ENSO Bimodality and Extremes

Regina R. Rodrigues; Aneesh Subramanian; Laure Zanna; Judith Berner

doi:10.1029/2019GL082270

ENSO Bimodality and Extremes

Regina R. Rodrigues, Aneesh Subramanian, Laure Zanna, Judith Berner

Mathematics

Research output: Contribution to journal › Article › peer-review

Abstract

Tropical sea surface temperature (SST) and winds vary on a wide range of timescales and have a substantial impact on weather and climate across the globe. Here we study the variability of SST and zonal wind during El Niño-Southern Oscillation (ENSO) between 1982 and 2014. We focus on changes in extreme statistics using higher-order moments of SST and zonal winds. We find that ENSO characteristics exhibit bimodal distributions and fat tails with extreme warm and cold temperatures in 1982–1999, but not during 2000–2014. The changes in the distributions coincide with changes in the intensity of ENSO events and the phase of the Interdecadal Pacific Oscillation. We also find that the strongest Easterly Wind Bursts occur during extreme El Niños and not during La Niñas. Maps of SST kurtosis can serve as a diagnostic for the thermocline feedback mechanism responsible for the differences in ENSO diversity between the two periods.

Original language	English (US)
Pages (from-to)	4883-4893
Number of pages	11
Journal	Geophysical Research Letters
Volume	46
Issue number	9
DOIs	https://doi.org/10.1029/2019GL082270
State	Published - May 16 2019

Keywords

ENSO diversity
Interdecadal Pacific Oscillation

ASJC Scopus subject areas

Geophysics
General Earth and Planetary Sciences

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10.1029/2019GL082270

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title = "ENSO Bimodality and Extremes",

abstract = "Tropical sea surface temperature (SST) and winds vary on a wide range of timescales and have a substantial impact on weather and climate across the globe. Here we study the variability of SST and zonal wind during El Ni{\~n}o-Southern Oscillation (ENSO) between 1982 and 2014. We focus on changes in extreme statistics using higher-order moments of SST and zonal winds. We find that ENSO characteristics exhibit bimodal distributions and fat tails with extreme warm and cold temperatures in 1982–1999, but not during 2000–2014. The changes in the distributions coincide with changes in the intensity of ENSO events and the phase of the Interdecadal Pacific Oscillation. We also find that the strongest Easterly Wind Bursts occur during extreme El Ni{\~n}os and not during La Ni{\~n}as. Maps of SST kurtosis can serve as a diagnostic for the thermocline feedback mechanism responsible for the differences in ENSO diversity between the two periods.",

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AU - Rodrigues, Regina R.

AU - Subramanian, Aneesh

AU - Zanna, Laure

AU - Berner, Judith

PY - 2019/5/16

Y1 - 2019/5/16

N2 - Tropical sea surface temperature (SST) and winds vary on a wide range of timescales and have a substantial impact on weather and climate across the globe. Here we study the variability of SST and zonal wind during El Niño-Southern Oscillation (ENSO) between 1982 and 2014. We focus on changes in extreme statistics using higher-order moments of SST and zonal winds. We find that ENSO characteristics exhibit bimodal distributions and fat tails with extreme warm and cold temperatures in 1982–1999, but not during 2000–2014. The changes in the distributions coincide with changes in the intensity of ENSO events and the phase of the Interdecadal Pacific Oscillation. We also find that the strongest Easterly Wind Bursts occur during extreme El Niños and not during La Niñas. Maps of SST kurtosis can serve as a diagnostic for the thermocline feedback mechanism responsible for the differences in ENSO diversity between the two periods.

AB - Tropical sea surface temperature (SST) and winds vary on a wide range of timescales and have a substantial impact on weather and climate across the globe. Here we study the variability of SST and zonal wind during El Niño-Southern Oscillation (ENSO) between 1982 and 2014. We focus on changes in extreme statistics using higher-order moments of SST and zonal winds. We find that ENSO characteristics exhibit bimodal distributions and fat tails with extreme warm and cold temperatures in 1982–1999, but not during 2000–2014. The changes in the distributions coincide with changes in the intensity of ENSO events and the phase of the Interdecadal Pacific Oscillation. We also find that the strongest Easterly Wind Bursts occur during extreme El Niños and not during La Niñas. Maps of SST kurtosis can serve as a diagnostic for the thermocline feedback mechanism responsible for the differences in ENSO diversity between the two periods.

KW - ENSO diversity

KW - Interdecadal Pacific Oscillation

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ENSO Bimodality and Extremes

Abstract

Keywords

ASJC Scopus subject areas

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