Journal of Geophysical Research: Space Physics最新文献

{"title":"Relativistic Electron Flux Decay and Recovery: Relative Roles of EMIC Waves, Chorus Waves, and Electron Injections","authors":"Zijin Zhang,&nbsp;Anton Artemyev,&nbsp;Didier Mourenas,&nbsp;Vassilis Angelopoulos,&nbsp;Xiao-Jia Zhang,&nbsp;S. Kasahara,&nbsp;Y. Miyoshi,&nbsp;A. Matsuoka,&nbsp;Y. Kasahara,&nbsp;T. Mitani,&nbsp;S. Yokota,&nbsp;T. Hori,&nbsp;K. Keika,&nbsp;T. Takashima,&nbsp;M. Teramoto,&nbsp;S. Matsuda,&nbsp;I. Shinohara","doi":"10.1029/2024JA033174","DOIUrl":"https://doi.org/10.1029/2024JA033174","url":null,"abstract":"<p>We investigate the dynamics of relativistic electrons in the Earth's outer radiation belt by analyzing the interplay of several key physical processes: electron losses due to pitch angle scattering from electromagnetic ion cyclotron (EMIC) waves and chorus waves, and electron flux increases from chorus wave-driven acceleration of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>100–300 keV seed electrons injected from the plasma sheet. We examine a weak geomagnetic storm on 17 April 2021, using observations from various spacecraft, including GOES, Van Allen Probes, ERG/ARASE, MMS, ELFIN, and POES. Despite strong EMIC- and chorus wave-driven electron precipitation in the outer radiation belt, trapped 0.1–1.5 MeV electron fluxes actually increased. We use theoretical estimates of electron quasi-linear diffusion rates by chorus and EMIC waves, based on statistics of their wave power distribution, to examine the role of those waves in the observed relativistic electron flux variations. We find that a significant supply of 100–300 keV electrons by plasma sheet injections together with chorus wave-driven acceleration can overcome the rate of chorus and EMIC wave-driven electron losses through pitch angle scattering toward the loss cone, explaining the observed net increase in electron fluxes. Our study emphasizes the importance of simultaneously taking into account resonant wave-particle interactions and modeled local energy gradients of electron phase space density following injections, to accurately forecast the dynamical evolution of trapped electron fluxes.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861211","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":"First Comprehensive Study of MSTID Generation and Propagation Characteristics in Iran","authors":"M. Vazifehkhah Hafteh,&nbsp;A. Mahmoudian","doi":"10.1029/2024JA033190","DOIUrl":"https://doi.org/10.1029/2024JA033190","url":null,"abstract":"<p>To investigate medium-scale TID (MSTIDs) at mid-latitudes across Iran, TEC data obtained from a dense ground-based GNSS receiver during the 7 months from May–November 2021 were analyzed. To remove the diurnal variability of the TEC, an 8th-order Butterworth bandpass filter was applied to the data. Then, two-dimensional TEC maps of the detrended TEC with a spatial resolution of 0.5<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 <mspace></mspace>\u0000 <mo>×</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ} times $</annotation>\u0000 </semantics></math> 0.5<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> in longitude and latitude were obtained. Considering MSTID periods, four bandpass filters were applied to the TEC data: 10–15, 15–20, 20–25, and 25–30 min. The objective was to determine whether MSTID propagation occurred during specific times and whether consistent directions were followed. The results indicate that MSTIDs in all bandpass filters exhibit the same direction at particular times. Distinctive MSTID features are revealed by lower period filters. To identify MSTID trends propagating throughout the region within each month, stations along a constant longitude were selected. The trends of each month were depicted using the Continuous Wavelet Transform (CWT) technique applied to the detrended TEC. The resulting 2D map illustrates MSTID occurrence trends based on the combination of day of the month and time of day. No nighttime trend, except for two cases in July, is observed. Most of the observed MSTID trends propagate southeastward. Notably, as the end of each month approaches, there is a time shift to earlier hours for MSTID activity. The horizontal phase velocity, wavelength, and amplitude of the trends fall within the range of 200–615 m/s, 152–460 km, and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≤</mo>\u0000 <mn>0.1</mn>\u0000 </mrow>\u0000 <annotation> ${le} 0.1$</annotation>\u0000 </semantics></math> dTECU, respectively.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860888","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":"Can XMM-Newton Be Used to Track Compositional Changes in the Solar Wind?","authors":"S. Nitti,&nbsp;J. A. Carter,&nbsp;S. F. Sembay,&nbsp;S. E. Milan,&nbsp;L. Zhao,&nbsp;S. T. Lepri,&nbsp;K. D. Kuntz","doi":"10.1029/2024JA033323","DOIUrl":"https://doi.org/10.1029/2024JA033323","url":null,"abstract":"<p>Geocoronal Solar Wind Charge Exchange (SWCX) is the process by which heavy ions from the solar wind undergo charge exchange with neutral hydrogen atoms from the Earth's exosphere, releasing photons at discrete energies characteristic of the solar wind ions. This paper investigates the solar wind types driving geocoronal SWCX. We find that during periods of time-variable SWCX, higher fractions of every ion species are recorded by ACE compared to the averages. Notably, a subset of the slow solar wind characterized by a systematic lower temperature and higher proton flux is surprisingly effective for producing SWCX. Given the degradation of the solar wind composition spectrometer on ACE in 2011, we explore the capabilities of XMM-Newton as an alternative sensor to monitor heavy ion composition in the solar wind. Unlike the distributions of other ion line fluxes analyzed, only OVIII, extracted via spectral analysis of XMM-Newton observations, display patterns similar to the corresponding parent ion abundances from ACE <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mfenced>\u0000 <mrow>\u0000 <msup>\u0000 <mi>O</mi>\u0000 <mrow>\u0000 <mn>8</mn>\u0000 <mo>+</mo>\u0000 </mrow>\u0000 </msup>\u0000 <mo>/</mo>\u0000 <mi>p</mi>\u0000 </mrow>\u0000 </mfenced>\u0000 </mrow>\u0000 <annotation> $left({mathrm{O}}^{mathrm{8}+}/mathrm{p}right)$</annotation>\u0000 </semantics></math>. Finally, we employ a Random Forest Classifier model to predict solar wind types based on literature results. When combining proton data with XMM-Newton features, the model performance improves significantly, achieving a macro-averaged F1 score of 0.80 (with a standard deviation of 0.06).</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033323","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861009","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":"Assessing the Impacts of Assimilating GOLD Disk O/N2 Observations on the Thermosphere-Ionosphere System","authors":"F. I. Laskar,&nbsp;N. M. Pedatella,&nbsp;M. V. Codrescu,&nbsp;R. W. Eastes,&nbsp;J. L. Anderson","doi":"10.1029/2024JA033163","DOIUrl":"https://doi.org/10.1029/2024JA033163","url":null,"abstract":"<p>The Global-scale Observations of Limb and Disk (GOLD) imagers scan the Earth's Thermosphere-Ionosphere (TI) in the far ultraviolet wavelengths. Measurements from GOLD daylit spectrum are used to retrieve the column integrated atomic oxygen to molecular nitrogen density ratio (O/N₂) over about one fourth of the globe. The present investigation assesses the impact of assimilating GOLD disk O/N₂ on the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCMX) using the Data Assimilation Research Testbed (DART) ensemble adjustment Kalman filter. Two Observing System Simulation Experiments (OSSEs) are performed, and improvements are quantified by calculating root mean square error (RMSE) and bias with respect to a truth run. In addition to solar and geomagnetic forcing, we introduced gravity wave forcing perturbations to increase the ensemble spread, which has not previously been applied in ensemble assimilation. One of the OSSEs assimilates only the lower atmosphere (LA, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&lt;</mo>\u0000 </mrow>\u0000 <annotation> ${&lt; } $</annotation>\u0000 </semantics></math>100 km) observations, referred to as LA experiment, and the second assimilates GOLD O/N₂ and LA observations, referred to as Whole Atmosphere (WA) experiment. The WA-analysis O/N₂ RMSE and bias are about 60% and 87% better compared to LA-analysis. Also, the O/N₂ RMSE and bias for the WA-analysis are about 23% and 54% better compared to WA 1-hr forecasts. The improvement in WA electron column density (ECD), a model equivalent of Total Electron Content (TEC), is about 24% compared to the LA experiment. These results demonstrate that the assimilation of GOLD O/N₂ improves both the thermosphere and ionosphere in a whole atmosphere data assimilation system.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033163","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860820","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":"Contribution of EMIC and Chorus Waves to the Formation of the Three-Belt of Ultra-Relativistic Electrons","authors":"Chang Yang,&nbsp;Jiaxu Yue,&nbsp;Hongming Yang,&nbsp;Zhaoguo He,&nbsp;Fuliang Xiao,&nbsp;Sai Zhang,&nbsp;Yihua He,&nbsp;Si Liu,&nbsp;Qinghua Zhou,&nbsp;Zhonglei Gao,&nbsp;Yuyue Jin,&nbsp;Hui Zhao,&nbsp;Archie James Johnston","doi":"10.1029/2024JA033380","DOIUrl":"https://doi.org/10.1029/2024JA033380","url":null,"abstract":"<p>The Earth's radiation belts are usually composed of an inner and an outer zone. Previous studies have reported a third belt of ultra-relativistic electrons, but the mechanism requires to be further clarified. Here we report a very interesting feature of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>3.4</mn>\u0000 <mo>−</mo>\u0000 <mn>6.3</mn>\u0000 </mrow>\u0000 <annotation> $3.4-6.3$</annotation>\u0000 </semantics></math> MeV electrons during two storms in October 2018. During the October 7 storm the electrons in the region <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>≈</mo>\u0000 <mn>3.5</mn>\u0000 <mo>−</mo>\u0000 <mn>5.0</mn>\u0000 </mrow>\u0000 <annotation> $Lapprox 3.5-5.0$</annotation>\u0000 </semantics></math> were quickly scattered by EMIC waves, leading to a storage ring left between <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>≈</mo>\u0000 <mn>3.0</mn>\u0000 <mo>−</mo>\u0000 <mn>3.5</mn>\u0000 </mrow>\u0000 <annotation> $Lapprox 3.0-3.5$</annotation>\u0000 </semantics></math>. Over the following days, due to the chorus-driven acceleration, electron fluxes significantly increased in the region <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>&gt;</mo>\u0000 <mn>4</mn>\u0000 </mrow>\u0000 <annotation> $L &gt; 4$</annotation>\u0000 </semantics></math>, consequently allowing for a three-belt structure. During the October 13 storm the electrons in the region <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>&gt;</mo>\u0000 <mn>5</mn>\u0000 </mrow>\u0000 <annotation> $L &gt; 5$</annotation>\u0000 </semantics></math> were swept away by EMIC waves, leaving a narrow outer radiation belt confined within the region <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>L</mi>\u0000 <mo>≈</mo>\u0000 <mn>4</mn>\u0000 <mo>−</mo>\u0000 <mn>5</mn>\u0000 </mrow>\u0000 <annotation> $Lapprox 4-5$</annotation>\u0000 </semantics></math> for several days. Numerical calculations demonstrate that the EMIC-driven loss and chorus-induced acceleration can account for the formation and evolution of the third-belt morphology.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861007","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":"Validation of Ionospheric Parameters From Electron Density Profiles of FY-3E Satellite Using Ionosonde, GIMs, Satellite Altimetry and Other Occultations","authors":"Binyi Huang,&nbsp;Peng Chen,&nbsp;Yibin Yao,&nbsp;Rong Wang,&nbsp;Yuchen Zhang","doi":"10.1029/2024JA032590","DOIUrl":"https://doi.org/10.1029/2024JA032590","url":null,"abstract":"<p>The FengYun-3E satellite (FY-3E) is the first to feature the GNSS Occultation Sounder II (GNOS-II). Occultation is effective for ionosphere detection, but data variations between FY-3E and other techniques are inevitable due to differing instruments and methodologies. Evaluating the GNOS-II performance against other techniques is imperative. We extract ionospheric parameters—the F2 layer peak height (hmF2), F2 layer critical frequency (foF2), and Vertical Total Electron Content (VTEC)—from FY-3E's electron density profile. We use ionosonde, Global Ionospheric Maps (GIMs), and Satellite Altimetry (SA), along with FY-3D and COSMIC-2 to analyze FY-3E's performance. Additionally, we use the International Reference Ionosphere (IRI-2020) to normalize VTEC, eliminating systematic biases due to altitude differences. Results show that FY-3E's foF2 has high consistency with ionosonde, while hmF2 shows larger differences. However, both foF2 and hmF2 from FY-3E, FY-3D, and COSMIC-2 have comparable data quality. TEC differences between FY-3E and GIMs are greater during equinoxes and in the daytime. Significant TEC deviations are observed, particularly in low-latitude region affected by the Equatorial Ionization Anomaly (EIA) during the daytime, with underestimation at EIA crests and overestimation at EIA troughs and around ±40° geomagnetic latitude, a phenomenon also observed when compared to SA. FY-3D and COSMIC-2 exhibit similar patterns, but FY-3E shows better consistency with GIMs and SA compared to FY-3D. Compared to FY-3D and FY-3E, COSMIC-2 has fewer overestimated profiles. Furthermore, FY-3E performs poorly in observing ionospheric structure in the EIA region but performs well in the Weddell Sea Anomaly (WSA) region, similar to FY-3E.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861008","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":"Wave-Telescope Analysis for Multipoint Observatories: Impact of Timing and Spatial Uncertainties","authors":"K. G. Klein,&nbsp;T. Broeren,&nbsp;O. Roberts,&nbsp;L. Schulz","doi":"10.1029/2024JA033428","DOIUrl":"https://doi.org/10.1029/2024JA033428","url":null,"abstract":"<p>The wave telescope technique is used to reconstruct spatial power distributions of space plasmas from multipoint spacecraft missions. This study aims to quantify the impact of uncalibrated uncertainties in the time synchronization and the spatial position on the accuracy of the wave telescope method for observatories with more than four spacecraft, for example, HelioSwarm a nine-spacecraft NASA observatory currently in Phase B. We simulate synthetic data with systemic timing and spatial errors modeled using geometries drawn from HelioSwarm's Design Reference Mission, applying the wave telescope technique to estimate wavevectors for two characteristic ion-scale waves. By carefully selecting optimal polyhedral configurations from the overall geometry, and combining signals from multiple polyhedra, the impact of systematic uncertainties and spatial aliasing can be significantly reduced, leading to more accurate wavevector identification for future multipoint missions.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033428","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860772","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 Multi-Platform Statistical Analysis of the Azimuthal Spatial Extent of the Microburst Precipitation Region","authors":"S. S. Elliott,&nbsp;C. Colpitts,&nbsp;A. W. Breneman,&nbsp;J. M. Pettit,&nbsp;K. A. Cantwell,&nbsp;C. A. Cattell,&nbsp;A. J. Halford,&nbsp;M. Shumko,&nbsp;J. Sample,&nbsp;A. Johnson,&nbsp;Y. Miyoshi,&nbsp;Y. Kasahara,&nbsp;R. N. Troyer,&nbsp;R. Millan,&nbsp;T. Hori,&nbsp;I. Shinohara,&nbsp;S. Matsuda,&nbsp;A. Matsuoka","doi":"10.1029/2024JA033208","DOIUrl":"https://doi.org/10.1029/2024JA033208","url":null,"abstract":"<p>Microbursts are impulsive injections of energetic (few keV to &gt;MeV) electrons into the atmosphere, primarily caused by nonlinear scattering driven by whistler mode chorus waves. While the relative importance of microburst precipitation as a loss process has not been fully quantified, many studies have shown microbursts may play a significant role in the loss of outer radiation belt electrons. We present a multi-platform statistical analysis of chorus and energetic electron precipitation in an attempt to constrain the azimuthal spatial extent (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∆</mo>\u0000 </mrow>\u0000 <annotation> $mathit{{increment}}$</annotation>\u0000 </semantics></math>MLT) of the microburst precipitation region and determine how this extent varies with geomagnetic activity. Statistical upper bounds of this azimuthal extent are determined with observations of general energetic electron precipitation that can include direct microburst detections, while statistical lower bounds determination requires direct microburst detections. The resulting distributions of both upper and lower bounds azimuthal extent suggest that microbursts may frequently constitute an important source of electron loss from the outer radiation belt. We find that 36% of upper bound events in the dawn sector span more than 5 hr in MLT. This azimuthal extent increases with geomagnetic activity, particularly in the dawn and noon MLT sectors.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033208","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860773","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":"Impact of Upward Propagating Migrating Diurnal and Semidiurnal Tides on the Ionosphere-Thermosphere Seasonal Variation","authors":"N. M. Pedatella,&nbsp;K. Wu,&nbsp;L. Qian,&nbsp;Q. Gan","doi":"10.1029/2024JA032855","DOIUrl":"https://doi.org/10.1029/2024JA032855","url":null,"abstract":"&lt;p&gt;The Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension (WACCM-X) is used to investigate the impact of the upward propagating migrating diurnal (DW1) and semidiurnal (SW2) tides on the seasonal variability in the ionosphere and thermosphere. In the lower thermosphere, the tides induce a westward acceleration that obtains maximum values of 10–20 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mtext&gt;ms&lt;/mtext&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;1&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{ms}}^{-1}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; around solstice. The tidal dissipation also changes the meridional circulation and leads to a &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∼&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sim} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 5 K cooling of the lower thermosphere. These changes result in a decrease in atomic oxygen in the lower thermosphere that maximizes during local winter. In the lower thermosphere, the DW1 has a greater impact around December solstice, while the SW2 has a greater impact around June solstice. The DW1 and SW2 induced changes in the lower thermosphere composition lead to changes in the thermosphere column integrated atomic oxygen to molecular nitrogen ratio (O/&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;). This leads to a reduction in the thermosphere annual variation at middle to high latitudes. The DW1 and SW2 also reduce the thermosphere neutral mass density. In the ionosphere, the DW1 and SW2 decrease the zonal and diurnal mean total electron content by &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∼&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sim} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 20% globally, which is primarily attributed to the reduction in thermosphere O/&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;N&lt;/mi&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{N}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. The SW2 is found to have a greater influence on the low latitude ionosphere compared to the DW1 due to the SW2 having a greater impact on the equatorial electrodynamics. The results demonstrate that the upward propagating DW1 and SW2 both have significant effects on the ionosphere and thermosphere, including influencing the seasonal variabi","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860477","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":"A Quiet-Day Ionospheric Electrodynamics Empirical Model in the Low and Middle Latitudes","authors":"Yuhan Wang,&nbsp;Zhipeng Ren,&nbsp;Yunbo Liu","doi":"10.1029/2024JA032937","DOIUrl":"https://doi.org/10.1029/2024JA032937","url":null,"abstract":"<p>In this paper, we develop a climatology model of the ionospheric electric field and potential at low and middle latitudes on quiet time, utilizing plasma drift observed from the ROCSAT-1 satellite. The meridional/vertical and zonal <b>E</b> × <b>B</b> drifts are transformed to the electric fields using modified Apex coordinates under the real geomagnetic field model. The electric field data are adjusted to different solar levels through bilinear fitting, and organized into seasonal, longitudinal, latitudinal bins. The fully normalized associated Legendre functions are chosen as the fitting basis modes. Our model can effectively describe the latitudinal dependence of the electrodynamics parameters cover equatorward of 35° magnetic latitude. The fitted drifts hold the fundamental characteristics of the results observed prior to fitting. The model potential can well shows the typical morphological characteristics that are in great agreement with prior research findings. Furthermore, the potential variations exhibit distinct seasonal, solar flux, and UT dependence under moderate and high solar flux conditions. Within the framework of this model, the potential, electric field, and drift can be mutually converted while maintaining self-consistency.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":"129 12","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860512","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}