Reactions of the Middle Atmosphere Circulation and Stationary Planetary Waves on the Solar Activity Effects in the Thermosphere

Koval, A. V.; Гаврилов, Н. М.; Pogoreltsev, Alexander; Shevchuk, Nikita

doi:10.1029/2019ja027392

Cited by 9 publications

(11 citation statements)

References 63 publications

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“…The modified SPWs in the northern stratosphere before and during SSW (Stray et al, 2015;Gavrilov et al, 2018) can then propagate along the waveguides to the southern upper atmosphere. Laskar et al (2019) showed similar significant weakening (up to a reversal) of both the mean and residual meridional circulation at MLT heights during SSW observed in the winters of 2009/10 and 2012/13, causing temperature fluctuations in the stratosphere of both hemispheres. Larger velocity add-ons in the southern MLT region after SSW in Fig.…”

Section: Residual Circulation At the Different Ssw Stagesmentioning

confidence: 55%

Modelling the residual mean meridional circulation at different stages of sudden stratospheric warming events

et al. 2021

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Abstract. Ensemble simulation of the atmospheric general circulation at altitudes up to the lower thermosphere is performed using the 3-D nonlinear mechanistic numerical model MUAM. The residual mean meridional circulation (RMC), which is the superposition of the mean Eulerian and wave-induced eddy components, is calculated for the boreal winter. Changes in the vertical and meridional RMC velocity components are analysed at different stages of a simulated composite sudden stratospheric warming (SSW) event averaged over 19 model runs. The simulation results show a general decrease in RMC velocity components up to 30 % during and after SSW in the mesosphere and lower thermosphere of the Northern Hemisphere. There are also increases in the downward and northward velocities at altitudes of 20–50 km at the northern polar latitudes during SSW. Associated vertical transport and adiabatic heating can contribute to warming the stratosphere and downward shifting of the stratopause during the composite SSW. The residual mean and eddy mass fluxes are calculated for different SSW stages. It is shown that before the SSW, planetary wave activity creates wave-induced eddy circulation cells in the northern upper stratosphere, which are directed upwards at middle latitudes, northward at high latitudes and downwards near the North Pole. These cells increase heat transport and adiabatic heating in the polar region. During SSW, the region of upward eddy vertical velocity is shifted to high latitudes, but the velocity is still downward near the North Pole. After SSW, upward eddy-induced fluxes span the entire polar region, producing upward transport and adiabatic cooling of the stratosphere and providing the return of the stratopause to higher altitudes. The obtained statistically significant results on the evolution of RMC and eddy circulation at different SSW stages at altitudes up to the lower thermosphere can be useful for a better understanding the mechanisms of planetary wave impacts on the mean flow and for the diagnostics of the transport of conservative tracers in the atmosphere.

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Section: Residual Circulation At the Different Ssw Stagesmentioning

confidence: 55%

Modelling the residual mean meridional circulation at different stages of sudden stratospheric warming events

et al. 2021

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“…Although many studies have been conducted on the responses of atmospheric circulation to solar activity, they focused on some kinds of atmospheric circulation in the middle and lower atmosphere or at specified latitude regions [40,41,43,44,46]. In this work, the responses of global atmospheric circulation from the ground to ~500 km to solar activity were analyzed.…”

Section: Discussionmentioning

confidence: 99%

“…Kodera and Kuroda [40] suggested that solar activity can change the balance between the dynamically and radiatively controlled states, which can influence stratopause circulation. Koval et al [41] used a general atmospheric circulation model to demonstrate that changes in solar activity can modify the middle atmospheric circulation. Vasilyeva et al [42] discussed the possible effects of solar activity on the tropospheric temperature regime based on the analysis of the tropospheric temperature regime in the northern and southern hemispheres in 1948-2006.…”

Section: Introductionmentioning

confidence: 99%

Impact of Solar Activity on Global Atmospheric Circulation Based on SD-WACCM-X Simulations from 2002 to 2019

Teng

Qin

et al. 2021

Atmosphere

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In this study, a global atmospheric model, Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (SD-WACCM-X), and the residual circulation principle were used to study the global atmospheric circulation from the lower to upper atmosphere (~500 km) from 2002 to 2019. Our analysis shows that the atmospheric circulation is clearly influenced by solar activity, especially in the upper atmosphere, which is mainly characterized by an enhanced atmospheric circulation in years with high solar activity. The atmospheric circulation in the upper atmosphere also exhibits an ~11 year period, and its variation is highly correlated with the temporal variation in the F10.7 solar index during the same time series, with a maximum correlation coefficient of up to more than 0.9. In the middle and lower atmosphere, the impact of solar activity on the atmospheric circulation is not as obvious as in the upper atmosphere due to some atmospheric activities such as the Quasi-Biennial Oscillation (QBO), El Niño–Southern Oscillation (ENSO), sudden stratospheric warming (SSW), volcanic forcing, and so on. By comparing the atmospheric circulation in different latitudinal regions between years with high and low solar activity, we found the atmospheric circulation in mid- and high-latitude regions is more affected by solar activity than in low-latitude and equatorial regions. In addition, clear seasonal variation in atmospheric circulation was detected in the global atmosphere, excluding the regions near 10−4 hPa and the lower atmosphere, which is mainly characterized by a flow from the summer hemisphere to the winter hemisphere. In the middle and low atmosphere, the atmospheric circulation shows a quasi-biennial oscillatory variation in the low-latitude and equatorial regions. This work provides a referable study of global atmospheric circulation and demonstrates the impacts of solar activity on global atmospheric circulation.

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“…The incoming solar radiation and heating depend on the SA, which undergoes cyclic changes with a period of about 11 years (see e.g., [8]). In the study [9], it was shown that SA changes in the thermosphere can significantly influence middle-atmosphere circulation and amplitudes of quasi-stationary PWs. Wave reflection in the lower thermosphere may also influence the circulation of the middle atmosphere (e.g., [9,10]).…”

Section: Introductionmentioning

confidence: 99%

“…In the study [9], it was shown that SA changes in the thermosphere can significantly influence middle-atmosphere circulation and amplitudes of quasi-stationary PWs. Wave reflection in the lower thermosphere may also influence the circulation of the middle atmosphere (e.g., [9,10]). Among the reasons for PW reflection at thermospheric heights can be significant temperature and wind gradients.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of the 4–10-Day Planetary Wave Structures in the Middle Atmosphere to the Solar Activity Effects in the Thermosphere

et al. 2022

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Numerical simulation of the general atmospheric circulation was performed to estimate changes in amplitudes of the westward-travelling planetary waves (PWs) at altitudes from the Earth’s surface up to 300 km under different solar activity (SA) levels. The three-dimensional nonlinear mechanistic model of circulation of the middle and upper atmosphere “MUAM” was used. The atmospheric general circulation and PW amplitudes were calculated based on ensembles containing 16 model runs for conditions corresponding to low and high SA. PWs having periods of 4–10 days were considered. Comparison with the data of digital ionosondes showed that the MUAM model is capable of reproducing the considered PW modes at thermospheric heights. It is shown that under high SA conditions, PW amplitudes are significantly larger in the thermosphere and smaller in the middle atmosphere. The observed PW structures are influenced not only by changes in atmospheric refractive index and Eliassen–Palm flux but also by varying PW reflection in the lower thermosphere, which can change proportions of the wave energy transferred from the lower atmosphere to the upper layers and reflected downwards.

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Reactions of the Middle Atmosphere Circulation and Stationary Planetary Waves on the Solar Activity Effects in the Thermosphere

Cited by 9 publications

References 63 publications

Modelling the residual mean meridional circulation at different stages of sudden stratospheric warming events

Modelling the residual mean meridional circulation at different stages of sudden stratospheric warming events

Impact of Solar Activity on Global Atmospheric Circulation Based on SD-WACCM-X Simulations from 2002 to 2019

Sensitivity of the 4–10-Day Planetary Wave Structures in the Middle Atmosphere to the Solar Activity Effects in the Thermosphere

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