Effect of geomagnetic activity on the northern annular mode: QBO dependence and the Holton-Tan relationship

Maliniemi, Ville; Asikainen, Timo; Мурсула, К.

doi:10.1002/2015jd024460

Cited by 31 publications

(37 citation statements)

References 61 publications

(114 reference statements)

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“…In fact SSW occurrence rate is highest in winters with low Ap (low EEP) and QBO-E, when SSW occurs in 15 out of 17 winters. This result agrees with earlier studies (Maliniemi et al, 2013(Maliniemi et al, , 2014(Maliniemi et al, , 2016(Maliniemi et al, , 2018Salminen et al, 2019) showing that the effect of energetic electron precipitation on polar vortex is stronger in QBO-E winter months. In QBO-E winters low EEP weakens the polar vortex and SSWs occur more often, while high EEP strengthens the polar vortex and SSWs occur less.…”

Section: Discussionsupporting

confidence: 93%

Dependence of Sudden Stratospheric Warmings on Internal and External Drivers

Salminen

Asikainen

Maliniemi

et al. 2020

Geophysical Research Letters

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A sudden stratospheric warming (SSW) is a large‐scale disturbance of the wintertime stratosphere, which occurs especially in the Northern Hemisphere. Earlier studies have shown that SSW occurrence depends on atmospheric internal factors and on solar activity. We examine SSW occurrence in northern winters 1957/1958–2016/2017, considering several factors that may affect the SSW occurrence: Quasi‐Biennial Oscillation (QBO), El Niño–Southern Oscillation (ENSO), geomagnetic activity, and solar radiation. We confirm the well‐known result that SSWs occur more often in easterly QBO phase than in westerly phase. We show that this difference depends on how the QBO phase is determined. We find that the difference in SSW occurrence between easterly and westerly QBO winters strengthens (weakens) if geomagnetic activity or solar activity is low (high), or if the ENSO is in a cold (warm) phase. In easterly QBO phase significantly more SSWs occur during low geomagnetic activity than high activity.

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Section: Discussionsupporting

confidence: 93%

Dependence of Sudden Stratospheric Warmings on Internal and External Drivers

Salminen

Asikainen

Maliniemi

et al. 2020

Geophysical Research Letters

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“…These results agree with the studies by Palamara and Bryant () and Maliniemi et al (, ), which concluded that the EEP effect on the NAO/NAM is larger in the QBO‐E phase. Lu et al () found that the EEP effect in May is stronger if the deseasonalized QBO at 50 hPa is westerly.…”

Section: Eep Effect Separately In the Two Qbo Phasessupporting

confidence: 93%

“…The dynamical effects on the southern polar vortex are much weaker, less significant, and even opposite to those in the Northern Hemisphere (Arsenovic et al, ; Lu et al, ; Tomikawa, ). The variations of polar vortex are also seen in the Northern Annular Mode (NAM) and North Atlantic Oscillation (NAO) surface climate modes (Baldwin & Dunkerton, ), and EEP (or geomagnetic activity as EEP proxy) has been found to correlate with these modes in several studies (Baumgaertner et al, ; Maliniemi et al, , ; Palamara & Bryant, ).…”

Section: Introductionmentioning

confidence: 98%

Effect of Energetic Electron Precipitation on the Northern Polar Vortex: Explaining the QBO Modulation via Control of Meridional Circulation

et al. 2019

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Energetic electron precipitation (EEP) affects the high‐latitude middle atmosphere by producing NOX compounds that destroy ozone. Earlier studies have shown that in the wintertime polar stratosphere, increased EEP enhances the westerly wind surrounding the pole, the polar vortex. This EEP effect has been found to depend on the quasi‐biennial oscillation (QBO) of equatorial winds, but the mechanism behind this modulation has so far remained unresolved. In this study we examine the atmospheric effect of EEP and its modulation by QBO using the corrected electron flux measurements by NOAA/POES satellites and the ERA‐Interim reanalysis data of zonal wind, temperature, and ozone in winter months of 1980–2016. We verify the EEP‐related strengthening of the polar vortex, warming (cooling) in the upper (lower) stratosphere and a reduction of ozone mass mixing ratio in the polar stratosphere. We also verify that the EEP effect is stronger and more significant especially in late winter, when the QBO at 30 hPa is easterly. We find here that the difference in the EEP effect between the two QBO phases is largest using a roughly 6‐month lag for QBO. We demonstrate that ozone mass mixing ratio in the lower polar stratosphere, a proxy for the strength of Brewer‐Dobson circulation, is also larger during QBO‐E than QBO‐W, with the difference maximizing when the QBO is lagged by 6 months. Our findings indicate that the modulation of the Brewer‐Dobson circulation by QBO controls how the EEP affects the polar vortex.

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“…A positive U anomaly emerges in the subtropical mid‐stratosphere in December and progresses poleward and downward (via wave–mean flow interaction), reaching the troposphere in February. These results are in agreement with earlier studies of GA and SA effects on winter surface climate (Ineson et al ., ; Gray et al ., ; Maliniemi et al ., ) and support the two different top‐down mechanisms related to particle precipitation and solar UV.…”

Section: Discussionmentioning

confidence: 96%

“…Recent studies of long‐term surface climate in winter have shown that the positive NAO response related to sunspot activity (SA) is obtained in late winter (February) (Gray et al ., ), whereas in early winter (December) a positive SLP anomaly over the Azores is observed 2–4 years after the sunspot maximum (Gray et al ., ; ). Solar wind driven particles/geomagnetic activity (GA) has a strong positive relation with NAO without any lag (Maliniemi et al ., ). GA maximizes a few years after sunspot maximum due to the occurrence of high‐speed solar wind streams from coronal holes (Ruzmaikin and Feynman, ; Mursula et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Assessing North Atlantic winter climate response to geomagnetic activity and solar irradiance variability

Maliniemi

Asikainen

Salminen

et al. 2019

Quart J Royal Meteoro Soc

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Recent studies suggest a response in the North Atlantic winter circulation which lags by a couple of years with respect to sunspot maximum. This has been explained by two different top‐down mechanisms: a solar wind driven particle effect in the polar atmosphere during the declining phase of the solar cycle, and the re‐emergence and amplification of heat anomalies in the Atlantic Ocean produced by enhanced solar ultraviolet (UV). Here we study how December to February climate is affected by two solar‐related drivers: geomagnetic activity (proxy of particle precipitation) and sunspot activity (proxy of solar UV) during 1948–2017. We use reanalysis data of sea‐level pressure (SLP) and zonal wind (U) to show that both geomagnetic activity and sunspot activity independently and simultaneously produce atmospheric circulation responses in the North Atlantic whose evolutions clearly differ from each other. Geomagnetic activity produces a strengthening of the polar vortex and a negative poleward SLP gradient between mid‐ and high latitudes, resembling a positive NAO‐type circulation pattern during December to February. Solar UV produces a positive U anomaly in the low‐latitude stratosphere during December, which moves poleward and downward during the winter resulting in a negative poleward SLP gradient between mid‐ and high latitudes during February. We find the lagged sunspot activity responses in SLP to form zonal pressure patterns (wave‐train structure) resembling the Eurasian pattern. Geomagnetic activity responses remain essentially the same when we introduce the lag with respect to sunspot activity supporting its independency as a driving mechanism. Our results suggest that solar wind related particle precipitation and (lagged) solar UV mechanism provide independent, significant circulation signals in the North Atlantic winter.

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Effect of geomagnetic activity on the northern annular mode: QBO dependence and the Holton-Tan relationship

Cited by 31 publications

References 61 publications

Dependence of Sudden Stratospheric Warmings on Internal and External Drivers

Dependence of Sudden Stratospheric Warmings on Internal and External Drivers

Effect of Energetic Electron Precipitation on the Northern Polar Vortex: Explaining the QBO Modulation via Control of Meridional Circulation

Assessing North Atlantic winter climate response to geomagnetic activity and solar irradiance variability

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