Origin of decadal El Niño-Southern Oscillation-like variability in a coupled general circulation model

Sang Wook Yeh, Benjamin Kirtman

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The origin of decadal El Niño-Southern Oscillation-like variability (hereinafter referred to as DEV) is analyzed in coupled general circulation model (CGCM) simulations. The CGCM experiments test the null hypothesis for the existence of DEV, that is, that DEV is linear, damped, and stochastically forced by atmospheric internal dynamics. In order to test this hypothesis we employ the interactive ensemble coupling strategy. It is found that the spatially averaged variance of sea surface temperature anomaly (SSTA) and heat content anomaly (HCA) associated with the DEV is linearly related to the amplitude of atmospheric internal dynamics. This result suggests that the DEV is primarily noise forced but that damped coupled feedbacks and/or internal ocean dynamics enhance this variability. The SSTA variability associated with the DEV appears to be of a basin-type standing mode with a triangular shape. However, the decadal evolution of the HCA associated with the DEV shows a systematic westward propagation from the central North Pacific and the eastern South Pacific. Both a singular vector analysis and noise variance analysis based on the coupled simulation results support the argument that atmospheric noise in the subtropics leads to the excitation of the DEV.

Original languageEnglish (US)
Article numberC01009
JournalJournal of Geophysical Research C: Oceans
Volume111
Issue number1
DOIs
StatePublished - Jan 8 2006
Externally publishedYes

Fingerprint

Southern Oscillation
general circulation model
anomalies
temperature anomaly
Enthalpy
sea surface temperature
anomaly
enthalpy
ocean dynamics
vector analysis
null hypothesis
variance analysis
simulation
Feedback
Temperature
ocean
basin
propagation
experiment
Experiments

ASJC Scopus subject areas

  • Oceanography
  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics

Cite this

Origin of decadal El Niño-Southern Oscillation-like variability in a coupled general circulation model. / Yeh, Sang Wook; Kirtman, Benjamin.

In: Journal of Geophysical Research C: Oceans, Vol. 111, No. 1, C01009, 08.01.2006.

Research output: Contribution to journalArticle

@article{b8f4af4d0ccc4cf59c45ec318b2e6017,
title = "Origin of decadal El Ni{\~n}o-Southern Oscillation-like variability in a coupled general circulation model",
abstract = "The origin of decadal El Ni{\~n}o-Southern Oscillation-like variability (hereinafter referred to as DEV) is analyzed in coupled general circulation model (CGCM) simulations. The CGCM experiments test the null hypothesis for the existence of DEV, that is, that DEV is linear, damped, and stochastically forced by atmospheric internal dynamics. In order to test this hypothesis we employ the interactive ensemble coupling strategy. It is found that the spatially averaged variance of sea surface temperature anomaly (SSTA) and heat content anomaly (HCA) associated with the DEV is linearly related to the amplitude of atmospheric internal dynamics. This result suggests that the DEV is primarily noise forced but that damped coupled feedbacks and/or internal ocean dynamics enhance this variability. The SSTA variability associated with the DEV appears to be of a basin-type standing mode with a triangular shape. However, the decadal evolution of the HCA associated with the DEV shows a systematic westward propagation from the central North Pacific and the eastern South Pacific. Both a singular vector analysis and noise variance analysis based on the coupled simulation results support the argument that atmospheric noise in the subtropics leads to the excitation of the DEV.",
author = "Yeh, {Sang Wook} and Benjamin Kirtman",
year = "2006",
month = "1",
day = "8",
doi = "10.1029/2005JC002985",
language = "English (US)",
volume = "111",
journal = "Journal of Geophysical Research: Oceans",
issn = "2169-9275",
publisher = "Wiley-Blackwell",
number = "1",

}

TY - JOUR

T1 - Origin of decadal El Niño-Southern Oscillation-like variability in a coupled general circulation model

AU - Yeh, Sang Wook

AU - Kirtman, Benjamin

PY - 2006/1/8

Y1 - 2006/1/8

N2 - The origin of decadal El Niño-Southern Oscillation-like variability (hereinafter referred to as DEV) is analyzed in coupled general circulation model (CGCM) simulations. The CGCM experiments test the null hypothesis for the existence of DEV, that is, that DEV is linear, damped, and stochastically forced by atmospheric internal dynamics. In order to test this hypothesis we employ the interactive ensemble coupling strategy. It is found that the spatially averaged variance of sea surface temperature anomaly (SSTA) and heat content anomaly (HCA) associated with the DEV is linearly related to the amplitude of atmospheric internal dynamics. This result suggests that the DEV is primarily noise forced but that damped coupled feedbacks and/or internal ocean dynamics enhance this variability. The SSTA variability associated with the DEV appears to be of a basin-type standing mode with a triangular shape. However, the decadal evolution of the HCA associated with the DEV shows a systematic westward propagation from the central North Pacific and the eastern South Pacific. Both a singular vector analysis and noise variance analysis based on the coupled simulation results support the argument that atmospheric noise in the subtropics leads to the excitation of the DEV.

AB - The origin of decadal El Niño-Southern Oscillation-like variability (hereinafter referred to as DEV) is analyzed in coupled general circulation model (CGCM) simulations. The CGCM experiments test the null hypothesis for the existence of DEV, that is, that DEV is linear, damped, and stochastically forced by atmospheric internal dynamics. In order to test this hypothesis we employ the interactive ensemble coupling strategy. It is found that the spatially averaged variance of sea surface temperature anomaly (SSTA) and heat content anomaly (HCA) associated with the DEV is linearly related to the amplitude of atmospheric internal dynamics. This result suggests that the DEV is primarily noise forced but that damped coupled feedbacks and/or internal ocean dynamics enhance this variability. The SSTA variability associated with the DEV appears to be of a basin-type standing mode with a triangular shape. However, the decadal evolution of the HCA associated with the DEV shows a systematic westward propagation from the central North Pacific and the eastern South Pacific. Both a singular vector analysis and noise variance analysis based on the coupled simulation results support the argument that atmospheric noise in the subtropics leads to the excitation of the DEV.

UR - http://www.scopus.com/inward/record.url?scp=33644745526&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33644745526&partnerID=8YFLogxK

U2 - 10.1029/2005JC002985

DO - 10.1029/2005JC002985

M3 - Article

VL - 111

JO - Journal of Geophysical Research: Oceans

JF - Journal of Geophysical Research: Oceans

SN - 2169-9275

IS - 1

M1 - C01009

ER -