The role of mean state on changes in El Niño’s flavor

Choi, Jung Ho; An, Soon Il; Kug, Jong‐Seong; Yeh, Sang‐Wook

doi:10.1007/s00382-010-0912-1

Cited by 114 publications

(109 citation statements)

References 51 publications

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“…As shown in Fig. 1a ) after 2000 in the east region, which concurs with previous studies that the coupling relationship weakened in the eastern Pacific in the 2000s (Choi et al 2011;Hu et al 2013;Zheng et al 2014). Similar variations in those two areas are also observed with the Optimum Interpolation version 2 SST data (Reynolds et al 2002;Supplement 2).…”

Section: Climate Shift In the Hf-sst Coupling Processsupporting

confidence: 91%

Bias Corrections of the Heat Flux Damping Process to Improve the Simulation of ENSO Post-2000

Zhao

Chen

Zheng

2015

SOLA

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Around 2000, El Niño-Southern Oscillation (ENSO) began to experience weaker-intensity, but more frequent events (i.e., the increased central-Pacific (CP) ENSO), when a climate transition characterized by a La Niña-like mean state coincidently occurred. Associated with this climate shift, the ENSO simulation and prediction skills of most models in the 2000s were significantly lower than those in the 1980−90s, which had common biases that were amplified through this climate transition. In this work, a model bias is examined with the heat flux (HF)-sea surface temperature (SST) coupling processes over the tropical Pacific, which experienced coupling strength modification around 2000 over both the regions west and east of 160°W. A simple ENSO coupled model trained with the observations before 2000 is used to demonstrate that this model bias can be alleviated by updating the HF-SST coupling parameters. After updating these parameters, the performance of the ENSO model is significantly improved for reproducing observations over the tropical Pacific after the year 2000, suggesting the potential for a substantial improvement in ENSO simulation and prediction.

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Section: Climate Shift In the Hf-sst Coupling Processsupporting

confidence: 91%

Bias Corrections of the Heat Flux Damping Process to Improve the Simulation of ENSO Post-2000

Zhao

Chen

Zheng

2015

SOLA

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“…According to previous studies, a remarkable change has taken place in the last few decades, in both the characteristics and development of the ENSO phenomena (An and Wang, 2000, Federov and Philander 2000, An 2008, Choi et al 2010, Yeh et al 2011. Alterations of the intensity, frequency and type of the ENSO have also been observed in recent decades Yu 2009, Lee andMcPhaden 2010).…”

Section: Introductionmentioning

confidence: 95%

“…The origin of the CP and EP ENSO is associated with different forcings, so EP ones are highly dependent on thermocline variations, while CP ones are mainly influenced by atmospheric forcing , Choi et al 2010. Likewise, other studies have shown the importance of the mean state in favouring EP or CP ENSO (Yeh et al 2009, Choi et al 2010, Yeh et al 2011.…”

Section: Introductionmentioning

confidence: 96%

“…Regarding the variability of the ENSO phenomenon, several authors have reported the different ENSO "flavours", eastern Pacific (EP) and central Pacific (CP), in the last century, suggesting great differences in their sources and impacts , Kao and Yu 2009, Yeh et al 2009, Choi et al 2010. The origin of the CP and EP ENSO is associated with different forcings, so EP ones are highly dependent on thermocline variations, while CP ones are mainly influenced by atmospheric forcing , Choi et al 2010.…”

Section: Introductionmentioning

confidence: 99%

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Changes in the interannual variability of the tropical Pacific as a response to an equatorial Atlantic forcing

Martín‐Rey¹,

Polo²,

Rodríguez‐Fonseca³

et al. 2012

Sci. Mar.

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SUMMARY: Previous studies have reported that the tropical Atlantic has had an influence on tropical Pacific interannual variability since the 1970s. This variability is studied in the present work, using simulations from a coupled model in the Indo-Pacific but with observed sea surface temperature (SST) prescribed over the Atlantic. The interannual variability is compared with that from a control simulation in which climatological SSTs are prescribed over the Atlantic. Differences in the Pacific mean state and in its variability are found in the forced simulation as a response to a warming in the equatorial Atlantic, characterized by a cooler background state and an increase in the variability over the tropical Pacific. A striking result is that the principal modes of tropical Pacific SST interannual variability show significant differences before and after the 1970s, providing new evidence of the Atlantic influence on the Pacific Ocean. Significant cooling (warming) in the equatorial Atlantic could have caused anomalous winds in the central-easter Pacific during the summer since 1970s. The thermocline depth also seems to be altered, triggering the dynamical processes involved in the development of El Niño (La Niña) phenomenon in the following winter. An increase in frequency of Niño and Niña events favouring the Central Pacific (CP) ones is observed in the last three decades. Further analyses using coupled models are still necessary to help us to understand the causes of this inter-basin connection.Keywords: Tropical Atlantic variability, Atlantic-Pacific connection, ENSO.RESUMEN: Cambios en la variabilidad interanual del PaCífiCo troPiCal Como resPuesta a un forzamiento del atlántiCo eCuatorial. -Trabajos previos han puesto de manifiesto como el Atlántico Tropical influye en la variabilidad interanual del Pacífico a partir de los años 70. El presente trabajo estudia la variabilidad del Pacífico Tropical a partir de simulaciones realizadas con un modelo acoplado en el Indo-Pacífico que considera la Temperatura de la Superficie del Mar (TSM) observada en el Atlántico como forzamiento externo. Los resultados de esta simulación son comparados con los obtenidos en una simulación de control, con TSM climatológicas en el Atlántico. La simulación forzada muestra cambios en el estado base y la variabilidad del Océano Pacífico relacionados con un calentamiento en el Atlántico ecuatorial, destacando un aumento de la variabilidad y un enfriamiento del Pacífico ecuatorial. Además, los principales modos de variabilidad del Pacífico antes y después de los 70 son diferentes, reafirmándose la influencia del Atlántico sobre el Océano Pacífico. Un enfriamiento (calentamiento) en el Atlántico ecuatorial podría generar vientos anómalos en el centro-este de la cuenca del Pacífico durante el verano desde dicha década. La profundidad de la termoclina también se modificaría, desencadenándose los procesos dinámicos involucrados en el desarrollo de El Niño (La Niña) en el invierno siguiente. Los resultados muestran un aumento de la frec...

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“…This is the case both with respect to the mean state and for key modes of variability, influenced by, or interacting with, the mean state (e.g. ENSO, Choi et al, 2011). Such biases are often reflected in a "double ITCZ" seen in the majority of CMIP3 and CMIP5 CCMs (Li and Xie, 2014;Oueslati and Bellon, 2015).…”

Section: Simulated Tropical Ocean Climatologymentioning

confidence: 99%

ESMValTool (v1.0) – a community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP

et al. 2016

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Abstract.A community diagnostics and performance metrics tool for the evaluation of Earth system models (ESMs) has been developed that allows for routine comparison of single or multiple models, either against predecessor versions or against observations. The priority of the effort so far has been to target specific scientific themes focusing on selected essential climate variables (ECVs), a range of known systematic biases common to ESMs, such as coupled tropical climate variability, monsoons, Southern Ocean processes, continental dry biases, and soil hydrology-climate interactions, as well as atmospheric CO 2 budgets, tropospheric and stratospheric ozone, and tropospheric aerosols. The tool is being developed in such a way that additional analyses can easily be added. A set of standard namelists for each scientific topic reproduces specific sets of diagnostics or performance metrics that have demonstrated their importance in ESM evaluation in the peer-reviewed literature. The Earth System Model Evaluation Tool (ESMValTool) is a community effort open to both users and developers encouraging open exchange of diagnostic source code and evaluation results from the Coupled Model Intercomparison Project (CMIP) ensemble. This will facilitate and improve ESM evaluation beyond the stateof-the-art and aims at supporting such activities within CMIP and at individual modelling centres. Ultimately, we envisage running the ESMValTool alongside the Earth System Grid Federation (ESGF) as part of a more routine evaluation of CMIP model simulations while utilizing observations available in standard formats (obs4MIPs) or provided by the user.

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The role of mean state on changes in El Niño’s flavor

Cited by 114 publications

References 51 publications

Bias Corrections of the Heat Flux Damping Process to Improve the Simulation of ENSO Post-2000

Bias Corrections of the Heat Flux Damping Process to Improve the Simulation of ENSO Post-2000

Changes in the interannual variability of the tropical Pacific as a response to an equatorial Atlantic forcing

ESMValTool (v1.0) – a community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP

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