scholarly journals Bifurcation analysis of delay-induced resonances of the El-Niño Southern Oscillation

2014 ◽  
Vol 470 (2169) ◽  
pp. 20140348 ◽  
Author(s):  
Bernd Krauskopf ◽  
Jan Sieber
Keyword(s):  
Bifurcation Analysis ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Equation Model ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
The Pacific ◽  
Delay Differential

Models of global climate phenomena of low to intermediate complexity are very useful for providing an understanding at a conceptual level. An important aspect of such models is the presence of a number of feedback loops that feature considerable delay times, usually due to the time it takes to transport energy (for example, in the form of hot/cold air or water) around the globe. In this paper, we demonstrate how one can perform a bifurcation analysis of the behaviour of a periodically forced system with delay in dependence on key parameters. As an example, we consider the El-Niño Southern Oscillation (ENSO), which is a sea-surface temperature (SST) oscillation on a multi-year scale in the basin of the Pacific Ocean. One can think of ENSO as being generated by an interplay between two feedback effects, one positive and one negative, which act only after some delay that is determined by the speed of transport of SST anomalies across the Pacific. We perform here a case study of a simple delayed-feedback oscillator model for ENSO, which is parametrically forced by annual variation. More specifically, we use numerical bifurcation analysis tools to explore directly regions of delay-induced resonances and other stability boundaries in this delay-differential equation model for ENSO.

scholarly journals The Impact of Obliquity Change on El Niño Southern Oscillation (ENSO) and La Niña Climate Episodes

2022 ◽  
Author(s):  
Paul C. Rivera
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Global Climate Model ◽  
La Niña ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
La Nina ◽  
The Impact

An alternative physical mechanism is proposed to describe the occurrence of the episodic El Nino Southern Oscillation (ENSO) and La Nina climatic phenomena. This is based on the earthquake-perturbed obliquity change (EPOCH) model previously discovered as a major cause of the global climate change problem. Massive quakes impart a very strong oceanic force that can move the moon which in turn pulls the earth’s axis and change the planetary obliquity. Analysis of the annual geomagnetic north-pole shift and global seismic data revealed this previously undiscovered force. Using a higher obliquity in the global climate model EdGCM and constant greenhouse gas forcing showed that the seismic-induced polar motion and associated enhanced obliquity could be the major mechanism governing the mysterious climate anomalies attributed to El Nino and La Nina cycles.

Highly Variable El Niño–Southern Oscillation Throughout the Holocene

Science ◽  
2013 ◽  
Vol 339 (6115) ◽  
pp. 67-70 ◽  
Author(s):  
Kim M. Cobb ◽  
Niko Westphal ◽  
Hussein R. Sayani ◽  
Jordan T. Watson ◽  
Emanuele Di Lorenzo ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Internal Variability ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Line Islands ◽  
Insolation Forcing ◽  
Fossil Coral

The El Niño–Southern Oscillation (ENSO) drives large changes in global climate patterns from year to year, yet its sensitivity to continued anthropogenic greenhouse forcing is uncertain. We analyzed fossil coral reconstructions of ENSO spanning the past 7000 years from the Northern Line Islands, located in the center of action for ENSO. The corals document highly variable ENSO activity, with no evidence for a systematic trend in ENSO variance, which is contrary to some models that exhibit a response to insolation forcing over this same period. Twentieth-century ENSO variance is significantly higher than average fossil coral ENSO variance but is not unprecedented. Our results suggest that forced changes in ENSO, whether natural or anthropogenic, may be difficult to detect against a background of large internal variability.

scholarly journals The effect of state dependence in a delay differential equation model for the El Niño Southern Oscillation

2019 ◽  
Vol 377 (2153) ◽  
pp. 20180121 ◽  
Author(s):  
Andrew Keane ◽  
Bernd Krauskopf ◽  
Henk A. Dijkstra
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
State Dependence ◽  
Dynamical Behaviour ◽  
The State ◽  
Delay Systems ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Delay Differential

Delay differential equations (DDEs) have been used successfully in the past to model climate systems at a conceptual level. An important aspect of these models is the existence of feedback loops that feature a delay time, usually associated with the time required to transport energy through the atmosphere and/or oceans across the globe. So far, such delays are generally assumed to be constant. Recent studies have demonstrated that even simple DDEs with non-constant delay times, which change depending on the state of the system, can produce surprisingly rich dynamical behaviour. Here, we present arguments for the state dependence of the delay in a DDE model for the El Niño Southern Oscillation phenomenon in the climate system. We then conduct a bifurcation analysis by means of continuation software to investigate the effect of state dependence in the delay on the observed dynamics of the system. More specifically, we show that the underlying delay-induced structure of resonance regions may change considerably in the presence of state dependence. This article is part of the theme issue ‘Nonlinear dynamics of delay systems’.

Does the El Niño–Southern Oscillation control the interhemispheric radiocarbon offset?

2007 ◽  
Vol 67 (1) ◽  
pp. 174-180 ◽  
Author(s):  
Chris S.M. Turney ◽  
Jonathan G. Palmer
Keyword(s):  
Southern Hemisphere ◽  
El Niño ◽  
Atmospheric Carbon Dioxide ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Ice Age ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Mean Values

AbstractSince the 1970s it has been recognised that Southern Hemisphere samples have a lower radiocarbon content than contemporaneous material in the Northern Hemisphere. This interhemispheric radiocarbon offset has traditionally been considered to be the result of a greater surface area in the southern ocean and high-latitude deepwater formation. This is despite the fact that the El Niño–Southern Oscillation (ENSO) is known to play a significant role in controlling the interannual variability of atmospheric carbon dioxide by changing the flux of ‘old’ CO2 from the tropical Pacific. Here we demonstrate that over the past millennium, the Southern Hemisphere radiocarbon offset is characterised by a pervasive 80-yr cycle with a step shift in mean values coinciding with the transition from the Medieval Warm Period to the Little Ice Age. The observed changes suggest an ENSO-like role in influencing the interhemispheric radiocarbon difference, most probably modulated by the Interdecadal Pacific Oscillation, and supports a tropical role in forcing centennial-scale global climate change.

scholarly journals Coastal vulnerability across the Pacific dominated by El Niño/Southern Oscillation

2015 ◽  
Vol 8 (10) ◽  
pp. 801-807 ◽  
Author(s):  
Patrick L. Barnard ◽  
Andrew D. Short ◽  
Mitchell D. Harley ◽  
Kristen D. Splinter ◽  
Sean Vitousek ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Coastal Vulnerability ◽  
The Pacific
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