Level Of Solar Activity Research Articles

Density‐Temperature Synchrony in the Hydrostatic Thermosphere

AbstractThe paper presents a detailed analysis of the density‐temperature (ρ‐T) synchrony in the thermosphere using a hydrostatic general circulation model. The numerical models in general offer not only great potential for forecasting the transient response of the thermosphere but also are excellent tools for understanding the driving mechanisms of various thermospheric trends and features. This study investigates and isolates the dependency of the ρ‐T synchrony on the season, altitude, space weather, high‐latitude electrodynamics, and the lower atmospheric tidal spectrum. The results demonstrate that the previously reported ρ‐T synchrony begins around 300‐km (350‐km) altitude at the equator (high latitudes). The effect of the lower atmospheric tidal spectrum on the ρ‐T synchrony patterns seems to be only marginal and more noticeable during the equinox months. The study demonstrates that the ρ‐T phase lag is larger in the high latitudes of the summer hemisphere and evolves through the day and is attributable to ion drag and temperature fluctuations via soft particle precipitation. The study provides physical insights into how the winds contribute to the ρ‐T synchrony. In addition, the results show that geomagnetic activity contributes significantly to the ρ‐T synchrony; the underlying mechanism may be related to temperature enhancements in the high latitudes via Joule heating and associated nonlinear interactions. While the ρ‐T phase lags attributable to different solar activity levels are modest, the solar heating is the primary source that maintains the ρ‐T synchrony in the low/middle latitudes via upward propagating thermal tides.

Stanisław Pigoń wobec dyskursu regionalności

Autor podejmuje problem obecności wiejskich, chłopskich wątków we współczesnym dyskursieregionalności (tzw. małych ojczyzn). Osoba profesora Stanisława Pigonia, wybitnegouczonego i myśliciela, jest doskonałym łącznikiem z tradycją i aksjologią wsi, która nadalwpływa na poczucie tożsamości i zakorzenienia oraz stan świadomości wspólnot lokalnych.Tekst sytuuje tę problematykę na tle historycznym, wiąże ją z kształtowaniem się w XIXwieku na wsi nowej świadomości narodowej i społecznej, z ożywieniem politycznym i kulturalnym.Omawia w związku z tym zarówno rolę wielkich wydarzeń historycznych (np.powstanie wiejskiej legendy Tadeusza Kościuszki jako chłopskiego przywódcy), jak i wielkichprzywódców ruchu ludowego (np. Wincentego Witosa i Macieja Rataja) w szerzeniu postawobywatelskich i patriotycznych. Dzięki temu polski chłop stał się Polakiem. Autor śledzi teżwielkie zmiany w kulturze i świadomości wsi w okresie dwudziestolecia międzywojennegoi w czasach powojennych. Zwraca uwagę na aktualność przesłania Stanisława Pigonia, żepochodzenie wiejskie, lokalna kultura, gwara i tradycja jest wielką wartością, ważnym elementempoczucia tożsamości lokalnej i narodowej.

On Ionic Contributions to Pedersen Conductance

AbstractIonospheric conductivity is a key parameter to understand the upper atmosphere electrodynamics, magnetosphere‐ionosphere‐thermosphere coupling and several geophysical processes. In the case of Pedersen conductivity, ions and electrons are moving in opposite direction, so that it results from the addition of the separate contributions. In this work, the role of the three main ions, that is, NO+, O2+, and O+, in the conductivity height profile and in the conductance global pattern is analyzed for different solar activity levels and seasons. NO+ is the is the main contributor for the maximum conductivity in all the cases in the E layer; however, O+ takes relevance with a significant percentage of the conductance at certain regions such as the South Atlantic Anomaly and the crests at the equatorial ionization anomaly, becoming the main conducting ion in these zones when the solar activity is high. Regarding seasonal effects, the role of NO+ in the conductivity is maximum on summer hemisphere, while O+ becomes important in winter and maximum with high solar activity. O2+ has maximum percentage close to magnetic poles, where the magnetic field strength is intense lowering the peak conducting level.

Reconstruction of the Production Rate of Cosmogenic 14C in the Earth’s Atmosphere for 17 000–5000 BC

Carbon isotope 14С is produced in the Earth’s atmosphere by energetic cosmic-ray (CR) particles. The data on its atmospheric abundance are used to reconstruct the rate of its production and to analyze past levels of CR intensity and solar activity. These data are obtained via measurement of the 14С abundance in tree rings, with their real age determined dendrochronologically. The 14С abundance depends on the carbon dioxide concentration in the atmosphere and on climatic changes that affect the processes of carbon exchange between natural reservoirs. The present study reports the results of reconstruction of the production rate for cosmogenic 14С in the Earth’s atmosphere in the interval from the onset of deglaciation (~17 000 BC) to the mid-Holocene. The climatic factors mentioned above were taken into account in this reconstruction.

Strong solar flare detection and its impact on ionospheric layers and on coordinates accuracy in the Western Balkans in October 2014

Activities on the Sun’s surface can produce dynamic conditions in the Earth’s outer space environment, which can affect the Earth, space-borne and ground-based technologies, including Global Navigation Satellite Systems (GNSS). Delay of GNSS signal can occur during its propagation through the upper Earth’s atmosphere—the ionosphere, representing the major limitation in GNSS positioning applications. In this paper, high level of solar activity and intense bursts of radiation from the release of magnetic energy on the Sun, known as solar flares, are studied. The investigation covers the detection of events on the Sun’s surface, conditions in near-Earth’s space environment, geomagnetic field, ionosphere and GNSS positioning estimates. In October 2014, more than 200 solar flares were detected and about a quarter of total amount belonged to solar flares of M and X class. Impact on ionospheric layers is studied: D layer with SuperSID (sudden ionospheric disturbances) monitor and electron density to F2 layer with GNSS-derived total electron content. Used GNSS stations belong to EUREF Permanent Network (EPN) in Bosnia and Herzegovina and Croatia. Precise Point Positioning is performed in the Bernese GNSS Software. Solar radio emissions were high in the second half of the month, when more M and X solar flares occurred. Ionospheric electron density was enhanced, reaching its peak during the high level of solar activity and the period of strongest solar flares occurrence, while position estimates show higher deviations from the EPN weekly solution in Up component (at least for two times). Higher-order ionospheric terms remained after applying the L3 ionosphere-free solution, which should be taken into account in precise positioning during increased level of solar activity.

Evaluation of the IRI-2016 and NeQuick electron content specification by COSMIC GPS radio occultation, ground-based GPS and Jason-2 joint altimeter/GPS observations

We examined performance of two empirical profile-based ionospheric models, namely IRI-2016 and NeQuick-2, in electron content (EC) and total electron content (TEC) representation for different seasons and levels of solar activity. We derived and analyzed EC estimates in several representative altitudinal intervals for the ionosphere and the plasmasphere from the COSMIC GPS radio occultation, ground-based GPS and Jason-2 joint altimeter/GPS observations. It allows us to estimate a quantitative impact of the ionospheric electron density profiles formulation in several altitudinal intervals and to examine the source of the model-data discrepancies of the EC specification from the bottom-side ionosphere towards the GPS orbit altitudes. The most pronounced model-data differences were found at the low latitude region as related to the equatorial ionization anomaly appearance. Both the IRI-2016 and NeQuick-2 models tend to overestimate the daytime ionospheric EC and TEC at low latitudes during all seasons of low solar activity. On the contrary, during high solar activity the model results underestimated the EC/TEC observations at low latitudes. We found that both models underestimated the EC for the topside ionosphere and plasmasphere regions for all levels of solar activity. For low solar activity, the underestimated EC from the topside ionosphere and plasmasphere can compensate the overestimation of the ionospheric EC and, consequently, can slightly decrease the resulted model overestimation of the ground-based TEC. For high solar activity, the underestimated EC from the topside ionosphere and plasmasphere leads to a strengthening of the model underestimation of the ground-based TEC values. We demonstrated that the major source of the model-data discrepancies in the EC/TEC domain comes from the topside ionosphere/plasmasphere system.

Improvement of the IRI Model Using F2 Layer Parameters Derived From GPS/COSMIC Radio Occultation Observations

AbstractIn this study, an improved ionospheric model is presented by applying self‐specified F2 layer parameters and an adaptive topside model into the International Reference Ionosphere (IRI) model. Three F2 layer parameters, the critical frequency (foF2), peak height (hmF2), and the scale height (Hsc) obtained from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations, are modeled by spherical harmonics expansion. The empirical orthogonal functions are used to construct the associated parameters in the adaptive topside model. The improved model is validated by incoherent scatter radar (ISR) data of Millstone station and the Global Ionospheric Maps. Results show that the NmF2 and hmF2 of improved model have better agreement with ISR measurements. The vertical total electron content deviation compared with Global Ionospheric Map is discussed in different seasons and levels of solar activity. With radio occultation‐based parameters, the accuracy of original IRI model is improved by 1 total electron content unit globally on average.

Calibration of full‐disk He i 10 830 Å filtergrams of the Chromospheric Telescope

The Chromospheric Telescope (ChroTel) is a small 10‐cm robotic telescope at Observatorio del Teide on Tenerife (Spain), which observes the entire sun in Hα, Ca ii K, and He i 10 830 Å. We present a new calibration method that includes limb‐darkening correction, removal of nonuniform filter transmission, and determination of He i Doppler velocities. Chromospheric full‐disk filtergrams are often obtained with Lyot filters, which may display nonuniform transmission causing large‐scale intensity variations across the solar disk. Removal of a 2D symmetric limb‐darkening function from full‐disk images results in a flat background. However, transmission artifacts remain and are even more distinct in these contrast‐enhanced images. Zernike polynomials are uniquely appropriate to fit these large‐scale intensity variations of the background. The Zernike coefficients show a distinct temporal evolution for ChroTel data, which is likely related to the telescope's alt‐azimuth mount that introduces image rotation. In addition, applying this calibration to sets of seven filtergrams that cover the He i triplet facilitates the determination of chromospheric Doppler velocities. To validate the method, we use three datasets with varying levels of solar activity. The Doppler velocities are benchmarked with respect to cotemporal high‐resolution spectroscopic data of the GREGOR Infrared Spectrograph (GRIS). Furthermore, this technique can be applied to ChroTel Hα and Ca ii K data. The calibration method for ChroTel filtergrams can be easily adapted to other full‐disk data exhibiting unwanted large‐scale variations. The spectral region of the He i triplet is a primary choice for high‐resolution near‐infrared spectropolarimetry. Here, the improved calibration of ChroTel data will provide valuable context data.

Long-term changes in the concentration of radiocarbon and the nature of the Hallstatt cycle

Radiocarbon (C14) is formed in the atmosphere as a result of the interaction of thermal neutrons with nitrogen according to scheme n(14N,14C)p. The effectiveness of C14 formation depends on the local spectrum of cosmic rays (CR) penetrating into the atmosphere. The local CR spectrum is determined by the level of solar activity and is characterized by the solar modulation parameter (SMP). The efficiency of formation C14 also depends on the magnitude of the dipole moment (DM) of the geomagnetic field shielding the atmosphere from the CRs penetrating into it.C14 concentration varies cyclically with time. The most famous long-term cycles are the ∼2300-year (Hallstatt cycle) and the ∼210-year (de Vries cycle).Analysis of the radiocarbon series shows that there is an amplitude modulation of the ∼210-year cycle. The modulating signal has a main period of about 2300 years. The nature of this modulation is analysed. Is it related to changes in solar activity or to variations in the geomagnetic field?Two models of amplitude modulation of radiocarbon variations are considered. In the first model (AM-1), there is amplitude modulation of ∼210-year variations of the SMP with a period of 2300 years. As a result of the simulation, it is shown that the amplitude of the ∼210-year oscillations in the concentration of radiocarbon does not depend on the phase of the 2300-year modulation. This contradicts the observations.In the second case (AM-2), the modulation of ∼210-year variations of the SMP is absent. But the existence of ∼2300-year oscillations of the dipole moment is allowed. In the second case, unlike AM-1, the amplitude of the 210-year oscillations in the C14 production rate depends on the phase of the 2300-year variations in the dipole moment, which agrees with the observations.Based on the comparison of AM-1 and AM-2 models of amplitude modulation, it can be concluded that changes in the dipole moment of the geomagnetic field are responsible for the observed ∼2300-year variations in the concentration of radiocarbon.

Solar energetic particles and galactic cosmic rays over millions of years as inferred from data on cosmogenic26Al in lunar samples

Aims.Lunar soil and rocks are not protected by a magnetic field or an atmosphere and are continuously irradiated by energetic particles that can produce cosmogenic radioisotopes directly inside rocks at different depths depending on the particle’s energy. This allows the mean fluxes of solar and galactic cosmic rays to be assessed on the very long timescales of millions of years.Methods.Here we show that lunar rocks can serve as a very good particle integral spectrometer in the energy range 20–80 MeV. We have developed a new method based on precise modeling, that is applied to measurements of26Al (half-life ≈0.7 megayears) in lunar samples from theApollomission, and present the first direct reconstruction (i.e., without any a priori assumptions) of the mean energy spectrum of solar and galactic energetic particles over a million of years.Results.We show that the reconstructed spectrum of solar energetic particles is totally consistent with that over the last decades, despite the very different levels of solar modulation of galactic cosmic rays (ϕ= 496 ± 40 MV over a million years versus (ϕ= 660 ± 20 MV for the modern epoch). We also estimated the occurrence probability of extreme solar events and argue that no events with theF(>30 MeV) fluence exceeding 5×1010and 1011cm−2are expected on timescales of a thousand and million years, respectively.Conclusions.We conclude that the mean flux of solar energetic particles hardly depends on the level of solar activity, in contrast to the solar modulation of galactic cosmic rays. This puts new observational constraints on solar physics and becomes important for assessing radiation hazards for the planned space missions.

Gradient Path Labelling method and tracking method for calculation of solar differential rotation using coronal bright points

Abstract With new space missions, such as Solar Dynamics Observatory (SDO), solar images are being produced in unprecedented volumes. To derive, as much as possible, information on evolution of solar activity from those huge datasets, the scientific community needs a new generation of software tools for automatic and efficient data processing. In the last decade, several research teams have been developing tools for obtaining more precise estimations of the solar rotation profile, but more are needed to improve knowledge about solar activity. We applied here a segmentation algorithm called Gradient Path Labelling (GPL), used originally to identify drusens in medical retinal images, to detect and track the coronal bright points (CBPs) using images from the AIA instrument onboard the SDO satellite. The CBPs have a tendency to change shape and size along time, to disappear and reappear at a corresponding heliographic position, therefore, decision trees were also included in the tracking solution. Since our CBP detection algorithm uses an active region mask to filter out the CBPs, whose centroid is inside the active regions, the number of identifications clearly depends on the level of solar activity. Our approach uses the commonly applied fitting relation to the latitudinal dependence of the rotational velocity, which resulted in calculation of the optimum fit parameters as well as the Gegenbauer orthogonal polynomials. Comparison of these parameters with the results presented in recent papers on this topic shows that our rotational velocity profile indicates slightly lower rotational velocities than the profiles obtained with other approaches. We also calculate the meridional motion of the CBPs, but comparison with other authors results, clearly show that a 3-day time interval is too short to estimate the latitudinal dependence of the CBP meridional motion. Distributions of the rotational velocity and meridional motion velocity uncertainties show that 85% of uncertainty values are lower than 1 degree/day. The evaluation of our test results shows that the applied algorithm is a promising tool that can help to refine the solar rotational profile.

Evolution of Power Anisotropy in Magnetic Field Fluctuations at Different Solar Activity Levels

Adhikari et al [33] recently developed a theoretical model to study anisotropy in magnetic field fluctuations using a dimensional analysis relating the power spectrum of the energy-containing and inertial ranges. We use the Adhikari et al and Zank et al [31] models to study the evolution of the power anisotropy in magnetic field fluctuations in the energy-containing and inertial ranges at different levels of solar activity. We obtain initial conditions at 1 au for the times 2003, 2009, and 2015 from Zhao et al [37] by assuming an 80:20 ratio between the turbulence energies, and a 2:1 ratio between the correlation lengths. The years 2003 and 2015 correspond to solar maxima and the year 2009 to a solar minimum. We find that the anisotropy in magnetic field fluctuations evolves differently during the solar minimum than during the solar maximum throughout the heliosphere.

A Method of Forecasting Solar Activity Based on Radio Astronomical Observations

We present the results of forecasting flare activity based on the data from microwave spectropolarimetric observations of active regions (ARs) obtained with the RATAN-600 radio telescope and the X-ray data from the GOES satellite as well as monitoring data. The method is designed for short-term (1–3-days) flare forecasts. Proton events are considered as part of the general flare problem. Obtaining a reliable forecast is a difficult process in view of the multi-parameter and multi-dimensional system of plasma parameter variations and multiple non-linear interconnections.We used a modified Tanaka–Enome criterion, as well a database of observational material collected over many years. The forecasting efficiency was analyzed depending on the threshold values of the criterion. We show that the quality of the radio astronomical forecast is determined by the level of sensitivity of the detector at short centimeterwavelengths and by the solar activity level.

The Umbra–Penumbra Area Ratio of Sunspots During the Maunder Minimum

Abstract The Maunder Minimum (MM) was a prolonged period of low solar activity that occurred between 1645 and 1715. The true level of solar activity corresponding to this epoch is still a matter of debate. In order to compare solar activity during the MM with that of other epochs, we have evaluated the umbra–penumbra area ratio (U/P hereafter) during the MM. Thus, we have analyzed 196 sunspot drawings, including 48 different sunspots observed during the period 1660–1709. The mode value of the ratio obtained from the occurrence frequency distribution lies between 0.15 and 0.25. Furthermore, the median and mean values are equal to 0.24 ± 0.07 and 0.27 ± 0.08 with a sigma clipping, respectively. These results are consistent with recent research using more modern data. Higher U/P values mean faster sunspot decay rates. From our results, the absence of sunspots during the MM could not be explained by changes in the U/P since the values of the ratio obtained in this work are similar to values found for other epochs.

Automatic Detection of Sunspots on Full-disk Solar Images Using the Simulated Annealing Genetic Method

Sunspots with strong magnetic fields are the most important manifestations of solar activity, appearing as dark features in the photosphere observed in continuum images. We proposed an artificial intelligence technology called the simulated annealing genetic (SAG) method, which combined the genetic algorithm and simulated annealing algorithm to self-adaptively derive dual thresholds for detecting the umbra and penumbra of sunspots simultaneously. Full-disk continuum intensity images obtained from Solar Dynamics Observatory/Helioseismic Magnetic Imager (HMI) at a cadence of four hours from 2010 May to 2016 December were used. The detection results showed that the dual thresholds derived by the SAG method have outstanding performance in segmenting the umbra and penumbra from the photosphere with a satisfactory robustness efficiently. The boundaries of the umbra and penumbra were finely delineated, even for sunspots at the extreme solar limb. The total sunspot areas, umbral areas, and penumbral areas match very well with the data reported from HMI Debrecen Data (HMIDD), with the correlation coefficients reaching 0.99, 0.99, and 0.95, respectively. The mean ratios of umbra to sunspot areas per year ranged from 0.159 to 0.233. The ratios decreased with an increase in solar activity, which implies that the ratio was related to the solar activity level.

Delayed response of the ionosphere to solar EUV variability

Abstract. Physical and chemical processes in the ionosphere are driven by complex interactions with the solar radiation. The ionospheric plasma is in particular sensitive to solar EUV and UV variations with a time delay between one and two days. This delay is assumed to be related to thermospheric transport processes from the lower ionosphere to the F region. In previous analyses, the delay has been investigated using the F10.7 index. Here we present preliminary results of the ionospheric delay based on a comprehensive and reliable database consisting of GNSS TEC Maps and EUV spectral flux data. We plan to specify the various dependencies from geographic/geomagnetic location, altitude, season, local time, geophysical and solar radiation conditions such as the solar activity level. The first results for dependencies from seasons and wavelengths regions of the EUV are presented in this paper. These results can provide more insight into ionospheric processes and are of interest for applications dependent on reliable ionospheric weather forecasts, e.g. GNSS error analyses, prediction and mitigation.

Plasma Dynamics Associated With Equatorial Ionospheric Irregularities

AbstractThe Communication/Navigation Outage Forecasting System satellite was operational from 2008, a period of deep solar minimum, to 2015, a period of moderate solar conditions. The behavior of the vertical plasma drift and the distribution of plasma depletions during the deep solar minimum of 2009 deviated substantially from the behavior that was observed during the solar moderate conditions encountered by the Communication/Navigation Outage Forecasting System satellite in 2014, which are typical of previous observations. Presented here are observations of the vertical drift of plasma depletions and the background plasma in which they are embedded. We find that depletions detected at local times after 2100 hr during solar minimum are typically found in background drifts that are weakly downward compared to the strongly downward background drifts observed during moderate solar activity levels. Additionally, at solar minimum, the drift within the depletions is upward with respect to the background as compared with observations at the same local times during solar moderate conditions for which the depleted plasma more nearly drifts with the background. We note that weak background plasma drifts observed throughout the night during solar minimum promote the continued growth of depletions that may evolve more slowly or be continuously generated to appear in the topside in the postmidnight hours.

The performance of the IRI-Plas model as compared with Alouette II and GIM-TEC data over the midlatitude station Alma-Ata

Climatic ionospheric models present an important medium for both investigation of physical structure and correction of detrimental effects of ionospheric variability on space based communication, navigation and positioning systems. International Reference Ionosphere Extended to Plasmasphere (IRI-Plas) is one of the empirical models that can provide ionospheric layer parameters and electron density profiles up to GPS satellite orbital height of 20,200 km. IRI-Plas can input not only F2 layer critical parameters, foF2 and hmF2, but also the Total Electron Content (TEC) values. In this study, Ne(h)-profiles and TEC values obtained from the IRI-Plas model are compared with topside Alouette II satellite profiles and Global Ionospheric Map (GIM) TEC values, respectively. The satellite Ne(h) profiles are averaged over a midlatitude region for various seasons of 1966 and 1969. It is observed that IRI-Plas is in good agreement with Alouette profiles between 300 km and 500 km. After 500 km up to 2000 km, the profiles seem to differ where IRI-Plas Ne(h) usually overestimates the Alouette profile. When IRI-Plas TEC is compared with GIM-TEC, it is observed that model TEC generally overestimates the GIM-TEC values during daytime hours. The lowest ΔTEC values (10–20%) are observed in March and September, and the highest values are observed in the months of January (around 30%) and July (up to 67%). During nighttime, the IRI-Plas model results mainly underestimate the observational ones, up to 30% in equinoctial months, and with ±10% discrepancies in January and July. Since the IRI-Plas model can scale foF2 and hmF2 values using an external TEC input by equating instantaneous and median slab thickness (TEC/NmF2 ratio), the correlation between GIM-TEC and ionosonde NmF2 values measured at the midlatitude station Alma-Ata located at [43.25°N, 76.92°E] is obtained for various seasons during 1999, 2000, 2008, 2009 and 2012. The study showed a positive correlation for all seasons and levels of solar activity. The correlation coefficients between the data sets were very high (greater than or equal to 0.79) for hourly data and (greater than or equal to 0.91) for monthly-medians at a significance level of 5%. Thus, for the practical applications, the correlation results can be used to update slab thickness model of IRI-Plas which will lead to better scaling of foF2 and hmF2 values and plasmaspheric Ne(h)-profile with external instantaneous TEC input.

Experiences with a three-current ionization chamber as primary detector standard for absolute calibration in space.

With ISS-SOLAR-SolACES, a new approach in terms of calibrating solar spectral irradiance (SSI) data was validated during the mission period from 2008 to 2017: an ionization chamber (IC) as primary detector standard, operated in space, allowed daily calibration measurements. Though primary photo-ionization efficiencies and higher-order ionization effects from photoelectrons are constant with time, filter transmissions and signal contributions from solar x-rays are to be determined for the SSI data evaluation, requiring a deeper investigation. The experiences made with ionization chambers in the laboratory and aboard the ISS-SOLAR-SolACES mission are presented. They include the determination of higher-order ionization effects, the measured transmission of the filters with time, and the treatment of the solar soft x-ray background. Recommended combinations of IC filling gases and filter materials as well as laboratory and in-space measurements will provide correction procedures for different levels of solar activity to achieve further improvement of SSI data accuracy in the spectral range from 1nm to 133nm. Results and Perspectives. The usage of the IC technology aims for establishing absolute SolACES-type calibration equipment in space, providing reference SSI data sets in solar and solar-terrestrial science, as well as in related applications such as global navigation satellite system signal evaluation.

Influence of Solar Activity on Penetration of Traveling Planetary‐Scale Waves From the Troposphere Into the Thermosphere

AbstractIn this study, numerical simulations of planetary‐scale waves (PSWs), generated in the troposphere, were performed for altitudes from the Earth's surface up to 300 km. The influence of thermospheric effects of solar activity (SA) on the amplitudes and phases of westward traveling PSWs with zonal wave numbers 1 and 2 and periods 4–16 days propagating from the troposphere was simulated. Such simulations for a large number of PSW modes in the thermosphere were made for the first time. The effects of SA changes at altitudes above 100 km were involved in the general circulation model MUAM. The ionospheric conductivities for minimum and maximum SA levels were included into the MUAM. The simulation results were averaged over two ensembles of model runs with different PSW phases for conditions corresponding to the high and low SA levels for January–February. PSW atmospheric refractivity index and Eliassen‐Palm flux were calculated. They correspond to simulated changes in PSW amplitudes. Changes in the zonal velocity and temperature caused by the SA variations can modify spatial distributions of the westward traveling PSWs. Wave amplitudes significantly (up to 100%) decrease at the thermospheric heights under high SA, which is accompanied by decreasing vertical component of the Eliassen‐Palm flux. The 7‐, 10‐, and 16‐day PSWs could have larger partial reflection and worse propagation conditions than the 4‐ and 5‐day waves in the Southern Hemisphere under the high SA. At altitudes below 100 km, minor differences in zonal velocity and PSW amplitudes between high and low SA are found.