Articles | Volume 43, issue 1
https://doi.org/10.5194/angeo-43-99-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/angeo-43-99-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
24 Jan 2025
Regular paper |
| 24 Jan 2025
| 24 Jan 2025
Simulation of interferometric imaging with EISCAT_3D for fine-scale in-beam incoherent scatter spectra measurements
Devin Huyghebaert
CORRESPONDING AUTHOR
Department of Physics and Technology, UiT The Arctic University of Norway, Tromsø, Norway
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Canada
Björn Gustavsson
Department of Physics and Technology, UiT The Arctic University of Norway, Tromsø, Norway
Juha Vierinen
Department of Physics and Technology, UiT The Arctic University of Norway, Tromsø, Norway
Andreas Kvammen
Department of Physics and Technology, UiT The Arctic University of Norway, Tromsø, Norway
Matthew Zettergren
Embry–Riddle Aeronautical University, Daytona Beach, FL, USA
John Swoboda
MIT Haystack Observatory, Westford, MA, USA
Ilkka Virtanen
Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
Spencer M. Hatch
Department of Physics and Technology, University of Bergen, Bergen, Norway
Karl M. Laundal
Department of Physics and Technology, University of Bergen, Bergen, Norway
Related authors
Dorota Jozwicki, Puneet Sharma, Devin Huyghebaert, and Ingrid Mann
Ann. Geophys., 42, 431–453, https://doi.org/10.5194/angeo-42-431-2024, https://doi.org/10.5194/angeo-42-431-2024, 2024
Short summary
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We investigated the relationship between polar mesospheric summer echo (PMSE) layers and the solar cycle. Our results indicate that the average altitude of PMSEs, the echo power in the PMSEs and the thickness of the layers are, on average, higher during the solar maximum than during the solar minimum. We infer that higher electron densities at ionospheric altitudes might be necessary to observe multilayered PMSEs. We observe that the thickness decreases as the number of multilayers increases.
Tinna L. Gunnarsdottir, Ingrid Mann, Wuhu Feng, Devin R. Huyghebaert, Ingemar Haeggstroem, Yasunobu Ogawa, Norihito Saito, Satonori Nozawa, and Takuya D. Kawahara
Ann. Geophys., 42, 213–228, https://doi.org/10.5194/angeo-42-213-2024, https://doi.org/10.5194/angeo-42-213-2024, 2024
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Several tons of meteoric particles burn up in our atmosphere each day. This deposits a great deal of material that binds with other atmospheric particles and forms so-called meteoric smoke particles. These particles are assumed to influence radar measurements. Here, we have compared radar measurements with simulations of a radar spectrum with and without dust particles and found that dust influences the radar spectrum in the altitude range of 75–85 km.
Theresa Rexer, Björn Gustavsson, Juha Vierinen, Andres Spicher, Devin Ray Huyghebaert, Andreas Kvammen, Robert Gillies, and Asti Bhatt
Geosci. Instrum. Method. Data Syst. Discuss., https://doi.org/10.5194/gi-2023-18, https://doi.org/10.5194/gi-2023-18, 2024
Preprint under review for GI
Short summary
Short summary
We present a second-level calibration method for electron density measurements from multi-beam incoherent scatter radars. It is based on the well-known Flat field correction method used in imaging and photography. The methods improve data quality and useability as they account for unaccounted, and unpredictable variations in the radar system. This is valuable for studies where inter-beam calibration is important such as studies of polar cap patches, plasma irregularities and turbulence.
Noora Partamies, Rowan Dayton-Oxland, Katie Herlingshaw, Ilkka Virtanen, Bea Gallardo-Lacourt, Mikko Syrjäsuo, Fred Sigernes, Takanori Nishiyama, Toshi Nishimura, Mathieu Barthelemy, Anasuya Aruliah, Daniel Whiter, Lena Mielke, Maxime Grandin, Eero Karvinen, Marjan Spijkers, and Vincent Ledvina
EGUsphere, https://doi.org/10.5194/egusphere-2024-3669, https://doi.org/10.5194/egusphere-2024-3669, 2024
This preprint is open for discussion and under review for Annales Geophysicae (ANGEO).
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We studied the first broad band emissions, called continuum, in the dayside aurora. They are similar to STEVE with white, pale pink or mauve coloured light. But unlike STEVE, they follow the dayside aurora forming rays and other dynamic shapes. We used ground optical and radar observations and found evidence of heating and upwelling of both plasma and neutral air. This study provides new information on conditions for continuum emission, but its understanding will require further work.
Dorota Jozwicki, Puneet Sharma, Devin Huyghebaert, and Ingrid Mann
Ann. Geophys., 42, 431–453, https://doi.org/10.5194/angeo-42-431-2024, https://doi.org/10.5194/angeo-42-431-2024, 2024
Short summary
Short summary
We investigated the relationship between polar mesospheric summer echo (PMSE) layers and the solar cycle. Our results indicate that the average altitude of PMSEs, the echo power in the PMSEs and the thickness of the layers are, on average, higher during the solar maximum than during the solar minimum. We infer that higher electron densities at ionospheric altitudes might be necessary to observe multilayered PMSEs. We observe that the thickness decreases as the number of multilayers increases.
Maxime Grandin, Noora Partamies, and Ilkka I. Virtanen
Ann. Geophys., 42, 355–369, https://doi.org/10.5194/angeo-42-355-2024, https://doi.org/10.5194/angeo-42-355-2024, 2024
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Auroral displays typically take place at high latitudes, but the exact latitude where the auroral breakup occurs can vary. In this study, we compare the characteristics of the fluxes of precipitating electrons from space during auroral breakups occurring above Tromsø (central part of the auroral zone) and above Svalbard (poleward boundary of the auroral zone). We find that electrons responsible for the aurora above Tromsø carry more energy than those precipitating above Svalbard.
Tinna L. Gunnarsdottir, Ingrid Mann, Wuhu Feng, Devin R. Huyghebaert, Ingemar Haeggstroem, Yasunobu Ogawa, Norihito Saito, Satonori Nozawa, and Takuya D. Kawahara
Ann. Geophys., 42, 213–228, https://doi.org/10.5194/angeo-42-213-2024, https://doi.org/10.5194/angeo-42-213-2024, 2024
Short summary
Short summary
Several tons of meteoric particles burn up in our atmosphere each day. This deposits a great deal of material that binds with other atmospheric particles and forms so-called meteoric smoke particles. These particles are assumed to influence radar measurements. Here, we have compared radar measurements with simulations of a radar spectrum with and without dust particles and found that dust influences the radar spectrum in the altitude range of 75–85 km.
Spencer Mark Hatch, Heikki Vanhamäki, Karl Magnus Laundal, Jone Peter Reistad, Johnathan K. Burchill, Levan Lomidze, David J. Knudsen, Michael Madelaire, and Habtamu Tesfaw
Ann. Geophys., 42, 229–253, https://doi.org/10.5194/angeo-42-229-2024, https://doi.org/10.5194/angeo-42-229-2024, 2024
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In studies of the Earth's ionosphere, a hot topic is how to estimate ionospheric conductivity. This is hard to do for a variety of reasons that mostly amount to a lack of measurements. In this study we use satellite measurements to estimate electromagnetic work and ionospheric conductances in both hemispheres. We identify where our model estimates are inconsistent with laws of physics, which partially solves a previous problem with unrealistic predictions of ionospheric conductances.
Samuel Kočiščák, Andreas Kvammen, Ingrid Mann, Nicole Meyer-Vernet, David Píša, Jan Souček, Audun Theodorsen, Jakub Vaverka, and Arnaud Zaslavsky
Ann. Geophys., 42, 191–212, https://doi.org/10.5194/angeo-42-191-2024, https://doi.org/10.5194/angeo-42-191-2024, 2024
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In situ observations are crucial for understanding interplanetary dust, yet not every spacecraft has a dedicated dust detector. Dust encounters happen at great speeds, leading to high energy density at impact, which leads to ionization and charge release, which is detected with electrical antennas. Our work looks at how the transient charge plume interacts with Solar Orbiter spacecraft. Our findings are relevant for the design of future experiments and the understanding of present data.
Yoshimasa Tanaka, Yasunobu Ogawa, Akira Kadokura, Takehiko Aso, Björn Gustavsson, Urban Brändström, Tima Sergienko, Genta Ueno, and Satoko Saita
Ann. Geophys., 42, 179–190, https://doi.org/10.5194/angeo-42-179-2024, https://doi.org/10.5194/angeo-42-179-2024, 2024
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We present via 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) to modeled multiple auroral images and ionospheric electron density data. It is demonstrated that G-ACT provides better reconstruction results than the normal ACT and can interpolate ionospheric electron density at a much higher spatial resolution than observed by the EISCAT_3D radar.
Theresa Rexer, Björn Gustavsson, Juha Vierinen, Andres Spicher, Devin Ray Huyghebaert, Andreas Kvammen, Robert Gillies, and Asti Bhatt
Geosci. Instrum. Method. Data Syst. Discuss., https://doi.org/10.5194/gi-2023-18, https://doi.org/10.5194/gi-2023-18, 2024
Preprint under review for GI
Short summary
Short summary
We present a second-level calibration method for electron density measurements from multi-beam incoherent scatter radars. It is based on the well-known Flat field correction method used in imaging and photography. The methods improve data quality and useability as they account for unaccounted, and unpredictable variations in the radar system. This is valuable for studies where inter-beam calibration is important such as studies of polar cap patches, plasma irregularities and turbulence.
Thomas B. Leyser, Tima Sergienko, Urban Brändström, Björn Gustavsson, and Michael T. Rietveld
Ann. Geophys., 41, 589–600, https://doi.org/10.5194/angeo-41-589-2023, https://doi.org/10.5194/angeo-41-589-2023, 2023
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Powerful radio waves transmitted into the ionosphere from the ground were used to study electron energization in the pumped ionospheric plasma turbulence, by detecting optical emissions from atomic oxygen. Our results obtained with the EISCAT (European Incoherent Scatter Scientific Association) facilities in northern Norway and optical detection with the ALIS (Auroral Large Imaging System) in northern Sweden suggest that long-wavelength upper hybrid waves are important in accelerating electrons.
Andreas Kvammen, Kristoffer Wickstrøm, Samuel Kociscak, Jakub Vaverka, Libor Nouzak, Arnaud Zaslavsky, Kristina Rackovic Babic, Amalie Gjelsvik, David Pisa, Jan Soucek, and Ingrid Mann
Ann. Geophys., 41, 69–86, https://doi.org/10.5194/angeo-41-69-2023, https://doi.org/10.5194/angeo-41-69-2023, 2023
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Collisional fragmentation of asteroids, comets and meteoroids is the main source of dust in the solar system. The dust distribution is however uncharted and the role of dust in the solar system is largely unknown. At present, the interplanetary medium is explored by the Solar Orbiter spacecraft. We present a novel method, based on artificial intelligence, that can be used for detecting dust impacts in Solar Orbiter observations with high accuracy, advancing the study of dust in the solar system.
Johann Stamm, Juha Vierinen, Björn Gustavsson, and Andres Spicher
Ann. Geophys., 41, 55–67, https://doi.org/10.5194/angeo-41-55-2023, https://doi.org/10.5194/angeo-41-55-2023, 2023
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The study of some ionospheric events benefit from the knowledge of how the physics varies over a volume and over time. Examples are studies of aurora or energy deposition. With EISCAT3D, measurements of ion velocity vectors in a volume will be possible for the first time. We present a technique that uses a set of such measurements to estimate electric field and neutral wind. The technique relies on adding restrictions to the estimates. We successfully consider restrictions based on physics.
Daniel K. Whiter, Noora Partamies, Björn Gustavsson, and Kirsti Kauristie
Ann. Geophys., 41, 1–12, https://doi.org/10.5194/angeo-41-1-2023, https://doi.org/10.5194/angeo-41-1-2023, 2023
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We measured the height of green and blue aurorae using thousands of camera images recorded over a 7-year period. Both colours are typically brightest at about 114 km altitude. When they peak at higher altitudes the blue aurora is usually higher than the green aurora. This information will help other studies which need an estimate of the auroral height. We used a computer model to explain our observations and to investigate how the green aurora is produced.
Knut Ola Dølven, Juha Vierinen, Roberto Grilli, Jack Triest, and Bénédicte Ferré
Geosci. Instrum. Method. Data Syst., 11, 293–306, https://doi.org/10.5194/gi-11-293-2022, https://doi.org/10.5194/gi-11-293-2022, 2022
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Sensors capable of measuring rapid fluctuations are important to improve our understanding of environmental processes. Many sensors are unable to do this, due to their reliance on the transfer of the measured property, for instance a gas, across a semi-permeable barrier. We have developed a mathematical tool which enables the retrieval of fast-response signals from sensors with this type of sensor design.
Carsten Baumann, Antti Kero, Shikha Raizada, Markus Rapp, Michael P. Sulzer, Pekka T. Verronen, and Juha Vierinen
Ann. Geophys., 40, 519–530, https://doi.org/10.5194/angeo-40-519-2022, https://doi.org/10.5194/angeo-40-519-2022, 2022
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The Arecibo radar was used to probe free electrons of the ionized atmosphere between 70 and 100 km altitude. This is also the altitude region were meteors evaporate and form secondary particulate matter, the so-called meteor smoke particles (MSPs). Free electrons attach to these MSPs when the sun is below the horizon and cause a drop in the number of free electrons, which are the subject of these measurements. We also identified a different number of free electrons during sunset and sunrise.
Mizuki Fukizawa, Takeshi Sakanoi, Yoshimasa Tanaka, Yasunobu Ogawa, Keisuke Hosokawa, Björn Gustavsson, Kirsti Kauristie, Alexander Kozlovsky, Tero Raita, Urban Brändström, and Tima Sergienko
Ann. Geophys., 40, 475–484, https://doi.org/10.5194/angeo-40-475-2022, https://doi.org/10.5194/angeo-40-475-2022, 2022
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The pulsating auroral generation mechanism has been investigated by observing precipitating electrons using rockets or satellites. However, it is difficult for such observations to distinguish temporal changes from spatial ones. In this study, we reconstructed the horizontal 2-D distribution of precipitating electrons using only auroral images. The 3-D aurora structure was also reconstructed. We found that there were both spatial and temporal changes in the precipitating electron energy.
Snizhana Ross, Arttu Arjas, Ilkka I. Virtanen, Mikko J. Sillanpää, Lassi Roininen, and Andreas Hauptmann
Atmos. Meas. Tech., 15, 3843–3857, https://doi.org/10.5194/amt-15-3843-2022, https://doi.org/10.5194/amt-15-3843-2022, 2022
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Radar measurements of thermal fluctuations in the Earth's ionosphere produce weak signals, and tuning to specific altitudes results in suboptimal resolution for other regions, making an accurate analysis of these changes difficult. A novel approach to improve the resolution and remove measurement noise is considered. The method can capture variable characteristics, making it ideal for the study of a large range of data. Synthetically generated examples and two measured datasets were considered.
Derek McKay, Juha Vierinen, Antti Kero, and Noora Partamies
Geosci. Instrum. Method. Data Syst., 11, 25–35, https://doi.org/10.5194/gi-11-25-2022, https://doi.org/10.5194/gi-11-25-2022, 2022
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When radio waves from our galaxy enter the Earth's atmosphere, they are absorbed by electrons in the upper atmosphere. It was thought that by measuring the amount of absorption, it would allow the height of these electrons in the atmosphere to be determined. If so, this would have significance for future instrument design. However, this paper demonstrates that it is not possible to do this, but it does explain how multiple-frequency measurements can nevertheless be useful.
Johann Stamm, Juha Vierinen, and Björn Gustavsson
Ann. Geophys., 39, 961–974, https://doi.org/10.5194/angeo-39-961-2021, https://doi.org/10.5194/angeo-39-961-2021, 2021
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Measurements of the electric field and neutral wind in the ionosphere are important for understanding energy flows or electric currents. With incoherent scatter radars (ISRs), we can measure the velocity of the ions, which depends on both the electrical field and the neutral wind. In this paper, we investigate methods to use ISR data to find reasonable values for both parameters. We find that electric field can be well measured down to 125 km height and neutral wind below this height.
Emranul Sarkar, Alexander Kozlovsky, Thomas Ulich, Ilkka Virtanen, Mark Lester, and Bernd Kaifler
Atmos. Meas. Tech., 14, 4157–4169, https://doi.org/10.5194/amt-14-4157-2021, https://doi.org/10.5194/amt-14-4157-2021, 2021
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The biasing effect in meteor radar temperature has been a pressing issue for the last 2 decades. This paper has addressed the underlying reasons for such a biasing effect on both theoretical and experimental grounds. An improved statistical method has been developed which allows atmospheric temperatures at around 90 km to be measured with meteor radar in an independent way such that any subsequent bias correction or calibration is no longer required.
Torbjørn Tveito, Juha Vierinen, Björn Gustavsson, and Viswanathan Lakshmi Narayanan
Ann. Geophys., 39, 427–438, https://doi.org/10.5194/angeo-39-427-2021, https://doi.org/10.5194/angeo-39-427-2021, 2021
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This work explores the role of EISCAT 3D as a tool for planetary mapping. Due to the challenges inherent in detecting the signals reflected from faraway bodies, we have concluded that only the Moon is a viable mapping target. We estimate the impact of the ionosphere on lunar mapping, concluding that its distorting effects should be easily manageable. EISCAT 3D will be useful for mapping the lunar nearside due to its previously unused frequency (233 MHz) and its interferometric capabilities.
Johann Stamm, Juha Vierinen, Juan M. Urco, Björn Gustavsson, and Jorge L. Chau
Ann. Geophys., 39, 119–134, https://doi.org/10.5194/angeo-39-119-2021, https://doi.org/10.5194/angeo-39-119-2021, 2021
Daniel Kastinen, Torbjørn Tveito, Juha Vierinen, and Mikael Granvik
Ann. Geophys., 38, 861–879, https://doi.org/10.5194/angeo-38-861-2020, https://doi.org/10.5194/angeo-38-861-2020, 2020
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We have applied three different methods to examine the observability, both tracking and discovery, of near-Earth objects (NEOs) by the EISCAT 3D radar system currently under construction. There are, to our knowledge, no previous studies on the expected discovery rates of NEOs using radar systems. We show that it is feasible to regularly track NEOs and mini-moons. We also show it is possible to discover new NEOs and mini-moons with EISCAT 3D, something never before done with radar systems.
Sam Tuttle, Betty Lanchester, Björn Gustavsson, Daniel Whiter, Nickolay Ivchenko, Robert Fear, and Mark Lester
Ann. Geophys., 38, 845–859, https://doi.org/10.5194/angeo-38-845-2020, https://doi.org/10.5194/angeo-38-845-2020, 2020
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Electric fields in the atmosphere near dynamic aurora are important in the physics of the electric circuit within the Earth's magnetic field. Oxygen ions emit light as they move under the influence of these electric fields; the flow of this emission is used to find the electric field at high temporal resolution. The solution needs two other simultaneous measurements of auroral emissions to give key parameters such as the auroral energy. The electric fields increase with brightness of the aurora.
Derek McKay and Andreas Kvammen
Geosci. Instrum. Method. Data Syst., 9, 267–273, https://doi.org/10.5194/gi-9-267-2020, https://doi.org/10.5194/gi-9-267-2020, 2020
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Researchers are making increasing use of machine learning to improve accuracy, efficiency and consistency. During such a study of the aurora, it was noted that biases or distortions had crept into the data because of the conditions (or ergonomics) of the human trainers. As using machine-learning techniques in auroral research is relatively new, it is critical that such biases are brought to the attention of the academic and citizen science communities.
Thomas B. Leyser, Björn Gustavsson, Theresa Rexer, and Michael T. Rietveld
Ann. Geophys., 38, 297–307, https://doi.org/10.5194/angeo-38-297-2020, https://doi.org/10.5194/angeo-38-297-2020, 2020
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Powerful radio waves transmitted into the ionosphere give the strongest turbulence effects in geomagnetic zenith, antiparallel to the magnetic field in the Northern Hemisphere. Our results obtained with the EISCAT (European Incoherent SCATter association) Heating facility in Norway and the EISCAT UHF incoherent scatter radar together with modelling suggest that the pump wave propagates in the L mode, rather than in the O mode that is usually assumed to be involved in such experiments.
Jorge Luis Chau, Juan Miguel Urco, Juha Pekka Vierinen, Ryan Andrew Volz, Matthias Clahsen, Nico Pfeffer, and Jörg Trautner
Atmos. Meas. Tech., 12, 2113–2127, https://doi.org/10.5194/amt-12-2113-2019, https://doi.org/10.5194/amt-12-2113-2019, 2019
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New systems to study the mesosphere are introduced. They result from the reengineering of previous systems, by making use of MIMO, spread-spectrum and compressed-sensing techniques that are widely used in telecommunications. The interferometer configuration is now implemented in transmission, making the location of meteor echoes possible with just one antenna on reception. Our novel concept makes the study of a mesosphere volume from different viewing points on the ground feasible and easy.
Nikolai Østgaard, Jone P. Reistad, Paul Tenfjord, Karl M. Laundal, Theresa Rexer, Stein E. Haaland, Kristian Snekvik, Michael Hesse, Stephen E. Milan, and Anders Ohma
Ann. Geophys., 36, 1577–1596, https://doi.org/10.5194/angeo-36-1577-2018, https://doi.org/10.5194/angeo-36-1577-2018, 2018
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In this paper we take advantage of having two auroral imaging missions giving simultaneous data of both the southern and northern aurora. Combined with all available in situ measurements from space and global ground-based networks, we explore the asymmetric behavior of geospace. We find large auroral asymmetries and different reconnection geometry in the two hemispheres. During substorm expansion phase asymmetries are reduced.
Jorge L. Chau, Derek McKay, Juha P. Vierinen, Cesar La Hoz, Thomas Ulich, Markku Lehtinen, and Ralph Latteck
Atmos. Chem. Phys., 18, 9547–9560, https://doi.org/10.5194/acp-18-9547-2018, https://doi.org/10.5194/acp-18-9547-2018, 2018
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Combining a phased-array power radar and a phased-array radio telescope, we have been able to identify and characterized horizontal structures and movement of noctilucent clouds, but at 3 m scales instead of optical scales. As a byproduct of our observations, we have studied their angular dependence. We show a new alternative to study these clouds on routine basis and therefore study the atmospheric dynamics that modulate them.
Thomas B. Leyser, H. Gordon James, Björn Gustavsson, and Michael T. Rietveld
Ann. Geophys., 36, 243–251, https://doi.org/10.5194/angeo-36-243-2018, https://doi.org/10.5194/angeo-36-243-2018, 2018
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Transmission of powerful radio waves into the overhead ionosphere is used to study plasma turbulence processes. It is well known that the ionospheric response to radio waves is the strongest in the direction of the geomagnetic field. We have found evidence that the transmitted radio wave can propagate in a mode that enables the wave to propagate much higher in altitude and deeper into the ionosphere than what is usually expected, which may account for the strong plasma response observed.
Derek McKay, Noora Partamies, and Juha Vierinen
Ann. Geophys., 36, 59–69, https://doi.org/10.5194/angeo-36-59-2018, https://doi.org/10.5194/angeo-36-59-2018, 2018
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This study used the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) and Finnish Meteorological Institute's all-sky camera. It looked at radio absorption and optical emission of the long east–west band of aurora (known as the growth phase arc), which forms at the start of substorms. The study found that radio absorption was consistently south of the bright auroral arc and that optical pulsating aurora occurs in the boundary region between the radio absorption zone and the bright arc.
Johannes Norberg, Ilkka I. Virtanen, Lassi Roininen, Juha Vierinen, Mikko Orispää, Kirsti Kauristie, and Markku S. Lehtinen
Atmos. Meas. Tech., 9, 1859–1869, https://doi.org/10.5194/amt-9-1859-2016, https://doi.org/10.5194/amt-9-1859-2016, 2016
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We validate 2-D ionospheric tomography reconstructions against EISCAT incoherent scatter radar measurements. The method is based on Bayesian statistical inversion. We employ ionosonde measurements for the choice of the prior distribution parameters and use a sparse matrix approximation for the computations. This results in a computationally efficient tomography algorithm with clear probabilistic interpretation. We find that ionosonde measurements improve the reconstruction significantly.
N. M. Schlatter, N. Ivchenko, B. Gustavsson, T. Leyser, and M. Rietveld
Ann. Geophys., 31, 1103–1108, https://doi.org/10.5194/angeo-31-1103-2013, https://doi.org/10.5194/angeo-31-1103-2013, 2013
C. K. Mutiso, M. D. Zettergren, J. M. Hughes, and G. G. Sivjee
Ann. Geophys., 31, 463–471, https://doi.org/10.5194/angeo-31-463-2013, https://doi.org/10.5194/angeo-31-463-2013, 2013
Related subject area
Subject: Earth's ionosphere & aeronomy | Keywords: Instruments and techniques
Estimation and evaluation of hourly Meteorological Operational (MetOp) satellites' GPS receiver differential code biases (DCBs) with two different methods
Comparison of meteor radar and TIDI winds in the Brazilian equatorial region
A technique for volumetric incoherent scatter radar analysis
Sounding of sporadic E layers from China Seismo-Electromagnetic Satellite (CSES) radio occultation and comparing with ionosonde measurements
Observing electric field and neutral wind with EISCAT 3D
Inferring thermospheric composition from ionogram profiles: a calibration with the TIMED spacecraft
Radar imaging with EISCAT 3D
Auroral ionospheric E region parameters obtained from satellite- based far-ultraviolet and ground-based ionosonde observations – effects of proton precipitation
Estimating satellite and receiver differential code bias using a relative Global Positioning System network
Validation of Clyde River SuperDARN radar velocity measurements with the RISR-C incoherent scatter radar
Linlin Li and Shuanggen Jin
Ann. Geophys., 41, 465–481, https://doi.org/10.5194/angeo-41-465-2023, https://doi.org/10.5194/angeo-41-465-2023, 2023
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We used the spherical harmonic function (SHF) and the local spherical symmetry (LSS) assumption methods to calculate the hourly and daily LEO satellite GPS differential code bias (DCB). The SHF method is more stable and precise than the LSS assumption. The daily DCB estimation is more accurate and stable than the hourly DCB due to more observation data. Hourly DCBs have large changes in one day, mainly be attributed to random errors because these error time series have a normal distribution.
Ana Roberta Paulino, Delis Otildes Rodrigues, Igo Paulino, Lourivaldo Mota Lima, Ricardo Arlen Buriti, Paulo Prado Batista, Aaron Ridley, and Chen Wu
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2023-23, https://doi.org/10.5194/angeo-2023-23, 2023
Revised manuscript accepted for ANGEO
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Comparisons of wind measurements using two different techniques (ground based radar and satellite) in Brasil during 2006 were made in order to point out the advantage of each instrument for studies in the mesosphere and upper thermosphere. (i) For short period variations, the measurements of the satellite was more advantageous. (ii) The month climatology using the radar were more appropriate. (iii) If the long period (longer than few months), both instruments responded satisfactorily.
Johann Stamm, Juha Vierinen, Björn Gustavsson, and Andres Spicher
Ann. Geophys., 41, 55–67, https://doi.org/10.5194/angeo-41-55-2023, https://doi.org/10.5194/angeo-41-55-2023, 2023
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The study of some ionospheric events benefit from the knowledge of how the physics varies over a volume and over time. Examples are studies of aurora or energy deposition. With EISCAT3D, measurements of ion velocity vectors in a volume will be possible for the first time. We present a technique that uses a set of such measurements to estimate electric field and neutral wind. The technique relies on adding restrictions to the estimates. We successfully consider restrictions based on physics.
Chengkun Gan, Jiayu Hu, Xiaomin Luo, Chao Xiong, and Shengfeng Gu
Ann. Geophys., 40, 463–474, https://doi.org/10.5194/angeo-40-463-2022, https://doi.org/10.5194/angeo-40-463-2022, 2022
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We develop a new criterion to determine Es, i.e., when the mean value of the absolute value of the difference between the normalized SNR is greater than 3 times the standard deviation. We show that Es have strong seasonal variations, with the highest occurrence rates in the summer season at midlatitudes mainly located at 90–110 km at 14:00–20:00 LT. The comparison of Es altitudes from radio occultation profiles with ionosonde revealed a large correspondence between both measurement techniques.
Johann Stamm, Juha Vierinen, and Björn Gustavsson
Ann. Geophys., 39, 961–974, https://doi.org/10.5194/angeo-39-961-2021, https://doi.org/10.5194/angeo-39-961-2021, 2021
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Measurements of the electric field and neutral wind in the ionosphere are important for understanding energy flows or electric currents. With incoherent scatter radars (ISRs), we can measure the velocity of the ions, which depends on both the electrical field and the neutral wind. In this paper, we investigate methods to use ISR data to find reasonable values for both parameters. We find that electric field can be well measured down to 125 km height and neutral wind below this height.
Christopher J. Scott, Shannon Jones, and Luke A. Barnard
Ann. Geophys., 39, 309–319, https://doi.org/10.5194/angeo-39-309-2021, https://doi.org/10.5194/angeo-39-309-2021, 2021
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The composition of the upper atmosphere has been difficult to measure with localised observations relying on spacecraft, suborbital rockets or measurements of airglow from ground-based observatories. The height profile of ionisation within the neutral upper atmosphere is influenced by the composition of the neutral gas. We present a method for determining the neutral upper-atmosphere composition from measurements of the ionisation profile and compare these with spacecraft measurements.
Johann Stamm, Juha Vierinen, Juan M. Urco, Björn Gustavsson, and Jorge L. Chau
Ann. Geophys., 39, 119–134, https://doi.org/10.5194/angeo-39-119-2021, https://doi.org/10.5194/angeo-39-119-2021, 2021
Harold K. Knight
Ann. Geophys., 39, 105–118, https://doi.org/10.5194/angeo-39-105-2021, https://doi.org/10.5194/angeo-39-105-2021, 2021
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Comparisons were made of ground-based ionosonde (a type of radar) observations of the ionosphere and satellite-based observations of auroral far-ultraviolet emissions to determine whether a remote sensing algorithm for determining auroral ionospheric electron densities from far-ultraviolet emissions was biased by the presence of proton precipitation, and it was found that there was no such bias.
Alaa A. Elghazouly, Mohamed I. Doma, and Ahmed A. Sedeek
Ann. Geophys., 37, 1039–1047, https://doi.org/10.5194/angeo-37-1039-2019, https://doi.org/10.5194/angeo-37-1039-2019, 2019
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Receiver and satellite differential code biases (DCBs) are one of the main error sources in estimating precise global ionosphere maps (GIMs) from Global Positioning System (GPS) data. This paper introduces a mathematical model for estimating satellite and receiver DCBs from a GPS network written in the MATLAB environment. Our code was tested and compared with Ionosphere Associated Analysis Centers (IAAC) and other researchers' code results. The results show an improvement for estimated DCBs.
Alexander Koustov, Robert Gillies, and Peter Bankole
Ann. Geophys., 36, 1657–1666, https://doi.org/10.5194/angeo-36-1657-2018, https://doi.org/10.5194/angeo-36-1657-2018, 2018
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Clyde River (CLY) SuperDARN radar velocities reflecting plasma flows in the ionosphere are consistent with measurements by the incoherent scatter radar RISR. While agreement is good in the range of RISR velocity magnitudes of 0–700 m s−1, CLY velocities become progressively smaller at faster flows. In one example of strong disagreements between the instruments, by 200 m s−1, the radars monitored strongly sheared flows. Validation of the CLY radar confirms the reliability of SuperDARN operation.
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Short summary
The EISCAT_3D radar is a new ionospheric radar under construction in the Fennoscandia region. The radar will make measurements of plasma characteristics at altitudes above approximately 60 km. The capability of the system to make these measurements at spatial scales of less than 100 m using multiple digitised signals from each of the radar antenna panels is highlighted. There are many ionospheric small-scale processes that will be further resolved using the techniques discussed here.
The EISCAT_3D radar is a new ionospheric radar under construction in the Fennoscandia region....
