Separating the stratospheric and tropospheric pathways of El Niño–Southern Oscillation teleconnections

By A. Butler, L. Polvani, C. Deser. 2013

169 citations recorded by the source corpus.

The El Niño–Southern Oscillation (ENSO) is a major driver of Northern Hemisphere wintertime variability and, generally, the key ingredient used in seasonal forecasts of wintertime surface climate. Modeling studies have recently suggested that ENSO teleconnections might involve both a tropospheric pathway and a stratospheric one. Here, using reanalysis data, we carefully distinguish between the two. We first note that the temperature and circulation anomalies associated with the tropospheric pathway are nearly equal and opposite during the warm (El Niño) and cold (La Niña) phases of ENSO, whereas those associated with the stratospheric pathway are of the same sign, irrespective of the ENSO phase. We then exploit this fact to isolate the two pathways. Our decomposition reveals that ENSOs climate impacts over North America are largely associated with the tropospheric pathway, whereas ENSOs climate impacts over the North Atlantic and Eurasia are greatly affected by the stratospheric pathway. The stratospheric pathway, which we here define on the basis of the occurrence of one or more sudden stratospheric warmings in a given winter, and whose signature projects very strongly on the North Atlantic Oscillation, is found to be present 60% of the time during ENSO winters (of either phase): it therefore likely plays an important role in improving seasonal forecasts, notably over the North Atlantic and the Eurasian continent.

Subfields: Atmospheric Science, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/d238479cba746b134f989771cff402c04e9fc722

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Citations in the corpus

The Role of the Stratosphere in Subseasonal to Seasonal Prediction: 2. Predictability Arising From Stratosphere‐Troposphere Coupling (2020, background): “In addition to extratropical tropospheric anomalies, the potential of probabilistic predictability on S2S timescales is suggested by teleconnections from tropical phenomena such as the QBO, ENSO, and the MJO.”
The predictability of the extratropical stratosphere on monthly time‐scales and its impact on the skill of tropospheric forecasts (2015, background): “These updates are included in a recent Butler et al. (2014) study relating SSW to the northern hemispheric winter climate in ENSO active years.”
Defining Sudden Stratospheric Warmings (2015, background): “An initial meeting was held during the SPARC General Assembly in Queenstown, New Zealand, in January 2014 to discuss a timeline and process for gathering input (Butler et al. 2014a).”
Seasonal winter forecasts and the stratosphere (2016, background): “…Hartmann, 2006; Bell et al., 2009; Butler and Polvani, 2011; Domeisen et al., 2015) and the need for this stratospheric response in order to generate a strong surface NAO signal in the Atlantic (Toniazzo and Scaife, 2006; Cagnazzo and Manzini, 2009; Ineson and Scaife, 2009; Butler et al., 2014).”
The Teleconnection of El Niño Southern Oscillation to the Stratosphere (2019, background): “A negative phase of the NAO is associated with colder weather over the eastern United States, northern Europe, and Siberia, warmer weather over Greenland, and wet anomalies over western Europe (Thompson et al., 2000; see Figures 6b and 6c).”