A comparison of the influence of additive and multiplicative stochastic forcing on a coupled model of ENSO

Christina L. Perez, Andrew M. Moore, Javier Zavala-Garay, Richard Kleeman

Research output: Contribution to journalArticle

Abstract

A currently popular idea is that El Niño-Southern Oscillation (ENSO) can be viewed as a linear deterministic system forced by noise representing processes with periods shorter than ENSO. Also, there is observational evidence to suggest that the Madden-Julian oscillation (MJO) acts to trigger and/or amplify the warm phase of ENSO in this way. The feedback of the slower process, ENSO, to higher-frequency atmospheric phenomena, of which a large part of the variability in the intraseasonal band is due to the MJO, has received little attention. This paper considers the hypothesis that the probability of an El Niño event is modified by high MJO activity and that, in turn, the MJO is regulated by ENSO activity. If this is indeed the case, then viewing ENSO as a low-frequency oscillation forced by additive stochastic noise would not present a complete picture. This paper tests the above hypothesis using a stochastically forced intermediate coupled model by allowing ENSO to directly influence the stochastic forcing. The model response to a variety of stochastic forcing types is found to be sensitive to the type of forcing applied. When the model is operated beyond its intrinsic Hopf bifurcation, its probability distribution function (PDF) is fundamentally altered when the stochastic forcing is changed from additive to multiplicative. The model integration period also influences the shape of the PDF, which is also compared to the PDF derived from observations. It is found that multiplicative stochastic forcing reproduces some measures of the observations better than the additive stochastic forcing.

Original languageEnglish (US)
Pages (from-to)5066-5085
Number of pages20
JournalJournal of Climate
Volume18
Issue number23
DOIs
StatePublished - Dec 1 2005

Fingerprint

Southern Oscillation
Madden-Julian oscillation
bifurcation
comparison
oscillation
distribution

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

A comparison of the influence of additive and multiplicative stochastic forcing on a coupled model of ENSO. / Perez, Christina L.; Moore, Andrew M.; Zavala-Garay, Javier; Kleeman, Richard.

In: Journal of Climate, Vol. 18, No. 23, 01.12.2005, p. 5066-5085.

Research output: Contribution to journalArticle

Perez, Christina L. ; Moore, Andrew M. ; Zavala-Garay, Javier ; Kleeman, Richard. / A comparison of the influence of additive and multiplicative stochastic forcing on a coupled model of ENSO. In: Journal of Climate. 2005 ; Vol. 18, No. 23. pp. 5066-5085.
@article{c53d028890a94a3398d9395910b8ffdf,
title = "A comparison of the influence of additive and multiplicative stochastic forcing on a coupled model of ENSO",
abstract = "A currently popular idea is that El Ni{\~n}o-Southern Oscillation (ENSO) can be viewed as a linear deterministic system forced by noise representing processes with periods shorter than ENSO. Also, there is observational evidence to suggest that the Madden-Julian oscillation (MJO) acts to trigger and/or amplify the warm phase of ENSO in this way. The feedback of the slower process, ENSO, to higher-frequency atmospheric phenomena, of which a large part of the variability in the intraseasonal band is due to the MJO, has received little attention. This paper considers the hypothesis that the probability of an El Ni{\~n}o event is modified by high MJO activity and that, in turn, the MJO is regulated by ENSO activity. If this is indeed the case, then viewing ENSO as a low-frequency oscillation forced by additive stochastic noise would not present a complete picture. This paper tests the above hypothesis using a stochastically forced intermediate coupled model by allowing ENSO to directly influence the stochastic forcing. The model response to a variety of stochastic forcing types is found to be sensitive to the type of forcing applied. When the model is operated beyond its intrinsic Hopf bifurcation, its probability distribution function (PDF) is fundamentally altered when the stochastic forcing is changed from additive to multiplicative. The model integration period also influences the shape of the PDF, which is also compared to the PDF derived from observations. It is found that multiplicative stochastic forcing reproduces some measures of the observations better than the additive stochastic forcing.",
author = "Perez, {Christina L.} and Moore, {Andrew M.} and Javier Zavala-Garay and Richard Kleeman",
year = "2005",
month = "12",
day = "1",
doi = "10.1175/JCLI3596.1",
language = "English (US)",
volume = "18",
pages = "5066--5085",
journal = "Journal of Climate",
issn = "0894-8755",
publisher = "American Meteorological Society",
number = "23",

}

TY - JOUR

T1 - A comparison of the influence of additive and multiplicative stochastic forcing on a coupled model of ENSO

AU - Perez, Christina L.

AU - Moore, Andrew M.

AU - Zavala-Garay, Javier

AU - Kleeman, Richard

PY - 2005/12/1

Y1 - 2005/12/1

N2 - A currently popular idea is that El Niño-Southern Oscillation (ENSO) can be viewed as a linear deterministic system forced by noise representing processes with periods shorter than ENSO. Also, there is observational evidence to suggest that the Madden-Julian oscillation (MJO) acts to trigger and/or amplify the warm phase of ENSO in this way. The feedback of the slower process, ENSO, to higher-frequency atmospheric phenomena, of which a large part of the variability in the intraseasonal band is due to the MJO, has received little attention. This paper considers the hypothesis that the probability of an El Niño event is modified by high MJO activity and that, in turn, the MJO is regulated by ENSO activity. If this is indeed the case, then viewing ENSO as a low-frequency oscillation forced by additive stochastic noise would not present a complete picture. This paper tests the above hypothesis using a stochastically forced intermediate coupled model by allowing ENSO to directly influence the stochastic forcing. The model response to a variety of stochastic forcing types is found to be sensitive to the type of forcing applied. When the model is operated beyond its intrinsic Hopf bifurcation, its probability distribution function (PDF) is fundamentally altered when the stochastic forcing is changed from additive to multiplicative. The model integration period also influences the shape of the PDF, which is also compared to the PDF derived from observations. It is found that multiplicative stochastic forcing reproduces some measures of the observations better than the additive stochastic forcing.

AB - A currently popular idea is that El Niño-Southern Oscillation (ENSO) can be viewed as a linear deterministic system forced by noise representing processes with periods shorter than ENSO. Also, there is observational evidence to suggest that the Madden-Julian oscillation (MJO) acts to trigger and/or amplify the warm phase of ENSO in this way. The feedback of the slower process, ENSO, to higher-frequency atmospheric phenomena, of which a large part of the variability in the intraseasonal band is due to the MJO, has received little attention. This paper considers the hypothesis that the probability of an El Niño event is modified by high MJO activity and that, in turn, the MJO is regulated by ENSO activity. If this is indeed the case, then viewing ENSO as a low-frequency oscillation forced by additive stochastic noise would not present a complete picture. This paper tests the above hypothesis using a stochastically forced intermediate coupled model by allowing ENSO to directly influence the stochastic forcing. The model response to a variety of stochastic forcing types is found to be sensitive to the type of forcing applied. When the model is operated beyond its intrinsic Hopf bifurcation, its probability distribution function (PDF) is fundamentally altered when the stochastic forcing is changed from additive to multiplicative. The model integration period also influences the shape of the PDF, which is also compared to the PDF derived from observations. It is found that multiplicative stochastic forcing reproduces some measures of the observations better than the additive stochastic forcing.

UR - http://www.scopus.com/inward/record.url?scp=31344473369&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=31344473369&partnerID=8YFLogxK

U2 - 10.1175/JCLI3596.1

DO - 10.1175/JCLI3596.1

M3 - Article

VL - 18

SP - 5066

EP - 5085

JO - Journal of Climate

JF - Journal of Climate

SN - 0894-8755

IS - 23

ER -