Fedor Bessarab | Immanuel Kant Baltic Federal University (original) (raw)

Papers by Fedor Bessarab

Izvestiya, Atmospheric and Oceanic Physics, 2019

The results of analyzing the planetary and tidal variabilities in the mesosphere, thermosphere, a... more The results of analyzing the planetary and tidal variabilities in the mesosphere, thermosphere, and ionosphere acquired in calculations for January 2009 using two versions of the EAGLE model are presented. It is shown that, during a sudden stratospheric warming (SSW), the planetary and tidal-wave activity increases in the lower thermosphere. The features of the changes in solar-migrating and nonmigrating components of tidal variabilities in the parameters of the thermosphere, ionosphere, and electric fields are considered. The reproduction of the vertical electromagnetic drift during the SSW period over the Jicamarca station is explained by a significant increase in the diurnal and semidiurnal tidal variability.

Russian Journal of Physical Chemistry B, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2019

43rd COSPAR Scientific Assembly. Held 28 January - 4 February, 2021

Cosmic Research, 2021

This paper presents the results of model calculations of the behavior of the ionosphere during a ... more This paper presents the results of model calculations of the behavior of the ionosphere during a complex space-weather event that occurred in September 2017. The main attention is paid to the analysis of the response of an integral characteristic of the ionosphere-global electron content (GEC)-to geomagnetic storms on September 7-8. Comparison of the temporal behavior of the model and experimental GEC showed there to be a good qualitative agreement between the temporal variations of hydroelectric power stations associated with geomagnetic storms. At the same time, the absence in the results of model calculations of positive hydroelectric disturbances observed on September 7, 8, and 11 is noted. It is hypothesized that these positive disturbances of the GEC on the indicated days may be associated with the observed solar-proton events and precipitation of protons from the magnetosphere, but not taken into account in model calculations.

2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC), 2018

The paper presents the results of the complex experiment (lidar and ozonometric observations), ca... more The paper presents the results of the complex experiment (lidar and ozonometric observations), carried out during the period of the 2013 major sudden stratospheric warming (SSW) in the North Asia region. The data of this experiment were supplemented by the ionospheric parameters observations. We considered variations in the critical frequency and peak height of the ionospheric F2-layer (foF2) from ionosonde measurements in Tomsk and Irkutsk, as well as the behavior of the total electron content (TEC) based on the phase dual-frequency GPS/GLONASS receivers' data. We revealed significant variations in the stratosphere ozone concentration, ionospheric electron density, as well as in the thermosphere O/N2 ratio with the similar pattern during the SSW. The ionospheric response to SSW in the middle and high-latitude regions is suggested to be caused by changes in the neutral composition at the thermosphere altitudes.

Russian Journal of Physical Chemistry B, 2018

The paper presents the results of modeling ionospheric parameters using the Global Self-Consisten... more The paper presents the results of modeling ionospheric parameters using the Global Self-Consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) of the Earth. Numerical experiments have been performed for three variants of the solar EUV spectrum data: the Nusinov model, EUVAC, and generalized solar flux measurements (SOLID). The calculations have been carried out on March 22, 2009 (F 10.7 ~ 68) and March 22, 2014 (F 10.7 ~ 154). The maximum ionization rate and, correspondingly, the critical frequency of the F2 layer have been obtained using the Nusinov model for low and high solar activities. The lowest ionization rates and values of foF2 have been obtained using the EUVAC model. Simulations with the SOLID spectrum show the better agreement of foF2 with the empirical model IRI-2007 at the maximum solar activity. At the same time, at the minimum solar activity, all models of the spectrum provide an underestimation of the values of the critical frequency of the F2 layer.

Journal of Geophysical Research: Space Physics, 2015

This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturban... more This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturbances during 2009 major sudden stratospheric warming (SSW) event. This period was characterized by extremely low solar and geomagnetic activity. The study was performed using two first principal models: thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) and global self-consistent model of thermosphere, ionosphere, and protonosphere (GSM TIP). The stratospheric anomalies during SSW event were modeled by specifying the temperature and density perturbations at the lower boundary of the TIME-GCM (30 km altitude) according to data from European Centre for Medium-Range Weather Forecasts. Then TIME-GCM output at 80 km was used as lower boundary conditions for driving GSM TIP model runs. We compare models' results with ground-based ionospheric data at low latitudes obtained by GPS receivers in the American longitudinal sector. GSM TIP simulation predicts the occurrence of the quasi-wave vertical structure in neutral temperature disturbances at 80-200 km altitude, and the positive and negative disturbances in total electron content at low latitude during the 2009 SSW event. According to our model results the formation mechanisms of the low-latitude ionospheric response are the disturbances in the n(O)/n(N 2) ratio and thermospheric wind. The change in zonal electric field is key mechanism driving the ionospheric response at low latitudes, but our model results do not completely reproduce the variability in zonal electric fields (vertical plasma drift) at low latitudes. Although importance of PW in generating ionospheric disturbances during SSW is suggested in early studies [Goncharenko et al., 2010a, 2010b; Pedatella and Forbes, 2010; Fejer et al., 2011], exact mechanisms are a subject of active research due to a variety and complexity of interactions of planetary waves with tides, gravity waves, and mean flow. Several mechanisms can modify thermospheric tides and through E region dynamo generate KLIMENKO ET AL.

Journal of Atmospheric and Terrestrial Physics, 1996

A global numerical model of the Earth's upper atmosphere has been used to simulate numerically th... more A global numerical model of the Earth's upper atmosphere has been used to simulate numerically the behavioar of the ionosphere observed by EISCAT on 24-25 March 1987 when the quiet day of 24 March was followed by the disturbed day of 25 March, with a Sudden Commencement (SC) starting about 1540 UT. We have selected the model input data for the auroral precipitating particle fluxes and the fieldaligned currents to obtain an acceptable agreement between the calculated and observed ionospheric variations. A rather good similarity between the calculated and observed variations of the electric field, Eregion electron concentration, F2-region ion temperature and electron concentration has been found. Spatial distributions of the electric potential and F2-region electron concentration and ion temperature have been obtained. The dynamics of the main ionospheric trough during the disturbed period has been investigated. It has been found that the equatorward movement of the midnight part of the trough is connected with the enhanced plasma transport, while the apparent westward and eastward movements of the evening and morning edges of the trough are connected with the "hot spots" caused by Joule heating of the ion gas.

Russian Journal of Physical Chemistry B, 2019

This article presents the main stages of the development of a new model, the entire atmosphere (E... more This article presents the main stages of the development of a new model, the entire atmosphere (EAGLE). We describe the models of the lower,middle, and upper atmospheres that constitute EAGLE and present the way we coupled. The results of the EAGLE model confirm that the four-peak longitude variation and the evening surge of the eastern electric field at the equator are consequences of the atmosphere-ionosphere interaction. This result illustrates that the EAGLE model is an useful tool for studying the influence of the atmosphere on the electric field in the equatorial ionosphere.

Russian Journal of Physical Chemistry B, 2017

We consider different approaches to calculating the ion composition in the lower ionosphere and u... more We consider different approaches to calculating the ion composition in the lower ionosphere and use two methods for modeling the concentration of molecular ions. The first method allows us to solve an equation with an effective recombination coefficient for the total concentration of molecular ions, and the second method calculates their concentrations separately. Numerical experiments were performed using a global self-consistent model of the thermosphere, ionosphere, and protonosphere (GSM TIP) for the conditions of March 16–20, 2015. We show that the second method, which provides a more accurate approximation, leads to significant consequences. Due to a strong change in the calculated concentration of ions in the E-region, the conductivity varies thus affecting the qualitative and quantitative behavior of the electric dynamo field at low and equatorial latitudes. Even without mesospheric tides and the electric dynamo field in the F-region, the calculation of partial concentration...

Russian Journal of Physical Chemistry B, 2020

Abstract Since 1964, the Kaliningrad branch of Pushkov Institute of Terrestrial Magnetism, Ionosp... more Abstract Since 1964, the Kaliningrad branch of Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences (IZMIRAN) has been conducting regular observations of the parameters of the lower atmosphere, ionosphere, and variations in the Earth’s magnetic field. The base of the measuring equipment, located in Ulyanovka village, Kaliningrad region (54° N, 20° E) consists of ionosonde for the vertical sounding of the ionosphere; two-frequency GPS/GLONASS receivers, which are used to determine the total electron content in the ionosphere; magnetic variation stations for the continuous recording of variations of the three components of the Earth’s magnetic field vector and calculating the local K -index; and a weather station. The simultaneous observations of variations in the magnetic field, as well as the ionospheric and meteorological parameters in the same observatory, offer a wide range of opportunities to study the atmospheric-ionospheric relations. This article provides a brief description of all the tools, provides a method for transmitting and storing the time series of measured parameters, and also presents examples of using these data for various geophysical studies.

Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2020

The paper presents the investigation of the Global Electron Content (GEC) variability during a ma... more The paper presents the investigation of the Global Electron Content (GEC) variability during a major Sudden Stratospheric Warming (SSW) event in January 2009. The two-hour values of the GEC obtained from the GIM, as well as the GEC calculated in the EAGLE and GSM TIP models, were used as initial data. It has been shown that during SSW event the amplitude of diurnal variations in GEC decreases and the amplitude of semidiurnal variations increases. GEC variability during SSW event increases, as well as during the small geomagnetic disturbance that occurred on January 26, 2009.

Geomagnetism and Aeronomy, 2021

A study of the wave changeability in the F2-layer critical frequency over Kaliningrad (54.6° N, 2... more A study of the wave changeability in the F2-layer critical frequency over Kaliningrad (54.6° N, 20° E) and Irkutsk (53° N, 103° E) stations during strong sudden stratospheric warmings is presented. Low solar activity was a common factor for all selected cases. The results of wavelet analysis of the time variations in foF2 showed that an amplification of the oscillations with periods of 4-10 days occurred in the majority of the warmings within a period of 1965-2009. The amplitude of long-period (25-30 days) oscillations, vice versa, decreased. A similar analysis performed for the 1975-1976 winter, during which there were no warmings, showed that the amplitudes of the foF2 oscillations with periods of 25-30 days, conversely, were very stable and changed insignificantly. The amplification of the variability in the foF2 oscillation spectrum in other frequency ranges also is another manifestation of stratospheric warmings over Kaliningrad and Irkutsk.

Solnechno-Zemnaya Fizika, 2018

We present the results of complex obser-vations of various parameters of the middle and upper atm... more We present the results of complex obser-vations of various parameters of the middle and upper atmosphere over Siberia in December 2012 – January 2013, during a major sudden stratospheric warming (SSW) event. We analyze variations in ozone concentration from microwave measurements, in stratosphere and lower mesosphere temperatures from lidar and satellite measurements, in the F2-layer critical frequency (foF2), in the total electron content (TEC), as well as in the ratio of concentrations of atomic oxygen to molecular nitrogen (O/N2) in the thermosphere. To interpret the observed disturbances in the upper atmosphere, the experimental measurements are compared with the results of model calculations obtained with the Global Self-consistent Model of Thermosphere—Ionosphere—Protonosphere (GSM TIP). The response of the upper atmosphere to the SSW event is shown to be a decrease in foF2 and TEC during the evolution of the warming event and a prolonged increase in O/N2, foF2, and TEC after ...

Geomagnetism and Aeronomy, 2018

⎯The results of numerical experiments on the modeling of thermospheric and ionospheric disturbanc... more ⎯The results of numerical experiments on the modeling of thermospheric and ionospheric disturbances under conditions of sudden stratospheric warming are presented to study the possible mechanisms of such disturbances. Local disturbances caused by a planetary wave with zonal wave number s = 1 and internal gravity waves (IGWs) propagating from the disturbed region in the stratosphere are taken into account as sources of disturbances. It is shown that the inclusion of an additional source of thermospheric disturbances caused by mesospheric variations of atmospheric parameters with IGW periods over the region of sudden stratospheric warming leads to significant changes in the parameters of the thermosphere and ionosphere, including a change in the global structure of the distributions of the gas components of the thermosphere and a shift in maximum concentrations of atomic oxygen to low latitudes of the Southern Hemisphere; there is an increase in the mean values, the diurnal and semidiurnal variations of the ion concentration in the F region of the ionosphere. These features of changes in the parameters of the thermosphere and ionosphere occurred with insignificant disturbances of tidal variations in the thermosphere.

Izvestiya, Atmospheric and Oceanic Physics, 2019

The results of analyzing the planetary and tidal variabilities in the mesosphere, thermosphere, a... more The results of analyzing the planetary and tidal variabilities in the mesosphere, thermosphere, and ionosphere acquired in calculations for January 2009 using two versions of the EAGLE model are presented. It is shown that, during a sudden stratospheric warming (SSW), the planetary and tidal-wave activity increases in the lower thermosphere. The features of the changes in solar-migrating and nonmigrating components of tidal variabilities in the parameters of the thermosphere, ionosphere, and electric fields are considered. The reproduction of the vertical electromagnetic drift during the SSW period over the Jicamarca station is explained by a significant increase in the diurnal and semidiurnal tidal variability.

Russian Journal of Physical Chemistry B, 2018

EGU General Assembly Conference Abstracts, Apr 1, 2019

43rd COSPAR Scientific Assembly. Held 28 January - 4 February, 2021

Cosmic Research, 2021

This paper presents the results of model calculations of the behavior of the ionosphere during a ... more This paper presents the results of model calculations of the behavior of the ionosphere during a complex space-weather event that occurred in September 2017. The main attention is paid to the analysis of the response of an integral characteristic of the ionosphere-global electron content (GEC)-to geomagnetic storms on September 7-8. Comparison of the temporal behavior of the model and experimental GEC showed there to be a good qualitative agreement between the temporal variations of hydroelectric power stations associated with geomagnetic storms. At the same time, the absence in the results of model calculations of positive hydroelectric disturbances observed on September 7, 8, and 11 is noted. It is hypothesized that these positive disturbances of the GEC on the indicated days may be associated with the observed solar-proton events and precipitation of protons from the magnetosphere, but not taken into account in model calculations.

2018 2nd URSI Atlantic Radio Science Meeting (AT-RASC), 2018

The paper presents the results of the complex experiment (lidar and ozonometric observations), ca... more The paper presents the results of the complex experiment (lidar and ozonometric observations), carried out during the period of the 2013 major sudden stratospheric warming (SSW) in the North Asia region. The data of this experiment were supplemented by the ionospheric parameters observations. We considered variations in the critical frequency and peak height of the ionospheric F2-layer (foF2) from ionosonde measurements in Tomsk and Irkutsk, as well as the behavior of the total electron content (TEC) based on the phase dual-frequency GPS/GLONASS receivers' data. We revealed significant variations in the stratosphere ozone concentration, ionospheric electron density, as well as in the thermosphere O/N2 ratio with the similar pattern during the SSW. The ionospheric response to SSW in the middle and high-latitude regions is suggested to be caused by changes in the neutral composition at the thermosphere altitudes.

Russian Journal of Physical Chemistry B, 2018

The paper presents the results of modeling ionospheric parameters using the Global Self-Consisten... more The paper presents the results of modeling ionospheric parameters using the Global Self-Consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) of the Earth. Numerical experiments have been performed for three variants of the solar EUV spectrum data: the Nusinov model, EUVAC, and generalized solar flux measurements (SOLID). The calculations have been carried out on March 22, 2009 (F 10.7 ~ 68) and March 22, 2014 (F 10.7 ~ 154). The maximum ionization rate and, correspondingly, the critical frequency of the F2 layer have been obtained using the Nusinov model for low and high solar activities. The lowest ionization rates and values of foF2 have been obtained using the EUVAC model. Simulations with the SOLID spectrum show the better agreement of foF2 with the empirical model IRI-2007 at the maximum solar activity. At the same time, at the minimum solar activity, all models of the spectrum provide an underestimation of the values of the critical frequency of the F2 layer.

Journal of Geophysical Research: Space Physics, 2015

This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturban... more This paper presents a study of mesosphere and low thermosphere influence on ionospheric disturbances during 2009 major sudden stratospheric warming (SSW) event. This period was characterized by extremely low solar and geomagnetic activity. The study was performed using two first principal models: thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) and global self-consistent model of thermosphere, ionosphere, and protonosphere (GSM TIP). The stratospheric anomalies during SSW event were modeled by specifying the temperature and density perturbations at the lower boundary of the TIME-GCM (30 km altitude) according to data from European Centre for Medium-Range Weather Forecasts. Then TIME-GCM output at 80 km was used as lower boundary conditions for driving GSM TIP model runs. We compare models' results with ground-based ionospheric data at low latitudes obtained by GPS receivers in the American longitudinal sector. GSM TIP simulation predicts the occurrence of the quasi-wave vertical structure in neutral temperature disturbances at 80-200 km altitude, and the positive and negative disturbances in total electron content at low latitude during the 2009 SSW event. According to our model results the formation mechanisms of the low-latitude ionospheric response are the disturbances in the n(O)/n(N 2) ratio and thermospheric wind. The change in zonal electric field is key mechanism driving the ionospheric response at low latitudes, but our model results do not completely reproduce the variability in zonal electric fields (vertical plasma drift) at low latitudes. Although importance of PW in generating ionospheric disturbances during SSW is suggested in early studies [Goncharenko et al., 2010a, 2010b; Pedatella and Forbes, 2010; Fejer et al., 2011], exact mechanisms are a subject of active research due to a variety and complexity of interactions of planetary waves with tides, gravity waves, and mean flow. Several mechanisms can modify thermospheric tides and through E region dynamo generate KLIMENKO ET AL.

Journal of Atmospheric and Terrestrial Physics, 1996

A global numerical model of the Earth's upper atmosphere has been used to simulate numerically th... more A global numerical model of the Earth's upper atmosphere has been used to simulate numerically the behavioar of the ionosphere observed by EISCAT on 24-25 March 1987 when the quiet day of 24 March was followed by the disturbed day of 25 March, with a Sudden Commencement (SC) starting about 1540 UT. We have selected the model input data for the auroral precipitating particle fluxes and the fieldaligned currents to obtain an acceptable agreement between the calculated and observed ionospheric variations. A rather good similarity between the calculated and observed variations of the electric field, Eregion electron concentration, F2-region ion temperature and electron concentration has been found. Spatial distributions of the electric potential and F2-region electron concentration and ion temperature have been obtained. The dynamics of the main ionospheric trough during the disturbed period has been investigated. It has been found that the equatorward movement of the midnight part of the trough is connected with the enhanced plasma transport, while the apparent westward and eastward movements of the evening and morning edges of the trough are connected with the "hot spots" caused by Joule heating of the ion gas.

Russian Journal of Physical Chemistry B, 2019

This article presents the main stages of the development of a new model, the entire atmosphere (E... more This article presents the main stages of the development of a new model, the entire atmosphere (EAGLE). We describe the models of the lower,middle, and upper atmospheres that constitute EAGLE and present the way we coupled. The results of the EAGLE model confirm that the four-peak longitude variation and the evening surge of the eastern electric field at the equator are consequences of the atmosphere-ionosphere interaction. This result illustrates that the EAGLE model is an useful tool for studying the influence of the atmosphere on the electric field in the equatorial ionosphere.

Russian Journal of Physical Chemistry B, 2017

We consider different approaches to calculating the ion composition in the lower ionosphere and u... more We consider different approaches to calculating the ion composition in the lower ionosphere and use two methods for modeling the concentration of molecular ions. The first method allows us to solve an equation with an effective recombination coefficient for the total concentration of molecular ions, and the second method calculates their concentrations separately. Numerical experiments were performed using a global self-consistent model of the thermosphere, ionosphere, and protonosphere (GSM TIP) for the conditions of March 16–20, 2015. We show that the second method, which provides a more accurate approximation, leads to significant consequences. Due to a strong change in the calculated concentration of ions in the E-region, the conductivity varies thus affecting the qualitative and quantitative behavior of the electric dynamo field at low and equatorial latitudes. Even without mesospheric tides and the electric dynamo field in the F-region, the calculation of partial concentration...

Russian Journal of Physical Chemistry B, 2020

Abstract Since 1964, the Kaliningrad branch of Pushkov Institute of Terrestrial Magnetism, Ionosp... more Abstract Since 1964, the Kaliningrad branch of Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences (IZMIRAN) has been conducting regular observations of the parameters of the lower atmosphere, ionosphere, and variations in the Earth’s magnetic field. The base of the measuring equipment, located in Ulyanovka village, Kaliningrad region (54° N, 20° E) consists of ionosonde for the vertical sounding of the ionosphere; two-frequency GPS/GLONASS receivers, which are used to determine the total electron content in the ionosphere; magnetic variation stations for the continuous recording of variations of the three components of the Earth’s magnetic field vector and calculating the local K -index; and a weather station. The simultaneous observations of variations in the magnetic field, as well as the ionospheric and meteorological parameters in the same observatory, offer a wide range of opportunities to study the atmospheric-ionospheric relations. This article provides a brief description of all the tools, provides a method for transmitting and storing the time series of measured parameters, and also presents examples of using these data for various geophysical studies.

Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2020

The paper presents the investigation of the Global Electron Content (GEC) variability during a ma... more The paper presents the investigation of the Global Electron Content (GEC) variability during a major Sudden Stratospheric Warming (SSW) event in January 2009. The two-hour values of the GEC obtained from the GIM, as well as the GEC calculated in the EAGLE and GSM TIP models, were used as initial data. It has been shown that during SSW event the amplitude of diurnal variations in GEC decreases and the amplitude of semidiurnal variations increases. GEC variability during SSW event increases, as well as during the small geomagnetic disturbance that occurred on January 26, 2009.

Geomagnetism and Aeronomy, 2021

A study of the wave changeability in the F2-layer critical frequency over Kaliningrad (54.6° N, 2... more A study of the wave changeability in the F2-layer critical frequency over Kaliningrad (54.6° N, 20° E) and Irkutsk (53° N, 103° E) stations during strong sudden stratospheric warmings is presented. Low solar activity was a common factor for all selected cases. The results of wavelet analysis of the time variations in foF2 showed that an amplification of the oscillations with periods of 4-10 days occurred in the majority of the warmings within a period of 1965-2009. The amplitude of long-period (25-30 days) oscillations, vice versa, decreased. A similar analysis performed for the 1975-1976 winter, during which there were no warmings, showed that the amplitudes of the foF2 oscillations with periods of 25-30 days, conversely, were very stable and changed insignificantly. The amplification of the variability in the foF2 oscillation spectrum in other frequency ranges also is another manifestation of stratospheric warmings over Kaliningrad and Irkutsk.

Solnechno-Zemnaya Fizika, 2018

We present the results of complex obser-vations of various parameters of the middle and upper atm... more We present the results of complex obser-vations of various parameters of the middle and upper atmosphere over Siberia in December 2012 – January 2013, during a major sudden stratospheric warming (SSW) event. We analyze variations in ozone concentration from microwave measurements, in stratosphere and lower mesosphere temperatures from lidar and satellite measurements, in the F2-layer critical frequency (foF2), in the total electron content (TEC), as well as in the ratio of concentrations of atomic oxygen to molecular nitrogen (O/N2) in the thermosphere. To interpret the observed disturbances in the upper atmosphere, the experimental measurements are compared with the results of model calculations obtained with the Global Self-consistent Model of Thermosphere—Ionosphere—Protonosphere (GSM TIP). The response of the upper atmosphere to the SSW event is shown to be a decrease in foF2 and TEC during the evolution of the warming event and a prolonged increase in O/N2, foF2, and TEC after ...

Geomagnetism and Aeronomy, 2018

⎯The results of numerical experiments on the modeling of thermospheric and ionospheric disturbanc... more ⎯The results of numerical experiments on the modeling of thermospheric and ionospheric disturbances under conditions of sudden stratospheric warming are presented to study the possible mechanisms of such disturbances. Local disturbances caused by a planetary wave with zonal wave number s = 1 and internal gravity waves (IGWs) propagating from the disturbed region in the stratosphere are taken into account as sources of disturbances. It is shown that the inclusion of an additional source of thermospheric disturbances caused by mesospheric variations of atmospheric parameters with IGW periods over the region of sudden stratospheric warming leads to significant changes in the parameters of the thermosphere and ionosphere, including a change in the global structure of the distributions of the gas components of the thermosphere and a shift in maximum concentrations of atomic oxygen to low latitudes of the Southern Hemisphere; there is an increase in the mean values, the diurnal and semidiurnal variations of the ion concentration in the F region of the ionosphere. These features of changes in the parameters of the thermosphere and ionosphere occurred with insignificant disturbances of tidal variations in the thermosphere.