ANGEO - recent papers

Estimating the source altitude of auroral precipitation from dispersed Alfvén waves in the dayside ionosphere

Fri, 04 Sep 2026 21:06:37 +0200

Estimating the source altitude of auroral precipitation from dispersed Alfvén waves in the dayside ionosphere
Etienne Gavazzi, Andres Spicher, Björn Gustavsson, Juha Vierinen, James Clemmons, Robert Pfaff, and Douglas Rowland
Ann. Geophys., 44, 903–920, https://doi.org/10.5194/angeo-44-903-2026, 2026
Auroras are caused by energetic electrons entering the upper atmosphere. For the smallest and most dynamic auroras, scientists think electrons are accelerated by waves (called Alfvén waves) thousands of kilometers above Earth. In this paper, we analyse data from a rocket that flew through auroras, applying existing and new techniques to estimate where the acceleration took place. Our results match theory, and we show how they can be used to study conditions in the near-Earth space environment.

Magnetotail response to corotating interaction region driven geomagnetic storms: Cluster observations

Tue, 01 Sep 2026 21:06:37 +0200

Magnetotail response to corotating interaction region driven geomagnetic storms: Cluster observations
Adriane Marques de Souza Franco, Rashmi Rawat, Mauricio José Alves Bolzan, and Ezequiel Echer
Ann. Geophys., 44, 881–901, https://doi.org/10.5194/angeo-44-881-2026, 2026
This study investigates 40 geomagnetic storms driven by corotating interaction regions and their impact on Earth's magnetotail. We find that short, 4 h energy pulses dominate the magnetotail during cyclic substorms. Furthermore, High-Intensity, Long-Duration, Continuous Auroral Activity (HILDCAA) events in the recovery phase facilitate energy distribution across 2–12 h periodicities in the auroral region. Spectral indices indicate strong turbulence in both regions.

Dune aurora: survey from a citizen science database

Thu, 27 Aug 2026 21:06:37 +0200

Dune aurora: survey from a citizen science database
Maxime Grandin, Liisa Juusola, Noora Partamies, Emma Bruus, Joona Rautiainen, Donna Lach, Jia Jia, Max van de Kamp, Eero Karvinen, Kirsti Kauristie, and Theresa Hoppe
Ann. Geophys., 44, 855–880, https://doi.org/10.5194/angeo-44-855-2026, 2026
Dune aurora is an intriguing phenomenon recently discovered thanks to citizen science. It is a dim, diffuse auroral form exhibiting wave-like stripes of brighter emission. We carry out the first statistical study of dune aurora, using 308 observation reports submitted to the Skywarden database by citizen scientists from Europe, North America, and Oceania. We find that dunes are an evening phenomenon, most often reported in March and October and associated with currents in the auroral atmosphere.

Post launch spectral and radiometric performances of MAJIS, the VIS-NIR imaging spectrometer of JUICE

Wed, 26 Aug 2026 21:06:37 +0200

Post launch spectral and radiometric performances of MAJIS, the VIS-NIR imaging spectrometer of JUICE
Yves Langevin, Sébastien Rodriguez, Sandrine Guerlet, François Poulet, Giuseppe Piccioni, Livio Agostini, Raymond Armante, Emiliano D'Aversa, Gianrico Filacchione, Leigh Fletcher, Fabrizio Oliva, Clément Royer, Benoît Seignovert, Katrin Stephan, Federico Tosi, and Tim Trent
Ann. Geophys., 44, 825–853, https://doi.org/10.5194/angeo-44-825-2026, 2026
We present an updated spectral and radiometric calibration of the Moons and Jupiter Imaging Spectrometer (MAJIS) aboard the Jupiter Icy Moons Explorer (JUICE), based on results of Earth and Moon observations in August 2024 and on observations of the MAJIS internal calibration unit. Very good agreements were obtained with results of other instruments and models. These MAJIS observations provide a promising teaser of what will be achieved by MAJIS in the system of Jupiter.

High latitude, dayside rapid geomagnetic variations observed with ground-based magnetometers in Greenland

Mon, 24 Aug 2026 21:06:37 +0200

High latitude, dayside rapid geomagnetic variations observed with ground-based magnetometers in Greenland
Marie Vigger Eldor, Magnar Gullikstad Johnsen, Nils Olsen, and Anna Naemi Willer
Ann. Geophys., 44, 811–823, https://doi.org/10.5194/angeo-44-811-2026, 2026
Rapid geomagnetic variations in the ultra-low frequency band are observed using ground-based magnetometers. We apply four years of data from West Greenland in a statistical analysis of the distribution of such variations. We identify a rapid geomagnetic variation population associated with the magnetospheric cusp that is separate from the auroral oval during summer. Earlier studies, which were mainly performed in winter, failed to unambiguously identify these variations.

Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 3: Observations of the Earth as calibration target

Fri, 21 Aug 2026 21:06:37 +0200

Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 3: Observations of the Earth as calibration target
Christopher Jarchow, Ladislav Rezac, Paul Hartogh, Ali Schulz-Ravanbakhsh, Thibault Cavalié, Fabrice Herpin, Raphael Moreno, and Axel Murk
Ann. Geophys., 44, 795–809, https://doi.org/10.5194/angeo-44-795-2026, 2026
The Jupiter Icy Moons Explorer is a spacecraft sent towards Jupiter to perform detailed observations of the giant gas planet & its Galilean satellites. The Submillimetre Wave Instrument onboard this spacecraft is a newly built instrument, which first of all has to demonstrate proper performance before the observed data can be trusted. Using the Earth as a well-known observation target, proper functionality of this instrument has been verified during the Lunar Earth Gravity Assist in August 2024.

Storm-time energy budget in the high latitude lower thermosphere–ionosphere: quantification of energy exchange and comparison of different drivers in TIE-GCM

Wed, 19 Aug 2026 21:06:37 +0200

Storm-time energy budget in the high latitude lower thermosphere–ionosphere: quantification of energy exchange and comparison of different drivers in TIE-GCM
Stelios Tourgaidis, Theodoros Sarris, Dimitrios Baloukidis, Stephan Buchert, Panagiotis Pirnaris, Konstantinos Papadakis, and Athanasios Balafoutis
Ann. Geophys., 44, 773–793, https://doi.org/10.5194/angeo-44-773-2026, 2026
The Lower Thermosphere-Ionosphere energy balance is driven by complex interactions between ions, neutrals and electrons. These processes are understood theoretically, but their estimates show large discrepancies between models. We calculate the storm-time energy budget according to the neutrals, ions and electrons using TIE-GCM (Thermosphere Ionosphere Electrodynamics General Circulation Model) using two different external drivers. Discrepancies between the model runs are discussed and the way forward to close the gaps in present knowledge is highlighted.

A near-sunset atmospheric sounding during the 14 October 2023 annular solar eclipse over Natal

Tue, 18 Aug 2026 21:06:37 +0200

A near-sunset atmospheric sounding during the 14 October 2023 annular solar eclipse over Natal
Igo Paulino, Francisco Raimundo da Silva, Ana Roberta Paulino, and Gilvan Borba
Ann. Geophys., 44, 765–772, https://doi.org/10.5194/angeo-44-765-2026, 2026
The study utilized a stratospheric balloon over Natal, Brazil, to investigate the atmospheric response to the 14 October 2023 annular solar eclipse near sunset. Measurements included temperature, pressure, relative humidity and ozone. Significant changes in these parameters were found at different altitudes. These complex changes confirm the importance of the annular eclipses as a driver of localized atmospheric dynamics.

Magnetosphere–ionosphere response to the 21 and 25 June 2015 coronal mass ejections

Mon, 17 Aug 2026 21:06:37 +0200

Magnetosphere–ionosphere response to the 21 and 25 June 2015 coronal mass ejections
Somaiyeh Sabri and Stefaan Poedts
Ann. Geophys., 44, 743–763, https://doi.org/10.5194/angeo-44-743-2026, 2026
Coronal mass ejections (CMEs) threaten Earth. We studied their interaction with the magnetosphere and ionosphere. Using the European Heliospheric Forecasting Information Asset (EUHFORIA), we calculated CME arrival times and investigated Earth's responses. Results show EUHFORIA and Gorgon-Space codes agree well in simulating CME propagation and interactions.

Analysis of 3GM High Accuracy Accelerometer data collected during JUICE lunar earth gravity assist

Fri, 14 Aug 2026 21:06:37 +0200

Analysis of 3GM High Accuracy Accelerometer data collected during JUICE lunar earth gravity assist
Umberto De Filippis, Paolo Cappuccio, Mauro Di Benedetto, Ivan di Stefano, Daniele Durante, and Luciano Iess
Ann. Geophys., 44, 731–741, https://doi.org/10.5194/angeo-44-731-2026, 2026
The High Accuracy Accelerometer calibrated data collected during the JUICE (JUpiter ICy moons Explorer) Lunar Earth Gravity assist flyby was compared with predicted non-gravitational signals derived from analytical models, showing good agreement. Moon gravity gradient and thermoelastic displacement of solar array during the penumbra phases have been detected. High Accurate Accelerometer detected also unexpected signals such as instrument interference and outgassing event.

What is the neutral wind in height-integrated ionospheric electrodynamics?

Wed, 05 Aug 2026 21:06:37 +0200

What is the neutral wind in height-integrated ionospheric electrodynamics?
Spencer Mark Hatch, Johnathan Burchill, Heikki Vanhamäki, Rafael Luiz Araujo de Mesquita, and Karl Magnus Laundal
Ann. Geophys., 44, 715–729, https://doi.org/10.5194/angeo-44-715-2026, 2026
Atmospheric winds at high altitudes (> 100 km) can play an important role in the electrodynamic processes that govern how ionospheric plasma interacts with Earth's neutral atmosphere. Here we investigate how a common idea in studies of ionospheric electrodynamics—that atmospheric winds can be ignored or represented via an average value—ignores the high variability of these winds. This variability forces a different formulation of the equations that govern ionosphere-thermosphere electrodynamics.

A numerical model for solving the linearized gravity-wave equations by a multilayer method

Tue, 28 Jul 2026 21:06:37 +0200

A numerical model for solving the linearized gravity-wave equations by a multilayer method
Alexandru Doicu, Dmitry S. Efremenko, and Thomas Trautmann
Ann. Geophys., 44, 655–688, https://doi.org/10.5194/angeo-44-655-2026, 2026
We created a new computer model to study gravity waves, which are ripples in the atmosphere that affect weather and climate. Our research aimed to improve how these waves are simulated, as they play a key role in understanding atmospheric behavior. We developed a stable and efficient model that can model gravity waves in the atmosphere. Our method is fast and accurate, offering better tools for scientists to predict atmospheric changes.

Harmonic content of Ap index

Tue, 28 Jul 2026 21:06:37 +0200

Harmonic content of Ap index
Marek Vandas, Evgeny Romashets, Tasmina Imam, Tanvir Hasan, Pranab Majumder, and Sanjay Karki
Ann. Geophys., 44, 689–696, https://doi.org/10.5194/angeo-44-689-2026, 2026
Fourier spectral analysis is applied to the planetary geomagnetic index $A_p$ for the February 2001, 2003, and 2017 time intervals.

High-latitude observations of ULF wave driven ion upflow

Tue, 28 Jul 2026 21:06:37 +0200

High-latitude observations of ULF wave driven ion upflow
Charlotte M. van Hazendonk, Lisa J. Baddeley, Karl M. Laundal, and Noora Partamies
Ann. Geophys., 44, 697–714, https://doi.org/10.5194/angeo-44-697-2026, 2026
This study shows the first observations of the upflow of ions in the Earth's ionosphere generated by ultra-low frequency waves. These waves are visible as auroral arcs. Using various instruments and models, their complex dynamics and the coupling between the ionosphere and magnetosphere were highlighted. Results show significant energy dissipation and currents, even from small-scale waves, highlighting the importance of a multi-instrument approach to understanding such phenomena.

Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 1: General overview

Thu, 09 Jul 2026 21:06:37 +0200

Juice/SWI during the Lunar-Earth-Gravity-Assist (LEGA) – Part 1: General overview
Paul Hartogh, Ladislav Rezac, Thibault Cavalié, Christopher Jarchow, Raphael Moreno, Ali Schulz-Ravanbakhsh, Alberto Carrasco Gallardo, Borys Dabrowski, Samuel Goodyear, Miriam Rengel, Fabrice Herpin, Yasuko Kasai, Mikko Kotiranta, Emmanuel Lellouch, Axel Murk, Michael Olberg, Slawomira Szutowicz, and Eva Wirström
Ann. Geophys., 44, 645–654, https://doi.org/10.5194/angeo-44-645-2026, 2026
We provide an introduction and overview about the initial Submillimetre Wave Instrument (SWI) characterization, operation, and in-flight calibration during the Lunar Earth Gravity Assist (LEGA) campaign of the Juice (Jupiter icy moons) spacecraft. A preliminary analysis on the frequency calibration is provided. For detailed analyses on total power and beam calibration and the observation and operations planning we refer to three other SWI papers prepared for this special issue of Annales Geophysicae (ANGEO).

Tracking ionospheric changes during solar eclipses: Concepción historical data

Tue, 07 Jul 2026 21:06:37 +0200

Tracking ionospheric changes during solar eclipses: Concepción historical data
Adán Y. Godoy, Manuel A. Bravo, Benjamín A. Urra, Carlos A. Castillo-Rivera, Marayén R. Canales, and Alberto J. Foppiano
Ann. Geophys., 44, 631–643, https://doi.org/10.5194/angeo-44-631-2026, 2026
Long-term analysis of 16 solar eclipses over south-central Chile using historical ionograms (1958–2024). Layer-dependent ionospheric responses were quantified, and fragile analog records were rescued and digitized, providing unique insights into eclipse-induced ionospheric variability.

Characterising mesoscale magnetopause surface waves within magnetosphere–ionosphere–ground coupling

Tue, 07 Jul 2026 21:06:37 +0200

Characterising mesoscale magnetopause surface waves within magnetosphere–ionosphere–ground coupling
Martin Archer, David Southwood, Song Zhang, Qiran Sun, and Mike Heyns
Ann. Geophys., 44, 595–630, https://doi.org/10.5194/angeo-44-595-2026, 2026
Waves on the boundary of our magnetic shield, the magnetosphere, act as a source of electrical currents in space that flow between outer space and the ionised top of our atmosphere. We develop a simple numerical model of how these waves couple to different regions of geospace to determine their likely impacts in the context of space weather and how these vary with conditions. We find the waves’ impacts can be significant, though are typically highly localised.

Spatial characteristics of the dayside auroral ionosphere observed by Incoherent Scatter Radar

Wed, 01 Jul 2026 21:06:37 +0200

Spatial characteristics of the dayside auroral ionosphere observed by Incoherent Scatter Radar
Ingeborg Frøystein, Andres Spicher, and Kjellmar Oksavik
Ann. Geophys., 44, 577–593, https://doi.org/10.5194/angeo-44-577-2026, 2026
The dayside auroral region is a highly dynamic region of the ionosphere that is influenced by the coupling between the solar wind, magnetosphere, and ionosphere. In this paper, we illustrate this dynamic nature and present a quantitative analysis of both altitudinal and latitudinal variation within the region. In addition, ionospheric parameters on closed field lines, along the open-closed field line boundary and in the polar cap are statistically compared.

The JUICE 2024 close flyby of the Moon: thermal assessment from MAJIS

Wed, 24 Jun 2026 21:06:37 +0200

The JUICE 2024 close flyby of the Moon: thermal assessment from MAJIS
Federico Tosi, Clément Royer, Federico Colaiuta, François Poulet, Tyler M. Powell, Benjamin T. Greenhagen, Yves Langevin, Alessandro Mura, Giuseppe Piccioni, Cédric Pilorget, Cristian Carli, and Francesca Zambon
Ann. Geophys., 44, 547–576, https://doi.org/10.5194/angeo-44-547-2026, 2026
Using mid-infrared data acquired by Moons and Jupiter Imaging Spectrometer (MAJIS) aboard the European Space Agency’s JUpiter ICy moons Explorer (JUICE) spacecraft during the 2024 lunar flyby, we retrieved lunar surface temperature and effective emissivity at high spatial and spectral resolution. By comparing three independent thermal-retrieval methods, we confirmed the main mare–highland contrasts and showed how roughness and observing geometry shape the infrared signal, providing a methodological test case for future MAJIS studies of Jupiter’s icy moons.

Equatorial ionospheric plasma bubbles during intense geomagnetic storms of Solar Cycle 25

Tue, 23 Jun 2026 21:06:37 +0200

Equatorial ionospheric plasma bubbles during intense geomagnetic storms of Solar Cycle 25
Nadia Imtiaz, Andres Calabia, Chukwuma Anoruo, Aqsa Zahid, Christine Amory-Mazaudier, and Binod Adhikari
Ann. Geophys., 44, 489–509, https://doi.org/10.5194/angeo-44-489-2026, 2026
Comprehensive analysis of geomagnetic storms from 23–25 March, 23–25 April, 4–6 November 2023, and 10–13 May 2024, reveals that solar wind parameters, geomagnetic activity, Joule heating, and Prompt Penetration Electric Fields significantly influence ionospheric Total Electron Content variations, Equatorial Ionization Anomaly crest formations, and post-sunset plasma irregularities. The storms highlighted the importance of inter-hemispheric asymmetries in Joule Heating, which affected the distribution and magnitude of ionospheric disturbances.