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Interferometric Imaging with EISCAT_3D for Fine-Scale In-Beam Incoherent Scatter Spectra Measurements Ann. Geophys. (IF 1.9) Pub Date : 2024-03-27 Devin Huyghebaert, Björn Gustavsson, Juha Vierinen, Andreas Kvammen, Matthew Zettergren, John Swoboda, Ilkka Virtanen, Spencer Hatch, Karl M. Laundal
Abstract. The 233 MHz EISCAT_3D radar system currently under construction in northern Fennoscandia will be able to resolve ionospheric structures smaller than the transmit beam dimensions through the use of interferometric imaging. This capability is made possible by the modular design and digitisation of the 119 91-antenna panels located at the main Skibotn site. The main array consists of a cluster
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Analysis of diurnal, seasonal and annual variations of fair weather atmospheric potential gradient at reduced number concentration of condensation nuclei from long-term measurements at Świder, Poland Ann. Geophys. (IF 1.9) Pub Date : 2024-03-08 Izabela Pawlak, Anna Odzimek, Daniel Kępski, Jose Tacza
Abstract. The ground-level atmospheric potential gradient (PG) has been measured with a radioactive collector method in Stanisław Kalinowski Geophysical Observatory in Świder (52.12° N, 21.23° E), Poland, for several decades. Long-term measurements analysed previously revealed rather typical behaviour in the diurnal and seasonal variations of the PG of a land station controlled by pollution. Observation
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Scalar-potential mapping of the steady-state magnetosheath model Ann. Geophys. (IF 1.9) Pub Date : 2024-03-07 Yasuhito Narita, Daniel Schmid, Simon Toepfer
Abstract. The steady-state magnetosheath model has various applications for studying the plasma and magnetic field profile around the planetary magnetospheres. In particular, the magnetosheath model is analytically obtained by solving the Laplace equation for parabolic boundaries (bow shock and magnetopause). We address the question, how can we utilize the magnetosheath model by transforming into a
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Climatological comparison of polar mesosphere summer echoes over the Arctic and Antarctica at 69° Ann. Geophys. (IF 1.9) Pub Date : 2024-02-28 Ralph Latteck, Damian J. Murphy
Abstract. Polar mesosphere summer echoes (PMSE) have been observed for more than 30 years with 50 MHz VHF radars at various locations in the Northern Hemisphere. Continuous observation of PMSE is conducted on the northern Norwegian island of Andøya (69.3° N) using the ALWIN radar (1999–2008) and MAARSY (since 2010). The same kind of PMSE measurements began in 2004 in the Southern Hemisphere with the
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Ionospheric density depletions around crustal fields at Mars and their connection to ion frictional heating Ann. Geophys. (IF 1.9) Pub Date : 2024-02-28 Hadi Madanian, Troy Hesse, Firdevs Duru, Marcin Pilinski, Rudy Frahm
Abstract. Mars' ionosphere is formed through ionization of the neutral atmosphere by solar irradiance, charge exchange, and electron impact. Observations by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft have shown a highly dynamic ionospheric layer at Mars impacted by loss processes including ion escape, transport, and electron recombination. The crustal fields at Mars can also significantly
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Characteristic analysis of the differences between total electron content (TEC) values in global ionosphere map (GIM) grids Ann. Geophys. (IF 1.9) Pub Date : 2024-02-20 Qisheng Wang, Jiaru Zhu, Genxin Yang
Abstract. Using total electron content (TEC) from a global ionosphere map (GIM) for ionospheric delay correction is a common method of eliminating ionospheric errors in satellite navigation and positioning. On this basis, the TEC of a puncture point can be obtained by GIM grid TEC interpolation. However, in terms of grid, only few studies have analyzed the TEC value size characteristics of its four
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Observations of polar mesospheric summer echoes resembling kilometer-scale varicose-mode flows Ann. Geophys. (IF 1.9) Pub Date : 2024-02-20 Jennifer Hartisch, Jorge L. Chau, Ralph Latteck, Toralf Renkwitz, Marius Zecha
Abstract. The mesosphere and lower thermosphere (MLT) region represents a captivating yet challenging field of research. Remote sensing techniques, such as radar, have proven invaluable for investigating this domain. The Middle Atmosphere Alomar Radar System (MAARSY), located in northern Norway (69∘ N, 16∘ E), uses polar mesospheric summer echoes (PMSEs) as tracers to study MLT dynamics across multiple
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How does auroral electron precipitation near the open–closed field line boundary compare to that within the auroral oval during substorm onset? Ann. Geophys. (IF 1.9) Pub Date : 2024-02-20 Maxime Grandin, Noora Partamies, Ilkka I. Virtanen
Abstract. Auroral electron precipitation during a substorm exhibits complex spatiotemporal variations which are still not fully understood, especially during the very dynamic phase immediately following the onset. Since during disturbed times the auroral oval typically extends across several hundreds of kilometers in the latitudinal direction, one may expect that precipitating electron spectra differ
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Estimating gradients of physical fields in space Ann. Geophys. (IF 1.9) Pub Date : 2024-02-06 Yufei Zhou, Chao Shen
Abstract. This study focuses on the development of a multi-point technique for future constellation missions, aiming to measure gradients at various orders, in particular the linear and quadratic gradients, of a general field. It is well established that, in order to estimate linear gradients, the spacecraft must not lie on a plane. Through analytical exploration within the framework of least squares
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High-time-resolution analysis of meridional tides in the upper mesosphere and lower thermosphere at mid-latitudes measured by the Falkland Islands SuperDARN radar Ann. Geophys. (IF 1.9) Pub Date : 2024-02-02 Gareth Chisham, Andrew J. Kavanagh, Neil Cobbett, Paul Breen, Tim Barnes
Abstract. Solar tides play a major role in the dynamics of the upper mesosphere and lower thermosphere (MLT). Hence, a comprehensive understanding of these tides is important for successful modelling of the MLT region. Most ground-based observations of tidal variations in the MLT have been from meteor radar measurements with a temporal resolution of 1 h. Here, we take a different perspective on these
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Investigation of the October effect in VLF signals Ann. Geophys. (IF 1.9) Pub Date : 2024-01-11 Marc Hansen, Daniela Banyś, Mark Clilverd, David Wenzel, M. Mainul Hoque
Abstract. Subionospheric Very Low Frequency (VLF) radio signals are reflected by free electrons in the ionospheric D-region at about 60–90 km altitude and can propagate over long distances, which makes them useful for monitoring the state of the D-region or perturbations due to solar flares. At the D-region height, the ionosphere is mainly ionized by the solar Lyman-α radiation. The reflection characteristics
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The Origins of a Near-Ecliptic Merged Interaction Region as a Magnetic-Cloud like Structure Embedded in a Co-rotating Interaction Region Ann. Geophys. (IF 1.9) Pub Date : 2024-01-10 Megan L. Maunder, Claire Foullon, Robert Forsyth, David Barnes, Jackie Davies
Abstract. Using remote-sensing and in-situ observations across multiple spacecraft with complimentary methods of analysis, we investigate a Magnetic Cloud Like-structure (MCL) observed in-situ on 3–4 July 2007 near the ecliptic at OMNI, STEREO-A and -B (all within 15° longitude of Earth). The MCL is entrained in a Corotating Interaction Region (CIR) originating in the Northern heliospheric sector,
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Ionospheric Upwelling and the Level of Associated Noise at Solar Minimum Ann. Geophys. (IF 1.9) Pub Date : 2024-01-04 Timothy Wemimo David, Chizurumoke Michael Michael, Darren M. Wright, Adetoro Temitope Talabi, Abayomi E. Ajetunmobi
Abstract. We have studied the ionospheric upwelling with magnitude above 1013 m−2 s−1 using the data during the IPY-ESR 2007 campaign, which coincides with solar minimum. The noise level in low, medium and high-flux upflows is investigated. We found that the noise level in high-flux upflow is about 93 % while the low and medium categories are 62 % and 80 %, respectively. This shows that robust and
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On the importance of middle atmosphere observations on ionospheric dynamics using WACCM-X and SAMI3 Ann. Geophys. (IF 1.9) Pub Date : 2024-01-03 Fabrizio Sassi, Angeline Burrell, Sarah McDonald, Jennifer Tate, John McCormack
Abstract. Recent advances in atmospheric observations and modelling have enabled the investigation of thermosphere-ionosphere interactions as a whole atmosphere problem. This study examines how dynamical variability in the middle atmosphere (MA) affects day-to-day changes in the thermosphere and ionosphere. Specifically, this study investigates ionosphere-thermosphere interactions during different
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Revisiting mirror modes in the plasma environment of comet 67P/Churyumov–Gerasimenko Ann. Geophys. (IF 1.9) Pub Date : 2023-12-12 Ariel Tello Fallau, Charlotte Goetz, Cyril Simon Wedlund, Martin Volwerk, Anja Moeslinger
Abstract. The plasma environment of comet 67P provides a unique laboratory to study plasma phenomena in the interplanetary medium. There, waves are generated which help the plasma relax back to stability through wave–particle interactions, transferring energy from the wave to the particles and vice versa. In this study, we focus on mirror-mode-like structures (low-frequency, transverse, compressional
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On mechanisms for high-frequency pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere Ann. Geophys. (IF 1.9) Pub Date : 2023-12-13 Thomas B. Leyser, Tima Sergienko, Urban Brändström, Björn Gustavsson, Michael T. Rietveld
Abstract. The EISCAT (European Incoherent Scatter Scientific Association) Heating facility was used to transmit powerful high-frequency (HF) electromagnetic waves into the F-region ionosphere to enhance optical emissions at 557.7 and 630.0 nm from atomic oxygen. The emissions were imaged by several stations of ALIS (Auroral Large Imaging System) in northern Sweden, and the EISCAT UHF incoherent scatter
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Local bow shock environment during magnetosheath jet formation: results from a hybrid-Vlasov simulation Ann. Geophys. (IF 1.9) Pub Date : 2023-12-07 Jonas Suni, Minna Palmroth, Lucile Turc, Markus Battarbee, Giulia Cozzani, Maxime Dubart, Urs Ganse, Harriet George, Evgeny Gordeev, Konstantinos Papadakis, Yann Pfau-Kempf, Vertti Tarvus, Fasil Tesema, Hongyang Zhou
Abstract. Magnetosheath jets are plasma structures that are characterised by enhanced dynamic pressure and/or plasma velocity. In this study, we investigate the formation of magnetosheath jets in four two-dimensional simulation runs of the global magnetospheric hybrid-Vlasov model Vlasiator. We focus on jets whose origins were not clearly determined in a previous study using the same simulations (Suni
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F-region drift current and magnetic perturbation distribution by the X-wave heating ionosphere Ann. Geophys. (IF 1.9) Pub Date : 2023-12-06 Yong Li, Hui Li, Jian Wu, Xingbao Lv, Chengxun Yuan, Ce Li, Zhongxiang Zhou
Abstract. We present a theoretical and numerical study of the drift current and magnetic perturbation model in the ionosphere by incorporating the ohmic heating model and the magnetohydrodynamic (MHD) momentum equation. Based on these equations, the ionospheric electron temperature and drift current are investigated. The results indicate that the maximum change in electron temperature ΔTe is about
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Does high-latitude ionospheric electrodynamics exhibit hemispheric mirror symmetry? Ann. Geophys. (IF 1.9) Pub Date : 2023-12-06 Spencer Mark Hatch, Heikki Vanhamäki, Karl Magnus Laundal, Jone Peter Reistad, Johnathan Burchill, Levan Lomidze, David Knudsen, Michael Madelaire, Habtamu Tesfaw
Abstract. Ionospheric electrodynamics is a problem of mechanical stress balance mediated by electromagnetic forces. Joule heating (the total rate of frictional heating of thermospheric gases and ionospheric plasma) and ionospheric Hall and Pedersen conductances comprise three of the most basic descriptors of this problem. More than half a century after identification of their central role in ionospheric
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Proton Plasma Asymmetries between the Convective-Electric-Field Hemispheres of Venus' Dayside Magnetosheath Ann. Geophys. (IF 1.9) Pub Date : 2023-12-06 Sebastián Rojas Mata, Gabriella Stenberg Wieser, Tielong Zhang, Yoshifumi Futaana
Abstract. Proton plasma asymmetries with respect to the convective electric field (E) are characterized in Venus’ dayside magnetosheath using measurements taken by an ion mass-energy spectrometer and a magnetometer. Investigating the spatial structure of the magnetosheath plasma in this manner provides insight into the coupling between solar-wind protons and planetary ions. A previously developed methodology
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The Role of Gravity Waves in the Mesosphere Inversion Layers (MILs) over low-latitude (3–15° N) Using SABER Satellite Observations Ann. Geophys. (IF 1.9) Pub Date : 2023-11-30 Chalachew Lingerew, Jaya Prakash Raju
Abstract. The Mesosphere transitional region over low latitude is a distinct and highly turbulent zone of the atmosphere. A transition MLT region is connected with dynamic processes, particularly gravity waves, as a causative of an inversion phenomenon. MLT inversions have been the subject of numerous investigations, but their formation mechanisms are still poorly understood. In this article, an attempt
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Auroral breakup detection in all-sky images by unsupervised learning Ann. Geophys. (IF 1.9) Pub Date : 2023-11-30 Noora Partamies, Bas Dol, Vincent Teissier, Liisa Juusola, Mikko Syrjäsuo, Hjalmar Mulders
Abstract. Due to a large number of automatic auroral camera systems on the ground, the image data analysis requires more efficiency than what a human expert visual inspection can provide. Furthermore, there is no solid consensus on how many different types or shapes exist in auroral displays. We report the first attempt to classify auroral morphological forms by unsupervised learning method on an image
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Application of Generalized – Aurora Computed Tomography to the EISCAT_3D project Ann. Geophys. (IF 1.9) Pub Date : 2023-11-27 Yoshimasa Tanaka, Yasunobu Ogawa, Akira Kadokura, Takehiko Aso, Björn Gustavsson, Urban Brändström, Tima Sergienko, Genta Ueno, Satoko Saita
Abstract. EISCAT_3D is a project to build a multiple-site phased-array incoherent scatter radar system in northern Fenno-Scandinavia. We demonstrate via numerical simulation how useful monochromatic images taken by a multi-point imager network are for auroral research in the EISCAT_3D project. We apply the generalized-aurora computed tomography (G-ACT) method to modelled observational data from real
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Observations of Ionospheric Disturbances Associated with the 4 August 2020 Port Beirut Explosion by DMSP and Ionosondes Ann. Geophys. (IF 1.9) Pub Date : 2023-11-21 Rezy Pradipta, Pei-Chen Lai
Abstract. A major explosion happened in Beirut on 4 August 2020, releasing a significant amount of energy into the atmosphere. The energy released may have reached the upper atmosphere and generated some traveling ionospheric disturbances (TIDs), which may affect radio wave propagation. In this study, we used data from the Defense Meteorological Satellite Program (DMSP) and ground-based ionosondes
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Probabilistic modelling of substorm occurrences with an echo state network Ann. Geophys. (IF 1.9) Pub Date : 2023-11-21 Shin'ya Nakano, Ryuho Kataoka, Masahito Nosé, Jesper W. Gjerloev
Abstract. The relationship between solar-wind conditions and substorm activity is modelled with an approach based on an echo state network. Substorms are a fundamental physical phenomenon in the magnetosphere–ionosphere system, but the deterministic prediction of substorm onset is very difficult because the physical processes that underlie substorm occurrences are complex. To model the relationship
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Three-dimensional ionospheric conductivity associated with pulsating auroral patches: reconstruction from ground-based optical observations Ann. Geophys. (IF 1.9) Pub Date : 2023-11-20 Mizuki Fukizawa, Yoshimasa Tanaka, Yasunobu Ogawa, Keisuke Hosokawa, Tero Raita, Kirsti Kauristie
Abstract. Pulsating auroras (PsAs) appear over a wide area within the aurora oval in the midnight–morning–noon sector. In previous studies, observations by magnetometers on board satellites have reported the presence of field-aligned currents (FACs) near the edges and interiors of pulsating aurora patches. PsAs are thus a key research target for understanding the magnetosphere–ionosphere coupling process
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Three principal components describe the spatiotemporal development of mesoscale ionospheric equivalent currents around substorm onsets Ann. Geophys. (IF 1.9) Pub Date : 2023-11-16 Liisa Juusola, Ari Viljanen, Noora Partamies, Heikki Vanhamäki, Mirjam Kellinsalmi, Simon Walker
Abstract. Substorms are a commonly occurring but insufficiently understood form of dynamics in the coupled magnetosphere–ionosphere system, associated with space weather disturbances and auroras. We have used principal component analysis (PCA) to characterize the spatiotemporal development of ionospheric equivalent currents as observed by the International Monitor for Auroral Geomagnetic Effects (IMAGE)
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Estimation and evaluation of hourly Meteorological Operational (MetOp) satellites' GPS receiver differential code biases (DCBs) with two different methods Ann. Geophys. (IF 1.9) Pub Date : 2023-11-14 Linlin Li, Shuanggen Jin
Abstract. Differential code bias (DCB) is one of the Global Positioning System (GPS) errors, which typically affects the calculation of total electron content (TEC) and ionospheric modeling. In the past, DCB was normally estimated as a constant in 1 d, while DCB of a low Earth orbit (LEO) satellite GPS receiver may have large variations within 1 d due to complex space environments and highly dynamic
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Are drivers of northern lights in the ionosphere? Ann. Geophys. (IF 1.9) Pub Date : 2023-11-13 Osuke Saka
Abstract. It is reported that transverse electric fields penetrating the ionosphere either from distant space or from the upper atmosphere produce charge separations along the field lines by building up positive charges immediately above the ionosphere. Those parallel electric fields produced by the charge separation deserve auroral driver. This paper discusses why and how these internal drivers in
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Subauroral Crosstalk in POES/Metop TED proton channels Ann. Geophys. (IF 1.9) Pub Date : 2023-11-09 Jan Maik Wissing, Olesya Yakovchuk
Abstract. Particle measurements are used for various purposes. The medium energy channels on the POES/Metop satellites, the MEPED channels, are widely used, for example in atmospheric ionization models, their low energy (eV and keV) counterpart, the TED detector, is not that popular. However the recent rise of the ionization/climate model altitudes will lead to increased interest in these low energy
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Calibrating estimates of ionospheric long-term change Ann. Geophys. (IF 1.9) Pub Date : 2023-11-08 Christopher John Scott, Matthew N. Wild, Luke Anthony Barnard, Bingkun Yu, Tatsuhiro Yokoyama, Michael Lockwood, Cathryn Mitchel, John Coxon, Andrew Kavanagh
Abstract. Long-term change in the height of the ionospheric F2 layer, hmF2, is predicted to result from increased levels of tropospheric greenhouse gases. Sufficiently long sequences of ionospheric data exist to investigate this long-term change, recorded by a global network of ionosondes. However, direct measurements of ionospheric layer height with these instruments is not possible. As a result,
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The m-dimensional spatial Nyquist limit using the wave telescope for larger numbers of spacecraft Ann. Geophys. (IF 1.9) Pub Date : 2023-11-07 Leonard Schulz, Karl-Heinz Glassmeier, Ferdinand Plaschke, Simon Toepfer, Uwe Motschmann
Abstract. Spacecraft constellations consisting of multiple satellites are becoming more and more interesting not only for commercial use but also for space science missions. The proposed and accepted scientific multi-satellite missions that will operate within Earth's magnetospheric environment, like HelioSwarm, require researchers to extend established methods for the analysis of multi-spacecraft
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Relativistic kinematic effects in the interaction time of whistler-mode chorus waves and electrons in the outer radiation belt Ann. Geophys. (IF 1.9) Pub Date : 2023-11-02 Livia R. Alves, Márcio E. S. Alves, Ligia A. da Silva, Vinicius Deggeroni, Paulo R. Jauer, David G. Sibeck
Abstract. Whistler-mode chorus waves propagate outside the plasmasphere, interacting with energetic electrons in the outer radiation belt. This leads to local changes in the phase space density distribution due to energy or pitch angle diffusion. The wave–particle interaction time (Tr) is crucial in estimating time-dependent processes such as the energy and pitch angle diffusion. Although the wave
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Permutation Entropy and Complexity Analysis of Large-scale Solar Wind Structures and Streams Ann. Geophys. (IF 1.9) Pub Date : 2023-10-24 Emilia Katja Johanna Kilpua, Simon Good, Matti Ala-Lahti, Adnane Osmane, Venla Koikkalainen
Abstract. In this work, we perform a statistical study of magnetic field fluctuations in the solar wind at 1 au using permutation entropy and complexity analysis. Slow and fast wind, magnetic clouds, interplanetary coronal mass ejection (ICME)-driven sheath regions and slow-fast stream interaction regions (SIRs) have been investigated separately. Our key finding is that there are significant differences
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Finding reconnection lines and flux rope axes via local coordinates in global ion-kinetic magnetospheric simulations Ann. Geophys. (IF 1.9) Pub Date : 2023-10-23 Markku Alho, Giulia Cozzani, Ivan Zaitsev, Fasil Tesema Kebede, Urs Ganse, Markus Battarbee, Maarja Bussov, Maxime Dubart, Sanni Hoilijoki, Leo Kotipalo, Konstantinos Papadakis, Yann Pfau-Kempf, Jonas Suni, Vertti Tarvus, Abiyot Workayehu, Hongyang Zhou, Minna Palmroth
Abstract. Magnetic reconnection is a crucially important process for energy conversion in plasma physics, the substorm cycle of Earth's magnetosphere and solar flares being prime examples. While 2D models have been widely applied to study reconnection, investigating reconnection in 3D is still in many aspects an open problem. Finding sites of magnetic reconnection in a 3D setting is not a trivial task
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Inferring neutral winds in the ionospheric transition region from atmospheric-gravity-wave traveling-ionospheric-disturbance (AGW-TID) observations with the EISCAT VHF radar and the Nordic Meteor Radar Cluster Ann. Geophys. (IF 1.9) Pub Date : 2023-10-18 Florian Günzkofer, Dimitry Pokhotelov, Gunter Stober, Ingrid Mann, Sharon L. Vadas, Erich Becker, Anders Tjulin, Alexander Kozlovsky, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Evgenia Belova, Johan Kero, Nicholas J. Mitchell, Claudia Borries
Abstract. Atmospheric gravity waves and traveling ionospheric disturbances can be observed in the neutral atmosphere and the ionosphere at a wide range of spatial and temporal scales. Especially at medium scales, these oscillations are often not resolved in general circulation models and are parameterized. We show that ionospheric disturbances forced by upward-propagating atmospheric gravity waves
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Statistical distribution of mirror-mode-like structures in the magnetosheaths of unmagnetized planets – Part 2: Venus as observed by the Venus Express spacecraft Ann. Geophys. (IF 1.9) Pub Date : 2023-10-10 Martin Volwerk, Cyril Simon Wedlund, David Mautner, Sebastián Rojas Mata, Gabriella Stenberg Wieser, Yoshifumi Futaana, Christian Mazelle, Diana Rojas-Castillo, César Bertucci, Magda Delva
Abstract. In this series of papers, we present statistical maps of mirror-mode-like (MM) structures in the magnetosheaths of Mars and Venus and calculate the probability of detecting them in spacecraft data. We aim to study and compare them with the same tools and a similar payload at both planets. We consider their dependence on extreme ultraviolet (EUV) solar flux levels (high and low). The detection
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Estimating Gradients of Physical Fields in Space Ann. Geophys. (IF 1.9) Pub Date : 2023-10-04 Yufei Zhou, Chao Shen
Abstract. This study focuses on the development of a multipoint technique for future constellation missions, aiming to measure gradients at various order, in particular the linear and quadratic gradients, of a general field. It is well-established that in order to estimate linear gradients, the spacecraft must not lie on a plane. Through analytical exploration within the framework of least-squares
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Scale Size Estimation of Magnetosheath Jets Ann. Geophys. (IF 1.9) Pub Date : 2023-10-04 Adrian Pöppelwerth, Georg Glebe, Johannes Z. D. Mieth, Florian Koller, Tomas Karlsson, Zoltan Vörös, Ferdinand Plaschke
Abstract. Transient enhancements in the dynamic pressure, so-called magnetosheath jets or simply jets, are abundantly found in the magnetosheath. After their formation at the bow shock, they travel through the magnetosheath towards the magnetopause. On their way through the magnetosheath, jets disturb the ambient plasma. In this paper, we use multi-point measurements from the Time History of Events
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Effects of ion composition on escape and morphology on Mars Ann. Geophys. (IF 1.9) Pub Date : 2023-09-28 Qi Zhang, Mats Holmström, Xiao-Dong Wang
Abstract. We refine a recently presented method to estimate ion escape from non-magnetized planets and apply it to Mars. The method combines in situ observations and a hybrid plasma model (ions as particles, electrons as a fluid). We use measurements from the Mars Atmosphere and Volatile Evolution (MAVEN) mission and Mars Express (MEX) for one orbit on 1 March 2015. Observed upstream solar-wind conditions
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Parallel electric fields produced by ionospheric injection Ann. Geophys. (IF 1.9) Pub Date : 2023-09-19 Osuke Saka
Abstract. It is well known that there exists a thin layer in the lower boundary of the ionosphere between altitudes of 80 and 140 km in which collisional ions and collisionless electrons mix. Local breakdown of charge neutrality may be initiated in this layer by electric fields from the magnetosphere as well as by electric fields generated there by the local neutral winds. The breakdown may be momentarily
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The record of the magnetic storm on 15 May 1921 in Stará Ďala (present-day Hurbanovo) and its compliance with the global picture of this extreme event Ann. Geophys. (IF 1.9) Pub Date : 2023-09-12 Eduard Koči, Fridrich Valach
Abstract. This paper deals with the most intense magnetic storm of the 20th century, which took place on 13–15 May 1921. Part of this storm was observed in the magnetic declination and vertical intensity at Stará Ďala, currently known as Hurbanovo. However, the sensitivity of the magnetometer was not determined there in the years when the storm occurred. Here, we estimated the sensitivity scale values
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Influence of Meteoric Smoke Particles on the Incoherent Scatter Measured with EISCAT VH Ann. Geophys. (IF 1.9) Pub Date : 2023-09-13 Tinna Lif Gunnarsdottir, Ingrid Mann, Wuhu Feng, Devin R. Huyghebaert, Ingemar Haeggstroem, Yasunobu Ogawa, Norihito Saito, Satonori Nozawa, Takuya D. Kawahara
Abstract. Meteoric ablation in the Earth’s atmosphere produces particles of nanometer-size and larger. These particles can become charged and influence the charge balance in the D-region (60–90 km) and the incoherent scatter observed with radar from there. Radar studies have shown that if enough dust particles are charged, they can influence the received radar spectrum below 100 km, provided the electron
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Impact Ionization Double Peaks Analyzed in High Temporal Resolution on Solar Orbiter Ann. Geophys. (IF 1.9) Pub Date : 2023-09-12 Samuel Kočiščák, Ingrid Mann, Nicole Meyer-Vernet, Audun Theodorsen, Jakub Vaverka, Arnaud Zaslavsky
Abstract. Solar Orbiter is equipped with electrical antennas performing fast measurements of the surrounding electric field. The antennas register high velocity dust impacts through the electrical signatures of impact ionization. Although the basic principle of the detection has been known for decades, the understanding of the underlying process is not complete, due to unique mechanical and electrical
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Analysis of in situ measurements of electron, ion and neutral temperatures in the lower thermosphere–ionosphere Ann. Geophys. (IF 1.9) Pub Date : 2023-09-11 Panagiotis Pirnaris, Theodoros Sarris
Abstract. Simultaneous knowledge of the temperatures of electrons, ions and neutrals is key to the understanding and quantification of energy transfer processes in planetary atmospheres. However, whereas electron and ion temperature measurements are routinely obtained from ground-based incoherent scatter radars, simultaneous measurements of electron, ion and neutral temperature measurements can only
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Observations of Polar Mesospheric Summer Echoes Resembling Kilometer-Scale Varicose-Mode Flows Ann. Geophys. (IF 1.9) Pub Date : 2023-09-08 Jennifer Hartisch, Jorge L. Chau, Ralph Latteck, Toralf Renkwitz, Marius Zeacha
Abstract. The mesosphere and lower thermosphere (MLT) region represents a captivating yet challenging field of research. Remote sensing techniques, such as radar, have proven invaluable for investigating this domain. The Middle Atmosphere Alomar Radar System (MAARSY), located in Northern Norway (69° N, 16° E), uses Polar Mesospheric Summer Echoes (PMSE) as tracers to study MLT dynamics across multiple
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Velocity of magnetic holes in the solar wind from Cluster multipoint measurements Ann. Geophys. (IF 1.9) Pub Date : 2023-08-21 Henriette Trollvik, Tomas Karlsson, Savvas Raptis
Abstract. We present the first statistical study on the velocity of magnetic holes (MHs) in the solar wind. Magnetic holes are localized depressions of the magnetic field, often divided into two classes: rotational and linear MHs. We have conducted a timing analysis of observations of MHs from the Cluster mission in the first quarter of 2005. In total, 69 events were used; out of these, there were
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Comparison of radiation belt electron fluxes simultaneously measured with PROBA-V/EPT and RBSP/MagEIS instruments Ann. Geophys. (IF 1.9) Pub Date : 2023-08-17 Alexandre Winant, Viviane Pierrard, Edith Botek
Abstract. Relativistic radiation belt electron observations from the Energetic Particle Telescope (EPT) on board the PROBA-V (Project for On-Board Autonomy and Vegetation) satellite are compared to those performed by the Magnetic Electron Ion Spectrometer (MagEIS) on board the Van Allen Probes formerly known as the Radiation Belt Storm Probes (RBSP). Despite their very different orbits, both instruments
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Climatological comparison of polar mesosphere summer echoes over the Arctic and Antarctica at 69° Ann. Geophys. (IF 1.9) Pub Date : 2023-08-17 Ralph Latteck, Damian J. Murphy
Abstract. Polar Mesosphere Summer Echoes (PMSE) have been observed for more than 30 years with 50-MHz VHF radars at various locations in the Northern Hemisphere. Continuous observations of PMSE are conducted on the northern Norwegian island of Andøya (69.3° N) using the ALWIN radar (1999–2008) and MAARSY (since 2010). The same kind of PMSE measurements began in 2004 in the southern hemisphere with
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Ionospheric density depletions around crustal fields at Mars and their connection to ion frictional heating Ann. Geophys. (IF 1.9) Pub Date : 2023-08-17 Hadi Madanian, Troy Hesse, Firdevs Duru, Marcin Pilinski, Rudy Frahm
Abstract. Mars’ ionosphere is formed through ionization of the neutral atmosphere by solar irradiance, charge exchange, and electron impact. Observations by Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft have shown a highly dynamic ionospheric layer at Mars impacted by loss processes including ion escape, transport, and electron recombination. The crustal fields at Mars can also significantly
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A statistical study of the magnetic signatures of the unique Tonga volcanic explosion of 15 January 2022 Ann. Geophys. (IF 1.9) Pub Date : 2023-08-16 Leonid Chernogor
Abstract. For the first time, a statistical study has been conducted of the geomagnetic bay and quasi-periodic disturbances based on the datasets collected at 19 recording stations participating in INTERMAGNET Magnetic Observatories. In order to identify the disturbances from the volcanic explosion, a preliminary analysis has been used of the state of space weather during the catastrophic Tonga volcanic
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Deep Temporal Convolutional Networks for F10.7 Radiation Flux Short-Term Forecasting Ann. Geophys. (IF 1.9) Pub Date : 2023-08-15 Luyao Wang, Hua Zhang, Xiaoxin Zhang, Guangshuai Peng, Zheng Li
Abstract. F10.7, the solar radiation flux at a wavelength of 10.7 cm (F10.7), is often used as an important parameter input in various space weather models and is also a key parameter for measuring the strength of solar activity levels. Therefore, it is valuable to study and forecast F10.7. In this paper, the temporal convolutional network (TCN) approach in deep learning is used to predict the daily
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Electron radiation belt safety indices based on the SafeSpace modelling pipeline and dedicated to the internal charging risk Ann. Geophys. (IF 1.9) Pub Date : 2023-08-04 Nour Dahmen, Antoine Brunet, Sebastien Bourdarie, Christos Katsavrias, Guillerme Bernoux, Stefanos Doulfis, Afroditi Nasi, Ingmar Sandberg, Constantinos Papadimitriou, Jesus Oliveros Fernandez, Ioannis Daglis
Abstract. In this paper, we present the SafeSpace prototype for a safety warning system, dedicated to the electron radiation-belt-induced internal charging hazard aboard spacecraft. The space weather tool relies on a synergy of physical models associated in a chain that covers the whole Sun–interplanetary-space–Earth's inner magnetosphere medium. With the propagation of uncertainties along the modelling
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Three-dimensional ionospheric conductivity associated with pulsating auroral patches: Reconstruction from ground-based optical observations Ann. Geophys. (IF 1.9) Pub Date : 2023-08-04 Mizuki Fukizawa, Yoshimasa Tanaka, Yasunobu Ogawa, Keisuke Hosokawa, Tero Raita
Abstract. Pulsating auroras (PsAs) appear over a wide area within the aurora oval from the midnight sector to the noon sector. In previous studies, observations by magnetometers onboard satellites have reported the presence of field-aligned currents (FACs) near the edges and interiors of pulsating aurora patches. PsAs are thus a key research target for understanding the magnetosphere–ionosphere coupling
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Simultaneous OI 630 nm imaging observations of thermospheric gravity waves and associated revival of fossil depletions around midnight near the EIA crest Ann. Geophys. (IF 1.9) Pub Date : 2023-07-27 Navin Parihar, Saranya Padincharapad, Anand Kumar Singh
Abstract. We report the F-region airglow imaging of fossil plasma depletions around midnight that revived afresh under the persisting thermospheric gravity wave (GW) activity. An all-sky imager recorded these events in OI 630 nm imaging over Ranchi (23.3º N, 85.3º E, mlat. ~19º N), India, on 16 April 2012. Northward propagating and east-west aligned GWs (λ ~210 km, ~64 m/s, and τ ~0.91 h) were seen
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Greenhouse gas effects on the solar cycle response of water vapour and noctilucent clouds Ann. Geophys. (IF 1.9) Pub Date : 2023-07-24 Ashique Vellalassery, Gerd Baumgarten, Mykhaylo Grygalashvyly, Franz-Josef Lübken
Abstract. The responses of water vapour (H2O) and noctilucent clouds (NLCs) to the solar cycle are studied using the Leibniz Institute for Middle Atmosphere (LIMA) model and the Mesospheric Ice Microphysics And tranSport (MIMAS) model. NLCs are sensitive to the solar cycle because their formation depends on background temperature and the H2O concentration. The solar cycle affects the H2O concentration
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On mechanisms for HF pump-enhanced optical emissions at 557.7 and 630.0 nm from atomic oxygen in the high-latitude F-region ionosphere Ann. Geophys. (IF 1.9) Pub Date : 2023-07-20 Thomas B. Leyser, Tima Sergienko, Urban Brändström, Björn Gustavsson, Michael T. Rietveld
Abstract. The EISCAT Heating facility was used to transmit powerful high frequency (HF) electromagnetic waves into the F-region ionosphere to enhance optical emissions at 557.7 and 630.0 nm from atomic oxygen. The emissions were imaged by three stations of the Auroral Large Imaging System in northern Sweden and the EISCAT UHF incoherent scatter radar was used to obtain plasma parameter values. The
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Characteristic Analysis of the Differences between TEC Values in GIM Grids Ann. Geophys. (IF 1.9) Pub Date : 2023-07-19 Qisheng Wang, Jiaru Zhu
Abstract. Using total electron content (TEC) from global ionosphere map (GIM) for ionospheric delay correction is a common method of eliminating ionospheric errors in satellite navigation and positioning. On this basis, the TEC of puncture point can be obtained by GIM grid TEC interpolation. However, in terms of grid, only few studies have analyzed the TEC value size characteristics of its four grid
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Comparison of meteor radar and TIDI winds in the Brazilian equatorial region Ann. Geophys. (IF 1.9) Pub Date : 2023-07-18 Ana Roberta Paulino, Delis Otildes Rodrigues, Igo Paulino, Lourivaldo Mota Lima, Ricardo Arlen Buriti, Paulo Prado Batista, Aaron Ridley, Chen Wu
Abstract. Using data collected from a meteor radar deployed at São João do Cariri (7.4°, 36.5° S) and the TIMED Doppler Interferometer (TIDI) on board the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite for 2006, comparisons of the horizontal winds (meridional and zonal components) were made in order to evaluate these techniques for scientific investigation and pointed
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On the relationship between the mesospheric sodium layer and the meteoric input function Ann. Geophys. (IF 1.9) Pub Date : 2023-07-17 Yanlin Li, Tai-Yin Huang, Julio Urbina, Fabio Vargas, Wuhu Feng
Abstract. This study examines the relationship between the concentration of atmospheric sodium and its Meteoric Input Function (MIF). We use the measurements from the Colorado State University (CSU) Lidar and the Andes Lidar Observatory (ALO) with a new numerical model that includes sodium chemistry in the mesosphere and lower thermosphere (MLT) region. The model is based on the continuity equation