Journal of Geophysical Research: Space Physics最新文献

{"title":"Resonant Scattering of Radiation Belt Electrons by Discrete Multi-Frequency ELF/VLF Waves From Ionospheric Heating","authors":"Shanshan Chang,&nbsp;Weihua Luo,&nbsp;Zhengping Zhu","doi":"10.1029/2025JA034074","DOIUrl":"https://doi.org/10.1029/2025JA034074","url":null,"abstract":"<p>This study investigates the resonant interactions between artificial Extremely Low Frequency and Very Low Frequency waves, generated via modulated ionospheric heating, and energetic electrons in Earth's radiation belts. Using test particle simulations, we analyze how discrete multi-frequency waves (with characteristics derived from DEMETER observations) scatter electrons, examining the dependence on wave frequency, electron energy, and equatorial pitch angle. Key findings reveal that higher-frequency waves resonate with a broader range of electrons but at higher magnetic latitudes, while lower-frequency waves are more effective for pitch-angle scattering. Multi-frequency waves, even with modest amplitudes (e.g., 10 pT per frequency), significantly enhance diffusion rates, particularly for 100–300 keV electrons near the loss cone, achieving bounce-averaged pitch-angle diffusion coefficients of ∼10⁻⁴/s. The results demonstrate strong energy dependence, with sub-MeV electrons exhibiting higher scattering rates than MeV-range populations. Diffusion coefficients generally increase with equatorial pitch angle but exhibit non-monotonic fluctuations due to the detuning of lower-frequency components. These findings highlight the potential use of ionospheric heating to artificially modulate radiation belt dynamics and suggest that multi-frequency wave generation could optimize electron scattering efficiency. This study bridges observational data with theoretical modeling, providing insights for future experiments aimed at controlled electron precipitation.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concurrent Observations of Plasma Bubbles and Field-Aligned Irregularities in Low-Latitudes of China","authors":"Wei Jia,&nbsp;Yaxian Li,&nbsp;Gang Chen,&nbsp;Jiyao Xu,&nbsp;Chunxiao Yan,&nbsp;Shaodong Zhang,&nbsp;Kun Wu,&nbsp;Wanlin Gong,&nbsp;Pengfei Hu,&nbsp;Yuanlin Jia","doi":"10.1029/2025JA033788","DOIUrl":"https://doi.org/10.1029/2025JA033788","url":null,"abstract":"<p>The Hainan COherent scatter Phased Array Radar (HCOPAR) and the 630 nm All-Sky Airglow Imager conducted simultaneous observations of the bottom-side Field-Aligned Irregularities (FAIs) and the dissipative equatorial plasma bubbles (EPBs) at low latitudes of China on 23 September 2014 and 13 April 2015, respectively. The 3m-scale irregularities inside the EPBs in the different dissipation phases are compared. In the early phase of equatorial plasma bubble dissipation, the echo occurrence rate and intensity on the western wall of EPBs were much higher than those in other parts, which is attributed to the gradient drift instability on the western wall. It is also found that there is a kind of secondary instability making contributions to the generation of meter-scale irregularities in different parts of bubbles. In the later phase of dissipation, the FAIs echo occurrence rate and intensity in all parts of bubbles decreased greatly, especially the difference between those on the eastern and western walls became very small, and the echoes in the depletion center almost disappeared. It is suggested that due to the decrease in the density gradient in the bubbles and the slowdown of eastward drift of bubbles, the influence of gradient drift instability on the western wall weakened significantly. Besides, the low-frequency drift instability and the subsequent secondary instability were suppressed. This study has revealed more details about the roles of plasma instabilities in the different dissipation phases and shed light on the driving mechanisms of meter-scale irregularities inside the large-scale bubbles.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144624607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diffusive Equilibrium: Modeling Anisotropic Maxwellian and Kappa Field Line Distributions in Io's Plasma Torus Using Multi-Fluid and Kinetic Approaches","authors":"Edward G. Nerney","doi":"10.1029/2024JA033582","DOIUrl":"https://doi.org/10.1029/2024JA033582","url":null,"abstract":"<p>Modeling density distributions along Jupiter's magnetic field lines is essential for understanding the Io plasma torus, moon plasma interactions, and plasma throughout the magnetosphere. This study compares multi-fluid and kinetic approaches to diffusive equilibrium and the effects of different plasma distribution functions and anisotropy. We establish a nominal equatorial centrifugal radial model of plasma densities and temperatures in the Io plasma torus (5–10 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>J</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${R}_{J}$</annotation>\u0000 </semantics></math>) and define six cases representing combinations of distribution functions (Maxwellian, standard Kappa, product Kappa, and “Fried-Egg”) and anisotropy parameters. We are the first to apply this to the product bi-kappa distribution to determine the steady-state variation of densities and temperatures along field lines. Our results show that the choice of plasma distribution function significantly affects predicted densities and temperatures along field lines. Anisotropy in temperatures influences plasma density distributions, impacting scale heights and peak densities. Different assumptions lead to different predictions for plasma conditions at various latitudes, especially along field lines intersecting Io's and Europa's orbits. These findings highlight the importance of selecting appropriate plasma distribution models tailored to Jupiter's magnetospheric conditions. Accurate plasma modeling is crucial for interpreting observations and understanding wave propagation, energy transport, and magnetospheric processes. We demonstrate practical applications by calculating Alfvén speeds and travel times, simulating spectral emissions using the CHIANTI atomic database, and calculating <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>N</mi>\u0000 <msup>\u0000 <mi>L</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> $N{L}^{2}$</annotation>\u0000 </semantics></math> profiles to investigate diffusion processes. Our analysis aids in selecting suitable plasma distribution models for different regions within Jupiter's magnetosphere, supporting future studies of the Io plasma torus and its interactions with Jupiter's moons.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033582","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144606491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of the Coronal Magnetic Fields Estimated by Kink Oscillations and Extrapolation","authors":"K. Safna Banu,&nbsp;Ram Ajor Maurya,&nbsp;P. T. Jain Jacob,&nbsp;Ankit Kumar","doi":"10.1029/2025JA033747","DOIUrl":"https://doi.org/10.1029/2025JA033747","url":null,"abstract":"<p>A series of events featuring decaying Transverse Coronal Loop Oscillations is examined utilizing high-resolution observations from the Atmospheric Imaging Assembly on board Solar Dynamic Observatory and Extreme Ultraviolet Imager from Solar Terrestrial Relations Observatory twin spacecrafts, A (ahead) and B (behind). We used two distinct methods, coronal seismology and extrapolations, independently to assess the coronal magnetic field values within oscillating loops. For the coronal seismology, we performed stereoscopic tracing of coronal loops to obtain an accurate measurement of their lengths. Subsequently, we estimated the oscillation parameters such as amplitude, period, phase, and damping time. Using the periods of oscillations and loop lengths, we calculated average magnetic field values within the oscillating coronal loops, ranging from 12 to 146 G. On the other hand, we performed non-linear extrapolations to match field lines with the coronal loops, resulting magnetic field values between 54 and 187 G. Our findings indicate that extrapolated field lines exhibited slightly higher values than those obtained through coronal seismology, though both methods provided reasonable estimates of the magnetic field strengths in the analyzed coronal loops.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144606471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Robust Global Analysis of Mid-Latitude Ionospheric Trough Morphology","authors":"Brenna Royersmith,&nbsp;Delores Knipp,&nbsp;Greg Starr,&nbsp;Y. Jade Morton,&nbsp;Sebastijan Mrak,&nbsp;Qian Wu","doi":"10.1029/2024JA033605","DOIUrl":"https://doi.org/10.1029/2024JA033605","url":null,"abstract":"<p>This study characterizes the main ionospheric trough (MIT) using a newly implemented detection method applied to ground-based Global Navigation Satellite System data. The MIT is a region of plasma depletion occurring primarily in the nighttime sub-auroral F-region ionosphere. Analysis is based on ground-based ionosphere total electron content (TEC) measurements from 2012 to 2024 and is applied to both hemispheres. The data are sorted by geomagnetic condition and season. We characterize MIT dynamics and compare the results with previous studies. Detection algorithm limitations, hemispheric asymmetry, trough depth, boundary wall steepness and position are statistically quantified and visualized. Main conclusions include: (a) Automatic trough detection is highest during geomagnetically active winter in the northern hemisphere (NH). (b) This detection method creates synoptic views of the trough which we can use to demonstrate control of sub-auroral polarization streams (SAPS) over the dusk/afternoon sector and influence of storm onset on the MIT. (c) There is a noticeable morning preference for the southern hemisphere (SH) trough. (d) The dawn-side SH trough appears equatorward relative to the NH, potentially due to influence from polar convection patterns. The dusk-side NH trough appears slightly equatorward of the SH trough as a response to SAPS. (e) The deepest trough occurs during dawn hours and demonstrates more consistent longitudinal patterns during quiet local winter. (f) The steepest trough boundary is at the poleward wall with a positive gradient at 12–15 local time in NH summer. Synoptic maps illustrate asymmetries in the trough structure and the influence of density plumes.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033605","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144606538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hemispherically and Longitudinally Asymmetric Ionospheric Response to the 23–24 March 2023 Geomagnetic Disturbances at Three Pairs of Conjugate Stations","authors":"Mayur Choudhary,&nbsp;Bitap Raj Kalita,&nbsp;Bibek Rai,&nbsp;Dibyendu Chakrabarty,&nbsp;M. Le Huy,&nbsp;Dung Nguyen Thanh,&nbsp;K. Wang,&nbsp;K. Hozumi,&nbsp;Abhishek Baruah,&nbsp;Nazim Uddin Ahmed","doi":"10.1029/2024JA033520","DOIUrl":"https://doi.org/10.1029/2024JA033520","url":null,"abstract":"<p>The effects of the 23–24 March 2023 geomagnetic storm in the magnetically conjugate low-latitude ionosphere-thermosphere along the 72°E ± 5°, 95°E ± 5° and 130°E ± 5° sectors are presented. The Total Electron Content (TEC)/NmF2 data from ground stations as well as satellite data, and model simulations are utilized to investigate the hemispheric and longitudinal variations. For the India-East Asia region, the most prominent TEC variations manifested only on 24th March. In all the three sectors, the northern VTEC/NmF2 showed a stronger negative effect with maximum depletion over the low-middle latitude station Dibrugarh (∼75–80%). The TEC map generated from the South–East Asia low latitude network suggested an underdeveloped EIA along 100°E on 24th March. The vertical electron density profiles estimated from COSMIC RO confirmed the hemispheric and longitudinal asymmetry of the F2 layer density. The conjugate hemisphere F2 layer height variation was indicative of equatorward winds in the Southern Hemisphere and poleward winds in the Northern Hemisphere. SWARM B on 24th March not only recorded the hemispheric asymmetry in the topside but also indicated equatorward winds in the southern hemisphere. The Thermosphere-Ionosphere-Electrodynamics General Circulation Model and WAM IPE models underestimated, whereas the IRI overestimated the low latitude storm time TEC. The negative effect can be attributed to the Disturbance Dynamo Electric Field, whereas the asymmetric equatorward expansion of the thermospheric composition perturbation and winds may have led to the hemispheric asymmetry of the storm response. Therefore, a conjugate ionospheric response in three close-by sectors suggests a possible role of inter-hemispheric meridional winds in equinoctial conditions for the asymmetric effects.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144606537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of Electric Field Pulse and Particle Dynamics in Earth's Magnetosphere to Enhanced Solar Wind Dynamic Pressure With Varied IMF Directions: A Statistical Study","authors":"Xuan Zhou,&nbsp;Xinliang Gao,&nbsp;Quanming Lu,&nbsp;Rajkumar Hajra,&nbsp;Jiuqi Ma","doi":"10.1029/2024JA033701","DOIUrl":"https://doi.org/10.1029/2024JA033701","url":null,"abstract":"<p>The electric field pulses caused by enhanced solar wind dynamic pressure are particularly effective in energization and inward transport of relativistic electrons in Earth's radiation belt. Utilizing electric field and particle measurements by Van Allen Probes and near-Earth solar wind measurements, we have conducted a statistical analysis to investigate the responses of electric field pulses and particle dynamics to enhanced solar wind dynamic pressure under varied interplanetary magnetic field (IMF) directions. On Earth's dayside, the generation of electric field pulses is independent of the IMF direction. In contrast, on the nightside, electric field pulses are more easily excited under northward IMF than under southward IMF. Interacted with the electric field pulses, the responses of electrons and protons show a day-night asymmetry under southward IMF. The statistical results also indicate that proton flux variations mostly cluster on the post-dawnside (MLT ∼ 6–12), while electron flux variations show a slight preference for the pre-duskside (MLT ∼ 12–18) under some conditions. Moreover, the occurrence rate of proton flux variation is lower than that of electrons, and a clear change in proton flux usually appears in lower energy channels. Our study provides new insights into understanding the interaction between solar winds and magnetospheres of the Earth and other magnetized planets.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MHD Simulation Study on Quasi-Steady Dawn-Dusk Convection Electric Field in Earth's Magnetosphere","authors":"Yusuke Ebihara,&nbsp;Masafumi Hirahara,&nbsp;Takashi Tanaka","doi":"10.1029/2025JA033731","DOIUrl":"https://doi.org/10.1029/2025JA033731","url":null,"abstract":"<p>We investigated the large-scale, quasi-steady magnetospheric electric field by using global magnetohydrodynamic (MHD) simulations. When a southward interplanetary magnetic field was imposed, a large-scale, dawn-dusk electric field appeared in the magnetosphere. The dawn-dusk electric field on the dayside is quasi-steady, and can be approximately represented by a scalar potential, that is, an electrostatic field. However, the positive space charge dominates the duskside magnetosphere, while the negative space charge dominates the dawnside magnetosphere. The results suggest the following. (a) At least in the global MHD simulation, space charge accumulation in the magnetosphere alone cannot fully account for the dawn-dusk electric field. Instead, plasma motion plays a primary role in generating the dawn-dusk electric field as previously suggested. (b) Steady convection electric field can be established when plasma flow remains steady. Even under such steady conditions, magnetic energy is continuously transferred from the solar wind to the polar ionosphere, as manifested by integral curves of the Poynting flux vector. This unidirectional energy flow is associated with the convective plasma motion that produces the steady dawn-dusk electric field. (c) Despite the electric field being steady, dynamical processes persist within the magnetosphere. It is also suggested that the magnetosphere basically maintains dynamic equilibrium through a balance of unidirectional energy flow from the solar wind to the ionosphere. When dynamic equilibrium is partially disrupted, the electric field becomes inductive. For the large-scale convection electric field, whether the electric field is electrostatic or inductive depends on the state of dynamic equilibrium.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033731","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparisons Between the Global Ionosphere Thermosphere Model and HIWIND Measurements","authors":"A. J. Ridley,&nbsp;A. Alhothali","doi":"10.1029/2024JA033521","DOIUrl":"https://doi.org/10.1029/2024JA033521","url":null,"abstract":"<p>Neutral winds in the daytime middle thermosphere are difficult to measure. The High altitude Interferometer WIND Observation instrument made measurements of these winds from a balloon in the summers of 2011 and 2018 during both daytime and nighttime at high latitudes. This paper presents a study comparing HIWIND neutral winds to global ionosphere thermosphere model (GITM) results. The meridional winds from GITM matched the trends and magnitude of the measurements of HIWIND, while the zonal winds showed much more disagreement in general. However, there existed a strong shear in the GITM results. When results from ±5° latitude were considered, they mostly bound the zonal HIWIND measurements. This study showed that: (a) HIWIND was on the edge of the high-latitude convection region where strong shears in the zonal flow occurred. Placement of the ion drifts and the aurora are important in determining the neutral winds in this region. GITM simulations using idealized drivers showed very different results. (b) On three of the 4 days, GITM's dawn region winds didn't match the HIWIND or GOCE wind measurements. These indicate that the placement of the aurora and ion drifts may be incorrect, or GITM's balance between acceleration terms could be off. (c) Viscosity and gradient in pressure accelerations were dominant, but mostly opposite. Ion drag and Coriolis were smaller, but are important, especially when the other two terms cancel each other. Specification of high-latitude drivers (i.e., the electric potential and auroral precipitation) are critically important to modeling the thermospheric winds.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033521","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Composite of the Effects of Major Sudden Stratospheric Warming Events on Carbon Dioxide Radiative Cooling in the Mesosphere-Lower-Thermosphere","authors":"Akash Kumar,&nbsp;M. V. Sunil Krishna,&nbsp;Alok K. Ranjan","doi":"10.1029/2025JA033941","DOIUrl":"https://doi.org/10.1029/2025JA033941","url":null,"abstract":"<p>The major sudden stratospheric warming (SSW) events strongly influence the mean structure of the entire atmosphere, from the troposphere to the thermosphere. These events disrupt the compositional and thermal structure of the mesosphere and lower thermosphere (MLT), causing spatiotemporal variations in the concentration of trace species of this region. Currently, the role of dynamical changes during SSW events on radiative cooling in the MLT region is not well understood. An investigation of the SSW-induced changes in carbon dioxide (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math>) radiative cooling in the MLT region is presented by examining the changes in the dynamics and transport of key species, such as <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> and atomic oxygen (O). A composite analysis has been performed to understand these changes during the major SSW events that occurred between 2005 and 2020. The variation of trace species is found to be associated with the change in vertical residual circulation. The results also show that <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> radiative cooling decreases during the mesospheric cooling that occurs during the stratospheric warming over the polar region. During the recovery stage of the SSW event, the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> radiative cooling enhances in the mesosphere. These variations in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math> radiative cooling are mainly caused by temperature perturbations and oxygen transport in the MLT region. The contribution of temperature change and transport have also been investigated in detail.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 7","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144589521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}