Extratropical Atmospheric Predictability From the Quasi‐Biennial Oscillation in Subseasonal Forecast Models

Garfinkel, Chaim I.; Schwartz, Chen; Domeisen, Daniela I. V.; Son, Seok‐Woo; Butler, Amy H.; White, Ian

doi:10.1029/2018jd028724

Cited by 64 publications

(83 citation statements)

References 55 publications

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“…Individual QBO wind cycles last anywhere from 22 to 34 months and average approximately 28 months (Baldwin et al, ). The QBO also affects tropical stratospheric temperatures and trace gas concentrations (Baldwin et al, ) and the stratospheric polar vortices through the so‐called Holton‐Tan effect (Anstey & Shepherd, ; Holton & Tan, ), which can lead to increased predictability of the extratropical stratosphere on subseasonal time scales (Garfinkel, Schwartz, et al, ).…”

Section: A Brief Overview Of the Stratospheric Circulationmentioning

confidence: 99%

“…In the tropics, the QBO has recently been found to have a possible downward influence on the tropical troposphere, in particular on the MJO (Geller et al, ; Marshall et al, ; Son et al, ; Yoo & Son, ). The QBO also has a downward impact on the subtropical jet and subtropical precipitation (Garfinkel & Hartmann, ; Haigh et al, ; Hansen et al, ; Seo et al, ) as well as polar stratospheric variability (Anstey & Shepherd, ; Garfinkel, Schwartz, et al, ; Holton & Tan, ). Finally, wind and temperature variability in the tropical tropopause layer governs the chemical composition of the stratosphere and therefore Earth's radiative budget, as tropospheric air parcels enter the stratosphere through the tropics.…”

Section: A Brief Overview Of the Stratospheric Circulationmentioning

confidence: 99%

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The Teleconnection of El Niño Southern Oscillation to the Stratosphere

Domeisen

Garfinkel²,

Butler

2019

Reviews of Geophysics

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316

284

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El Niño and La Niña events in the tropical Pacific have significant and disrupting impacts on the global atmospheric and oceanic circulation. El Niño Southern Oscillation (ENSO) impacts also extend above the troposphere, affecting the strength and variability of the stratospheric polar vortex in the high latitudes of both hemispheres, as well as the composition and circulation of the tropical stratosphere. El Niño events are associated with a warming and weakening of the polar vortex in the polar stratosphere of both hemispheres, while a cooling can be observed in the tropical lower stratosphere. These impacts are linked by a strengthened Brewer-Dobson circulation. Anomalous upward wave propagation is observed in the extratropics of both hemispheres. For La Niña, these anomalies are often opposite. The stratosphere in turn affects surface weather and climate over large areas of the globe. Since these surface impacts are long-lived, the changes in the stratosphere can lead to improved surface predictions on time scales of weeks to months. Over the past decade, our understanding of the mechanisms through which ENSO can drive impacts remote from the tropical Pacific has improved. This study reviews the possible mechanisms connecting ENSO to the stratosphere in the tropics and the extratropics of both hemispheres while also considering open questions, including nonlinearities in the teleconnections, the role of ENSO diversity, and the impacts of climate change and variability.Plain Language Summary El Niño and La Niña events, the irregular warming and cooling of the tropical Pacific that occurs every couple of years, have disrupting impacts spanning the entire world. These remote impacts, so-called "teleconnections", also reach the stratosphere, the layer of the atmosphere starting at around 10 km above the Earth's surface. El Niño leads to a warming of the stratosphere in both hemispheres, while the lower tropical stratosphere cools. These signatures are linked by a strengthened stratospheric circulation from the tropics to the polar regions. El Niño also leads to more frequent breakdowns of the stratospheric polar vortex, a band of strong eastward winds in the polar stratosphere. For La Niña, these effects tend to be opposite, though they are not always robust, suggesting nonlinear or nonstationary effects, long-term variability, and trends in the teleconnections. The observational data record is not yet long enough to make conclusions with certainty, and models that try to reproduce the teleconnections indicate that teleconnections might be more linear than the limited number of observations indicate. Further research will be needed to separate the El Niño and La Niña teleconnections from other effects and to determine to what extent nonlinearity and nonstationarity are indeed present.

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Section: A Brief Overview Of the Stratospheric Circulationmentioning

confidence: 99%

Section: A Brief Overview Of the Stratospheric Circulationmentioning

confidence: 99%

The Teleconnection of El Niño Southern Oscillation to the Stratosphere

Domeisen

Garfinkel²,

Butler

2019

Reviews of Geophysics

Self Cite

316

284

View full text Add to dashboard Cite

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“…On the other hand, of the eight La Niña winters that were followed by late FWs, seven had midwinter SSWs. Thus, it is likely that the occurrence of midwinter SSWs, which is related to both QBO and ENSO (Butler & Polvani, 2011;Garfinkel & Hartmann, 2010;Garfinkel et al, 2018) but also internal atmospheric variability, ultimately dictates the timing of radiative recovery of the vortex to its westerly state and any subsequent ability of the vortex to reverse in a FW (Hu et al, 2014).…”

Section: Observed and Simulated Differences In Early And Late Fws Andmentioning

confidence: 99%

Predictability of Northern Hemisphere Final Stratospheric Warmings and Their Surface Impacts

Butler

Charlton‐Perez

Domeisen

et al. 2019

Geophysical Research Letters

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Each spring, the climatological westerly winds of the Northern Hemisphere (NH) stratospheric polar vortex turn easterly as the stratospheric equator‐to‐pole temperature gradient relaxes. The timing of this event is dictated both by the annual return of sunlight to the pole and by dynamical influences from the troposphere. Here we consider the predictability of NH final stratospheric warmings in multimodel hindcasts from the Subseasonal to Seasonal project database. We evaluate how well the Subseasonal to Seasonal prediction systems perform in capturing the timing of final warmings. We compare the predictability of early warmings (which are more strongly driven by wave forcing) and late warmings and find that late warmings are more skillfully predicted at longer lead times. Finally, we find significantly increased predictive skill of NH near‐surface temperature anomalies at Weeks 3–4 lead times following only early final warmings.

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“…It is driven by upward propagating waves forced in the tropical troposphere by deep convection. Given its wide‐ranging influence on the dynamics of the lower atmosphere over seasonal and interannual time scales, the QBO is viewed as a potential source of predictability on these time scales (e.g., Garfinkel et al, ; Scaife et al, ) Here we describe the current understanding of the QBO's influence on the CIT and identify gaps in our understanding of this process that could be addressed in future studies.…”

Section: Interseasonal Variabilitymentioning

confidence: 98%

Whole Atmosphere Coupling on Intraseasonal and Interseasonal Time Scales: A Potential Source of Increased Predictive Capability

2019

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Recent advances in developing accurate, physics‐based models of the coupled ionosphere‐thermosphere (CIT) system have now made these models an integral part of next‐generation space weather prediction capabilities. These advances have produced a better understanding of how the CIT is affected by variability in the neutral lower atmosphere. However, the impacts on the CIT of lower atmospheric variability over time scales with characteristic periods longer than ~10 days have received little attention, despite clear evidence of this variability in atmospheric circulation patterns throughout the stratosphere, mesosphere, and lower thermosphere. This review synthesizes the state of knowledge on long‐term variability (>10 days) originating in the lower atmosphere and its impacts on the CIT, highlighting the following critical points and challenges: (a) planetary wave oscillations are likely to couple the lower and upper atmospheres, especially those corresponding to normal modes of the atmosphere, but it remains unclear whether they impact the ionosphere directly via wind‐dynamo coupling, or indirectly via modulation of solar and lunar tides; (b) while fast moving planetary wave oscillations are ubiquitous in the CIT especially during solstices, there is only sporadic evidence that the slowest moving modes are also present in the upper atmosphere; (c) there is abundant evidence of long‐term variations of tidal amplitudes in the CIT, but how and why such variations occur still remain; (d) interseasonal variations associated with major tropospheric and stratospheric variability have been observed, but the physical pathways are still poorly understood.

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Extratropical Atmospheric Predictability From the Quasi‐Biennial Oscillation in Subseasonal Forecast Models

Cited by 64 publications

References 55 publications

The Teleconnection of El Niño Southern Oscillation to the Stratosphere

The Teleconnection of El Niño Southern Oscillation to the Stratosphere

Predictability of Northern Hemisphere Final Stratospheric Warmings and Their Surface Impacts

Whole Atmosphere Coupling on Intraseasonal and Interseasonal Time Scales: A Potential Source of Increased Predictive Capability

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