Non-linearity in the pathway of El Niño-Southern Oscillation to the tropical North Atlantic

2021 ◽  
pp. 1-54
Author(s):  
Jake W. Casselman ◽  
Andréa S. Taschetto ◽  
Daniela I.V. Domeisen
Keyword(s):  
North Atlantic ◽  
El Niño ◽  
Climate Model ◽  
El Nino ◽  
Southern Oscillation ◽  
Static Stability ◽  
Reanalysis Data ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Tropical North Atlantic

AbstractEl Niño-Southern Oscillation can influence the Tropical North Atlantic (TNA), leading to anomalous sea surface temperatures (SST) at a lag of several months. Several mechanisms have been proposed to explain this teleconnection. These mechanisms include both tropical and extratropical pathways, contributing to anomalous trade winds and static stability over the TNA region. The TNA SST response to ENSO has been suggested to be nonlinear. Yet the overall linearity of the ENSO-TNA teleconnection via the two pathways remains unclear. Here we use reanalysis data to confirm that the SST anomaly (SSTA) in the TNA is nonlinear with respect to the strength of the SST forcing in the tropical Pacific, as further increases in El Niño magnitudes cease to create further increases of the TNA SSTA. We further show that the tropical pathway is more linear than the extratropical pathway by sub-dividing the inter-basin connection into extratropical and tropical pathways. This is confirmed by a climate model participating in the CMIP5. The extratropical pathway is modulated by the North Atlantic Oscillation (NAO) and the location of the SSTA in the Pacific, but this modulation insufficiently explains the nonlinearity in TNA SSTA. As neither extratropical nor tropical pathways can explain the nonlinearity, this suggests that external factors are at play. Further analysis shows that the TNA SSTA is highly influenced by the preconditioning of the tropical Atlantic SST. This preconditioning is found to be associated with the NAO through SST-tripole patterns.

Modulation of the Global Atmospheric Circulation by Combined Activity in the Madden–Julian Oscillation and the El Niño–Southern Oscillation during Boreal Winter

2010 ◽  
Vol 23 (15) ◽  
pp. 4045-4059 ◽  
Author(s):  
Paul E. Roundy ◽  
Kyle MacRitchie ◽  
Jonas Asuma ◽  
Timothy Melino
Keyword(s):  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Boreal Winter ◽  
Madden Julian Oscillation ◽  
The North ◽  
The North Atlantic

Abstract Composite global patterns associated with the El Niño–Southern Oscillation (ENSO) and the Madden–Julian oscillation (MJO) are frequently applied to help make predictions of weather around the globe at lead times beyond a few days. However, ENSO modulates the background states through which the MJO and its global response patterns propagate. This paper explores the possibility that nonlinear variations confound the combined use of composites based on the MJO and ENSO separately. Results indicate that when both modes are active at the same time, the associated patterns in the global flow are poorly represented by simple linear combinations of composites based on the MJO and ENSO individually. Composites calculated by averaging data over periods when both modes are present at the same time more effectively describe the associated weather patterns. Results reveal that the high-latitude response to the MJO varies with ENSO over all longitudes, but especially across the North Pacific Rim, North America, and the North Atlantic. Further analysis demonstrates that the MJO influence on indexes of the North Atlantic Oscillation is greatest during La Niña conditions or during periods of rapid adjustment in the phase of ENSO.

scholarly journals Mixed-Mode Oscillations of El Niño–Southern Oscillation

2016 ◽  
Vol 73 (4) ◽  
pp. 1755-1766 ◽  
Author(s):  
Andrew Roberts ◽  
John Guckenheimer ◽  
Esther Widiasih ◽  
Axel Timmermann ◽  
Christopher K. R. T. Jones
Keyword(s):  
Ocean Circulation ◽  
El Niño ◽  
Mixed Mode ◽  
Climate Model ◽  
El Nino ◽  
Southern Oscillation ◽  
Tropical Pacific ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Critical Threshold

Abstract Very strong El Niño events occur sporadically every 10–20 yr. The origin of this bursting behavior still remains elusive. Using a simplified three-dimensional dynamical model of the tropical Pacific climate system, which captures El Niño–Southern Oscillation (ENSO) combined with recently developed mathematical tools for fast–slow systems, the authors show that decadal ENSO bursting behavior can be explained as a mixed-mode oscillation (MMO), which also predicts a critical threshold for rapid amplitude growth. It is hypothesized that the MMO dynamics of the low-dimensional climate model can be linked to a saddle-focus equilibrium point, which mimics a tropical Pacific Ocean state without ocean circulation.

scholarly journals Extreme rainfall activity in the Australian tropics reflects changes in the El Niño/Southern Oscillation over the last two millennia

2015 ◽  
Vol 112 (15) ◽  
pp. 4576-4581 ◽  
Author(s):  
Rhawn F. Denniston ◽  
Gabriele Villarini ◽  
Angelique N. Gonzales ◽  
Karl-Heinz Wyrwoll ◽  
Victor J. Polyak ◽  
...  
Keyword(s):  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Extreme Rainfall ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Extreme Rainfall Events ◽  
Rainfall Events

Assessing temporal variability in extreme rainfall events before the historical era is complicated by the sparsity of long-term “direct” storm proxies. Here we present a 2,200-y-long, accurate, and precisely dated record of cave flooding events from the northwest Australian tropics that we interpret, based on an integrated analysis of meteorological data and sediment layers within stalagmites, as representing a proxy for extreme rainfall events derived primarily from tropical cyclones (TCs) and secondarily from the regional summer monsoon. This time series reveals substantial multicentennial variability in extreme rainfall, with elevated occurrence rates characterizing the twentieth century, 850–1450 CE (Common Era), and 50–400 CE; reduced activity marks 1450–1650 CE and 500–850 CE. These trends are similar to reconstructed numbers of TCs in the North Atlantic and Caribbean basins, and they form temporal and spatial patterns best explained by secular changes in the dominant mode of the El Niño/Southern Oscillation (ENSO), the primary driver of modern TC variability. We thus attribute long-term shifts in cyclogenesis in both the central Australian and North Atlantic sectors over the past two millennia to entrenched El Niño or La Niña states of the tropical Pacific. The influence of ENSO on monsoon precipitation in this region of northwest Australia is muted, but ENSO-driven changes to the monsoon may have complemented changes to TC activity.

scholarly journals Land surface anomaly simulations and predictions with a climate model: an El Niño Southern Oscillation case study

2008 ◽  
Vol 367 (1890) ◽  
pp. 917-923 ◽  
Author(s):  
Debbie Putt ◽  
Keith Haines ◽  
Robert Gurney ◽  
Chunlei Liu
Keyword(s):  
Soil Moisture ◽  
El Niño ◽  
Land Surface ◽  
Climate Models ◽  
Snow Water Equivalent ◽  
Climate Model ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation

The ability of climate models to reproduce and predict land surface anomalies is an important but little-studied topic. In this study, an atmosphere and ocean assimilation scheme is used to determine whether HadCM3 can reproduce and predict snow water equivalent and soil moisture during the 1997–1998 El Niño Southern Oscillation event. Soil moisture is reproduced more successfully, though both snow and soil moisture show some predictability at 1- and 4-month lead times. This result suggests that land surface anomalies may be reasonably well initialized for climate model predictions and hydrological applications using atmospheric assimilation methods over a period of time.

scholarly journals El Niño−Southern Oscillation frequency cascade

2015 ◽  
Vol 112 (44) ◽  
pp. 13490-13495 ◽  
Author(s):  
Malte F. Stuecker ◽  
Fei-Fei Jin ◽  
Axel Timmermann
Keyword(s):  
Annual Cycle ◽  
El Niño ◽  
Climate Model ◽  
East Asian Monsoon ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Northwest Pacific ◽  
Tight Coupling

The El Niño−Southern Oscillation (ENSO) phenomenon, the most pronounced feature of internally generated climate variability, occurs on interannual timescales and impacts the global climate system through an interaction with the annual cycle. The tight coupling between ENSO and the annual cycle is particularly pronounced over the tropical Western Pacific. Here we show that this nonlinear interaction results in a frequency cascade in the atmospheric circulation, which is characterized by deterministic high-frequency variability on near-annual and subannual timescales. Through climate model experiments and observational analysis, it is documented that a substantial fraction of the anomalous Northwest Pacific anticyclone variability, which is the main atmospheric link between ENSO and the East Asian Monsoon system, can be explained by these interactions and is thus deterministic and potentially predictable.

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