ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator model
IntroductionObservational and modeling studies have examined the interactions between El Niño-Southern Oscillation (ENSO) and the equatorial Atlantic variability as incorporated into the classical charge-recharge oscillator model of ENSO. These studies included the role of the Atlantic in the predic...
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Frontiers Media S.A.
2023-01-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2022.1001743/full |
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| author | Rodrigo Crespo-Miguel Irene Polo Carlos R. Mechoso Carlos R. Mechoso Belén Rodríguez-Fonseca Belén Rodríguez-Fonseca Francisco J. Cao-García Francisco J. Cao-García |
| author_facet | Rodrigo Crespo-Miguel Irene Polo Carlos R. Mechoso Carlos R. Mechoso Belén Rodríguez-Fonseca Belén Rodríguez-Fonseca Francisco J. Cao-García Francisco J. Cao-García |
| author_sort | Rodrigo Crespo-Miguel |
| collection | DOAJ |
| description | IntroductionObservational and modeling studies have examined the interactions between El Niño-Southern Oscillation (ENSO) and the equatorial Atlantic variability as incorporated into the classical charge-recharge oscillator model of ENSO. These studies included the role of the Atlantic in the predictability of ENSO but assumed stationarity in the relationships, i.e., that models’ coefficients do not change over time. A recent work by the authors has challenged the stationarity assumption in the ENSO framework but without considering the equatorial Atlantic influence on ENSO.MethodsThe present paper addresses the changing relationship between ENSO and the Atlantic El Niño using an extended version of the recharge oscillator model. The classical two-variable model of ENSO is extended by adding a linear coupling on the SST anomalies in the equatorial Atlantic. The model’s coefficients are computed for different periods. This calculation is done using two methods to fit the model to the data: (1) the traditional method (ReOsc), and (2) a novel method (ReOsc+) based on fitting the Fisher’s Z transform of the auto and cross-correlation functions.ResultsWe show that, during the 20th century, the characteristic damping rate of the SST and thermocline depth anomalies in the Pacific have decreased in time by a factor of 2 and 3, respectively. Moreover, the damping time of the ENSO fluctuations has doubled from 10 to 20 months, and the oscillation period of ENSO has decreased from 60-70 months before the 1960s to 50 months afterward. These two changes have contributed to enhancing ENSO amplitude. The results also show that correlations between ENSO and the Atlantic SST strengthened after the 70s and the way in which the impact of the equatorial Atlantic is added to the internal ENSO variability.ConclusionsThe remote effects of the equatorial Atlantic on ENSO must be considered in studies of ENSO dynamics and predictability during specific time-periods. Our results provide further insight into the evolution of the ENSO dynamics and its coupling to the equatorial Atlantic, as well as an improved tool to study the coupling of climatic and ecological variables. |
| first_indexed | 2024-04-10T23:09:54Z |
| format | Article |
| id | doaj.art-41ed7c2e087f4576bc8506a1267944ae |
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| language | English |
| last_indexed | 2024-04-10T23:09:54Z |
| publishDate | 2023-01-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Marine Science |
| spelling | doaj.art-41ed7c2e087f4576bc8506a1267944ae2023-01-13T06:32:25ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-01-01910.3389/fmars.2022.10017431001743ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator modelRodrigo Crespo-Miguel0Irene Polo1Carlos R. Mechoso2Carlos R. Mechoso3Belén Rodríguez-Fonseca4Belén Rodríguez-Fonseca5Francisco J. Cao-García6Francisco J. Cao-García7Departamento de Estructura de la Materia, Física Térmica y Electrónica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid, SpainDepartamento de Física de la Tierra y Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid, SpainDepartamento de Física de la Tierra y Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid, SpainDepartment of Atmospheric and Oceanic Sciences, University of California, Los Angeles (UCLA), Los Angeles, CA, United StatesDepartamento de Física de la Tierra y Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid, SpainInstituto de Geociencias (IGEO), Centro Superior de Investigaciones Científicas-Universidad Complutense de Madrid (CSIC-UCM), Madrid, SpainDepartamento de Estructura de la Materia, Física Térmica y Electrónica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, Madrid, SpainInstituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Madrid, SpainIntroductionObservational and modeling studies have examined the interactions between El Niño-Southern Oscillation (ENSO) and the equatorial Atlantic variability as incorporated into the classical charge-recharge oscillator model of ENSO. These studies included the role of the Atlantic in the predictability of ENSO but assumed stationarity in the relationships, i.e., that models’ coefficients do not change over time. A recent work by the authors has challenged the stationarity assumption in the ENSO framework but without considering the equatorial Atlantic influence on ENSO.MethodsThe present paper addresses the changing relationship between ENSO and the Atlantic El Niño using an extended version of the recharge oscillator model. The classical two-variable model of ENSO is extended by adding a linear coupling on the SST anomalies in the equatorial Atlantic. The model’s coefficients are computed for different periods. This calculation is done using two methods to fit the model to the data: (1) the traditional method (ReOsc), and (2) a novel method (ReOsc+) based on fitting the Fisher’s Z transform of the auto and cross-correlation functions.ResultsWe show that, during the 20th century, the characteristic damping rate of the SST and thermocline depth anomalies in the Pacific have decreased in time by a factor of 2 and 3, respectively. Moreover, the damping time of the ENSO fluctuations has doubled from 10 to 20 months, and the oscillation period of ENSO has decreased from 60-70 months before the 1960s to 50 months afterward. These two changes have contributed to enhancing ENSO amplitude. The results also show that correlations between ENSO and the Atlantic SST strengthened after the 70s and the way in which the impact of the equatorial Atlantic is added to the internal ENSO variability.ConclusionsThe remote effects of the equatorial Atlantic on ENSO must be considered in studies of ENSO dynamics and predictability during specific time-periods. Our results provide further insight into the evolution of the ENSO dynamics and its coupling to the equatorial Atlantic, as well as an improved tool to study the coupling of climatic and ecological variables.https://www.frontiersin.org/articles/10.3389/fmars.2022.1001743/fullEl Niño-Southern Oscillation (ENSO)equatorial Atlantic sea surface temperaturerecharge oscillator modelatmospheric teleconnectionstropical basin interactions |
| spellingShingle | Rodrigo Crespo-Miguel Irene Polo Carlos R. Mechoso Carlos R. Mechoso Belén Rodríguez-Fonseca Belén Rodríguez-Fonseca Francisco J. Cao-García Francisco J. Cao-García ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator model Frontiers in Marine Science El Niño-Southern Oscillation (ENSO) equatorial Atlantic sea surface temperature recharge oscillator model atmospheric teleconnections tropical basin interactions |
| title | ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator model |
| title_full | ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator model |
| title_fullStr | ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator model |
| title_full_unstemmed | ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator model |
| title_short | ENSO coupling to the equatorial Atlantic: Analysis with an extended improved recharge oscillator model |
| title_sort | enso coupling to the equatorial atlantic analysis with an extended improved recharge oscillator model |
| topic | El Niño-Southern Oscillation (ENSO) equatorial Atlantic sea surface temperature recharge oscillator model atmospheric teleconnections tropical basin interactions |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2022.1001743/full |
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