The ENSO Signal in the Stratosphere

Calvo, Natalia; García‐Herrera, Ricardo; García, Rolando R.

doi:10.1196/annals.1446.008

Cited by 21 publications

(19 citation statements)

References 68 publications

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“…Negative signal can be found over the equator at pressure level 1 hPa. The results agree with (Chen et al, 2009;Calvo and Marsh, 2011;Calvo et al, 2008). We cannot find any significant response in meridional wind analysis (left panels).…”

Section: Resultssupporting

confidence: 84%

The stratospheric response to external factors based on MERRA data using linear multivariate linear regression analysis

Kozubek

Rozanov

Križan

2014

Preprint

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<p><strong>Abstract.</strong> The stratosphere is influenced by many external forcings (natural or anthropogenic). There are many studies which are focused on this problem and that is why we can compare our results with them. This study is focused on the variability and trends of temperature and circulation characteristics (zonal and meridional wind component) in connection with different phenomena variation in the stratosphere and lower mesosphere. We consider the interactions between the troposphere–stratosphere-lower mesosphere system and external and internal phenomena, e.g. solar cycle, QBO, NAO or ENSO using multiple linear techniques. The analysis was applied to the period 1979–2012 based on the current reanalysis data, mainly the MERRA reanalysis dataset (Modern Era Retrospective-analysis for Research and Applications) for pressure levels: 1000–0.1 hPa. We do not find a strong temperature signal for solar flux over the tropics about 30 hPa (ERA-40 results) but the strong positive signal has been observed near stratopause almost in the whole analyzed area. This could indicate that solar forcing is not represented well in the higher pressure levels in MERRA. The analysis of ENSO and ENSO Modoki shows that we should take into account more than one ENSO index for similar analysis. Previous studies show that the volcanic activity is important parameter. The signal of volcanic activity in MERRA is very weak and insignificant.</p>

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Section: Resultssupporting

confidence: 84%

The stratospheric response to external factors based on MERRA data using linear multivariate linear regression analysis

Kozubek

Rozanov

Križan

2014

Preprint

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“…For 1 month following the ENSO maxima (Figure 1b), there are significant upward fluxes of wave energy in the troposphere near 30°N and very significant downward fluxes in the Northern Hemisphere stratosphere. These features show some agreement with Garfinkel and Hartmann [2008] and Calvo et al [2008] and suggest a broad meridional overturning of wave energy.…”

Section: Resultssupporting

confidence: 59%

“…Both models show distinct upward flux differences at higher latitudes of the Northern Hemisphere early in ENSO events [see also Taguchi , 2008]. Calvo et al [2008] show upward vertical flux departures in the Northern Hemisphere for WACCM3. However, there are substantial differences from those of WACCM1b.…”

Section: Introductionmentioning

confidence: 99%

Tropospheric‐stratospheric wave propagation during El Niño‐Southern Oscillation

Weare

2010

J. Geophys. Res.

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[1] Traditional and 3-D extended Eliassen-Palm (EP) fluxes for the globe between the 3 and 600 hPa levels are used to calculate El Niño-Southern Oscillation (ENSO) composites. Few of the warm minus cold departures of the traditional EP fluxes are significant at the 95% confidence level. In contrast, the ENSO composite differences of the longitudinally dependent extended EP flux have broad regions of significance for a wide range of latitudes, longitudes, and heights. During an ENSO event, there are significant vertical fluxes of wave energy across the tropopause over the subtropical Pacific. In addition, there is substantial meridional exchange of wave energy in the upper troposphere and lower stratosphere in this region. Proceeding northward, the changes in the stratosphere are associated with meridional exchanges of wave energy and strong vertical fluxes of wave energy across the Pacific and North America. The higher-latitude changes have a westward tilt with height and eastward group velocities, both suggesting the importance of Rossby waves. In the Atlantic region, there are strong downward fluxes of wave energy, which may be part of an important ENSO pathway into Europe. Overall, these results strongly suggest the importance of nonzonally averaged dynamics in the stratospheric responses to ENSO.

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“…Over the past decades, it has been discovered through both observations and model simulations that even areas as remote from the equatorial Pacific as the stratosphere (reviewed in section ) are influenced by ENSO (e.g., Calvo et al, ; Hamilton, , ; Manzini, ; Reid et al, ; Van Loon & Labitzke, ; Yulaeva & Wallace, ). El Niño modulates temperatures and winds in the tropical stratosphere (Figure and section ) and hence the radiative budget and chemical composition of the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

The Teleconnection of El Niño Southern Oscillation to the Stratosphere

Domeisen

Garfinkel²,

Butler

2019

Reviews of Geophysics

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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The ENSO Signal in the Stratosphere

Cited by 21 publications

References 68 publications

The stratospheric response to external factors based on MERRA data using linear multivariate linear regression analysis

The stratospheric response to external factors based on MERRA data using linear multivariate linear regression analysis

Tropospheric‐stratospheric wave propagation during El Niño‐Southern Oscillation

The Teleconnection of El Niño Southern Oscillation to the Stratosphere

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