Articles | Volume 43, issue 1
https://doi.org/10.5194/angeo-43-331-2025
© 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-43-331-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
27 Jun 2025
Regular paper |
| 27 Jun 2025
| 27 Jun 2025
Indications for particle precipitation impact on the ion-neutral collision frequency analyzed with EISCAT measurements
Florian Günzkofer
CORRESPONDING AUTHOR
Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany
Gunter Stober
Institute of Applied Physics, Microwave Physics, University of Bern, Bern, Switzerland
Oeschger Center for Climate Change Research, Microwave Physics, University of Bern, Bern, Switzerland
Johan Kero
Swedish Institute of Space Physics (IRF), Kiruna, Sweden
David R. Themens
Space Environment and Radio Engineering Group (SERENE), School of Engineering, University of Birmingham, B15 2TT Birmingham, UK
Department of Physics, University of New Brunswick, 8 Bailey Drive, PO Box 4440, Fredericton, NB E3B 5A3, Canada
Anders Tjulin
EISCAT AB, Kiruna, Sweden
Njål Gulbrandsen
Tromsø Geophysical Observatory, UiT – The Arctic University of Norway, Tromsø, Norway
Masaki Tsutsumi
National Institute of Polar Research, Tachikawa, Japan
The Graduate University for Advanced Studies (SOKENDAI), Tokyo, Japan
Claudia Borries
Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany
Related authors
Florian Günzkofer, Gunter Stober, Dimitry Pokhotelov, Yasunobu Miyoshi, and Claudia Borries
Atmos. Meas. Tech., 16, 5897–5907, https://doi.org/10.5194/amt-16-5897-2023, https://doi.org/10.5194/amt-16-5897-2023, 2023
Short summary
Short summary
Electric currents in the ionosphere can impact both satellite and ground-based infrastructure. These currents depend strongly on the collisions of ions and neutral particles. Measuring ion–neutral collisions is often only possible via certain assumptions. The direct measurement of ion–neutral collision frequencies is possible with multifrequency incoherent scatter radar measurements. This paper presents one analysis method of such measurements and discusses its advantages and disadvantages.
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, and Claudia Borries
Ann. Geophys., 41, 409–428, https://doi.org/10.5194/angeo-41-409-2023, https://doi.org/10.5194/angeo-41-409-2023, 2023
Short summary
Short summary
Gravity waves (GWs) are waves in Earth's atmosphere and can be observed as cloud ripples. Under certain conditions, these waves can propagate up into the ionosphere. Here, they can cause ripples in the ionosphere plasma, observable as oscillations of the plasma density. Therefore, GWs contribute to the ionospheric variability, making them relevant for space weather prediction. Additionally, the behavior of these waves allows us to draw conclusions about the atmosphere at these altitudes.
Devin Huyghebaert, Juha Vierinen, Björn Gustavsson, Ralph Latteck, Toralf Renkwitz, Marius Zecha, Claudia C. Stephan, J. Federico Conte, Daniel Kastinen, Johan Kero, and Jorge L. Chau
EGUsphere, https://doi.org/10.5194/egusphere-2025-2323, https://doi.org/10.5194/egusphere-2025-2323, 2025
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
The phenomena of meteors occurs at altitudes of 60–120 km and can be used to measure the neutral atmosphere. We use a large high power radar system in Norway (MAARSY) to determine changes to the atmospheric density between the years of 2016–2023 at altitudes of 85–115 km. The same day-of-year is compared, minimizing changes to the measurements due to factors other than the atmosphere. This presents a novel method by which to obtain atmospheric neutral density variations.
J. Federico Conte, Jorge L. Chau, Toralf Renkwitz, Ralph Latteck, Masaki Tsutsumi, Christoph Jacobi, Njål Gulbrandsen, and Satonori Nozawa
EGUsphere, https://doi.org/10.5194/egusphere-2025-1996, https://doi.org/10.5194/egusphere-2025-1996, 2025
This preprint is open for discussion and under review for Annales Geophysicae (ANGEO).
Short summary
Short summary
Analysis of 10 years of continuous measurements provided MMARIA/SIMONe Norway and MMARIA/SIMONe Germany reveals that the divergent and vortical motions in the mesosphere and lower thermosphere exchange the dominant role depending on the height and the time of the year. At summer mesopause altitudes over middle latitudes, the horizontal divergence and the relative vorticity contribute approximately the same, indicating an energetic balance between mesoscale divergent and vortical motions.
Alistair Bell, Axel Murk, and Gunter Stober
EGUsphere, https://doi.org/10.5194/egusphere-2025-1396, https://doi.org/10.5194/egusphere-2025-1396, 2025
Short summary
Short summary
Increases in middle atmospheric water vapour from the 2022 Hunga eruption have been measured worldwide. This study uses remote sensing measurements at two latitudes and accurate radiative transfer modeling to show significant long-wave heating effects. Though minimal at the surface, the water vapour enhancement can alter middle-atmospheric dynamics, potentially affecting ozone chemistry and weather patterns.
Zishun Qiao, Alan Z. Liu, Gunter Stober, Javier Fuentes, Fabio Vargas, Christian L. Adami, and Iain M. Reid
Atmos. Meas. Tech., 18, 1091–1104, https://doi.org/10.5194/amt-18-1091-2025, https://doi.org/10.5194/amt-18-1091-2025, 2025
Short summary
Short summary
This paper describes the installation of the Chilean Observation Network De Meteor Radars (CONDOR) and its initial results. The routine winds are point-to-point comparable to the co-located lidar winds. The retrievals of spatially resolved horizontal wind fields and vertical winds are also facilitated, benefiting from the extensive meteor detections. The successful deployment and maintenance of CONDOR provide 24/7 and state-of-the-art wind measurements to the research community.
Alistair Bell, Eric Sauvageat, Gunter Stober, Klemens Hocke, and Axel Murk
Atmos. Meas. Tech., 18, 555–567, https://doi.org/10.5194/amt-18-555-2025, https://doi.org/10.5194/amt-18-555-2025, 2025
Short summary
Short summary
Hardware and software developments have been made on a 22 GHz microwave radiometer for the measurement of middle-atmospheric water vapour near Bern, Switzerland. Previous measurements dating back to 2010 have been re-calibrated and an improved optimal estimation retrieval performed on these measurements, giving a 13-year dataset. Measurements made with new and improved instrumental hardware are used to correct previous measurements, which show better agreement than the non-corrected dataset.
Maria Gloria Tan Jun Rios, Claudia Borries, Huixin Liu, and Jens Mielich
Ann. Geophys., 43, 73–89, https://doi.org/10.5194/angeo-43-73-2025, https://doi.org/10.5194/angeo-43-73-2025, 2025
Short summary
Short summary
This study analyzes changes in the ionospheric response to solar flux over five complete solar cycles (1957 to 2023). We use Juliusruh hourly data of the peak electron density of the F2 layer, NmF2, and three solar extreme ultraviolet (EUV) radiation proxies. The response is better represented by a cubic regression, and F30 shows the highest correlation for describing NmF2 dependence over time. These results reveal a decrease in NmF2 influenced by the intensity of the solar activity index.
Guochun Shi, Hanli Liu, Masaki Tsutsumi, Njål Gulbrandsen, Alexander Kozlovsky, Dimitry Pokhotelov, Mark Lester, Kun Wu, and Gunter Stober
EGUsphere, https://doi.org/10.5194/egusphere-2024-3749, https://doi.org/10.5194/egusphere-2024-3749, 2024
Short summary
Short summary
People are increasingly concerned about climate change due to its widespread impacts, including rising temperatures, extreme weather events, and ecosystem disruptions. Addressing these challenges requires urgent global action to reduce greenhouse gas emissions and adapt to a rapidly changing environment.
Guochun Shi, Witali Krochin, Eric Sauvageat, and Gunter Stober
Atmos. Chem. Phys., 24, 10187–10207, https://doi.org/10.5194/acp-24-10187-2024, https://doi.org/10.5194/acp-24-10187-2024, 2024
Short summary
Short summary
Here we investigated ozone anomalies over polar regions during sudden stratospheric and final stratospheric warming with ground-based microwave radiometers at polar latitudes compared with reanalysis and satellite data. The underlying dynamical and chemical mechanisms are responsible for the observed ozone anomalies in both events. Our research sheds light on these processes, emphasizing the need for a deeper understanding of these processes for more accurate climate modeling and forecasting.
Witali Krochin, Axel Murk, and Gunter Stober
Atmos. Meas. Tech., 17, 5015–5028, https://doi.org/10.5194/amt-17-5015-2024, https://doi.org/10.5194/amt-17-5015-2024, 2024
Short summary
Short summary
Atmospheric tides are global-scale oscillations with periods of a fraction of a day. Their observation in the middle atmosphere is challenging and rare, as it requires continuous measurements with a high temporal resolution. In this paper, temperature time series of a ground-based microwave radiometer were analyzed with a spectral filter to derive thermal tide amplitudes and phases in an altitude range of 25–50 km at the geographical locations of Payerne and Bern (Switzerland).
Arthur Gauthier, Claudia Borries, Alexander Kozlovsky, Diego Janches, Peter Brown, Denis Vida, Christoph Jacobi, Damian Murphy, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Johan Kero, Nicholas Mitchell, Tracy Moffat-Griffin, and Gunter Stober
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2024-13, https://doi.org/10.5194/angeo-2024-13, 2024
Revised manuscript accepted for ANGEO
Short summary
Short summary
This study focuses on the TIMED Doppler Interferometer (TIDI)-Meteor Radar(MR) comparison of zonal and meridional winds and their dependence on local time and latitude. The correlation calculation between TIDI winds measurements and MR winds shows good agreement. A TIDI-MR seasonal comparison and the altitude-latitude dependence for winds is performed. TIDI reproduce the mean circulation well when compared with the MRs and might be useful as a lower boundary for general circulation models.
Gunter Stober, Sharon L. Vadas, Erich Becker, Alan Liu, Alexander Kozlovsky, Diego Janches, Zishun Qiao, Witali Krochin, Guochun Shi, Wen Yi, Jie Zeng, Peter Brown, Denis Vida, Neil Hindley, Christoph Jacobi, Damian Murphy, Ricardo Buriti, Vania Andrioli, Paulo Batista, John Marino, Scott Palo, Denise Thorsen, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Kathrin Baumgarten, Johan Kero, Evgenia Belova, Nicholas Mitchell, Tracy Moffat-Griffin, and Na Li
Atmos. Chem. Phys., 24, 4851–4873, https://doi.org/10.5194/acp-24-4851-2024, https://doi.org/10.5194/acp-24-4851-2024, 2024
Short summary
Short summary
On 15 January 2022, the Hunga Tonga-Hunga Ha‘apai volcano exploded in a vigorous eruption, causing many atmospheric phenomena reaching from the surface up to space. In this study, we investigate how the mesospheric winds were affected by the volcanogenic gravity waves and estimated their propagation direction and speed. The interplay between model and observations permits us to gain new insights into the vertical coupling through atmospheric gravity waves.
Peter Dalin, Urban Brändström, Johan Kero, Peter Voelger, Takanori Nishiyama, Trond Trondsen, Devin Wyatt, Craig Unick, Vladimir Perminov, Nikolay Pertsev, and Jonas Hedin
Atmos. Meas. Tech., 17, 1561–1576, https://doi.org/10.5194/amt-17-1561-2024, https://doi.org/10.5194/amt-17-1561-2024, 2024
Short summary
Short summary
A novel infrared imaging instrument (OH imager) was put into operation in November 2022 at the Swedish Institute of Space Physics in Kiruna (Sweden). The OH imager is dedicated to the study of nightglow emissions coming from the hydroxyl (OH) and molecular oxygen (O2) layers in the mesopause (80–100 km). Based on a brightness ratio of two OH emission lines, the neutral temperature is estimated at around 87 km. The average daily winter temperature for the period January–April 2023 is 203±10 K.
Florian Günzkofer, Gunter Stober, Dimitry Pokhotelov, Yasunobu Miyoshi, and Claudia Borries
Atmos. Meas. Tech., 16, 5897–5907, https://doi.org/10.5194/amt-16-5897-2023, https://doi.org/10.5194/amt-16-5897-2023, 2023
Short summary
Short summary
Electric currents in the ionosphere can impact both satellite and ground-based infrastructure. These currents depend strongly on the collisions of ions and neutral particles. Measuring ion–neutral collisions is often only possible via certain assumptions. The direct measurement of ion–neutral collision frequencies is possible with multifrequency incoherent scatter radar measurements. This paper presents one analysis method of such measurements and discusses its advantages and disadvantages.
Juliana Jaen, Toralf Renkwitz, Huixin Liu, Christoph Jacobi, Robin Wing, Aleš Kuchař, Masaki Tsutsumi, Njål Gulbrandsen, and Jorge L. Chau
Atmos. Chem. Phys., 23, 14871–14887, https://doi.org/10.5194/acp-23-14871-2023, https://doi.org/10.5194/acp-23-14871-2023, 2023
Short summary
Short summary
Investigation of winds is important to understand atmospheric dynamics. In the summer mesosphere and lower thermosphere, there are three main wind flows: the mesospheric westward, the mesopause southward (equatorward), and the lower-thermospheric eastward wind. Combining almost 2 decades of measurements from different radars, we study the trend, their interannual oscillations, and the effects of the geomagnetic activity over these wind maxima.
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, and Claudia Borries
Ann. Geophys., 41, 409–428, https://doi.org/10.5194/angeo-41-409-2023, https://doi.org/10.5194/angeo-41-409-2023, 2023
Short summary
Short summary
Gravity waves (GWs) are waves in Earth's atmosphere and can be observed as cloud ripples. Under certain conditions, these waves can propagate up into the ionosphere. Here, they can cause ripples in the ionosphere plasma, observable as oscillations of the plasma density. Therefore, GWs contribute to the ionospheric variability, making them relevant for space weather prediction. Additionally, the behavior of these waves allows us to draw conclusions about the atmosphere at these altitudes.
Guochun Shi, Witali Krochin, Eric Sauvageat, and Gunter Stober
Atmos. Chem. Phys., 23, 9137–9159, https://doi.org/10.5194/acp-23-9137-2023, https://doi.org/10.5194/acp-23-9137-2023, 2023
Short summary
Short summary
We present the interannual and climatological behavior of ozone and water vapor from microwave radiometers in the Arctic.
By defining a virtual conjugate latitude station in the Southern Hemisphere, we investigate altitude-dependent interhemispheric differences and estimate the ascent and descent rates of water vapor in both hemispheres. Ozone and water vapor measurements will create a deeper understanding of the evolution of middle atmospheric ozone and water vapor.
Gunter Stober, Alan Liu, Alexander Kozlovsky, Zishun Qiao, Witali Krochin, Guochun Shi, Johan Kero, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Kathrin Baumgarten, Evgenia Belova, and Nicholas Mitchell
Ann. Geophys., 41, 197–208, https://doi.org/10.5194/angeo-41-197-2023, https://doi.org/10.5194/angeo-41-197-2023, 2023
Short summary
Short summary
The Hunga Tonga–Hunga Ha‘apai volcanic eruption was one of the most vigorous volcanic explosions in the last centuries. The eruption launched many atmospheric waves traveling around the Earth. In this study, we identify these volcanic waves at the edge of space in the mesosphere/lower-thermosphere, leveraging wind observations conducted with multi-static meteor radars in northern Europe and with the Chilean Observation Network De Meteor Radars (CONDOR).
Gunter Stober, Alan Liu, Alexander Kozlovsky, Zishun Qiao, Ales Kuchar, Christoph Jacobi, Chris Meek, Diego Janches, Guiping Liu, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Evgenia Belova, Johan Kero, and Nicholas Mitchell
Atmos. Meas. Tech., 15, 5769–5792, https://doi.org/10.5194/amt-15-5769-2022, https://doi.org/10.5194/amt-15-5769-2022, 2022
Short summary
Short summary
Precise and accurate measurements of vertical winds at the mesosphere and lower thermosphere are rare. Although meteor radars have been used for decades to observe horizontal winds, their ability to derive reliable vertical wind measurements was always questioned. In this article, we provide mathematical concepts to retrieve mathematically and physically consistent solutions, which are compared to the state-of-the-art non-hydrostatic model UA-ICON.
Witali Krochin, Francisco Navas-Guzmán, David Kuhl, Axel Murk, and Gunter Stober
Atmos. Meas. Tech., 15, 2231–2249, https://doi.org/10.5194/amt-15-2231-2022, https://doi.org/10.5194/amt-15-2231-2022, 2022
Short summary
Short summary
This study leverages atmospheric temperature measurements performed with a ground-based radiometer making use of data that was collected during a 4-year observational campaign applying a new retrieval algorithm that improves the maximal altitude range from 45 to 55 km. The measurements are validated against two independent data sets, MERRA2 reanalysis data and the meteorological analysis of NAVGEM-HA.
Sumanta Sarkhel, Gunter Stober, Jorge L. Chau, Steven M. Smith, Christoph Jacobi, Subarna Mondal, Martin G. Mlynczak, and James M. Russell III
Ann. Geophys., 40, 179–190, https://doi.org/10.5194/angeo-40-179-2022, https://doi.org/10.5194/angeo-40-179-2022, 2022
Short summary
Short summary
A rare gravity wave event was observed on the night of 25 April 2017 over northern Germany. An all-sky airglow imager recorded an upward-propagating wave at different altitudes in mesosphere with a prominent wave front above 91 km and faintly observed below. Based on wind and satellite-borne temperature profiles close to the event location, we have found the presence of a leaky thermal duct layer in 85–91 km. The appearance of this duct layer caused the wave amplitudes to diminish below 91 km.
Juliana Jaen, Toralf Renkwitz, Jorge L. Chau, Maosheng He, Peter Hoffmann, Yosuke Yamazaki, Christoph Jacobi, Masaki Tsutsumi, Vivien Matthias, and Chris Hall
Ann. Geophys., 40, 23–35, https://doi.org/10.5194/angeo-40-23-2022, https://doi.org/10.5194/angeo-40-23-2022, 2022
Short summary
Short summary
To study long-term trends in the mesosphere and lower thermosphere (70–100 km), we established two summer length definitions and analyzed the variability over the years (2004–2020). After the analysis, we found significant trends in the summer beginning of one definition. Furthermore, we were able to extend one of the time series up to 31 years and obtained evidence of non-uniform trends and periodicities similar to those known for the quasi-biennial oscillation and El Niño–Southern Oscillation.
Christoph Jacobi, Friederike Lilienthal, Dmitry Korotyshkin, Evgeny Merzlyakov, and Gunter Stober
Adv. Radio Sci., 19, 185–193, https://doi.org/10.5194/ars-19-185-2021, https://doi.org/10.5194/ars-19-185-2021, 2021
Short summary
Short summary
We compare winds and tidal amplitudes in the upper mesosphere/lower thermosphere region for cases with disturbed and undisturbed geomagnetic conditions. The zonal winds in both the mesosphere and lower thermosphere tend to be weaker during disturbed conditions. The summer equatorward meridional wind jet is weaker for disturbed geomagnetic conditions. The effect of geomagnetic variability on tidal amplitudes, except for the semidiurnal tide, is relatively small.
Gunter Stober, Alexander Kozlovsky, Alan Liu, Zishun Qiao, Masaki Tsutsumi, Chris Hall, Satonori Nozawa, Mark Lester, Evgenia Belova, Johan Kero, Patrick J. Espy, Robert E. Hibbins, and Nicholas Mitchell
Atmos. Meas. Tech., 14, 6509–6532, https://doi.org/10.5194/amt-14-6509-2021, https://doi.org/10.5194/amt-14-6509-2021, 2021
Short summary
Short summary
Wind observations at the edge to space, 70–110 km altitude, are challenging. Meteor radars have become a widely used instrument to obtain mean wind profiles above an instrument for these heights. We describe an advanced mathematical concept and present a tomographic analysis using several meteor radars located in Finland, Sweden and Norway, as well as Chile, to derive the three-dimensional flow field. We show an example of a gravity wave decelerating the mean flow.
Dimitry Pokhotelov, Isabel Fernandez-Gomez, and Claudia Borries
Ann. Geophys., 39, 833–847, https://doi.org/10.5194/angeo-39-833-2021, https://doi.org/10.5194/angeo-39-833-2021, 2021
Short summary
Short summary
During geomagnetic storms, enhanced solar wind and changes in the interplanetary magnetic field lead to ionisation anomalies across the polar regions. The superstorm of 20 November 2003 was one of the largest events in recent history. Numerical simulations of ionospheric dynamics during the storm are compared with plasma observations to understand the mechanisms forming the polar plasma anomalies. The results are important for understanding and forecasting space weather in polar regions.
Gunter Stober, Ales Kuchar, Dimitry Pokhotelov, Huixin Liu, Han-Li Liu, Hauke Schmidt, Christoph Jacobi, Kathrin Baumgarten, Peter Brown, Diego Janches, Damian Murphy, Alexander Kozlovsky, Mark Lester, Evgenia Belova, Johan Kero, and Nicholas Mitchell
Atmos. Chem. Phys., 21, 13855–13902, https://doi.org/10.5194/acp-21-13855-2021, https://doi.org/10.5194/acp-21-13855-2021, 2021
Short summary
Short summary
Little is known about the climate change of wind systems in the mesosphere and lower thermosphere at the edge of space at altitudes from 70–110 km. Meteor radars represent a well-accepted remote sensing technique to measure winds at these altitudes. Here we present a state-of-the-art climatological interhemispheric comparison using continuous and long-lasting observations from worldwide distributed meteor radars from the Arctic to the Antarctic and sophisticated general circulation models.
Joel P. Younger, Iain M. Reid, Chris L. Adami, Chris M. Hall, and Masaki Tsutsumi
Atmos. Meas. Tech., 14, 5015–5027, https://doi.org/10.5194/amt-14-5015-2021, https://doi.org/10.5194/amt-14-5015-2021, 2021
Short summary
Short summary
A radar in Svalbard usually used to study meteor trails was used to observe a thin icy layer in the upper atmosphere. New methods used the layer to measure wind speed over short periods of time and found that the layer is most reflective within 6.8 ± 3.3° of vertical. Analysis of meteor trail radar echo durations found that the layer may shorten meteor trail echoes, but more data are needed. This study shows new uses for data collected by meteor radars for other purposes.
Daniel Kastinen, Johan Kero, Alexander Kozlovsky, and Mark Lester
Atmos. Meas. Tech., 14, 3583–3596, https://doi.org/10.5194/amt-14-3583-2021, https://doi.org/10.5194/amt-14-3583-2021, 2021
Short summary
Short summary
When a meteor enters the atmosphere, it causes a trail of diffusing plasma that moves with the neutral wind. An interferometric radar system can measure such trails and determine its location. However, there is a chance of determining the wrong position due to noise. We simulate this behaviour and use the simulations to successfully determine the true location of ambiguous events. We also successfully test two simple temporal integration methods for avoiding such erroneous determinations.
Gunter Stober, Diego Janches, Vivien Matthias, Dave Fritts, John Marino, Tracy Moffat-Griffin, Kathrin Baumgarten, Wonseok Lee, Damian Murphy, Yong Ha Kim, Nicholas Mitchell, and Scott Palo
Ann. Geophys., 39, 1–29, https://doi.org/10.5194/angeo-39-1-2021, https://doi.org/10.5194/angeo-39-1-2021, 2021
Daniel Kastinen and Johan Kero
Atmos. Meas. Tech., 13, 6813–6835, https://doi.org/10.5194/amt-13-6813-2020, https://doi.org/10.5194/amt-13-6813-2020, 2020
Short summary
Short summary
The behaviour of position determination with interferometric radar systems and possible ambiguities therein depends on the spatial configuration of the radar-receiving antennas and their individual characteristics. We have simulated the position determination performance of five different radar systems. These simulations showed that ambiguities are dynamic and need to be examined on a case-by-case basis. However, the simulations can be used to analyse and understand previously ambiguous data.
Masatoshi Yamauchi, Magnar G. Johnsen, Carl-Fredrik Enell, Anders Tjulin, Anna Willer, and Dmitry A. Sormakov
Ann. Geophys., 38, 1159–1170, https://doi.org/10.5194/angeo-38-1159-2020, https://doi.org/10.5194/angeo-38-1159-2020, 2020
Short summary
Short summary
The paper reports a new finding on space weather effects at around 70–75 ° geographic latitudes. We found that X flares cause an unexpectedly strong ionospheric current driven by solar flares. The effect is as large as a substorm that is known to cause strong auroras and may enhance ongoing substorms. However, it has been overlooked in the past due to the narrow latitudinal range at high latitudes. Since severe magnetic storms often occur with X flares, this may cause geomagnetic hazards.
Gunter Stober, Kathrin Baumgarten, John P. McCormack, Peter Brown, and Jerry Czarnecki
Atmos. Chem. Phys., 20, 11979–12010, https://doi.org/10.5194/acp-20-11979-2020, https://doi.org/10.5194/acp-20-11979-2020, 2020
Short summary
Short summary
This paper presents a first cross-comparison of meteor ground-based observations and a meteorological analysis (NAVGEM-HA) to compare a seasonal climatology of winds and temperatures at the mesosphere/lower thermosphere. The validation is insofar unique as we not only compare the mean state but also provide a detailed comparison of the short time variability of atmospheric tidal waves. Our analysis questions previous results claiming the importance of lunar tides.
Leonie Bernet, Elmar Brockmann, Thomas von Clarmann, Niklaus Kämpfer, Emmanuel Mahieu, Christian Mätzler, Gunter Stober, and Klemens Hocke
Atmos. Chem. Phys., 20, 11223–11244, https://doi.org/10.5194/acp-20-11223-2020, https://doi.org/10.5194/acp-20-11223-2020, 2020
Short summary
Short summary
With global warming, water vapour increases in the atmosphere. Water vapour is an important gas because it is a natural greenhouse gas and affects the formation of clouds, rain and snow. How much water vapour increases can vary in different regions of the world. To verify if it increases as expected on a regional scale, we analysed water vapour measurements in Switzerland. We found that water vapour generally increases as expected from temperature changes, except in winter.
Franziska Schranz, Jonas Hagen, Gunter Stober, Klemens Hocke, Axel Murk, and Niklaus Kämpfer
Atmos. Chem. Phys., 20, 10791–10806, https://doi.org/10.5194/acp-20-10791-2020, https://doi.org/10.5194/acp-20-10791-2020, 2020
Short summary
Short summary
We measured middle-atmospheric ozone, water vapour and zonal and meridional wind with two ground-based microwave radiometers which are located at Ny-Alesund, Svalbard, in the Arctic. In this article we present measurements of the small-scale horizontal ozone gradients during winter 2018/2019. We found a distinct seasonal variation of the ozone gradients which is linked to the planetary wave activity. We further present the signatures of the SSW in the ozone, water vapour and wind measurements.
Jonas Hagen, Klemens Hocke, Gunter Stober, Simon Pfreundschuh, Axel Murk, and Niklaus Kämpfer
Atmos. Chem. Phys., 20, 2367–2386, https://doi.org/10.5194/acp-20-2367-2020, https://doi.org/10.5194/acp-20-2367-2020, 2020
Short summary
Short summary
The middle atmosphere (30 to 70 km altitude) is stratified and, despite very strong horizontal winds, there is less mixing between the horizontal layers. An important driver for the energy exchange between the layers in this regime is atmospheric tides, which are waves that are driven by the diurnal cycle of solar heating. We measure these tides in the wind field for the first time using a ground-based passive instrument. Ultimately, such measurements could be used to improve atmospheric models.
Sven Wilhelm, Gunter Stober, and Peter Brown
Ann. Geophys., 37, 851–875, https://doi.org/10.5194/angeo-37-851-2019, https://doi.org/10.5194/angeo-37-851-2019, 2019
Short summary
Short summary
We report on long-term observations of atmospheric parameters in the mesosphere and lower thermosphere made over the last 2 decades for the northern-latitude locations of Andenes, Juliusruh, and Tavistock. The observations are based on meteor wind measurements and further include the long-term variability of winds, tides, and the kinetic energy of gravity waves and planetary waves. Furthermore, the influence on an 11-year oscillation on the winds and tides is presented.
Kathrin Baumgarten and Gunter Stober
Ann. Geophys., 37, 581–602, https://doi.org/10.5194/angeo-37-581-2019, https://doi.org/10.5194/angeo-37-581-2019, 2019
Short summary
Short summary
The paper presents the variability in thermal tides in the middle atmosphere from temperature observations as well as from horizontal wind data using a new diagnostic approach which takes into account a possible intermittency of tides. The data are analyzed from a local as well as from a global perspective to distinguish between different tidal modes. Surprisingly, there are dominating tidal modes, which are seen in the local data, and a phase relation between temperature and winds is evaluated.
Wen Yi, Xianghui Xue, Iain M. Reid, Damian J. Murphy, Chris M. Hall, Masaki Tsutsumi, Baiqi Ning, Guozhu Li, Robert A. Vincent, Jinsong Chen, Jianfei Wu, Tingdi Chen, and Xiankang Dou
Atmos. Chem. Phys., 19, 7567–7581, https://doi.org/10.5194/acp-19-7567-2019, https://doi.org/10.5194/acp-19-7567-2019, 2019
Short summary
Short summary
The seasonal variations in the mesopause densities, especially with regard to its global structure, are still unclear. In this study, we report the climatology of the mesopause density estimated using multiyear observations from nine meteor radars from Arctic to Antarctic latitudes. The results reveal a significant AO and SAO in mesopause density, an asymmetry between the two polar regions and evidence of intraseasonal oscillations (ISOs), perhaps associated with the ISOs of the troposphere.
Dimitry Pokhotelov, Gunter Stober, and Jorge Luis Chau
Atmos. Chem. Phys., 19, 5251–5258, https://doi.org/10.5194/acp-19-5251-2019, https://doi.org/10.5194/acp-19-5251-2019, 2019
Short summary
Short summary
Twelve years of radar observations from a mid-latitude location in Kühlungsborn, Germany have been analysed to study characteristics of mesospheric summer echoes (MSEs). The statistical analysis shows that MSEs have a strong daytime preference and early summer seasonal preference. It is demonstrated that the meridional wind transport from polar regions is the important controlling factor for MSEs, while no clear connection to geomagnetic and solar activity is found.
Fazlul I. Laskar, Gunter Stober, Jens Fiedler, Meers M. Oppenheim, Jorge L. Chau, Duggirala Pallamraju, Nicholas M. Pedatella, Masaki Tsutsumi, and Toralf Renkwitz
Atmos. Chem. Phys., 19, 5259–5267, https://doi.org/10.5194/acp-19-5259-2019, https://doi.org/10.5194/acp-19-5259-2019, 2019
Short summary
Short summary
Meteor radars are used to track and estimate the fading time of meteor trails. In this investigation, it is observed that the diffusion time estimated from such trail fading time is anomalously higher during noctilucent clouds (NLC) than that in its absence. We propose that NLC particles absorb background electrons and thus modify the background electrodynamics, leading to such an anomaly.
Nikoloz Gudadze, Gunter Stober, and Jorge L. Chau
Atmos. Chem. Phys., 19, 4485–4497, https://doi.org/10.5194/acp-19-4485-2019, https://doi.org/10.5194/acp-19-4485-2019, 2019
Short summary
Short summary
We show a possibility of measuring mean vertical winds during the summer months using polar mesosphere summer echo (PMSE) observations. Middle Atmosphere Alomar Radar System observations of PMSE five-beam radial velocities are analysed to obtain the results. We found that sampling issues are the reason for bias in vertical wind measurements at the edges of PMSE altitudes. However, the PMSE is a good tracer for the mean vertical wind estimation at the central altitudes with its peak occurrence.
Sven Wilhelm, Gunter Stober, Vivien Matthias, Christoph Jacobi, and Damian J. Murphy
Ann. Geophys., 37, 1–14, https://doi.org/10.5194/angeo-37-1-2019, https://doi.org/10.5194/angeo-37-1-2019, 2019
Short summary
Short summary
This study shows that the mesospheric winds are affected by an expansion–shrinking of the mesosphere and lower thermosphere that takes place due to changes in the intensity of the solar radiation, which affects the density within the atmosphere. On seasonal timescales, an increase in the neutral density occurs together with a decrease in the eastward-directed zonal wind. Further, even after removing the seasonal and the 11-year solar cycle variations, we show a connection between them.
Michael Gerding, Jochen Zöllner, Marius Zecha, Kathrin Baumgarten, Josef Höffner, Gunter Stober, and Franz-Josef Lübken
Atmos. Chem. Phys., 18, 15569–15580, https://doi.org/10.5194/acp-18-15569-2018, https://doi.org/10.5194/acp-18-15569-2018, 2018
Short summary
Short summary
We describe the first comparative study of noctilucent clouds (NLCs) and mesospheric summer echoes at midlatitudes. Therefore, this study compares fresh clouds (small particles) with fully evolved clouds in the mesosphere, hinting at their evolution. It is shown that, in contrast to higher latitudes, here only a thin layer of fresh particles exist above the NLCs. This gives evidence that NLCs are not formed locally but are typically advected. This needs to be acknowledged in trend studies.
Gunter Stober, Jorge L. Chau, Juha Vierinen, Christoph Jacobi, and Sven Wilhelm
Atmos. Meas. Tech., 11, 4891–4907, https://doi.org/10.5194/amt-11-4891-2018, https://doi.org/10.5194/amt-11-4891-2018, 2018
J. Federico Conte, Jorge L. Chau, Fazlul I. Laskar, Gunter Stober, Hauke Schmidt, and Peter Brown
Ann. Geophys., 36, 999–1008, https://doi.org/10.5194/angeo-36-999-2018, https://doi.org/10.5194/angeo-36-999-2018, 2018
Short summary
Short summary
Based on comparisons of meteor radar measurements with HAMMONIA model simulations, we show that the differences exhibited by the semidiurnal solar tide (S2) observed at middle and high latitudes of the Northern Hemisphere between equinox times are mainly due to distinct behaviors of the migrating semidiurnal (SW2) and the non-migrating westward-propagating wave number 1 semidiurnal (SW1) tidal components.
Dimitry Pokhotelov, Erich Becker, Gunter Stober, and Jorge L. Chau
Ann. Geophys., 36, 825–830, https://doi.org/10.5194/angeo-36-825-2018, https://doi.org/10.5194/angeo-36-825-2018, 2018
Short summary
Short summary
Atmospheric tides are produced by solar heating of the lower atmosphere. The tides propagate to the upper atmosphere and ionosphere playing an important role in the vertical coupling. Ground radar measurements of the seasonal variability of tides are compared with global numerical simulations. The agreement with radar data and limitations of the numerical model are discussed. The work represents a first step in modelling the impact of tidal dynamics on the upper atmosphere and ionosphere.
Sabine Wüst, Thomas Offenwanger, Carsten Schmidt, Michael Bittner, Christoph Jacobi, Gunter Stober, Jeng-Hwa Yee, Martin G. Mlynczak, and James M. Russell III
Atmos. Meas. Tech., 11, 2937–2947, https://doi.org/10.5194/amt-11-2937-2018, https://doi.org/10.5194/amt-11-2937-2018, 2018
Short summary
Short summary
OH*-spectrometer measurements allow the analysis of gravity wave ground-based periods, but spatial information cannot necessarily be deduced. We combine the approach of Wachter at al. (2015) in order to derive horizontal wavelengths (but based on only one OH* spectrometer) with additional information about wind and temperature and compute vertical wavelengths. Knowledge of these parameters is a precondition for the calculation of further information such as the wave group velocity.
Gunter Stober, Svenja Sommer, Carsten Schult, Ralph Latteck, and Jorge L. Chau
Atmos. Chem. Phys., 18, 6721–6732, https://doi.org/10.5194/acp-18-6721-2018, https://doi.org/10.5194/acp-18-6721-2018, 2018
Rolf Rüfenacht, Gerd Baumgarten, Jens Hildebrand, Franziska Schranz, Vivien Matthias, Gunter Stober, Franz-Josef Lübken, and Niklaus Kämpfer
Atmos. Meas. Tech., 11, 1971–1987, https://doi.org/10.5194/amt-11-1971-2018, https://doi.org/10.5194/amt-11-1971-2018, 2018
Short summary
Short summary
Wind information throughout the middle-atmosphere is crucial for the understanding of atmospheric dynamics but became available only recently, thanks to developments in remote sensing and modelling approaches. We present the first thorough assessment of the quality of the wind estimates by comparing co-located observations from lidar and microwave radiometry and opposing them to the major atmospheric models. Moreover we evaluated a new approach for measuring mesopause region wind by radiometry.
Qiang Li, Markus Rapp, Gunter Stober, and Ralph Latteck
Ann. Geophys., 36, 577–586, https://doi.org/10.5194/angeo-36-577-2018, https://doi.org/10.5194/angeo-36-577-2018, 2018
Short summary
Short summary
With the powerful MAARSY radar, we detected 3D wind fields and the vertical winds show a non-Gaussian distribution. We further obtained the frequency spectrum of vertical wind. The distribution of the spectral slopes under different wind conditions is derived and their comparisons with the background horizontal winds show that the spectra become steeper with increasing wind velocities under quiet conditions, approach a slope of −5/3 at 10 m/s and then maintain this slope for even stronger winds.
Sven Wilhelm, Gunter Stober, and Jorge L. Chau
Ann. Geophys., 35, 893–906, https://doi.org/10.5194/angeo-35-893-2017, https://doi.org/10.5194/angeo-35-893-2017, 2017
Short summary
Short summary
A comparison between winds and tides in the mesosphere and lower thermosphere based on measurements from a meteor radar (MR) and a medium-frequency radar in northern Norway was done to estimate potential biases between the two systems. Our results indicate reasonable agreement for the zonal and meridional wind components between 78 and 92 km. Based on these findings, we have taken the MR data as a reference and thus construct a consistent and homogenous wind from approximately 60 to 110 km.
Gunter Stober, Vivien Matthias, Christoph Jacobi, Sven Wilhelm, Josef Höffner, and Jorge L. Chau
Ann. Geophys., 35, 711–720, https://doi.org/10.5194/angeo-35-711-2017, https://doi.org/10.5194/angeo-35-711-2017, 2017
Ryosuke Shibuya, Kaoru Sato, Masaki Tsutsumi, Toru Sato, Yoshihiro Tomikawa, Koji Nishimura, and Masashi Kohma
Atmos. Chem. Phys., 17, 6455–6476, https://doi.org/10.5194/acp-17-6455-2017, https://doi.org/10.5194/acp-17-6455-2017, 2017
Short summary
Short summary
The first observations made by a complete PANSY radar system (Program of the Antarctic Syowa MST/IS radar) installed at Syowa Station were successfully performed from 16 to 24 March 2015. Over this period, quasi-12 h period disturbances in the mesosphere at heights of 70 to 80 km were observed. Combining the observational data and numerical simulation outputs, we found that quasi-12 h disturbances are due to large-scale inertia–gravity waves, not to semi-diurnal migrating tides.
Qiang Li, Markus Rapp, Anne Schrön, Andreas Schneider, and Gunter Stober
Ann. Geophys., 34, 1209–1229, https://doi.org/10.5194/angeo-34-1209-2016, https://doi.org/10.5194/angeo-34-1209-2016, 2016
Short summary
Short summary
Turbulence is an essential process in the atmosphere and ocean. Clear-air turbulence is a well-known threat for the safety of aviation. Using a powerful MST radar, we detected turbulence and compared it with the results from radiosondes. The correlation between turbulence and background conditions, e.g., Richardson number and wind shears, is determined. There is a nearly negative correlation between turbulence and Richardson number independent of the length scale over which it was calculated.
Ch. Jacobi, N. Samtleben, and G. Stober
Adv. Radio Sci., 14, 169–174, https://doi.org/10.5194/ars-14-169-2016, https://doi.org/10.5194/ars-14-169-2016, 2016
Short summary
Short summary
VHF meteor radar observations of mesosphere/lower thermosphere daily temperatures have been performed at Collm, Germany. The data have been analyzed with respect to long-period oscillations at time scales of 2 to 30 days. The results reveal that oscillations with periods of up to 6 days are more frequently observed during summer, while those with longer periods have larger amplitudes during winter. The results are comparable with analyses from radar wind measurements.
Silje Eriksen Holmen, Chris M. Hall, and Masaki Tsutsumi
Atmos. Chem. Phys., 16, 7853–7866, https://doi.org/10.5194/acp-16-7853-2016, https://doi.org/10.5194/acp-16-7853-2016, 2016
Short summary
Short summary
Atmospheric temperatures at 90 km height above Tromsø, Norway, from 2003 to 2014 have been determined using meteor radar. Periodic oscillations ranging from ~ 9 days to a year were found in the dataset, which were related to the large-scale circulation in the middle atmosphere and with wave activity. A trend analysis was performed, revealing an overall weak cooling trend from 2003 to 2014, which is in line with other recent studies on mesopause region (~ 90 km) temperature trends.
Maria Mihalikova, Kaoru Sato, Masaki Tsutsumi, and Toru Sato
Ann. Geophys., 34, 543–555, https://doi.org/10.5194/angeo-34-543-2016, https://doi.org/10.5194/angeo-34-543-2016, 2016
Juha Vierinen, Jorge L. Chau, Nico Pfeffer, Matthias Clahsen, and Gunter Stober
Atmos. Meas. Tech., 9, 829–839, https://doi.org/10.5194/amt-9-829-2016, https://doi.org/10.5194/amt-9-829-2016, 2016
Short summary
Short summary
This paper describes the use of pseudorandom coded continuous wave radar transmissions for meteor radar. This avoids range-aliased echoes, maximizes pulse compression gain, is less susceptible to RFI, allows time resolution to be changed flexibly, and enables multiple transmitters to operate on the same frequency without interfering each other. These features make the radar well suited for multi-static meteor radar networks. We show results from a measurement campaign to demonstrate the method.
T. Renkwitz, C. Schult, R. Latteck, and G. Stober
Adv. Radio Sci., 13, 41–48, https://doi.org/10.5194/ars-13-41-2015, https://doi.org/10.5194/ars-13-41-2015, 2015
S. Sommer, G. Stober, J. L. Chau, and R. Latteck
Adv. Radio Sci., 12, 197–203, https://doi.org/10.5194/ars-12-197-2014, https://doi.org/10.5194/ars-12-197-2014, 2014
T. Takahashi, S. Nozawa, M. Tsutsumi, C. Hall, S. Suzuki, T. T. Tsuda, T. D. Kawahara, N. Saito, S. Oyama, S. Wada, T. Kawabata, H. Fujiwara, A. Brekke, A. Manson, C. Meek, and R. Fujii
Ann. Geophys., 32, 1195–1205, https://doi.org/10.5194/angeo-32-1195-2014, https://doi.org/10.5194/angeo-32-1195-2014, 2014
G. Stober, S. Sommer, M. Rapp, and R. Latteck
Atmos. Meas. Tech., 6, 2893–2905, https://doi.org/10.5194/amt-6-2893-2013, https://doi.org/10.5194/amt-6-2893-2013, 2013
C. Schult, G. Stober, J. L. Chau, and R. Latteck
Ann. Geophys., 31, 1843–1851, https://doi.org/10.5194/angeo-31-1843-2013, https://doi.org/10.5194/angeo-31-1843-2013, 2013
H. Suzuki, T. Nakamura, M. K. Ejiri, T. Ogawa, M. Tsutsumi, M. Abo, T. D. Kawahara, Y. Tomikawa, A. S. Yukimatu, and N. Sato
Ann. Geophys., 31, 1793–1803, https://doi.org/10.5194/angeo-31-1793-2013, https://doi.org/10.5194/angeo-31-1793-2013, 2013
V. Matthias, P. Hoffmann, A. Manson, C. Meek, G. Stober, P. Brown, and M. Rapp
Ann. Geophys., 31, 1397–1415, https://doi.org/10.5194/angeo-31-1397-2013, https://doi.org/10.5194/angeo-31-1397-2013, 2013
G. Stober, C. Schult, C. Baumann, R. Latteck, and M. Rapp
Ann. Geophys., 31, 473–487, https://doi.org/10.5194/angeo-31-473-2013, https://doi.org/10.5194/angeo-31-473-2013, 2013
J. Kero, C. Szasz, and T. Nakamura
Ann. Geophys., 31, 439–449, https://doi.org/10.5194/angeo-31-439-2013, https://doi.org/10.5194/angeo-31-439-2013, 2013
T. Dunker, U.-P. Hoppe, G. Stober, and M. Rapp
Ann. Geophys., 31, 61–73, https://doi.org/10.5194/angeo-31-61-2013, https://doi.org/10.5194/angeo-31-61-2013, 2013
M. Rapp, J. M. C. Plane, B. Strelnikov, G. Stober, S. Ernst, J. Hedin, M. Friedrich, and U.-P. Hoppe
Ann. Geophys., 30, 1661–1673, https://doi.org/10.5194/angeo-30-1661-2012, https://doi.org/10.5194/angeo-30-1661-2012, 2012
Related subject area
Subject: Earth's ionosphere & aeronomy | Keywords: Ionosphere–atmosphere interactions
Polar mesospheric summer echo (PMSE) multilayer properties during the solar maximum and solar minimum
Calibrating estimates of ionospheric long-term change
On the importance of middle-atmosphere observations on ionospheric dynamics using WACCM-X and SAMI3
Analysis of in situ measurements of electron, ion and neutral temperatures in the lower thermosphere–ionosphere
Effects of the terdiurnal tide on the sporadic E (Es) layer development at low latitudes over the Brazilian sector
Mid-latitude neutral wind responses to sub-auroral polarization streams
Arecibo measurements of D-region electron densities during sunset and sunrise: implications for atmospheric composition
Entangled dynamos and Joule heating in the Earth's ionosphere
Evidence of vertical coupling: meteorological storm Fabienne on 23 September 2018 and its related effects observed up to the ionosphere
Quasi-10 d wave modulation of an equatorial ionization anomaly during the Southern Hemisphere stratospheric warming of 2002
Quarterdiurnal signature in sporadic E occurrence rates and comparison with neutral wind shear
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.
Christopher John Scott, Matthew N. Wild, Luke Anthony Barnard, Bingkun Yu, Tatsuhiro Yokoyama, Michael Lockwood, Cathryn Mitchel, John Coxon, and Andrew Kavanagh
Ann. Geophys., 42, 395–418, https://doi.org/10.5194/angeo-42-395-2024, https://doi.org/10.5194/angeo-42-395-2024, 2024
Short summary
Short summary
Long-term change in the ionosphere are expected due to increases in greenhouse gases in the lower atmosphere. Empirical formulae are used to estimate height. Through comparison with independent data we show that there are seasonal and long-term biases introduced by the empirical model. We conclude that estimates of long-term changes in ionospheric height need to account for these biases.
Fabrizio Sassi, Angeline G. Burrell, Sarah E. McDonald, Jennifer L. Tate, and John P. McCormack
Ann. Geophys., 42, 255–269, https://doi.org/10.5194/angeo-42-255-2024, https://doi.org/10.5194/angeo-42-255-2024, 2024
Short summary
Short summary
This study shows how middle-atmospheric data (starting at 40 km) affect day-to-day ionospheric variability. We do this by using lower atmospheric measurements that include and exclude the middle atmosphere in a coupled ionosphere–thermosphere model. Comparing the two simulations reveals differences in two thermosphere–ionosphere coupling mechanisms. Additionally, comparison against observations showed that including the middle-atmospheric data improved the resulting ionosphere.
Panagiotis Pirnaris and Theodoros Sarris
Ann. Geophys., 41, 339–354, https://doi.org/10.5194/angeo-41-339-2023, https://doi.org/10.5194/angeo-41-339-2023, 2023
Short summary
Short summary
The relation between electron, ion and neutral temperatures in the lower thermosphere–ionosphere (LTI) is key to understanding the energy balance and transfer between species. However, their simultaneous measurement is rare in the LTI. Based on data from the AE-C, AE-D, AE-E and DE-2 satellites of the 1970s and 1980s, a large number of events where neutrals are hotter than ions are identified and statistically analyzed. Potential mechanisms that could trigger these events are proposed.
Pedro Alves Fontes, Marcio Tadeu de Assis Honorato Muella, Laysa Cristina Araújo Resende, Vânia Fátima Andrioli, Paulo Roberto Fagundes, Valdir Gil Pillat, Paulo Prado Batista, and Alexander Jose Carrasco
Ann. Geophys., 41, 209–224, https://doi.org/10.5194/angeo-41-209-2023, https://doi.org/10.5194/angeo-41-209-2023, 2023
Short summary
Short summary
In the terrestrial ionosphere, sporadic (metallic) layers are formed. The formation of these layers are related to the action of atmospheric waves. These waves, also named tides, are due to the absorption of solar radiation in the atmosphere. We investigated the role of the tides with 8 h period in the formation of the sporadic layers. The study was conducted using ionosonde and meteor radar data, as well as computing simulations. The 8 h tides intensified the density of the sporadic layers.
Daniel D. Billett, Kathryn A. McWilliams, Robert B. Kerr, Jonathan J. Makela, Alex T. Chartier, J. Michael Ruohoniemi, Sudha Kapali, Mike A. Migliozzi, and Juanita Riccobono
Ann. Geophys., 40, 571–583, https://doi.org/10.5194/angeo-40-571-2022, https://doi.org/10.5194/angeo-40-571-2022, 2022
Short summary
Short summary
Sub-auroral polarisation streams (SAPSs) are very fast plasma flows that occur at mid-latitudes, which can affect the atmosphere. In this paper, we use four ground-based radars to obtain a wide coverage of SAPSs that occurred over the USA, along with interferometer cameras in Virginia and Massachusetts to measure winds. The winds are strongly affected but in different ways, implying that the balance forces on the atmosphere is strongly dependent on proximity to the disturbance.
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
Short summary
Short summary
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.
Stephan C. Buchert
Ann. Geophys., 38, 1019–1030, https://doi.org/10.5194/angeo-38-1019-2020, https://doi.org/10.5194/angeo-38-1019-2020, 2020
Short summary
Short summary
Winds in the Earth's upper atmosphere cause magnetic and electric variations both at the ground and in space all over the Earth. According to the model of entangled dynamos the true cause is wind differences between regions in the Northern and Southern Hemispheres that are connected by the Earth's dipole-like magnetic field. The power produced in the southern dynamo heats the northern upper atmosphere and vice versa. The dynamos exist owing to this entanglement, an analogy to quantum mechanics.
Petra Koucká Knížová, Kateřina Podolská, Kateřina Potužníková, Daniel Kouba, Zbyšek Mošna, Josef Boška, and Michal Kozubek
Ann. Geophys., 38, 73–93, https://doi.org/10.5194/angeo-38-73-2020, https://doi.org/10.5194/angeo-38-73-2020, 2020
Short summary
Short summary
Severe meteorological storm Fabienne passing above central Europe was observed. Significant variations of atmospheric and ionospheric parameters were detected. Above Europe, stratospheric temperature and wind significantly changed in coincidence with frontal transition. Within ionospheric parameters, we have detected significant wave-like activity shortly after the cold front crossed the observational point. During the storm event, we have observed strong horizontal plasma flow shears.
Xiaohua Mo and Donghe Zhang
Ann. Geophys., 38, 9–16, https://doi.org/10.5194/angeo-38-9-2020, https://doi.org/10.5194/angeo-38-9-2020, 2020
Christoph Jacobi, Christina Arras, Christoph Geißler, and Friederike Lilienthal
Ann. Geophys., 37, 273–288, https://doi.org/10.5194/angeo-37-273-2019, https://doi.org/10.5194/angeo-37-273-2019, 2019
Short summary
Short summary
Sporadic E (Es) layers in the Earth's ionosphere are produced by ion convergence due to vertical wind shear in the presence of a horizontal component of the Earth's magnetic field. We present analyses of the 6 h tidal signatures in ES occurrence rates derived from GPS radio observations. Times of maxima in ES agree well with those of negative wind shear obtained from radar observation. The global distribution of ES amplitudes agrees with wind shear amplitudes from numerical modeling.
Cited articles
Akbari, H., Bhatt, A., La Hoz, C., and Semeter, J. L.: Incoherent Scatter Plasma Lines: Observations and Applications, Space Sci. Rev., 212, 249–294, https://doi.org/10.1007/s11214-017-0355-7, 2017. a
Baloukidis, D., Sarris, T., Tourgaidis, S., Pirnaris, P., Aikio, A., Virtanen, I., Buchert, S., and Papadakis, K.: A Comparative Assessment of the Distribution of Joule Heating in Altitude as Estimated in TIE-GCM and EISCAT Over One Solar Cycle, J. Geophys. Res.-Space Phys., 128, e2023JA031526, https://doi.org/10.1029/2023JA031526, 2023. a, b, c
Baumgarten, K. and Stober, G.: On the evaluation of the phase relation between temperature and wind tides based on ground-based measurements and reanalysis data in the middle atmosphere, Ann. Geophys., 37, 581–602, https://doi.org/10.5194/angeo-37-581-2019, 2019. a
Baumjohann, W. and Treumann, R. A.: Basic space plasma physics, World Scientific, 340 pp., https://doi.org/10.1142/p015, 1996. a
Becker, E.: Mean-Flow Effects of Thermal Tides in the Mesosphere and Lower Thermosphere, J. Atmos. Sci., 74, 2043–2063, https://doi.org/10.1175/JAS-D-16-0194.1, 2017. a
Brekke, A. and Kamide, Y.: On the relationship between Joule and frictional heating in the polar ionosphere., J. Atmos. Terr. Phys., 58, 139–143, https://doi.org/10.1016/0021-9169(95)00025-9, 1996. a
Chapman, S.: The electrical conductivity of the ionosphere: A review, Il Nuovo Cimento, 4, 1385–1412, https://doi.org/10.1007/BF02746310, 1956. a, b
Deng, Y., Fuller-Rowell, T. J., Akmaev, R. A., and Ridley, A. J.: Impact of the altitudinal Joule heating distribution on the thermosphere, J. Geophys. Res.-Space Phys., 116, A05313, https://doi.org/10.1029/2010JA016019, 2011. a, b
Emmert, J. T., Drob, D. P., Picone, J. M., Siskind, D. E., Jones, M., Mlynczak, M. G., Bernath, P. F., Chu, X., Doornbos, E., Funke, B., Goncharenko, L. P., Hervig, M. E., Schwartz, M. J., Sheese, P. E., Vargas, F., Williams, B. P., and Yuan, T.: NRLMSIS 2.0: A Whole Atmosphere Empirical Model of Temperature and Neutral Species Densities, Earth Space Sci., 8, e01321, https://doi.org/10.1029/2020EA001321, 2021. a
Fang, X., Randall, C. E., Lummerzheim, D., Wang, W., Lu, G., Solomon, S. C., and Frahm, R. A.: Parameterization of monoenergetic electron impact ionization, Geophys. Res. Lett., 37, L22106, https://doi.org/10.1029/2010GL045406, 2010. a, b
Fang, X., Lummerzheim, D., and Jackman, C. H.: Proton impact ionization and a fast calculation method, J. Geophys. Res.-Space Phys., 118, 5369–5378, https://doi.org/10.1002/jgra.50484, 2013. a, b
Folkestad, K., Hagfors, T., and Westerlund, S.: EISCAT: An updated description of technical characteristics and operational capabilities, Radio Sci., 18, 867–879, https://doi.org/10.1029/RS018i006p00867, 1983. a
Frøystein, I. and Johnsen, M. G.: A critical review and presentation of the complete, historic series of K-indices as determined at Norwegian Magnetic Observatories since 1939, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-3254, 2024. a
Gjerloev, J. W.: The SuperMAG data processing technique, J. Geophys. Res.-Space Phys., 117, A09213, https://doi.org/10.1029/2012JA017683, 2012. a
Gledhill, J. A.: The effective recombination coefficient of electrons in the ionosphere between 50 and 150 km, Radio Sci., 21, 399–408, https://doi.org/10.1029/RS021i003p00399, 1986. a, b
Grandin, M., Partamies, N., and Virtanen, I. I.: Statistical comparison of electron precipitation during auroral breakups occurring either near the open–closed field line boundary or in the central part of the auroral oval, Ann. Geophys., 42, 355–369, https://doi.org/10.5194/angeo-42-355-2024, 2024. a
Grassmann, V.: The effect of different collision operators on EISCAT's standard data analysis model, J. Atmos. Terr. Phys., 55, 567–571, https://doi.org/10.1016/0021-9169(93)90005-J, 1993a. a
Grassmann, V.: An incoherent scatter experiment for the measurement of particle collisions, J. Atmos. Terr. Phys., 55, 573–576, https://doi.org/10.1016/0021-9169(93)90006-K, 1993b. a, b, c, d
Günzkofer, F., Pokhotelov, D., Stober, G., Liu, H., Liu, H. L., Mitchell, N. J., Tjulin, A., and Borries, C.: Determining the Origin of Tidal Oscillations in the Ionospheric Transition Region With EISCAT Radar and Global Simulation Data, J. Geophys. Res.-Space Phys., 127, e2022JA030861, https://doi.org/10.1029/2022JA030861, 2022. a, b
Günzkofer, F., Pokhotelov, D., Stober, G., Mann, I., Vadas, S. L., Becker, E., Tjulin, A., Kozlovsky, A., Tsutsumi, M., Gulbrandsen, N., Nozawa, S., Lester, M., Belova, E., Kero, J., Mitchell, N. J., and Borries, C.: 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., 41, 409–428, https://doi.org/10.5194/angeo-41-409-2023, 2023a. a
Günzkofer, F., Liu, H., Stober, G., Pokhotelov, D., and Borries, C.: Evaluation of the Empirical Scaling Factor of Joule Heating Rates in TIE-GCM With EISCAT Measurements, Earth Space Sci., 11, e2023EA003447, https://doi.org/10.1029/2023EA003447, 2024. a, b, c
Günzkofer, F., Stober, G., Kero, J., Themens, D., Tjulin, A., Gulbrandsen, N., Tsutsumi, M., and Borries, C.: The impact of particle precipitation on the ion-neutral collision frequency analyzed with EISCAT measurements, Zenodo [data set], https://doi.org/10.5281/zenodo.14646603, 2025. a
Hagan, M. E. and Forbes, J. M.: Migrating and nonmigrating semidiurnal tides in the upper atmosphere excited by tropospheric latent heat release, J. Geophys. Res.-Space Phys., 108, 1062, https://doi.org/10.1029/2002JA009466, 2003. a
Hall, C. M. and Tsutsumi, M.: Changes in mesospheric dynamics at 78° N, 16° E and 70° N, 19° E: 2001–2012, J. Geophys. Res.-Atmos., 118, 2689–2701, https://doi.org/10.1002/jgrd.50268, 2013. a
Hays, P. B., Jones, R. A., and Rees, M. H.: Auroral heating and the composition of the neutral atmosphere, Planet. Space Sci., 21, 559–573, https://doi.org/10.1016/0032-0633(73)90070-6, 1973. a, b
Holdsworth, D. A., Reid, I. M., and Cervera, M. A.: Buckland Park all-sky interferometric meteor radar, Radio Sci., 39, RS5009, https://doi.org/10.1029/2003RS003014, 2004. a
Ieda, A.: Ion-Neutral Collision Frequencies for Calculating Ionospheric Conductivity, J. Geophys. Res.-Space Phys., 125, e27128, https://doi.org/10.1029/2019JA027128, 2020. a, b, c, d
Kurihara, J., Oyama, S., Nozawa, S., Tsuda, T. T., Fujii, R., Ogawa, Y., Miyaoka, H., Iwagami, N., Abe, T., Oyama, K. I., Kosch, M. J., Aruliah, A., Griffin, E., and Kauristie, K.: Temperature enhancements and vertical winds in the lower thermosphere associated with auroral heating during the DELTA campaign, J. Geophys. Res.-Space Phys., 114, A12306, https://doi.org/10.1029/2009JA014392, 2009. a, b, c
Lehtinen, M. S. and Huuskonen, A.: General incoherent scatter analysis and GUISDAP, J. Atmos. Terr. Phys., 58, 435–452, https://doi.org/10.1016/0021-9169(95)00047-X, 1996. a
Lieberman, R. S. and Hays, P. B.: An Estimate of the Momentum Deposition in the Lower Thermosphere by the Observed Diurnal Tide., J. Atmos. Sci., 51, 3094–3108, https://doi.org/10.1175/1520-0469(1994)051<3094:AEOTMD>2.0.CO;2, 1994. a
Lindzen, R. S.: Atmospheric Tides, Annu. Rev. Earth Planet. Sci., 7, 199, https://doi.org/10.1146/annurev.ea.07.050179.001215, 1979. a
Liu, H.-L.: Variability and predictability of the space environment as related to lower atmosphere forcing, Space Weather, 14, 634–658, https://doi.org/10.1002/2016SW001450, 2016. a
Maute, A., Lu, G., Knipp, D. J., Anderson, B. J., and Vines, S. K.: Importance of lower atmospheric forcing and magnetosphere-ionosphere coupling in simulating neutral density during the February 2016 geomagnetic storm, Frontiers in Astronomy and Space Sciences, 9, 932748, https://doi.org/10.3389/fspas.2022.932748, 2022. a
McCrea, I., Aikio, A., Alfonsi, L., Belova, E., Buchert, S., Clilverd, M., Engler, N., Gustavsson, B., Heinselman, C., Kero, J., Kosch, M., Lamy, H., Leyser, T., Ogawa, Y., Oksavik, K., Pellinen-Wannberg, A., Pitout, F., Rapp, M., Stanislawska, I., and Vierinen, J.: The science case for the EISCAT_3D radar, Prog. Earth Planet. Sci, 2, 21, https://doi.org/10.1186/s40645-015-0051-8, 2015. a
Mironova, I. A., Aplin, K. L., Arnold, F., Bazilevskaya, G. A., Harrison, R. G., Krivolutsky, A. A., Nicoll, K. A., Rozanov, E. V., Turunen, E., and Usoskin, I. G.: Energetic Particle Influence on the Earth's Atmosphere, Space Sci. Rev., 194, 1–96, https://doi.org/10.1007/s11214-015-0185-4, 2015. a
Monro, P. E., Nisbet, J. S., and Stick, T. L.: Effects of tidal oscillations in the neutral atmosphere on electron densities in the E-region, J. Atmos. Terr. Phys., 38, 523–528, https://doi.org/10.1016/0021-9169(76)90010-6, 1976. a
Newell, P. T. and Gjerloev, J. W.: Evaluation of SuperMAG auroral electrojet indices as indicators of substorms and auroral power, J. Geophys. Res.-Space Phys., 116, A12211, https://doi.org/10.1029/2011JA016779, 2011. a
Nicolls, M. J., Bahcivan, H., Häggström, I., and Rietveld, M.: Direct measurement of lower thermospheric neutral density using multifrequency incoherent scattering, Geophys. Res. Lett., 41, 8147–8154, https://doi.org/10.1002/2014GL062204, 2014. a, b, c
Nozawa, S., Ogawa, Y., Oyama, S., Fujiwara, H., Tsuda, T., Brekke, A., Hall, C. M., Murayama, Y., Kawamura, S., Miyaoka, H., and Fujii, R.: Tidal waves in the polar lower thermosphere observed using the EISCAT long run data set obtained in September 2005, J. Geophys. Res.-Space Phys., 115, A08312, https://doi.org/10.1029/2009JA015237, 2010. a
Nygrén, T.: Studies of the E-region ion-neutral collision frequency using the EISCAT incoherent scatter radar, Adv. Space Res., 18, 79–82, https://doi.org/10.1016/0273-1177(95)00843-4, 1996. a
Nykiel, G., Ferreira, A., Günzkofer, F., Iochem, P., Tasnim, S., and Sato, H.: Large-Scale Traveling Ionospheric Disturbances Over the European Sector During the Geomagnetic Storm on March 23-24, 2023: Energy Deposition in the Source Regions and the Propagation Characteristics, J. Geophys. Res.-Space Phys., 129, e2023JA032145, https://doi.org/10.1029/2023JA032145, 2024. a
Olson, W. P. and Moe, K.: Influence of precipitating charged particles on the high latitude thermosphere, J. Atmos. Terr. Phys., 36, 1715, https://doi.org/10.1016/0021-9169(74)90156-1, 1974. a
Oyama, S., Watkins, B. J., Maeda, S., Shinagawa, H., Nozawa, S., Ogawa, Y., Brekke, A., Lathuillere, C., and Kofman, W.: Generation of the lower-thermospheric vertical wind estimated with the EISCAT KST radar at high latitudes during periods of moderate geomagnetic disturbance, Ann. Geophys., 26, 1491–1505, https://doi.org/10.5194/angeo-26-1491-2008, 2008. a, b, c, d
Oyama, S., Kurihara, J., Watkins, B. J., Tsuda, T. T., and Takahashi, T.: Temporal variations of the ion-neutral collision frequency from EISCAT observations in the polar lower ionosphere during periods of geomagnetic disturbances, J. Geophys. Res.-Space Phys., 117, A05308, https://doi.org/10.1029/2011JA017159, 2012. a, b, c
Qian, L. and Solomon, S. C.: Thermospheric Density: An Overview of Temporal and Spatial Variations, Space Sci. Rev., 168, 147–173, https://doi.org/10.1007/s11214-011-9810-z, 2012. a
Rees, D., Tobiska, K., Bowman, B., Vaughan, B., and Owens, J.: The New COSPAR International Reference Atmosphere (CIRA2014): Overview, Space Research Today, 188, 4–8, https://doi.org/10.1016/j.srt.2013.11.005, 2013. a
Schunk, R. W. and Walker, J. C. G.: Transport processes in the E region of the ionosphere, J. Geophys. Res., 76, 6159–6171, https://doi.org/10.1029/JA076i025p06159, 1971. a, b
Sheng, C., Deng, Y., Zhang, S.-R., Nishimura, Y., and Lyons, L. R.: Relative Contributions of Ion Convection and Particle Precipitation to Exciting Large-Scale Traveling Atmospheric and Ionospheric Disturbances, J. Geophys. Res.-Space Phys., 125, e27342, https://doi.org/10.1029/2019JA027342, 2020. a
Smith, M. F., Rees, D., and Fuller-Rowell, T. J.: The consequences of high latitude particle precipitation on global thermospheric dynamics, Planet. Space Sci., 30, 1259–1267, https://doi.org/10.1016/0032-0633(82)90099-X, 1982. a
Stober, G., Baumgarten, K., McCormack, J. P., Brown, P., and Czarnecki, J.: Comparative study between ground-based observations and NAVGEM-HA analysis data in the mesosphere and lower thermosphere region, Atmos. Chem. Phys., 20, 11979–12010, https://doi.org/10.5194/acp-20-11979-2020, 2020. a
Stober, G., Kozlovsky, A., Liu, A., Qiao, Z., Tsutsumi, M., Hall, C., Nozawa, S., Lester, M., Belova, E., Kero, J., Espy, P. J., Hibbins, R. E., and Mitchell, N.: Atmospheric tomography using the Nordic Meteor Radar Cluster and Chilean Observation Network De Meteor Radars: network details and 3D-Var retrieval, Atmos. Meas. Tech., 14, 6509–6532, https://doi.org/10.5194/amt-14-6509-2021, 2021a. a
Stober, G., Kuchar, A., Pokhotelov, D., Liu, H., Liu, H.-L., Schmidt, H., Jacobi, C., Baumgarten, K., Brown, P., Janches, D., Murphy, D., Kozlovsky, A., Lester, M., Belova, E., Kero, J., and Mitchell, N.: Interhemispheric differences of mesosphere–lower thermosphere winds and tides investigated from three whole-atmosphere models and meteor radar observations, Atmos. Chem. Phys., 21, 13855–13902, https://doi.org/10.5194/acp-21-13855-2021, 2021b. a
Stober, G., Liu, A., Kozlovsky, A., Qiao, Z., Kuchar, A., Jacobi, C., Meek, C., Janches, D., Liu, G., Tsutsumi, M., Gulbrandsen, N., Nozawa, S., Lester, M., Belova, E., Kero, J., and Mitchell, N.: Meteor radar vertical wind observation biases and mathematical debiasing strategies including the 3DVAR+DIV algorithm, Atmos. Meas. Tech., 15, 5769–5792, https://doi.org/10.5194/amt-15-5769-2022, 2022. a
Tjulin, A.: EISCAT Experiments, Tech. rep., EISCAT AB, https://eiscat.se/wp-content/uploads/2024/08/Experiments_v20240807.pdf (last access: 25 June 2025), 2024. a
Truskowski, A. O., Forbes, J. M., Zhang, X., and Palo, S. E.: New perspectives on thermosphere tides: 1. Lower thermosphere spectra and seasonal-latitudinal structures, Earth Planet. Space, 66, 136, https://doi.org/10.1186/s40623-014-0136-4, 2014. a
Waldteufel, P.: A study of seasonal changes in the lower thermosphere and their implications, Planet. Space Sci., 18, 741–748, https://doi.org/10.1016/0032-0633(70)90055-3, 1970. a
Watson, C., Themens, D. R., and Jayachandran, P. T.: Development and Validation of Precipitation Enhanced Densities for the Empirical Canadian High Arctic Ionospheric Model, Space Weather, 19, e2021SW002779, https://doi.org/10.1029/2021SW002779, 2021. a
Yue, J., Yu, W., Pedatella, N., Bruinsma, S., Wang, N., and Liu, H.: Contribution of the lower atmosphere to the day-to-day variation of thermospheric density, Adv. Space Res., 72, 5460–5475, https://doi.org/10.1016/j.asr.2022.06.011, 2023. a
Zhang, Y., Paxton, L. J., Lu, G., and Yee, S.: Impact of nitric oxide, solar EUV and particle precipitation on thermospheric density decrease, J. Atmos. Solar-Terr. Phy., 182, 147–154, https://doi.org/10.1016/j.jastp.2018.11.016, 2019. a
Short summary
The Earth’s magnetic field is not closed at high latitudes. Electrically charged particles can penetrate the Earth’s atmosphere, deposit their energy, and heat the local atmosphere–ionosphere. This presumably causes an upwelling of the neutral atmosphere, which affects the atmosphere–ionosphere coupling. We apply a new analysis technique to infer the atmospheric density from incoherent scatter radar measurements. We identify signs of particle precipitation impact on the neutral atmosphere.
The Earth’s magnetic field is not closed at high latitudes. Electrically charged particles can...
