Two ensemble simulations of a new Earth system model (ESM) SOCOLv4 (SOlar Climate Ozone Links, ve... more Two ensemble simulations of a new Earth system model (ESM) SOCOLv4 (SOlar Climate Ozone Links, version 4) for the period from 2015 to 2099 under moderate (SSP2-4.5) and severe (SSP5-8.5) scenarios of greenhouse gas (GHG) emission growth were analyzed to investigate changes in key dynamical processes relevant for Arctic stratospheric ozone. The model shows a 5–10 K cooling and 5%–20% humidity increase in the Arctic lower–upper stratosphere in March (when the most considerable ozone depletion may occur) between 2080–2099 and 2015–2034. The minimal temperature in the lower polar stratosphere in March, which defines the strength of ozone depletion, appears when the zonal mean meridional heat flux in the lower stratosphere in the preceding January–February is the lowest. In the late 21st century, the strengthening of the zonal mean meridional heat flux with a maximum of up to 20 K m/s (∼25%) in the upper stratosphere close to 70°N in January–February is obtained in the moderate scenario ...
Processes behind Sudden Stratospheric Warming (SSW), which occurs more frequently in the northern... more Processes behind Sudden Stratospheric Warming (SSW), which occurs more frequently in the northern hemispheric polar latitudes and its influence from the stratosphere to the upper atmosphere are well documented. However, physical processes associated with SSW, although it ensues rarely in the southern hemisphere (SH), have a strong influence on the background atmosphere from the stratosphere to the mesosphere and are poorly understood. Using a ground-based meteor radar, satellite-borne Microwave-Limb sounder, and Modern-Era Retrospective Analysis for Research and Applications observations, we identified cooling of Antarctic mesopause by 26 K in response to a 66 K warming in the polar stratosphere during the 2019 minor SSW in the SH. The observed cooling is attributed to the interplay between planetary waves, CO2 infrared cooling, and O3 depletion, rather than adiabatic cooling due to gravity waves alone during SSW. It is proposed that anthropogenic and other sources generating chemic...
<p>Previous studies disclosed oscillations of ionospheric parameters, in pa... more <p>Previous studies disclosed oscillations of ionospheric parameters, in particular, the critical frequency of the F2 layer, <em>f<sub>0</sub>F2</em>, with periods longer than 2 days. This allows suggestions that planetary waves (PWs) propagating from the lower atmosphere can influence the ionospheric electron density. However, someatmospheric modeling showed that PWs with observed periods may have difficulties for direct propagation to altitudes above 110 km. Since 2018, regular observations of ionospheric parameters with the DPS-4 ionosonde are been performed at the Peterhof Scientific Station of Saint Petersburg State University (60° N, 30° E). In this study, we analyzed results for spectra of oscillations of ionospheric parameters in the range of periods 0.5 – 40 days according to these measurements. In addition to these spectra we analyzed similar spectra obtained from the MERRA-2 data of meteorological reanalysis for different locations in the lower and middle atmosphere. Lomb-Scargle spectra were obtained for 90-day running intervals. They contain maxima at periods 1 day and 0.5 day, which may correspond to the diurnal and semidiurnal tides. The spectra also have maxima at periods 2 – 40 days, which can be associated with planetary waves (PWs). The analysis shows that big amplitudes of oscillations with periods <em>τ</em> ~ 2 – 40 d are frequently observed in the northern spring and summer months, when westward stratospheric winds prevent PW propagation from the lower to the upper atmosphere. However, the analysis of atmospheric waveguides revealed that PWs can cross the equator above altitudes of 60 km. Therefore, PWs observed in summer ionosphere can, in prinsiple, propagate from the lower wave sources located in the winter hemisphere.Obtained correlation coefficients between variations of the spectral densities at ionospheric and tropospheric heights at different latitudes demonstrate sufficient statistical confidence for PWs with periods of several days. This gives evidences about possible PW coupling between dynamical processes in the lower atmosphere and ionosphere. The spectral analysis was supported by the Russian Science Foundation (grant #20-77-10006) and the analysis of PW coupling was supported by the Ministry of Education of the Russian Federation (agreement 075-15-2021-583). Used ionosonde data were acquired in the “Geomodel” Resource Center of SPbSU.</p>
25th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics, 2019
Numerical simulations have been performed to estimate sensitivity of ozone fluxes to the impact o... more Numerical simulations have been performed to estimate sensitivity of ozone fluxes to the impact of mesoscale orographic gravity waves (OGWs) in the middle atmosphere at different phases of simulated stratospheric warming (SW) events during boreal winter. The numerical model of general circulation of the middle and upper atmosphere (MUAM) with implemented OGW parameterization has been used. The simulations demonstrate a weakening of the vertical ozone fluxes during and after simulated SW compared to the time intervals before SW, which corresponds to the changes in meridional mean circulation. The most significant differences in ozone fluxes due to OGW effects are obtained in the Northern Hemisphere. These differences are up to 20% at middle latitudes and may reach 100% at high latitudes. The results indicate a strong sensitivity of the meridional circulation and hence, the ozone fluxes to the influence of OGWs at different phases of simulated SWs.
Numerical simulation has been used to examine the effect of changes in solar activity (SA) in the... more Numerical simulation has been used to examine the effect of changes in solar activity (SA) in the thermosphere on amplitudes of long-period planetary waves (PW) for the winter period in the Northern Hemisphere. The model of the middle and upper atmosphere (MUAM) is used. It allows simulations of general atmospheric circulation at altitudes 0–300 km. In order to reproduce SA changes, different values of the solar radio flux at a wavelength of 10.7 cm at an altitude of more than 100 km are set in the MUAM radiation block. To take into account the effect of charged particles in the ionosphere on the neutral gas dynamics, ionospheric conductivities for different SA levels are included in MUAM. To improve the statistical reliability of the results, two ensembles of model simulations consisting of 16 runs corresponding to the minimum and maximum SA have been obtained. The statistical confidence of average differences in PW amplitudes between high and low SA has been calculated. The result...
Journal of Geophysical Research: Atmospheres, 2022
To estimate reaction of the atmospheric circulation in the middle and upper atmosphere to changes... more 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.
This dataset contains model output files and examples of scripts for depicting figures related to... more This dataset contains model output files and examples of scripts for depicting figures related to the article "Influence of thermospheric impacts of solar activity on the general circulation and long-period planetary waves in the middle atmosphere " by A.V. Koval, N. M. Gavrilov, A. I. Pogoreltsev, N. O. Shevchuk. <br> Contents:<br> Output data from model simulations averaged over 16 pairs of model runs with high and low solar activity: <br> gh_m1_hsa5.dx, gh_m1_lsa5.dx – amplitudes of the geopotential height variations in g.p.m. at high and low solar activity caused by long-period PW modes with zonal wavenumber 1 averaged over 80 time subintervals selected from pairs of the MUAM runs (structure described in w1_tp1_hsa.ctl, w1_tp1_lsa.ctl).<br> gh_m2_hsa5.dx, gh_m2_lsa5.dx, gh_m3_hsa5.dx, gh_m3_lsa5.dx, gh_m4_hsa5.dx, gh_m4_lsa5.dx – the same but for zonal wavenumbers 2,3,4.<br> gh_m1_disp_dif5.dx – dispersion of differences in corresponding w...
Two ensemble simulations of a new Earth system model (ESM) SOCOLv4 (SOlar Climate Ozone Links, ve... more Two ensemble simulations of a new Earth system model (ESM) SOCOLv4 (SOlar Climate Ozone Links, version 4) for the period from 2015 to 2099 under moderate (SSP2-4.5) and severe (SSP5-8.5) scenarios of greenhouse gas (GHG) emission growth were analyzed to investigate changes in key dynamical processes relevant for Arctic stratospheric ozone. The model shows a 5–10 K cooling and 5%–20% humidity increase in the Arctic lower–upper stratosphere in March (when the most considerable ozone depletion may occur) between 2080–2099 and 2015–2034. The minimal temperature in the lower polar stratosphere in March, which defines the strength of ozone depletion, appears when the zonal mean meridional heat flux in the lower stratosphere in the preceding January–February is the lowest. In the late 21st century, the strengthening of the zonal mean meridional heat flux with a maximum of up to 20 K m/s (∼25%) in the upper stratosphere close to 70°N in January–February is obtained in the moderate scenario ...
Processes behind Sudden Stratospheric Warming (SSW), which occurs more frequently in the northern... more Processes behind Sudden Stratospheric Warming (SSW), which occurs more frequently in the northern hemispheric polar latitudes and its influence from the stratosphere to the upper atmosphere are well documented. However, physical processes associated with SSW, although it ensues rarely in the southern hemisphere (SH), have a strong influence on the background atmosphere from the stratosphere to the mesosphere and are poorly understood. Using a ground-based meteor radar, satellite-borne Microwave-Limb sounder, and Modern-Era Retrospective Analysis for Research and Applications observations, we identified cooling of Antarctic mesopause by 26 K in response to a 66 K warming in the polar stratosphere during the 2019 minor SSW in the SH. The observed cooling is attributed to the interplay between planetary waves, CO2 infrared cooling, and O3 depletion, rather than adiabatic cooling due to gravity waves alone during SSW. It is proposed that anthropogenic and other sources generating chemic...
&amp;lt;p&amp;gt;Previous studies disclosed oscillations of ionospheric parameters, in pa... more &amp;lt;p&amp;gt;Previous studies disclosed oscillations of ionospheric parameters, in particular, the critical frequency of the F2 layer, &amp;lt;em&amp;gt;f&amp;lt;sub&amp;gt;0&amp;lt;/sub&amp;gt;F2&amp;lt;/em&amp;gt;, with periods longer than 2 days. This allows suggestions that planetary waves (PWs) propagating from the lower atmosphere can influence the ionospheric electron density. However, someatmospheric modeling showed that PWs with observed periods may have difficulties for direct propagation to altitudes above 110 km. Since 2018, regular observations of ionospheric parameters with the DPS-4 ionosonde are been performed at the Peterhof Scientific Station of Saint Petersburg State University (60&amp;amp;#176; N, 30&amp;amp;#176; E). In this study, we analyzed results for spectra of oscillations of ionospheric parameters in the range of periods 0.5 &amp;amp;#8211; 40 days according to these measurements. In addition to these spectra we analyzed similar spectra obtained from the MERRA-2 data of meteorological reanalysis for different locations in the lower and middle atmosphere. Lomb-Scargle spectra were obtained for 90-day running intervals. They contain maxima at periods 1 day and 0.5 day, which may correspond to the diurnal and semidiurnal tides. The spectra also have maxima at periods 2 &amp;amp;#8211; 40 days, which can be associated with planetary waves (PWs). The analysis shows that big amplitudes of oscillations with periods &amp;lt;em&amp;gt;&amp;amp;#964;&amp;lt;/em&amp;gt; ~ 2 &amp;amp;#8211; 40 d are frequently observed in the northern spring and summer months, when westward stratospheric winds prevent PW propagation from the lower to the upper atmosphere. However, the analysis of atmospheric waveguides revealed that PWs can cross the equator above altitudes of 60 km. Therefore, PWs observed in summer ionosphere can, in prinsiple, propagate from the lower wave sources located in the winter hemisphere.Obtained correlation coefficients between variations of the spectral densities at ionospheric and tropospheric heights at different latitudes demonstrate sufficient statistical confidence for PWs with periods of several days. This gives evidences about possible PW coupling between dynamical processes in the lower atmosphere and ionosphere. The spectral analysis was supported by the Russian Science Foundation (grant #20-77-10006) and the analysis of PW coupling was supported by the Ministry of Education of the Russian Federation (agreement 075-15-2021-583). Used ionosonde data were acquired in the &amp;amp;#8220;Geomodel&amp;amp;#8221; Resource Center of SPbSU.&amp;lt;/p&amp;gt;
25th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics, 2019
Numerical simulations have been performed to estimate sensitivity of ozone fluxes to the impact o... more Numerical simulations have been performed to estimate sensitivity of ozone fluxes to the impact of mesoscale orographic gravity waves (OGWs) in the middle atmosphere at different phases of simulated stratospheric warming (SW) events during boreal winter. The numerical model of general circulation of the middle and upper atmosphere (MUAM) with implemented OGW parameterization has been used. The simulations demonstrate a weakening of the vertical ozone fluxes during and after simulated SW compared to the time intervals before SW, which corresponds to the changes in meridional mean circulation. The most significant differences in ozone fluxes due to OGW effects are obtained in the Northern Hemisphere. These differences are up to 20% at middle latitudes and may reach 100% at high latitudes. The results indicate a strong sensitivity of the meridional circulation and hence, the ozone fluxes to the influence of OGWs at different phases of simulated SWs.
Numerical simulation has been used to examine the effect of changes in solar activity (SA) in the... more Numerical simulation has been used to examine the effect of changes in solar activity (SA) in the thermosphere on amplitudes of long-period planetary waves (PW) for the winter period in the Northern Hemisphere. The model of the middle and upper atmosphere (MUAM) is used. It allows simulations of general atmospheric circulation at altitudes 0–300 km. In order to reproduce SA changes, different values of the solar radio flux at a wavelength of 10.7 cm at an altitude of more than 100 km are set in the MUAM radiation block. To take into account the effect of charged particles in the ionosphere on the neutral gas dynamics, ionospheric conductivities for different SA levels are included in MUAM. To improve the statistical reliability of the results, two ensembles of model simulations consisting of 16 runs corresponding to the minimum and maximum SA have been obtained. The statistical confidence of average differences in PW amplitudes between high and low SA has been calculated. The result...
Journal of Geophysical Research: Atmospheres, 2022
To estimate reaction of the atmospheric circulation in the middle and upper atmosphere to changes... more 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.
This dataset contains model output files and examples of scripts for depicting figures related to... more This dataset contains model output files and examples of scripts for depicting figures related to the article "Influence of thermospheric impacts of solar activity on the general circulation and long-period planetary waves in the middle atmosphere " by A.V. Koval, N. M. Gavrilov, A. I. Pogoreltsev, N. O. Shevchuk. <br> Contents:<br> Output data from model simulations averaged over 16 pairs of model runs with high and low solar activity: <br> gh_m1_hsa5.dx, gh_m1_lsa5.dx – amplitudes of the geopotential height variations in g.p.m. at high and low solar activity caused by long-period PW modes with zonal wavenumber 1 averaged over 80 time subintervals selected from pairs of the MUAM runs (structure described in w1_tp1_hsa.ctl, w1_tp1_lsa.ctl).<br> gh_m2_hsa5.dx, gh_m2_lsa5.dx, gh_m3_hsa5.dx, gh_m3_lsa5.dx, gh_m4_hsa5.dx, gh_m4_lsa5.dx – the same but for zonal wavenumbers 2,3,4.<br> gh_m1_disp_dif5.dx – dispersion of differences in corresponding w...
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