Nonlinearity in the North Pacific Atmospheric Response to a Linear ENSO Forcing

Jiménez‐Esteve, Bernat; Domeisen, Daniela I. V.

doi:10.1029/2018gl081226

Cited by 50 publications

(33 citation statements)

References 64 publications

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“…This result, which applies to strong El Niño-and La Niña-like SST forcings, is in agreement with previous works using similar sensitivity experiments (e.g. Hoerling et al 1997Hoerling et al , 2001Sardeshmukh et al 2000;Jiménez-Esteve and Domeisen 2019;Tracasa-Castro et al 2019) but is in conflict with Rao and Ren (2016b), who reported no asymmetry for strong events. In the same study, however, Rao and Ren observed asymmetries in coupled experiments for both the strong and moderate case.…”

Section: Summary and Discussionsupporting

confidence: 93%

“…Several studies adopted the same approach (e.g. Hoerling et al 2001;Rao and Ren 2016b;Jiménez-Esteve and Domeisen 2019;Tracasa-Castro et al 2019), which here we justify by the aim of focusing on asymmetries arising from one source only, i.e. cooling versus warming of the tropical Pacific, while excluding other factors such as pattern diversity, variations in timing and SST amplitude differences.…”

Section: Summary and Discussionmentioning

confidence: 99%

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Multi-model assessment of the late-winter extra-tropical response to El Niño and La Niña

et al. 2020

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El Niño-Southern Oscillation (ENSO) is known to affect the Northern Hemisphere tropospheric circulation in late-winter (January-March), but whether El Niño and La Niña lead to symmetric impacts and with the same underlying dynamics remains unclear, particularly in the North Atlantic. Three state-of-the-art atmospheric models forced by symmetric anomalous sea surface temperature (SST) patterns, mimicking strong ENSO events, are used to robustly diagnose symmetries and asymmetries in the extra-tropical ENSO response. Asymmetries arise in the sea-level pressure (SLP) response over the North Pacific and North Atlantic, as the response to La Niña tends to be weaker and shifted westward with respect to that of El Niño. The difference in amplitude can be traced back to the distinct energy available for the two ENSO phases associated with the non-linear diabatic heating response to the total SST field. The longitudinal shift is embedded into the large-scale Rossby wave train triggered from the tropical Pacific, as its anomalies in the upper troposphere show a similar westward displacement in La Niña compared to El Niño. To fully explain this shift, the response in tropical convection and the related anomalous upper-level divergence have to be considered together with the climatological vorticity gradient of the subtropical jet, i.e. diagnosing the tropical Rossby wave source. In the North Atlantic, the ENSO-forced SLP signal is a well-known dipole between middle and high latitudes, different from the North Atlantic Oscillation, whose asymmetry is not indicative of distinct mechanisms driving the teleconnection for El Niño and La Niña.

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Section: Summary and Discussionsupporting

confidence: 93%

Section: Summary and Discussionmentioning

confidence: 99%

Multi-model assessment of the late-winter extra-tropical response to El Niño and La Niña

et al. 2020

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“…It has been used to simulate a wide range of atmospheric processes, including SST forced atmospheric teleconnections (e.g. Thomson and Vallis 2018 ; Jiménez-Esteve and Domeisen 2019 ). It uses the Geophysical Fluid Dynamics Laboratory (GFDL) dynamical core.…”

Section: Methodsmentioning

confidence: 99%

“…It uses the Geophysical Fluid Dynamics Laboratory (GFDL) dynamical core. Here, we use the same general model configuration as in Jiménez-Esteve and Domeisen ( 2019 ). In this configuration, simple moist processes are considered through evaporation from the surface and fast condensation (i.e.…”

Section: Methodsmentioning

confidence: 99%

Revisiting remote drivers of the 2014 drought in South-Eastern Brazil

et al. 2020

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South-Eastern Brazil experienced a devastating drought associated with significant agricultural losses in austral summer 2014. The drought was linked to the development of a quasi-stationary anticyclone in the South Atlantic in early 2014 that affected local precipitation patterns over South-East Brazil. Previous studies have suggested that the unusual blocking was triggered by tropical Pacific sea surface temperature (SST) anomalies and, more recently, by convection over the Indian Ocean related to the Madden–Julian Oscillation. Further investigation of the proposed teleconnections appears crucial for anticipating future economic impacts. In this study, we use numerical experiments with an idealized atmospheric general circulation model forced with the observed 2013/2014 SST anomalies in different ocean basins to understand the dominant mechanism that initiated the 2014 South Atlantic anticyclonic anomaly. We show that a forcing with global 2013/2014 SST anomalies enhances the chance for the occurrence of positive geopotential height anomalies in the South Atlantic. However, further sensitivity experiments with SST forcings in separate ocean basins suggest that neither the Indian Ocean nor tropical Pacific SST anomalies alone have contributed significantly to the anomalous atmospheric circulation that led to the 2014 South-East Brazil drought. The model study rather points to an important role of remote forcing from the South Pacific, local South Atlantic SSTs, and internal atmospheric variability in driving the persistent blocking over the South Atlantic.

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“…Various models of Earth's atmosphere have been constructed using Isca and are described in more detail elsewhere (e.g., [11,[28][29][30][31]). Here, we give three examples covering the range of possibilities.…”

Section: Earthmentioning

confidence: 99%

Hierarchical Modeling of Solar System Planets with Isca

Thomson

Vallis

2019

Atmosphere

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We describe the use of Isca for the hierarchical modeling of Solar System planets, with particular attention paid to Earth, Mars, and Jupiter. Isca is a modeling framework for the construction and use of models of planetary atmospheres at varying degrees of complexity, from featureless model planets with an atmosphere forced by a thermal relaxation back to a specified temperature, through aquaplanets with no continents (or no ocean) with a simple radiation scheme, to near-comprehensive models with a multi-band radiation scheme, a convection scheme, and configurable continents and topography. By a judicious choice of parameters and parameterization schemes, the model may be configured for fairly arbitrary planets, with stellar radiation input determined by astronomical parameters, taking into account the planet's obliquity and eccentricity. In this paper, we describe the construction and use of models at varying levels of complexity for Earth, Mars and Jupiter using the primitive equations and/or the shallow water equations.Atmosphere 2019, 10, 803 2 of 21 with a nominal troposphere that in some respects is quite Earth-like: its temperature falls from about 320 K at its base to 53 K at its top, possibly containing both water and ammonia/methane clouds.Beyond our Solar System, there are likely billions of planets in our galaxy alone, with over 4000 confirmed planets at the time of writing (NASA Exoplanet Archive [7]). Many of these planets are undoubtedly similar to those mentioned above, but some surely different-tidally-locked "Hot-Jupiters", being but one example class [8,9].Given such a diversity-a diversity far greater than that of the stars around which the planets orbit-the question arises as to how such planets should be modeled. On Earth, we may reasonably seek to model Earth's atmosphere and climate in some detail using very complex models-such as comprehensive General Circulation Models (GCMs) or Earth System Models (ESMs)-in which we seek to put the most realistic representation of physical and chemical (and sometimes biological) processes possible. Such models are extensions of those used for weather forecasting and, similar to weather forecast models, one goal is to be as quantitatively accurate as possible.However, several factors suggest that such an approach is not always ideal for planetary atmospheres:

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Nonlinearity in the North Pacific Atmospheric Response to a Linear ENSO Forcing

Cited by 50 publications

References 64 publications

Multi-model assessment of the late-winter extra-tropical response to El Niño and La Niña

Multi-model assessment of the late-winter extra-tropical response to El Niño and La Niña

Revisiting remote drivers of the 2014 drought in South-Eastern Brazil

Hierarchical Modeling of Solar System Planets with Isca

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