Role of nonlinear ocean dynamic response to wind on the asymmetrical transition of El Niño and La Niña

Soon-Il An, Ji Won Kim

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

To understand why El Niño is frequently followed by La Niña while the opposite occurs rarely, we analyze the inherent asymmetry in a delayed negative feedback loop in the framework of delayed oscillator theory using observational data. The asymmetrical response of the ocean wave to wind is much larger than that of the wind intensity to sea surface temperature (SST) and that of the subsurface temperature to thermocline. Strong oceanic response during El Niño compared to La Niña is presumably due to the relatively shallow mean thermocline over the western Pacific, which efficiently traps the atmospheric momentum in the shallow upper ocean, and the asymmetrical wind pattern response to SST. A modified delayed oscillator model experiment verifies that the asymmetrical ocean wave response to wind is more important in the asymmetrical transition of El Niño and La Niña than asymmetrical wind intensity response to SST and asymmetrical subsurface temperature response to thermocline.

Original languageEnglish
Pages (from-to)393-400
Number of pages8
JournalGeophysical Research Letters
Volume44
Issue number1
DOIs
Publication statusPublished - 2017 Jan 16

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ocean dynamics
dynamic response
thermoclines
thermocline
sea surface temperature
ocean
ocean wave
oceans
oscillators
upper ocean
negative feedback
asymmetry
momentum
temperature
traps
experiment

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

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abstract = "To understand why El Ni{\~n}o is frequently followed by La Ni{\~n}a while the opposite occurs rarely, we analyze the inherent asymmetry in a delayed negative feedback loop in the framework of delayed oscillator theory using observational data. The asymmetrical response of the ocean wave to wind is much larger than that of the wind intensity to sea surface temperature (SST) and that of the subsurface temperature to thermocline. Strong oceanic response during El Ni{\~n}o compared to La Ni{\~n}a is presumably due to the relatively shallow mean thermocline over the western Pacific, which efficiently traps the atmospheric momentum in the shallow upper ocean, and the asymmetrical wind pattern response to SST. A modified delayed oscillator model experiment verifies that the asymmetrical ocean wave response to wind is more important in the asymmetrical transition of El Ni{\~n}o and La Ni{\~n}a than asymmetrical wind intensity response to SST and asymmetrical subsurface temperature response to thermocline.",
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Role of nonlinear ocean dynamic response to wind on the asymmetrical transition of El Niño and La Niña. / An, Soon-Il; Kim, Ji Won.

In: Geophysical Research Letters, Vol. 44, No. 1, 16.01.2017, p. 393-400.

Research output: Contribution to journalArticle

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