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The climatological average zonal-mean (a) temperature (T ), (b) zonal wind (U ) and (c) meridional wind (V ) between December and February from 1988 to 2010, the zonal-mean (d) temperature (e) zonal wind and (f) meridional wind during seven days centered around 10 major SSW events between 1988 and 2010 event and the zonal-mean anomalies from climatological mean during the composite SSW event in (g) temperature (h) zonal wind and (i) meridional wind.
Source publication
A stratospheric sudden warming (SSW) is a dynamical phenomenon of the
wintertime stratosphere caused by the interaction between planetary Rossby
waves propagating from the troposphere and the stratospheric zonal-mean flow.
While the effects of SSW events are seen predominantly in high latitudes,
they can also produce significant changes in middle a...
Contexts in source publication
Context 1
... tempera- ture and winds with respect to climatological values. The cli- matological values of zonal-mean temperature and winds are calculated as the 22-year (1988-2010) seasonal average over the winter months of December, January and February. The climatological zonal-mean temperature (T ), zonal wind (U ) and meridional wind (V ) are shown in Fig. 1a, b and c respec- tively. The normal wintertime separated polar stratopause (Fig. 1a), the eastward zonal-mean stratospheric winds and westward upper MLT zonal winds ( The winters with major SSWs were 1988-1989, 1998-1999, 2000-2001, 2001-2002, 2002-2003, 2003-2004, 20052006, 2007-2008, 2008-2009 and 2009-2010. Out of the 10 SSW ...
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... values of zonal-mean temperature and winds are calculated as the 22-year (1988-2010) seasonal average over the winter months of December, January and February. The climatological zonal-mean temperature (T ), zonal wind (U ) and meridional wind (V ) are shown in Fig. 1a, b and c respec- tively. The normal wintertime separated polar stratopause (Fig. 1a), the eastward zonal-mean stratospheric winds and westward upper MLT zonal winds ( The winters with major SSWs were 1988-1989, 1998-1999, 2000-2001, 2001-2002, 2002-2003, 2003-2004, 20052006, 2007-2008, 2008-2009 and 2009-2010. Out of the 10 SSW winters, the 1998-1999, 2003-2004, 2005-2006, 2007-2008 and 2009-2010 phase of the QBO. To ...
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... 20052006, 2007-2008, 2008-2009 and 2009-2010. Out of the 10 SSW winters, the 1998-1999, 2003-2004, 2005-2006, 2007-2008 and 2009-2010 phase of the QBO. To make the composites for zonal-mean temperature and winds, the temperature and wind were aver- aged for 7 days during the SSW centered on the day of wind reversal at 10 hPa at 60 • N. In Fig. 1d, the lowering of the polar stratopause associated with the SSW can be seen along with a reversal of the high latitude polar zonal-mean jet in Fig. 1e from eastward to westward. The pole-to-pole flow in the mesosphere is disrupted at the time of the SSW and the NH polar high and middle latitudes show an equatorward meridional wind in ...
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... the QBO. To make the composites for zonal-mean temperature and winds, the temperature and wind were aver- aged for 7 days during the SSW centered on the day of wind reversal at 10 hPa at 60 • N. In Fig. 1d, the lowering of the polar stratopause associated with the SSW can be seen along with a reversal of the high latitude polar zonal-mean jet in Fig. 1e from eastward to westward. The pole-to-pole flow in the mesosphere is disrupted at the time of the SSW and the NH polar high and middle latitudes show an equatorward meridional wind in Fig. 1f. Figure 1g, h and i show the zonal-mean temperature, zonal-mean zonal wind and zonal-mean meridional wind anomaly during the SSW calculated as ...
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... N. In Fig. 1d, the lowering of the polar stratopause associated with the SSW can be seen along with a reversal of the high latitude polar zonal-mean jet in Fig. 1e from eastward to westward. The pole-to-pole flow in the mesosphere is disrupted at the time of the SSW and the NH polar high and middle latitudes show an equatorward meridional wind in Fig. 1f. Figure 1g, h and i show the zonal-mean temperature, zonal-mean zonal wind and zonal-mean meridional wind anomaly during the SSW calculated as the difference be- tween the zonal-mean temperature and winds during the SSW from the climatological mean values. In the high lat- itude regions (poleward of 60 • N), the anomalous strato- ...
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... pole-to-pole flow in the mesosphere is disrupted at the time of the SSW and the NH polar high and middle latitudes show an equatorward meridional wind in Fig. 1f. Figure 1g, h and i show the zonal-mean temperature, zonal-mean zonal wind and zonal-mean meridional wind anomaly during the SSW calculated as the difference be- tween the zonal-mean temperature and winds during the SSW from the climatological mean values. In the high lat- itude regions (poleward of 60 • N), the anomalous strato- spheric warming and mesospheric cooling can be clearly seen in Fig. 1g. ...
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... zonal-mean zonal wind and zonal-mean meridional wind anomaly during the SSW calculated as the difference be- tween the zonal-mean temperature and winds during the SSW from the climatological mean values. In the high lat- itude regions (poleward of 60 • N), the anomalous strato- spheric warming and mesospheric cooling can be clearly seen in Fig. 1g. The stratospheric warming (caused by break- ing planetary waves) and mesospheric cooling (caused by reversal in gravity wave forcing in the mesosphere) reach peak values of ∼ 30 K in these composite plots. For indi- vidual years, the magnitudes can be even larger. In the mid- dle and low latitudes in the stratosphere there is ...
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... the maximum magnitudes of warm- ing and cooling are less than 3 K. These alternating warming and cooling cells in the stratosphere and mesosphere are a robust feature associated with branches of the residual cir- culation changes that are driven by breaking planetary wand gravity waves ( Chandran et al., 2014). The zonal-mean wind anomaly plot of Fig. 1h shows large westward wind reversal in the stratosphere poleward of 40 • N. In the upper MLT there is a net eastward acceleration of the zonal-mean wind caused by enhanced penetration of eastward gravity waves into this region. The mesospheric wind, which is normally westward in winter in mid-high latitudes, reverses to eastward dur- ...
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... flow and eastward acceleration between 60 and 100 km. The southern hemispheric low latitudes experi- ence a net westward forcing (with ∼ peak values of 10 m s −1 ) of the zonal-mean flow between 40 and 70 km and an east- ward forcing in the mesosphere (60-100 km), with peak val- ues between 5 and 10 m s −1 . The meridional wind anomaly shown in Fig. 1h shows a deceleration of the middle atmo- sphere pole-to-pole flow in the Northern Hemisphere and in southern hemispheric low latitudes. The meridional circula- tion reverses in the northern hemispheric high latitudes and becomes equatorward driven by the gravity wave upwelling ...
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... a consequence, the GWF in the mesosphere poleward of 40 • N becomes eastward, reaching maximum values of ∼ 30 m s −1 d −1 in the opposite direction, as can be seen in Fig. 2b. The GWF anomaly shown in Fig. 2c is eastward at all latitudes above 10 • N, which can be attributed to the enhanced westward acceleration in the zonal wind anomaly shown in Fig. 1h, which filters out more of the westward gravity waves. In the bottom panels from Fig. 2d ...
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... as difference between the SSW values from the seasonal mean in panels g, h and i. The seasonal average (from 1 December to 28 February) of zonal-mean temperature, zonal wind and meridional winds (panels a, b and c in Figs. 4 and 5) during 2005-2006 and 2008-2009 are generally similar to the climatological zonal-mean tem- perature shown in Fig. 1a, b and c. However, there are some significant differences in the zonal wind in [2005][2006]. The zonal-mean zonal wind in Fig. 4b for 2005-2006 shows dif- ferences from the climatology plot shown in Fig. 1b at low latitudes (between 0 and 20 • N) in the Northern Hemisphere below 30 km, where it is westward indicating it is the east- erly ...
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... a, b and c in Figs. 4 and 5) during 2005-2006 and 2008-2009 are generally similar to the climatological zonal-mean tem- perature shown in Fig. 1a, b and c. However, there are some significant differences in the zonal wind in [2005][2006]. The zonal-mean zonal wind in Fig. 4b for 2005-2006 shows dif- ferences from the climatology plot shown in Fig. 1b at low latitudes (between 0 and 20 • N) in the Northern Hemisphere below 30 km, where it is westward indicating it is the east- erly phase of the QBO. Above that at low latitudes from 30 to 40 km, the wind is eastward. In Fig. 5b, the zonal-mean zonal wind is eastward at 20 km at the equator, indicating it is the westerly phase of the ...
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... zonal wind anomaly with respect to the seasonal mean shown in Figs. 4h and 5h shows patterns similar to the com- posite zonal wind anomaly shown in Fig. 1h. In the Northern Hemisphere, poleward of 40 • N in the upper stratosphere ...
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... the low latitude site at Kauai the upper stratosphere warms by ∼ 10 K during the 2006 SSW and by ∼ 4-5 K during the 2009 SSW. The zonal-mean wind also weakens and even reverses in the lower stratosphere at Kauai during both the events. The meridional wind shows variability, which is along similar patterns as seen in the zonal-mean wind plots of Figs. 1, 4 and ...
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Citations
... 45 Oberheide, et al. (2020) reported a O/N2 column density depletion of more than 10% at the onset of SSW using observations by the Global-Scale Observations of the Limb and Disk instrument on the geostationary SES-14 communications satellite during the 2019 major SSW event. The atmospheric responses observed by ground sites always have a longitudinal asymmetry, which is caused by the structure and evolution of the planetary waves (PWs) and the pole vortex during SSW events (Chandran and Collins, 2014). 50 ...
... The model is free-running above 60 km. It has been shown in previous reports that model simulations can serve as comprehensive tools to reproduce the 115 atmospheric evolution of SSW events (Chandran and Collins, 2014, De Wit, et al., 2014, Yang, et al., 2017, Wonseok Lee, et al., 2021. The output of SD-WACCM includes the temperatures and GPHs, and the air densities are calculated using the same method as for the Aura/MLS data. ...
... The peak density amplification altitude during the event fell to 46 km over high latitudes. Longitudinal variations in the temperatures and wind have been reported at the same latitude, modulated by planetary waves and gravity waves (Hoffmann, et al., 2007, Chandran and Collins, 2014, Yang, et al., 2017. Fig. 3 reveals the climatological horizontal density distributions at altitudes of 80 km, 60 km, and 40 km for November 20, 2020, and January 4 and 7, 2021, from Aura/MLS. ...
Sudden stratospheric warmings (SSWs) are dramatic events in the polar winter stratosphere that are accompanied by atmospheric parameter anomalies in the stratosphere and mesosphere. Microwave Limb Sounder and Global Navigation Satellite System Occultation Sounder observations on board the Chinese FengYun 3 satellites indicate a rapid increase of over 50 % in the mesospheric density at high latitudes around the onset date during the 2021 major SSW event. The amplification of the zonal mean density around the onset is proportional to the latitude increase with a maximum increment of 83.3 % at 59 km above 80° N, which is more than three times larger than the climatological standard deviation (23.1 %). The horizontal density distributions are influenced by the changing polar vortex fields. A simulation using a specified dynamics version of the Whole Atmosphere Community Climate Model is consistent overall with the observations and presents a severe change in the planetary wave forcing and residual meridional circulation mass flux followed by a change in the density tendency. These results demonstrate that the observed enhanced density is primarily attributed to the altered planetary waves and residual circulation during the SSW event. The observations and simulations also indicate that the density anomalies could extend to middle latitudes. Obvious density disturbances in the upper stratosphere and mesosphere were observed by lidar deployed in Beijing (40.3° N, 116.2° E).
... Rapid changes in zonal circulation and temperature in the polar stratosphere occur during sudden stratospheric warming (SSW) events. The impact of these dramatic changes extends both vertically, down into the troposphere and up into the mesosphere (Baldwin et al., 2021), and horizontally into mid-and low latitudes (Chandran and Collins, 2014). While the onset of SSW may develop over a few days, the main phase of warming and the recovery phase can last for weeks and months, respectively (Baldwin et al., 2021;Li et al., 2023). ...
Two cold weather events in the winter of 2018 in East Asia (–26°C on 24–25 January in Changchun, Northern China) and in Eastern Europe (–16°C on 24–27 February in Kharkiv, Northern Ukraine) had common features in their occurrence. Both events occurred with the contribution of downward stratospheric influence but differed in the stratospheric polar vortex dynamics. Strong vortex conditions that preceded the vortex perturbation and split during the Sudden Stratospheric Warming in February were observed in January. Regardless of the vortex conditions, the midlatitude stratosphere warming above the tropopause was accompanied by the tropopause descent by 2–3 km and air downwelling through the troposphere. At the same time, the midtropospheric layer at altitudes of 3–5 km with a temperature up to –30°C was pushed to the surface, and the surface temperature dropped by 18°C in Changchun and by 14°C in Kharkiv. The surface northerlies made some contribution to cooling events by transporting cold air from higher latitudes.
... Studies related to the latitudinal coupling between the tropical and extra-tropical regions in the middle and upper atmospheres during the NH major SSW events are crucial for an improved understanding of the middle atmospheric mean meridional circulation changes, but they are sparse [24,28]. Though a few modeling studies exist to forecast and characterize the impact of SSW on the lower [25], middle, and upper atmosphere [29,30], discrepancies still exist in some models to correctly describe the mesosphere lower thermosphere (MLT) circulation [31]. ...
Using a network of meteor radar observations, observational evidence of polar-to-tropical mesospheric coupling during the 2018 major sudden stratosphere warming (SSW) event in the northern hemisphere is presented. In the tropical lower mesosphere, a maximum zonal wind reversal (−24 m/s) is noted and compared with that identified in the extra-tropical regions. Moreover, a time delay in the wind reversal between the tropical/polar stations and the mid-latitudes is detected. A wide spectrum of waves with periods of 2 to 16 days and 30–60 days were observed. The wind reversal in the mesosphere is due to the propagation of dominant intra-seasonal oscillations (ISOs) of 30–60 days and the presence and superposition of 8-day period planetary waves (PWs). The ISO phase propagation is observed from high to low latitudes (60° N to 20° N) in contrast to the 8-day PW phase propagation, indicating the change in the meridional propagation of winds during SSW, hence the change in the meridional circulation. The superposition of dominant ISOs and weak 8-day PWs could be responsible for the delay of the wind reversal in the tropical mesosphere. Therefore, this study has strong implications for understanding the reversed (polar to tropical) mesospheric meridional circulation by considering the ISOs during SSW.
... Sudden stratospheric warming (SSW) is one of the large-scale meteorological phenomena in the stratosphere of the winter hemisphere over the polar region, and is accompanied by dramatic changes in temperature, wind, and the polar vortex [1][2][3]. The key mechanism of SSW formation is attributed to the amplified upward propagation of stationary planetary waves from the troposphere and their nonlinear interaction with the mean flow in the stratosphere [4]. ...
... Forbes and Zhang (2012) showed that the underlying mechanism for lunar tidal enhancement during the SSW event was due to changes in the zonalmean temperature and wind structure of the middle atmosphere that occurred during the SSW [26]. The occurrence of SSWs is accompanied by dramatic changes in temperature, wind and polar the vortex [1][2][3]. ...
... Forbes and Zhang (2012) showed that the underlying mechanism for lunar tidal enhancement during the SSW event was due to changes in the zonal-mean temperature and wind structure of the middle atmosphere that occurred during the SSW [26]. The occurrence of SSWs is accompanied by dramatic changes in temperature, wind and polar the vortex [1][2][3]. ...
The International Global Navigation Satellite Systems Service (IGS) ionospheric total electron content (TEC) data are used to study the periodic perturbation in the ionosphere during the 2019 Antarctic sudden stratospheric warming (SSW) event, a rare Southern Hemisphere minor SSW event in the last 40 years. A 14.5 day periodic signal with a zonal wavenumber of 0 is observed in the mesosphere and the lower thermosphere (MLT) region and the ionosphere during this SSW period, which could be related to the lunar tide. The 14.5 day periodic disturbance in the IGS TEC exhibits local time dependence and latitudinal variation, with the maximum amplitude appearing between 1000 and 1600 LT in the equatorial ionization anomaly (EIA) crest regions. Additionally, the 14.5 day periodic oscillation shows an obvious longitudinal variability, with the weakest amplitude appearing in the longitudinal region of 30° W–60° E.
... Importantly, the definition of a standard criterion for SSW events has progressed (Butler & Gerber, 2018). Modelling and forecasting of SSW events also were provided (Chandran & Collins, 2014;Tripathi et al., 2016;Karpechko et al., 2018;Rao et al., 2018;Ta guchi, 2018). These studies require statistical, correlative, spectral, and comparative data analysis methods and model reproduction of the observed processes. ...
... Atmospheric dynamics during SSWs, in addition to PW effects, are also studied from the perspective of the two-way vertical troposphere-stratosphere-mesosphere coupling, covering both upward and downward propagation of perturbations and taking into account changes in the chemical composition of the air (Baldwin & Dunkerton, 2001;Huret et al., 2006;Funke et al., 2009;Kvissel et al., 2012;de Wit et al., 2014;Orsolini et al., 2017;Gardner, 2018;Ryan et al., 2018). The phenomena accompanying SSW are analysed: splitting and displacement of the strato spheric polar vortex Manney et al., 2009;Chandran & Collins, 2014;Butler et al., 2020), of the stratopause elevation (Chandran et al., 2013;France & Harvey, 2013;Limpasuvan et al., 2016;Scheffler et al., 2022), vertical movements and mesospheric intrusions (Huret et al., 2006;Manney et al., 2009;Salmi et al., 2011;Kvissel et al., 2012;Orsolini et al., 2017;Ryan et al., 2018), and impact on the weather on the Earth's surface (Baldwin & Dunkerton, 2001;Kodera et al., 2016;Yu et al., 2018;Domeisen et al., 2020;Curbelo et al., 2021;Choi et al., 2021;Hongming et al., 2022). ...
We describe the methods and data sources for investigating the stratospheric ozone and planetary waves in the atmosphere in the framework of research provided by our international team. Selected ground-based and satellite instruments for ozone measurements and related reanalyses are described. Examples of data and analysis tools are shown. The technique of planetary wave spectral analysis under conditions of dynamic changes during sudden stratospheric warmings is presented. A brief description of the main results, obtained with the participation of the authors, using combined methods of analysis are considered. We describe procedures for the investigation of a long-term eastward displacement of the zonal ozone minimum over the Antarctic in the spring months, analysis of the spatial and temporal characteristics of the teleconnection between the tropical thermal source and the Antarctic stratosphere, and the creation of the predictive index used for the forecast of possible ozone hole anomalous development in spring months. Examples of application of analysis methods to retrieve the changes in the zonal asymmetry of the Arctic stratopause and features of the annual ozone cycle in connection with zonal ozone asymmetry are discussed.
... During a major event, planetary waves propagate into the stratosphere and break at high latitudes, inducing a slowdown of the polar stratospheric winds that prompts an enhanced mass flux toward the pole where air then descends and is heated adiabatically (Baldwin et al., 2021;. This rapid increase in polar temperatures propagates down to the troposphere and is accompanied by an anomalous cooling of tropical stratospheric temperatures, with both phenomena persisting for several weeks following the SSW (Baldwin et al., 2021;Chandran & Collins, 2014). Sigmond et al. (2013) suggest that the tropospheric response to an SSW is easier to forecast compared to conditions before an SSW event. ...
Near‐space balloon networks have the potential to improve numerical weather prediction (NWP) through data assimilation (DA) by providing in situ observations in an otherwise data‐sparse stratosphere. This study investigates the prospective value of stratospheric balloon winds to NOAA NWP by examining Loon data quality and conducting a 2‐month observing system experiment (OSE) using NOAA's Finite‐Volume Cubed‐Sphere Global Forecast System. During the study period (December 2018–January 2019), Loon winds show good correspondence to collocated rawinsonde (RAOBS) winds, while a considerable difference in tropical stratospheric winds is observed between NOAA and ECMWF operational analyses. The OSE, one run with Loon winds assimilated and another without, suggests that additional stratospheric wind observations can improve NWP. Loon wind assimilation acts to decelerate the strong tropical easterly stratospheric jet west of where Loon winds are observed while accelerating less intense subtropical easterly motions. Differences in observation‐minus‐background statistics between the two runs reveal that the backgrounds for Loon winds and RAOBS winds and temperatures improve when Loon winds are assimilated. This positively impacts short‐term forecasts of the lower stratospheric circulation during the study period. Additionally, Loon wind assimilation improves the tropical stratospheric response to the 2019 New Year sudden stratospheric warming (SSW) event by significantly reducing the short‐term forecast error following the SSW. The findings emphasize the value of stratospheric winds toward improving global NWP, and imply the importance of including near‐space observing systems in the Earth‐observing architecture.
... Rapid changes in zonal circulation and temperature in the polar stratosphere occur during sudden stratospheric warming (SSW) events. The impact of these dramatic changes extends both vertically, down into the troposphere and up into the mesosphere (Baldwin et al., 2021), and horizontally into mid-and low latitudes (Chandran and Collins, 2014). While the onset of SSW may develop over a few days, the main phase of warming and the recovery phase can last for weeks and months, respectively (Baldwin et al., 2021;Li et al., 2023). ...
... Due to the filtering of gravity waves (GWs) by the stratospheric zonal wind (Lindzen, 1981;McLandress, 1998), the variation in the stratospheric temperature gradient and the winds could effectively modulate the mesospheric circulation and thus temperature (e.g., Chandran & Collins, 2014;Karlsson et al., 2011;Li et al., 2016;Shepherd, 2000). Polar mesospheric clouds (PMCs), also known as noctilucent clouds, are the highest clouds on Earth that form in the polar summer mesopause region and are considered to be important indicators of variations in temperature and circulation in the mesosphere (Hervig et al., , 2015. ...
A strong Southern Hemisphere (SH) sudden stratospheric warming event occurred in September 2019 and significantly weakened the stratospheric polar vortex. Due to the positive zonal wind anomalies in the troposphere, the barotropic/baroclinic instability, primarily controlled by the horizontal/vertical wind shear, weakened in the upper troposphere at midlatitudes in late September and early October. As a result, planetary waves (PWs) were deflected equatorward near the tropopause rather than upward into the stratosphere, resulting in less perturbation to the stratospheric polar vortex. After October 15, the westward zonal wind anomalies propagate downward and reach the troposphere, increasing the tropospheric barotropic/baroclinic instability. This benefits the propagation of PWs into the stratosphere, leading to the early breaking of the stratospheric polar vortex. In turn, the SH mesosphere becomes anomalously cold due to the stratospheric wind filtering on the gravity waves, leading to the much earlier onset of SH polar mesospheric clouds.
... Due to the filtering of gravity waves (GWs) by the stratospheric zonal wind (Lindzen, 1981;McLandress, 1998), the variation in the stratospheric temperature gradient and the winds could effectively modulate the mesospheric circulation and thus temperature (e.g., Chandran & Collins, 2014;Karlsson et al., 2011;Li et al., 2016;Shepherd, 2000). Polar mesospheric clouds (PMCs), also known as noctilucent clouds, are the highest clouds on Earth that form in the polar summer mesopause region and are considered to be important indicators of variations in temperature and circulation in the mesosphere (Hervig et al., , 2015. ...
... studies dedicated to QBO in the middle atmosphere, Chandran and Collins (2014) and Lubis et al. (2016) should be noted, where WACCM model is used, and Fischer et al. (2008) with the model SOCOL. ...
To estimate reaction of the atmospheric circulation in the middle and upper atmosphere to changes in phases of equatorial stratospheric quasi‐biennial oscillation (QBO), the three‐dimensional nonlinear middle and upper atmosphere model (MUAM) is used. This model allows continuous simulations of atmospheric wave propagation from the ground to the thermosphere (300 km and above). The main atmospheric hydrodynamic fields (wind and temperature), components of residual meridional circulation (RMC), and fluxes of mass are calculated based on ensembles containing 16 pairs of model runs for initial conditions corresponding to easterly and westerly QBO phases. To minimize uncertainties in determination of the QBO phases, an approach based on the usage of empirical orthogonal functions (EOFs) is applied. Statistically significant results are obtained illustrating how changes in the planetary waves (PWs) structures promote the spread of QBO effects to polar latitudes and to the thermosphere, through changes in the Eliassen‐Palm (EP) flux and its divergence, or through the formation of an eddy meridional circulation. The main contribution to the cooling of the polar winter stratosphere during the westerly QBO is made by the weakening of wave activity, in particular, the weakening of the vertical EP flux, which leads to a weakening of the poleward heat flux. The sensitivity of the wave‐induced eddy circulation to changes in the QBO phase is higher than that of the RMC, demonstrating that PWs propagating from the lower troposphere are the most important mechanism for the transfer of global circulation disturbances from the equatorial QBO region to polar latitudes.
