Journal of Geophysical Research: Space Physics最新文献

{"title":"Responses of High-Latitude Mesopause Height and Temperature to Geomagnetic Storms","authors":"Meng Sun,&nbsp;Jianyong Lu,&nbsp;Jingyuan Li,&nbsp;Guanchun Wei,&nbsp;Zheng Li,&nbsp;Ningtao Huang,&nbsp;Mingming Zhan","doi":"10.1029/2024JA033624","DOIUrl":"https://doi.org/10.1029/2024JA033624","url":null,"abstract":"<p>The impact of geomagnetic storms on the mesopause structure, especially at high latitudes, has received limited attention. In this study, we analyze data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite to investigate how mesopause height and temperature respond to four intense geomagnetic storms: July 2003 (summer in the Northern Hemisphere, NH), July 2004 (winter in the Southern Hemisphere, SH), November 2004 (winter in the NH), and December 2006 (summer in the SH). Before the winter storms, the mesopause is located at approximately 95–100 km at high latitudes. Following the storms, it decreases by ∼8 km at 70°N and 70°S, and the reduction is less at other latitudes. Additionally, mesopause temperature increases significantly during winter storms, with a maximum rise of ∼17 K observed at 70°N and 70°S. These pronounced changes in mesopause height and temperature are evident only during winter storms and occur approximately 0.5 days after the AE index enhancement, whereas summer storms show no substantial impact. This difference is attributed to the higher altitude of the mesopause in winter, which enhances its sensitivity to geomagnetic activity. The observed temperature increases in the mesopause region are primarily driven by chemical heating from an exothermic reaction (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>O</mi>\u0000 <mo>+</mo>\u0000 <mi>O</mi>\u0000 <mo>+</mo>\u0000 <mi>M</mi>\u0000 <mspace></mspace>\u0000 <mo>→</mo>\u0000 <msub>\u0000 <mrow>\u0000 <mspace></mspace>\u0000 <mi>O</mi>\u0000 </mrow>\u0000 <mn>2</mn>\u0000 </msub>\u0000 <mo>+</mo>\u0000 <mi>M</mi>\u0000 </mrow>\u0000 <annotation> $mathrm{O}+mathrm{O}+mathrm{M},to {,mathrm{O}}_{2}+mathrm{M}$</annotation>\u0000 </semantics></math>), and radiative heating from enhanced ozone absorption of solar energy during storms. Furthermore, the lowering of the mesopause height is caused by downward heat conduction from the heated lower thermosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865879","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":"Observations of Intense Energy Conversion Events in the Earth's Magnetotail","authors":"Y. T. Tang,&nbsp;S. Y. Huang,&nbsp;Z. G. Yuan,&nbsp;K. Jiang,&nbsp;Z. Wang,&nbsp;Q. Y. Xiong,&nbsp;R. T. Lin,&nbsp;L. Yu,&nbsp;H. Bai","doi":"10.1029/2024JA033416","DOIUrl":"https://doi.org/10.1029/2024JA033416","url":null,"abstract":"<p>Using the high-resolution data from the Magnetospheric Multiscale mission, we performed a statistical analysis on intense energy conversion events (IECEs) in the Earth's magnetotail. The results show that the average duration of IECEs is 0.14 s, and the spatial scale of more than 95% of IECEs is smaller than one ion inertial length. Intense energy conversion events can occur not only in flux ropes, magnetic holes, dipolarization fronts and magnetic reconnection region in the plasma sheet, but also in the plasma sheet boundary layer. Intense energy conversion events prefer to occur in the duskside and the northern hemisphere, showing obvious dawn-dusk asymmetry. The occurrence rate of IECEs is much higher when the interplanetary magnetic field is quasi-southward. Our results can deepen our understanding of energy conversion and dynamic processes in the planetary magnetotail.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865774","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":"Multispecies MHD Simulations of the Crustal Field Influence at the Mars Magnetotail Current Sheet","authors":"N. A. Quartey,&nbsp;M. W. Liemohn","doi":"10.1029/2024JA033445","DOIUrl":"https://doi.org/10.1029/2024JA033445","url":null,"abstract":"<p>The magnetotail current sheet of Mars exhibits a dawn-to-dusk asymmetry that has been seen in satellite observations and MHD simulations. However, the influence of season has not been thoroughly investigated in MHD simulations. This investigation incorporates seasonal variations, driven by planetary eccentricity and solar variability, within the BATS-R-US multispecies MHD code to examine the influence of crustal magnetic fields and the ionosphere on the magnetotail current sheet. The solar wind interaction at Mars is analyzed for the following cases: solar maximum at perihelion (PERMAX), solar maximum at aphelion (APHMAX), solar minimum at perihelion (PERMIN), and solar minimum at aphelion (APHMIN). Simulation results show that the current sheet exhibits a duskward shift at solar maximum and a dawnward shift at solar minimum. In simulations that omit the crustal sources, the current sheet remains symmetric along the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>Y</mi>\u0000 <mo>=</mo>\u0000 <mn>0</mn>\u0000 </mrow>\u0000 <annotation> $Y=0$</annotation>\u0000 </semantics></math> plane. Because these results did not induce a shift, the ionization rates were adjusted for the PERMAX and APHMIN cases. The ionization rates were increased by four orders of magnitude in the PERMAX case, but the current sheet remained symmetric. However, the current sheet in the APHMIN case shifted slightly duskward when the ionization rates were decreased by nine orders of magnitude. It was determined that the crustal magnetic fields dominate the magnetotail current sheet shift, and the code setups from this investigation should be scrutinized for refined model comparison.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033445","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865778","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":"Statistical Analysis of Ultra-Low-Frequency Total Electron Content Disturbances: Relationship to Magnetospheric Waves","authors":"Michael D. Hartinger,&nbsp;Xueling Shi,&nbsp;Olga Verkhoglyadova,&nbsp;Xing Meng,&nbsp;Dogacan Su Ozturk,&nbsp;Angelyn Moore,&nbsp;Yangyang Shen,&nbsp;Anton Artemyev,&nbsp;D. Megan Gillies,&nbsp;Vassilis Angelopoulos","doi":"10.1029/2024JA033456","DOIUrl":"https://doi.org/10.1029/2024JA033456","url":null,"abstract":"<p>Disturbances in ionospheric Total Electron Content (dTEC) with frequencies of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>1–100 mHz can be driven from above by processes in the magnetosphere and below by processes on the Earth's surface and lower atmosphere. Past studies showed the potential of dTEC as a diagnostic of magnetospheric Ultra Low Frequency (ULF) wave activity and demonstrated that ULF dTEC can impact space weather by, for example, changing ionospheric conductance. However, most past work has focused on single event studies, lacked magnetospheric context, or used sampling rates too low to capture most ULF waves. Here, we perform a statistical study using Time History of Events and Macrsoscale Interactions during Substorms (THEMIS) satellite conjunctions with a ground-based magnetometer and Global Navigation Satellite System (GNSS) receiver at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>65° magnetic latitude. We find that magnetospheric ULF waves generate dTEC variations across the broad range of frequencies examined in this study (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>2–50 mHz), and that ULF dTEC wave power is correlated with Kp, AE, solar wind speed, and magnetic field wave power observed in the magnetosphere and on the ground. We further find that magnetospheric ULF waves generate dTEC amplitudes up to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 <mo>∼</mo>\u0000 <mn>4</mn>\u0000 </mrow>\u0000 <annotation> ${&lt; } sim 4$</annotation>\u0000 </semantics></math> TECU (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 <mn>30</mn>\u0000 <mi>%</mi>\u0000 </mrow>\u0000 <annotation> ${sim} 30%$</annotation>\u0000 </semantics></math> background), with the largest amplitudes occurring during geomagnetically active conditions, at frequencies below 7 mHz, and at local times near midnight. We finally discuss the implications of our results for magnetosphere-ionosphere coupling and remote sensing techniques related to ULF waves.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865777","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":"Dynamics of Proton Flux in the South Atlantic Anomaly During the Super Geomagnetic Storm in May 2024","authors":"Xiaoheng Xu,&nbsp;Yingqi Ma,&nbsp;Longlong Zhang,&nbsp;Tian Yu,&nbsp;Jieyi Wang,&nbsp;Maosheng He,&nbsp;Chunqin Wang,&nbsp;Hui Li","doi":"10.1029/2024JA033536","DOIUrl":"https://doi.org/10.1029/2024JA033536","url":null,"abstract":"<p>This study presents the short-term dynamic changes in proton flux within the South Atlantic Anomaly (SAA), during a super geomagnetic storm in May 2024. By integrating proton observation data (≥35, ≥70, ≥140 MeV) from multiple National Oceanic and Atmospheric Administration and Meteorological Operational satellite programme satellites with a short-time-scale running average (3-day), we improve spatial resolution and reduce the smoothing effects associated with long-time-scale averaging (∼1 month). The results reveal a rapid (∼20%) decline in proton flux within the SAA region during the main phase of the geomagnetic storm. After reaching its minimum, the proton flux in the SAA rapidly recovered during the recovery phase. Additionally, under the influence of solar proton events, a significant increase in high-energy proton flux was observed during the recovery phase of the storm. Notably, we found a previously unidentified characteristic: a time delay of ∼2.5 days between the minimum proton flux in the SAA and the minimum Dst index (−412 nT).</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856945","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":"Midlatitude Neutral Wind Response During the Mother's Day Super-Intense Geomagnetic Storm in 2024 Using Observations From the Chinese Meridian Project","authors":"Xin Wang,&nbsp;Ercha Aa,&nbsp;Yanhong Chen,&nbsp;Jiaojiao Zhang,&nbsp;Yajun Zhu,&nbsp;Lei Cai,&nbsp;Xian Lu,&nbsp;Bingxian Luo,&nbsp;Siqing Liu,&nbsp;Ming Li,&nbsp;Hua Shen,&nbsp;Tianjiao Yuan","doi":"10.1029/2024JA033574","DOIUrl":"https://doi.org/10.1029/2024JA033574","url":null,"abstract":"<p>Using new observations from the Chinese Meridian Project (CMP), this study examines the characteristics of neutral winds in the East Asian sector during the Mother's Day super-intense storm in May 2024, primarily focusing on its effects on the disturbances over China and adjacent areas. It is the first time that new measurements from three Dual-Channel Optical Interferometers (DCOIs) are utilized to analyze storm-time neutral winds at an altitude of 250 km in northern China. By developing all northern-hemisphere Super Dual Auroral Radar Network radars including six Chinese Dual Auroral Radar Network (CN-DARN) radars, the newly derived ionospheric convection pattern and its impacts on neutral winds can be well analyzed. The results show that a strong equatorward wind with a maximum amplitude of ∼400 m/s in the meridional component was observed for the first time during the storm main phase. In the East Asian sector, a negative ionospheric storm over China and adjacent areas was accompanied by this enhancement in equatorward wind in the night of May 10. Additionally, ionospheric convection expanded to 43° magnetic latitude (MLAT) with eastward ion velocities exceeding 800 m/s around 50° MLAT. This can strengthen zonal wind in northern China, producing a notable eastward surge of ∼230 m/s measured by new DCOIs in the dawnside sub-auroral region. Wave-like oscillations in neutral winds were observed by multi-DCOI stations, which were associated with the storm-time Traveling Atmospheric Disturbances (TADs). During the storm recovery phase, a high-level total electron content cluster shifted from eastern China to the central regions, which may be attributed to enhanced ∑[O]/[N₂].</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033574","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143861515","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":"Statistical Investigation of Deformation of Electron Pitch Angle Distributions Associated With Chorus Waves Observed by the Arase Satellite","authors":"S. Tokuda,&nbsp;T. Zushi,&nbsp;S. Kurita,&nbsp;H. Kojima,&nbsp;S. Kasahara,&nbsp;S. Yokota,&nbsp;K. Keika,&nbsp;T. Hori,&nbsp;Y. Kasahara,&nbsp;S. Matsuda,&nbsp;A. Matsuoka,&nbsp;M. Teramoto,&nbsp;K. Yamamoto,&nbsp;Y. Miyoshi,&nbsp;I. Shinohara","doi":"10.1029/2024JA033684","DOIUrl":"https://doi.org/10.1029/2024JA033684","url":null,"abstract":"<p>Whistler-mode chorus waves play important roles in the development of energetic electron populations in the Earth's inner magnetosphere. We have statistically analyzed rapid changes in the electron flux associated with chorus waves using data from the Arase satellite. The Arase satellite observations obtained from 23 March 2017 to 12 October 2018 show that the rapid changes are concentrated near the magnetic equator from nightside to dawnside. We compared the energy and pitch angle range of the rapid changes in the electron flux with the region bounded by the resonance energy curve of whistler mode waves which are calculated from properties of the observed chorus waves in 46 events. This comparison shows that, for most of the events, the energy and pitch angle range of the rapid changes in the electron flux can be explained by the first-order cyclotron resonance with the observed chorus waves. We also found that the timescale for the change in the electron pitch angle distribution ranges from several seconds to a few tens of seconds. This timescale is much faster than that expected by quasi-linear diffusion theory, suggesting that nonlinear wave-particle interactions play important roles in the deformation of the electron pitch angle distributions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033684","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856943","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":"CSES Satellite Observation of Nightside Bremsstrahlung X-Ray Distributions Induced by Energetic Electron Precipitation","authors":"Li Liao,&nbsp;Shufan Zhao,&nbsp;Qiaochu Li,&nbsp;Xuan Dong,&nbsp;HengXin Lu,&nbsp;Xuhui Shen","doi":"10.1029/2024JA033700","DOIUrl":"https://doi.org/10.1029/2024JA033700","url":null,"abstract":"<p>High-energy electrons can penetrate deeply into the ionospheric D-region, ionizing neutral molecules and producing reactive odd nitrogen and odd hydrogen, which ultimately impact the surface climate and temperature regime of the atmosphere. Although several instruments have been developed to measure precipitating electrons, accurately measuring precipitating electrons remains a highly challenging task. It is well known that high-energy electrons entering the lower ionosphere release both electrons and X-rays through a process known as bremsstrahlung radiation. By measuring the X-rays produced through this process, the flux of the precipitating electrons can be derived. In recent years, there have been numerous observations of X-ray emissions recorded by balloons-based measurement, but relatively few have been recorded from satellites. We analyze the characteristics of X-rays distribution detected by the CSES satellite from 2019 to 2022. The results indicate that the distribution of X-ray rates on the nightside corresponds closely with precipitated energetic electrons, especially at energies below 800 keV. Bremsstrahlung X-ray rates significantly increase when the Kp index exceeds 2 in high-latitude regions. X-rays generated by lightning-induced electron precipitation are primarily found in the region where 2.5 &lt; <i>L</i> &lt; 3, spanning 150°E to 260°E in the northern hemisphere and 300°E to 360°E in the southern hemisphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856944","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":"Magnetosheath Jet-Triggered ULF Waves: Energy Deposition in the Ionosphere","authors":"E. Krämer,&nbsp;M. Hamrin,&nbsp;H. Gunell,&nbsp;L. Baddeley,&nbsp;N. Partamies,&nbsp;S. Raptis,&nbsp;K. Herlingshaw,&nbsp;A. Schillings","doi":"10.1029/2025JA033792","DOIUrl":"https://doi.org/10.1029/2025JA033792","url":null,"abstract":"<p>Magnetosheath jets, transient plasma structures of enhanced dynamic pressure, have been observed to trigger ultra-low frequency (ULF) waves in the magnetosphere. These ULF waves contribute to energy transport in the magnetosphere-ionosphere system. Therefore, there is a need to estimate the energy input into the ionosphere due to jet-triggered ULF waves. In this study, we combine measurements from Magnetospheric Multiscale, ground-based magnetometers, the EISCAT radar on Svalbard, and SuperDARN to estimate the Joule heating in the ionosphere resulting from jet impacts at the magnetopause. Focusing on three jets observed on 2016-01-07 we were able to calculate the Joule heating for two jets. We found an average Joule heating rate of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>0.38</mn>\u0000 </mrow>\u0000 <annotation> $0.38$</annotation>\u0000 </semantics></math> mW/m² which is on par with other processes such as field line resonances. However, due to the short duration and spatial confinement of the jet-induced ULF waves, the average energy input was only <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>9</mn>\u0000 <mo>⋅</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>10</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> $9cdot 1{0}^{10}$</annotation>\u0000 </semantics></math> J. This suggests that the energy deposition of jet-triggered ULF waves is small compared to other magnetospheric processes, and thus does not significantly impact the average energy budget of the magnetosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JA033792","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850992","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":"Height and Intensity Variations of Mid-Latitude Sporadic E-Layers Observed by FORMOSAT-3/COSMIC and Ionosondes","authors":"Xu Yan,&nbsp;Hongtao Cai,&nbsp;Lihui Qiu,&nbsp;Jiawei Zhou,&nbsp;Hong Zhang,&nbsp;Lubing Yang,&nbsp;Chao Xiong","doi":"10.1029/2024JA033378","DOIUrl":"https://doi.org/10.1029/2024JA033378","url":null,"abstract":"&lt;p&gt;Although the climatology of sporadic E (Es) layers has been studied with Radio Occultation (RO) and ionosonde techniques, detailed comparisons between the findings of these two different methods remain limited. The present study uses 11 years of COSMIC mission and ionosonde observations to investigate diurnal and annual variations in the intensity and height of midlatitude Es layers, providing a comprehensive comparative analysis. Radio Occultation observations show regular diurnal and annual variations in Es layer intensity and height. The &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;S&lt;/mi&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mi&gt;max&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${S4}_{max }$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; index, which has been identified with the Es intensity, takes maximal values before local noon and later in the day near sunset. In addition, the RO Es layer heights (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;h&lt;/mi&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${hEs}_{RO}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) are found to be higher near sunrise and late afternoon hours. The ionosonde critical frequencies (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;f&lt;/mi&gt;\u0000 &lt;mi&gt;o&lt;/mi&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $foEs$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) exhibit a broad maximum at prenoon, but not a second peak later in the day. The virtual layer heights (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mi&gt;h&lt;/mi&gt;\u0000 &lt;mo&gt;′&lt;/mo&gt;\u0000 &lt;/msup&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${h}^{prime }Es$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) maximize at the same time as it happens in RO observations, taking, however, values that are distinctly higher than the corresponding &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;h&lt;/mi&gt;\u0000 &lt;mi&gt;E&lt;/mi&gt;\u0000 &lt;mi&gt;s&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"130 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849243","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}