Journal of Geophysical Research: Space Physics最新文献

{"title":"Comparison of F-Region Ion Velocities Measured by Swarm Satellites and EISCAT Radars","authors":"M. L. Mekuriaw,&nbsp;A. T. Aikio,&nbsp;L. Cai,&nbsp;H. Vanhamäki,&nbsp;I. I. Virtanen,&nbsp;S. Buchert,&nbsp;N. Ivchenko,&nbsp;W. Miloch,&nbsp;Y. Jin,&nbsp;D. Knudsen,&nbsp;J. K. Burchill","doi":"10.1029/2025JA034422","DOIUrl":"https://doi.org/10.1029/2025JA034422","url":null,"abstract":"<p>Ionospheric ion flow velocities measured by the Swarm satellites are compared with the ion velocities estimated from the European Incoherent Scatter (EISCAT) radar measurements in Tromsø and on Svalbard. A comparison is carried out between the cross-track horizontal ion velocity component given by the Swarm Electric Field Instrument and the corresponding component by the EISCAT radars. This paper describes the comparison procedure between the two very different measurement methods and discusses the challenges in the comparison. Several events are found with eastward or westward ion flow channels that exceed 1,000 m/s. The example events shown occur between the Region 1 and 2 current sheets in the afternoon and post-midnight sectors, and one event in the vicinity of the dayside cusp. However, since the flow channels are relatively narrow and short-lived, it is difficult to capture the ion flow channel by ground-based radar measurements. A Linear fit for the selected conjunction events shows that on average, the Swarm ion velocities are larger than EISCAT ion velocities by a factor of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>1.34</mn>\u0000 <mo>±</mo>\u0000 <mn>0.07</mn>\u0000 </mrow>\u0000 <annotation> $1.34pm 0.07$</annotation>\u0000 </semantics></math>. The main reason for the smaller ion velocity estimates by EISCAT compared to Swarm is likely the coarser spatial and temporal resolution of the radar experiment, which prevents measurement of the narrow ionospheric flow channels. Ion composition at Swarm altitudes may also play a minor role by affecting the standard Swarm analysis velocity values.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA034422","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366333","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":"Northern Crest Weakening Induces Large-Scale Hemispheric EIA Disappearance in GOLD Observations During a Storm","authors":"Kun Wu,&nbsp;Liying Qian,&nbsp;Fuliang Xiao,&nbsp;Si Liu,&nbsp;Ji Luo,&nbsp;Xuguang Cai,&nbsp;Guochun Shi","doi":"10.1029/2025JA034385","DOIUrl":"https://doi.org/10.1029/2025JA034385","url":null,"abstract":"<p>The equatorial ionization anomaly (EIA) is a crucial phenomenon for understanding the ionospheric dynamics. However, the discrepancies in observations from different instruments resulting from the north-south EIA differences remain unreported and understudied. Here, we present the first comprehensive observation of a large-scale single-peak EIA event, detected by the Global-scale Observations of the Limb and Disk (GOLD) mission from longitude ∼−80° to ∼−20° during a storm. However, total electron content (TEC) observations and Whole Atmosphere Community Climate Model-eXtended (WACCM-X) simulations show that the single-peak EIA observed by GOLD is not a real single-peak structure. WACCM-X simulations reveal that the rapid weakening of the northern crest west of 20°W makes the OI 135.6 nm emission undetectable by GOLD, resulting in an unrealistic single-peak EIA in GOLD observations. This weakening is attributed to downward plasma transport by neutral winds dominating over upward plasma transport by <i>E</i> <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>×</mo>\u0000 </mrow>\u0000 <annotation> ${times} $</annotation>\u0000 </semantics></math> <i>B</i>, which lowers the F-region peak electron density height (hmF2) altitude and accelerates recombination. In addition, disturbance dynamo electric field caused by geomagnetic storms should have played an important role in the processes mentioned above. This study reveals unique EIA evolution dynamics and exposes limitations in single-data set observations, establishing multi-instrument validation as essential for EIA characteristic investigations.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366340","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":"Identifying Scales of the Ionospheric Structure Through Scintillation Events","authors":"K. Meziane,&nbsp;A. M. Hamza,&nbsp;K. Song,&nbsp;P. T. Jayachandran","doi":"10.1029/2025JA034326","DOIUrl":"https://doi.org/10.1029/2025JA034326","url":null,"abstract":"<p>In the polar regions, ionospheric electron density structures are known to develop as a result of plasma instabilities driven by currents and pressure gradients. These plasma structures are typically investigated through in situ observations using instruments aboard spacecraft and rockets. In addition, measurements recorded by ground-based Global Navigation Satellite System GNSS receivers provide valuable indirect data about the impact of ionospheric irregularities on the propagation of radio waves emitted by satellites. At high latitudes, the Canadian High Arctic Ionospheric Network records fluctuations in the amplitude of trans-ionospheric radio signals from GNSS satellites, which are then analyzed to determine the characteristic length scales of the ionospheric plasma. Probability distributions of these fluctuations are constructed across frequency ranges. The distributions are found to be well-described by the Castaing function, which was introduced in the context of fluid dynamics to describe the distribution of velocity fluctuations in two-dimensional neutral fluid turbulence. Our analysis reveals that the Castaing distribution scale parameter decreases as the frequency of amplitude fluctuations increases, meaning that only high-frequency amplitude fluctuations conform to Gaussian statistics. For some scintillation event cases, a Gaussian distribution is observed at frequency scales where the signal power density level falls below the instrumental noise level. The results of our study suggest that the radio wave propagation occurred through an ionospheric layer with a weak electron density gradient, yet abundant in small-scale electron density structures. These results also suggest that a plasma dynamical equilibrium is reached only when small scales dominate the interaction processes in the plasma.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366265","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":"Nightside Ionospheric Oxygen Outflows During Geomagnetic Storms: Van Allen Probes Statistics","authors":"C.-N. Chen,&nbsp;Q.-G. Zong,&nbsp;Z.-Y. Liu","doi":"10.1029/2025JA034349","DOIUrl":"https://doi.org/10.1029/2025JA034349","url":null,"abstract":"<p>Oxygen ions (O+) contribute dominantly to the energy density of the ring current during geomagnetic storms, thereby driving the evolution of storms. The majority of magnetospheric oxygen ions originate from the high latitude ionosphere in the form of ionospheric outflows. In this work, we employ Van Allen Probes data from January 2013 to December 2018 to analyze ionospheric oxygen outflows during storms. A superposed epoch analysis discovered that the statistical oxygen ion fluence enhanced more than twice during storms, with the total outflow rate reaching 4.36 × 10²⁴ s⁻¹ in the main phase and 2.34 × 10²⁴ s⁻¹ in the recovery phase compared to 0.46 × 10²⁴ s⁻¹ in quiet times. An examination of the magnetic latitude-local time distributions of these outflows indicates that this enhancement stems from both an increase in outflow flux at specific locations and an increase in the area of outflow. Statistical analysis shows that the ionospheric footprints of these outflows migrate equatorward with increasing geomagnetic activity. However, the equatorward expansion of the auroral oval is more pronounced, resulting in a growing proportion of outflows originating from within the auroral oval as geomagnetic activity develops. Further investigation of the geomagnetic indices combining local magnetic and electric fields relates this enhancement to: (a) the increased geomagnetic disturbance during storms; (b) enhanced plasma waves in the ultra-low-frequency range and near oxygen ion gyrofrequency, whose power shows a positive correlation with oxygen outflow rates. Besides, the distributions by season show that the total outflow rate more than doubles in local summer compared to other seasons.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366334","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":"Comparison Study of Upper Stratosphere and Lower Mesosphere Temperature Climatology Over Beijing (40.5°N, 116.2°E) and Haikou (19.9°N, 110.3°E), China With Rayleigh Lidar and TIMED/SABER Measurements","authors":"Yuxuan Wu,&nbsp;Zelong Wang,&nbsp;Kexin Wang,&nbsp;Wenhao Ruan,&nbsp;Lifang Du,&nbsp;Haoran Zheng,&nbsp;Jing Jiao,&nbsp;Zhiqing Chen,&nbsp;Yuchang Xun,&nbsp;Guotao Yang","doi":"10.1029/2025JA033948","DOIUrl":"https://doi.org/10.1029/2025JA033948","url":null,"abstract":"<p>The observation and study of middle atmospheric temperatures play a crucial role in understanding various complex dynamical and radiative processes. Based on Rayleigh lidar measurements from Beijing (40.5°N, 116.2°E) and Haikou (19.9°N, 110.3°E) in 2022 and 2023, over a total of 249 and 139 nights comprising 2,237 and 1,276 hr, respectively, this study analyzes and compares the atmospheric temperature variation characteristics between 30 and 60 km in the middle and low latitudes. The results reveal significant differences in temperature variations between the two locations. The monthly mean stratopause temperature over Beijing varies between 253 and 267 K, exhibiting an annual oscillation (AO). In contrast, the stratopause temperature over Haikou varies between 263 and 273 K, showing a semi-annual oscillation (SAO). The temperatures are used to derive the seasonal variation of lapse rate (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mo>∂</mo>\u0000 <mover>\u0000 <mi>T</mi>\u0000 <mo>‾</mo>\u0000 </mover>\u0000 <mo>/</mo>\u0000 <mo>∂</mo>\u0000 <mi>z</mi>\u0000 </mrow>\u0000 <annotation> ${-}mathit{partial }overline{T}/mathit{partial }z$</annotation>\u0000 </semantics></math>) and the buoyancy frequency square (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>N</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${N}^{2}$</annotation>\u0000 </semantics></math>). The lapse rate and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>N</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${N}^{2}$</annotation>\u0000 </semantics></math> in both locations exhibit an annual oscillation, with summer extrema in the upper stratosphere and lower mesosphere. Beijing has greater stability in the lower mesosphere, while Haikou shows higher stability in the upper stratosphere. Using the SABER kinetic temperature data set from 2023, which spans 50°S–50°N and 180°W–180°E, it was found that the boundary between AO and SAO in stratopause temperature is located around 28°N and 18°S, respectively, highlighting an asymmetric structure between the Northern and Southern Hemispheres, which is potentially driven by the stronger intensity of AO in the Southern Hemisphere. This work enhances the understanding of the relationship between the seasonal variations of stratopause temperature and geographical latitude.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317387","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":"Medium-Scale Traveling Ionospheric Disturbances Observed by Nadir-Viewing 630 nm Airglow Imaging From the International Space Station","authors":"Yuta Hozumi,&nbsp;Akinori Saito,&nbsp;Michi Nishioka,&nbsp;Takeshi Sakanoi,&nbsp;Jia Yue,&nbsp;Min-Yang Chou,&nbsp;Satoshi Andoh,&nbsp;Atsushi Yamazaki,&nbsp;Yuichi Otsuka,&nbsp;Kazuo Shiokawa","doi":"10.1029/2025JA034097","DOIUrl":"https://doi.org/10.1029/2025JA034097","url":null,"abstract":"<p>Nighttime medium-scale traveling ionospheric disturbances (MSTIDs) were investigated for wave parameters, occurrence, and seasonal–longitudinal climatology using 630 nm OI airglow from the Visible and Near-Infrared Spectral Imager (VISI) aboard the International Space Station. Although MSTIDs are widely studied from the ground, their global behavior remains less understood due to limited geographic coverage. We present new insights into MSTID climatology derived from spaceborne measurements. VISI's two fields of view, pointing forward and backward from nadir, enable discrimination of ionospheric signals from ground-based light contamination. Case studies show that the two views capture subtle structural differences consistent with an equatorward-tilted vertical geometry of MSTIDs. Comparisons with simultaneous total electron content from Japanese nationwide global navigation satellite system receiver network and with all-sky airglow imagers of the Optical Mesosphere Thermosphere Imagers network reveal that measured wave parameters—wavelength, wavefront orientation, phase speed, and amplitude—agree with established MSTID characteristics. Analysis of 3 years (2013–2015) of VISI data yielded 676 MSTID events across both hemispheres, exhibiting strong seasonal and longitudinal variations. Local summer maxima and activity enhancements appear in regions with high sporadic-E (Es) occurrence. In the Northern Hemisphere, the primary peak occurs around the June solstice, with particularly high rates in the Asia–west Pacific sector. In the Southern Hemisphere, a semiannual pattern emerges, featuring a primary peak during the December solstice and a secondary peak during the June solstice in the same Asia–west Pacific sector. These findings suggest Es-related E–F coupling plays a key role in MSTID generation, with conjugate-hemisphere coupling further modulating global distribution.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317386","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":"The Impact of the 10 December 2023 ICME Event on Martian Space Environment and Ion Escape Processes: A Multi-Fluid Hall-MHD Study","authors":"Zehan Yang,&nbsp;Haoyu Lu,&nbsp;Shibang Li,&nbsp;Nihan Chen,&nbsp;Yihui Song,&nbsp;Jianxuan Wang,&nbsp;Yuchen Cao,&nbsp;Jianing Zhao,&nbsp;Hanbo Yang","doi":"10.1029/2025JA034387","DOIUrl":"https://doi.org/10.1029/2025JA034387","url":null,"abstract":"<p>Interplanetary coronal mass ejections (ICMEs), which originate from solar coronal mass eruptions, are frequently intense space weather events manifested as extremely intensified solar wind conditions. Such upstream disturbances tend to trigger dynamic alterations in the Martian space environment and exert a substantial influence on the corresponding ion escape processes. However, the physical mechanisms behind the enhanced ion escape rates during interplanetary CME (ICME) events remain unelucidated. By employing a global multi-fluid Hall magnetohydrodynamic model, this study investigates the impact of the 10 December 2023 ICME event on the Martian space environment and reveals the physical mechanisms driving the enhanced ion escape rate. Simulation results indicate that during the ICME event, the Martian space environment experiences significant compression, and the associated electromagnetic fields exhibit substantial enhancement. Concurrently, the global ion escape rate increases by a factor of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>5.6</mn>\u0000 </mrow>\u0000 <annotation> $5.6$</annotation>\u0000 </semantics></math>. By comparing the physical characteristics of the plume and magnetotail escape channels between the pre-ICME and the ICME-phases, it can be deduced that the increased ion escape through the plume is driven by the enhanced escape velocity accelerated by the stronger motional electric field. Meanwhile, the elevated ion escape rate in the magnetotail is attributed to the stronger Hall electric field and the increased ion density resulting from the strengthened day-to-night ion transport. These findings demonstrate that extreme space weather modulates ion escape from Mars by impacting its surrounding electromagnetic environments and associated plasma transport, providing a valuable perspective on the long-term evolution of the Martian atmosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317673","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":"Contrasting Latitudinal/Longitudinal Response of Equatorial Ionization Anomaly (EIA) Around ±\u0000 \u0000 \u0000 \u0000 75\u0000 °\u0000 \u0000 $mathbf{75}mathbf{{}^{circ}}$\u0000 Longitude Sectors During the 23–24 April 2023 Geomagnetic Storm","authors":"S. S. Rao,&nbsp;Nandita Srivastava,&nbsp;D. Chakrabarty,&nbsp;Monti Chakraborty","doi":"10.1029/2025JA034563","DOIUrl":"https://doi.org/10.1029/2025JA034563","url":null,"abstract":"<p>We present hitherto unreported contrasting latitudinal/longitudinal features of Equatorial Ionization Anomaly (EIA) during the geomagnetic storm of 23–24 April 2023, using Total Electron Content measurements around <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 <mn>75</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $pm 75{}^{circ}$</annotation>\u0000 </semantics></math> longitude sectors. Besides the change in the strength of EIA due to the storm-time Prompt Penetration and Disturbance Dynamo electric fields, a longitudinally elongated EIA over the Indian sector is observed along with a latitudinally expanded EIA over the American longitude sector during this storm. Early and late appearances of EIA are also observed, particularly over the American sector. Based on neutral wind data of Thermosphere Ionosphere Electrodynamic General Circulation Model, we suggest that the storm-time neutral wind dynamics over a given longitude sector have worked in tandem with storm-time electric fields to generate these contrasting EIA features. These results hold important clues for understanding the low-latitude ionosphere during space weather events under the combined effects of electric fields and neutral winds.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317672","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":"Strong Substorm Development From Polar-Cap Arc Laydown Along the Auroral Poleward Boundary","authors":"Larry R. Lyons,&nbsp;Yukitoshi Nishimura,&nbsp;Jiang Liu,&nbsp;Sneha Yadav,&nbsp;Ying Zou,&nbsp;William A. Bristow,&nbsp;Eric Donovan,&nbsp;Nozomu Nishitani,&nbsp;Kazuo Shiokawa,&nbsp;Keisuke Hosokawa","doi":"10.1029/2025JA034161","DOIUrl":"https://doi.org/10.1029/2025JA034161","url":null,"abstract":"<p>Meso-scale enhanced flow channels often extend across the polar cap from the dayside to the nightside auroral oval, where they enter the oval via localized reconnection and cause auroral oval disturbances. Examples here show such flows associated with azimuthally moving polar cap arcs that develop an equatorward portion that bends in the direction opposite to the arc's motion, becoming nearly parallel to the nightside auroral oval and possibly becoming an oval poleward boundary arc. The arcs then continue to move equatorward, and “lay down” along the auroral oval, leading to an explosive substorm onset (or expansion enhancement) that rapidly expands azimuthally with laying down of the arc, and later expands further with westward traveling surge sliding along the arc. This gives a longitudinally broad region of expansion-phase aurora, and a similarly broad magnetic depression, indicating large and broad substorm energy release. The surge sliding along the poleward boundary arc occurs at a higher latitude than the laydown portion of onset, so that sliding leads to later magnetic depressions at locations west of the initial onset and at higher latitudes. The polar cap arc appears to be pushed equatorward and westward (for By &gt;0) by the flow of new plasma moving across the polar cap, the arc being like a weather front that demarcates an advancing boundary between plasma regimes along polar cap field lines. The onset and expansion of the activity appear to be driven by the flow of this new plasma from the polar cap to the region of expansion phase activity.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317390","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":"Investigation of Thermospheric Horizontal and Vertical Neutral Winds via Tristatic Observations Over Alaska","authors":"M. J. Kim,&nbsp;Y. Nishimura,&nbsp;Y. Deng,&nbsp;C. Sheng,&nbsp;L. R. Lyons,&nbsp;M. G. Conde","doi":"10.1029/2024JA033631","DOIUrl":"https://doi.org/10.1029/2024JA033631","url":null,"abstract":"<p>Thermospheric-neutral winds in the F-region play a key role in the magnetosphere-ionosphere-thermosphere coupling system of the Earth. In this study, we reconstruct the full components of the thermospheric neutral winds, horizontal and vertical winds, using tristatic observations of line-of-sight (LOS) winds obtained from three Scanning Doppler Imager (SDI) instruments over Alaska. With the reconstructed neutral winds, we examine the meso-scale structures of 3D neutral winds inside the common volume of tristatic observations during the auroral activities observed by Time History of Events and Macroscale Interactions during Substorms (THEMIS) All Sky Imagers (ASI). Compared to the horizontal wind derived by the monostatic fitting, our reconstruction method provides better agreements of neutral wind features shown in LOS winds, including spatial maps of vertical winds. Our results also show the nonuniform wind flows in both horizontal and vertical directions during the auroral activities with fluctuations in both components within a few tens of minutes. The results indicate that the vertical and horizontal winds have more meso-scale features and rapid variations within the smaller horizontal domain (100 s of km) than those seen in earlier studies. The results also imply that the ion-neutral coupling plays an important role in generating the meso-scale structures of neutral winds.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145317207","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}