along the flanks of the equatorial Pacific cold tongue that is associated with the SST wanning due to El Niño events. Similar relations are seen during La Niña events except that the changes are in opposite sense. As such, the signal-to-noise ratio and, thus, the predictability for the eastern equatorial Pacific SST is relatively high during warm events compared to cold events.

Original languageEnglish (US)
Article numberD23106
JournalJournal of Geophysical Research C: Oceans
Volume114
Issue number23
DOIs
StatePublished - 2009

Fingerprint

Wind stress
Southern Oscillation
Pacific Ocean
sea surface temperature
ocean
Heat flux
Signal to noise ratio
Temperature distribution
zonal wind
wind stress
forecasting
thermocline
thermoclines
surface wind
signal-to-noise ratio
heat flux
tongue
climate
signal to noise ratios
time lag

ASJC Scopus subject areas

  • Atmospheric Science
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Variability of El Niño-Southern Oscillation-related noise in the equatorial Pacific Ocean. / Wu, Renguang; Kirtman, Benjamin.

In: Journal of Geophysical Research C: Oceans, Vol. 114, No. 23, D23106, 2009.

Research output: Contribution to journalArticle

@article{cdad3f93c6604d69a972be4303d38fbf,
title = "Variability of El Ni{\~n}o-Southern Oscillation-related noise in the equatorial Pacific Ocean",
abstract = "This study documents the variability of noise in the equatorial Pacific associated with the El Ni{\~n}o and La Ni{\~n}a events based on the ensemble retrospective forecasts of the Climate Forecast System, It is found that the noise (measured by the ensemble spread) in the western equatorial Pacific zonal wind stress is enhanced around and before the peak of El Ni{\~n}o events and weakened around 2-3 months after the peak of El Ni{\~n}o events. The change in the wind stress noise is communicated to the thermocline depth in the eastern equatorial Pacific with about 1 month time lag. The eastern equatorial Pacific SST noise, however, decreases during the decay stages of El Ni{\~n}o events while the corresponding noise in the surface zonal wind and heat flux increases. This decrease in the SST noise is related to the weakening of the SST front and the suppression of the tropical instability waves along the flanks of the equatorial Pacific cold tongue that is associated with the SST wanning due to El Ni{\~n}o events. Similar relations are seen during La Ni{\~n}a events except that the changes are in opposite sense. As such, the signal-to-noise ratio and, thus, the predictability for the eastern equatorial Pacific SST is relatively high during warm events compared to cold events.",
author = "Renguang Wu and Benjamin Kirtman",
year = "2009",
doi = "10.1029/2009JD0124562",
language = "English (US)",
volume = "114",
journal = "Journal of Geophysical Research: Oceans",
issn = "2169-9275",
publisher = "Wiley-Blackwell",
number = "23",

}

TY - JOUR

T1 - Variability of El Niño-Southern Oscillation-related noise in the equatorial Pacific Ocean

AU - Wu, Renguang

AU - Kirtman, Benjamin

PY - 2009

Y1 - 2009

N2 - This study documents the variability of noise in the equatorial Pacific associated with the El Niño and La Niña events based on the ensemble retrospective forecasts of the Climate Forecast System, It is found that the noise (measured by the ensemble spread) in the western equatorial Pacific zonal wind stress is enhanced around and before the peak of El Niño events and weakened around 2-3 months after the peak of El Niño events. The change in the wind stress noise is communicated to the thermocline depth in the eastern equatorial Pacific with about 1 month time lag. The eastern equatorial Pacific SST noise, however, decreases during the decay stages of El Niño events while the corresponding noise in the surface zonal wind and heat flux increases. This decrease in the SST noise is related to the weakening of the SST front and the suppression of the tropical instability waves along the flanks of the equatorial Pacific cold tongue that is associated with the SST wanning due to El Niño events. Similar relations are seen during La Niña events except that the changes are in opposite sense. As such, the signal-to-noise ratio and, thus, the predictability for the eastern equatorial Pacific SST is relatively high during warm events compared to cold events.

AB - This study documents the variability of noise in the equatorial Pacific associated with the El Niño and La Niña events based on the ensemble retrospective forecasts of the Climate Forecast System, It is found that the noise (measured by the ensemble spread) in the western equatorial Pacific zonal wind stress is enhanced around and before the peak of El Niño events and weakened around 2-3 months after the peak of El Niño events. The change in the wind stress noise is communicated to the thermocline depth in the eastern equatorial Pacific with about 1 month time lag. The eastern equatorial Pacific SST noise, however, decreases during the decay stages of El Niño events while the corresponding noise in the surface zonal wind and heat flux increases. This decrease in the SST noise is related to the weakening of the SST front and the suppression of the tropical instability waves along the flanks of the equatorial Pacific cold tongue that is associated with the SST wanning due to El Niño events. Similar relations are seen during La Niña events except that the changes are in opposite sense. As such, the signal-to-noise ratio and, thus, the predictability for the eastern equatorial Pacific SST is relatively high during warm events compared to cold events.

UR - http://www.scopus.com/inward/record.url?scp=72049125312&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=72049125312&partnerID=8YFLogxK

U2 - 10.1029/2009JD0124562

DO - 10.1029/2009JD0124562

M3 - Article

AN - SCOPUS:72049125312

VL - 114

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 2169-9275

IS - 23

M1 - D23106

ER -