Nonlinear response of tropical lower stratospheric temperature and water vapor to ENSO

Gordon, A.; Garfinkel, Chaim I.; Oman, Luke D.; Li, Feng; Davis, Sean; Pawson, Steven

doi:10.5194/acp-2017-520

Cited by 8 publications

(18 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Richter et al (2015) found a more linear stratospheric response to El Niño in simulations, with strong amplitude in the case of extreme El Niño (the 1982/1983 and 1997/1998 events in their study). Unprecedented variations in the stratosphere caused by extreme El Niño events, such as in the quasi-biennial oscillation (QBO) and water vapor, have been observed (Avery et al, 2017;Christiansen et al, 2016;Dunkerton, 2016;Garfinkel et al, 2017;Varotsos et al, 2017). Palmeiro et al (2017) found that the 2015/2016 El Niño led to a stronger northern polar vortex in winter, which is not consistent with the well-known result that El Niño events can warm and weaken the northern polar vortex.…”

Section: Introductionmentioning

confidence: 89%

Does Extreme El Niño Have a Different Effect on the Stratosphere in Boreal Winter Than Its Moderate Counterpart?

et al. 2018

View full text Add to dashboard Cite

A robust impact of El Niño on the Northern Hemisphere (NH) polar stratosphere has been demonstrated by previous studies, although whether this applies to extreme El Niño is uncertain. The time evolution of the response of the NH stratospheric vortex to extreme El Niño, compared with that to moderate eastern Pacific El Niño, is addressed by means of composite analysis using the National Centers for Environmental Prediction/Department of Energy reanalysis data set from 1980 to 2016. Lead‐lag analysis indicates that the El Niño signal actually leads the stratospheric response by ~2 months. Considering the time lag, the signal of December‐January‐February El Niño in the NH stratospheric vortex should mature in the February‐March‐April season (late winter/early spring). The patterns of circulation and temperature for late winter/early spring during extreme and moderate El Niño events are significant, exhibiting similar structure. The results are confirmed with the Whole Atmosphere Community Climate Model version 4 model, which is forced with observed SSTs of extreme and moderate El Niño in winter (December‐January‐February) to analyze the day‐to‐day propagation of their signals. Note that the magnitudes of the stratospheric responses are much larger in the case of extreme El Niño, as stronger upward propagation of planetary waves leads to a weaker northern polar vortex than during moderate El Niño events.

show abstract

Section: Introductionmentioning

confidence: 89%

Does Extreme El Niño Have a Different Effect on the Stratosphere in Boreal Winter Than Its Moderate Counterpart?

et al. 2018

View full text Add to dashboard Cite

show abstract

“…2008; Oman and Douglass 2014) described in Garfinkel et al. (2018a, b). This model couples the GEOS-5 (Rienecker et al.…”

Section: Datamentioning

confidence: 98%

“…One of the integrations of Garfinkel et al. (2018a) ends in December 2008, and we do not include this integration here. 41 ensemble members covering the period 1980 to 2009 are analyzed, and all are free-running and have observed sea surface temperature (SST) variations imposed globally.…”

Section: Datamentioning

confidence: 99%

“…Full details of the model ensemble are included in Garfinkel et al. (2018a). These same experiments were analyzed in Garfinkel et al.…”

Section: Datamentioning

confidence: 99%

“…These same experiments were analyzed in Garfinkel et al. (2018a, b) with a focus on the surface impacts of ENSO over North Pacific and North America and on the tropical stratosphere; here we focus on the Arctic stratospheric response and the subpolar surface response.…”

Section: Datamentioning

confidence: 99%

See 2 more Smart Citations

The salience of nonlinearities in the boreal winter response to ENSO: Arctic stratosphere and Europe

et al. 2019

Self Cite

View full text Add to dashboard Cite

The Arctic stratospheric response to El Niño (EN) and La Niña (LN) is evaluated in a 41 member ensemble of the period 1980 to 2009 in the Goddard Earth Observing System Chemistry-Climate Model. We consider whether the responses to EN and LN are equal in magnitude and opposite in sign, whether the responses to moderate and extreme events are proportionate, and if the response depends on whether sea surface temperature anomalies (SSTs) peak in the Eastern Pacific (EP) or Central Pacific (CP). There is no indication of any nonlinearities between EN and LN, though in ~ 15% of the ensemble members the stratospheric sudden warming (SSW) frequencies for EN and LN are similar, suggesting that a similar SSW frequency for EN and LN, as has occurred over the past ~ 60 years, can occur by chance. The response to extreme EN events is not proportionate to the amplitude of the underlying SST anomalies in spring. EP EN events preferentially increase zonal wavenumber 1 and decrease zonal wavenumber 2 as compared to CP EN events, however the zonal-mean Arctic stratospheric and subpolar surface response is generally little different between EP EN and CP EN once one accounts for the relative weakness of CP events. These differences between EP and CP events and between moderate and extreme EN events only emerge if at least 25 events are composited, however, due to the small signal-to-noise ratio, and hence these differences may be of little practical benefit.

show abstract

The salience of nonlinearities in the boreal winter response to ENSO: North Pacific and North America

et al. 2018

Self Cite

View full text Add to dashboard Cite

The prominence of nonlinearities in the response to El Niño as compared to La Niña, to moderate El Niño events as compared to extreme El Ninño events, and to different flavors of El Niño events, are analyzed using the NASA Goddard Earth Observing System Chemistry-Climate Model. In the Central North Pacific region where the sea level pressure response to El Niño-Southern Oscillation (ENSO) peaks, nonlinearities are relatively muted. In contrast, changes to the east of this region (i.e. the far-Northeastern Pacific) and to the north of this region (over Alaska) in response to different ENSO phases are more clearly nonlinear, and become statistically robust after more than 15 events are considered. The relative prominence of these nonlinearities is related to the zonal wavenumber of the tropical precipitation response. Associated with these nonlinearities over the far-Northeastern Pacific are nonlinearities in precipitation over Western United States and surface temperature over Northwest North America and Midwestern United States. In all regions at least 15 events of each type are necessary before nonlinearities can be identified as statistically significant at the 95% confidence level due to the presence of internal atmospheric variability. As there have only been a similar number of ENSO events to the total needed for significance since 1920, it is not surprising that it has been difficult to establish statistically significant nonlinearities using observational data.

show abstract

Nonlinear response of tropical lower stratospheric temperature and water vapor to ENSO

Cited by 8 publications

References 38 publications

Does Extreme El Niño Have a Different Effect on the Stratosphere in Boreal Winter Than Its Moderate Counterpart?

Does Extreme El Niño Have a Different Effect on the Stratosphere in Boreal Winter Than Its Moderate Counterpart?

The salience of nonlinearities in the boreal winter response to ENSO: Arctic stratosphere and Europe

The salience of nonlinearities in the boreal winter response to ENSO: North Pacific and North America

Contact Info

Product

Resources

About