Articles | Volume 43, issue 2
https://doi.org/10.5194/angeo-43-427-2025
© 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-43-427-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
16 Jul 2025
Regular paper |
| 16 Jul 2025
| 16 Jul 2025
TIMED Doppler Interferometer measurements of neutral winds at the mesosphere and lower thermosphere and comparison to meteor radar winds
Arthur Gauthier
CORRESPONDING AUTHOR
Institute of Applied Physics, University of Bern, Bern, Switzerland
Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland
Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany
Claudia Borries
Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany
Alexander Kozlovsky
Sodankylä Geophysical Observatory, University of Oulu, Oulu, Finland
Diego Janches
ITM Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
Peter Brown
Dept. of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada
Western Institute for Earth and Space Exploration, University of Western Ontario, London, Ontario, Canada
Denis Vida
Dept. of Physics and Astronomy, University of Western Ontario, London, Ontario, Canada
Christoph Jacobi
Institute for Meteorology, Leipzig University, Leipzig, Germany
Damian Murphy
Australian Antarctic Division, Kingston, Tasmania, Australia
Masaki Tsutsumi
National Institute of Polar Research, Tachikawa, Japan
The Graduate University for Advanced Studies (SOKENDAI), Tokyo, Japan
Njål Gulbrandsen
Tromsø Geophysical Observatory, UiT – The Arctic University of Norway, Tromsø, Norway
Satonori Nozawa
Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
Mark Lester
University of Leicester, Leicester, UK
Johan Kero
Swedish Institute of Space Physics (IRF), Kiruna, Sweden
Nicholas Mitchell
British Antarctic Survey, Cambridge, CB3 0ET, UK
Department of Electronic and Electrical Engineering, University of Bath, Bath, UK
Tracy Moffat-Griffin
British Antarctic Survey, Cambridge, CB3 0ET, UK
Institute of Applied Physics, University of Bern, Bern, Switzerland
Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland
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Christoph Jacobi, Ales Kuchar, Manfred Ern, Toralf Renkwitz, Ralph Latteck, and Jorge L. Chau
Adv. Radio Sci., 24, 15–28, https://doi.org/10.5194/ars-24-15-2026, https://doi.org/10.5194/ars-24-15-2026, 2026
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Analyses of more than four decades (1979–2024) of mean horizontal winds in the mesopause region at about 90 km altitude show long-term trends and an influence of the 11-year solar cycle. After the 1990s, both linear trends and the solar cycle effect change and strongly weaken, indicating a change in dynamics or solar forcing. Gravity wave proxies also show a solar cycle effect, which decreases after the 1990s.
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
Atmos. Meas. Tech., 19, 4277–4292, https://doi.org/10.5194/amt-19-4277-2026, https://doi.org/10.5194/amt-19-4277-2026, 2026
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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 (Middle Atmosphere Alomar Radar System (MAARSY)) to measure the meteors and determine changes to the atmospheric density between the years of 2016–2023 at altitudes of 85–115 km. The same time period between years are compared, minimizing changes to the measurements due to factors other than the atmosphere.
Gunter Stober, Hanli Liu, Zishun Qiao, Kaoru Sato, Loretta Pearl Poku, Witali Krochin, Alan Liu, Alexander Kozlovsky, Diego Janches, Jie Zeng, Wen Yi, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Johan Kero, and Nicholas Mitchell
EGUsphere, https://doi.org/10.5194/egusphere-2026-3156, https://doi.org/10.5194/egusphere-2026-3156, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
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Vertical winds are a crucial atmospheric parameter in the mesosphere/lower thermosphere and are connected to adiabatic heating and cooling of the atmosphere. Mesospheric temperatures are affected by the vertical transport driven by a pole-to-pole circulation with upwelling in the summer hemisphere and downwelling in the winter hemisphere. We present results based on a new retrieval technique for the seasonal climatological vertical winds and an intercomparison to current state-of-the-art models.
Witali Krochin, Axel Murk, and Gunter Stober
EGUsphere, https://doi.org/10.5194/egusphere-2026-2364, https://doi.org/10.5194/egusphere-2026-2364, 2026
This preprint is open for discussion and under review for Annales Geophysicae (ANGEO).
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This manuscript presents measurements of the microwave emission spectra of oxygen. These spectra depend strongly on the geomagnetic field, since oxygen's magnetic dipole couples to it what produces measurable spectral shifts. The interaction is analyzed in detail, including observation geometry and polarization. Using the relation between magnetic field and spectral characteristics, a method is proposed for remote monitoring of geomagnetic variations.
Rahul Rathi, Adrian Grocott, Tim K. Yeoman, and Mark Lester
Ann. Geophys., 44, 353–368, https://doi.org/10.5194/angeo-44-353-2026, https://doi.org/10.5194/angeo-44-353-2026, 2026
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We investigate high-latitude medium scale traveling ionospheric disturbances (MSTIDs) over European Incoherent Scatter (EISCAT)-3D site. Using Hankasalmi radar data during solar max & min years of solar cycles 23 & 24, we observed that MSTIDs normally propagate equatorward with velocity and period of 50–150 m s-1 and 30–60 minutes, respectively. Along with seasonal variation, MSTIDs showed dependency on solar activity as well as on northward and southward interplanetary magnetic field (IMF) Bz.
Loretta Pearl Poku, Gunter Stober, Witali Krochin, Alan Liu, Alexander Kozlovsky, Diego Janches, Jie Zeng, Wen Yi, Masaki Tsutsumi, Njål Gulbrandsen, Satonori Nozawa, Mark Lester, Johan Kero, and Nicholas Mitchell
EGUsphere, https://doi.org/10.5194/egusphere-2025-6377, https://doi.org/10.5194/egusphere-2025-6377, 2026
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This study presents 3D spatially resolved wind fields in the MLT using advanced retrieval techniques. Specifically, a novel SVVP method in spherical coordinates to enhance the physical consistency of wind retrievals compared to the conventional VVP method in plane geometry and the 3DVAR+DIV method. The SVVP provides a robust framework for future MLT dynamics studies, and the 3DVAR+DIV retrieval is beneficial for high-resolution case studies due to its ability to capture small-scale variability.
Wen Yi, Jianyuan Wang, Xianghui Xue, Chengyun Yang, Iain M. Reid, Robert A. Vincent, Andrew Mackinnon, Damian J. Murphy, Njål Gulbrandsen, Masaki Tsutsumi, Baiqi Ning, Guozhu Li, Nicholas J. Mitchell, Tracy Moffat-Griffin, Toshitaka Tsuda, Alan Z. Liu, Zishun Qiao, Haiying Li, Paulo P. Batista, Jianfei Wu, Tingdi Chen, and Xiankang Dou
EGUsphere, https://doi.org/10.5194/egusphere-2026-1883, https://doi.org/10.5194/egusphere-2026-1883, 2026
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This study provides observational evidence that the solar zenith angle (SZA) influences the vertical structure of diurnal tides in the MLT region. Diurnal tides are strongest at low and mid-latitudes (10–50° N/S) and weaker near the Equator and at polar latitudes. The results further suggest that background zonal winds influence tidal propagation and structure through filtering and momentum drag.
Alex Timothy Chartier, Ryan Poffenbarger, Rafael Mesquita, Diego Janches, Jorge Chau, Toralf Renkwitz, Ralph Latteck, and William Bristow
EGUsphere, https://doi.org/10.5194/egusphere-2026-1634, https://doi.org/10.5194/egusphere-2026-1634, 2026
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We created a new long-term record of upper atmosphere winds using data from a global network of radars spanning more than 30 years. Because these measurements do not directly show altitude, we developed a method to estimate where the signals come from and tested it against other observations and models. The results show good agreement, meaning these data can now be used with greater confidence to study atmospheric motion and its effects on communication and space systems.
Witali Krochin, Axel Murk, Andres Luder, and Gunter Stober
Atmos. Meas. Tech., 19, 2103–2123, https://doi.org/10.5194/amt-19-2103-2026, https://doi.org/10.5194/amt-19-2103-2026, 2026
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In this manuscript a new fully polarimetric radiometer for ground-based temperature sounding, TEMPERA-C (Campaign Temperature Radiometer), is presented. The advantages of the fully polarimetric approach are discussed, and a fully polarimetric calibration method is described in detail. The final measurements and the continuous series of temperature retrievals from the high altitude research station on the Jungfraujoch are also shown in this manuscript.
Adrianos Filinis, Alistair Bell, Axel Murk, and Gunter Stober
Atmos. Meas. Tech., 19, 1783–1799, https://doi.org/10.5194/amt-19-1783-2026, https://doi.org/10.5194/amt-19-1783-2026, 2026
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Water vapor is an essential climate variable in the Earth's atmosphere and plays an important role in the radiative balance, serving as the most significant greenhouse gas in the upper troposphere. Hence, high-quality and continuous measurements are required. In this paper, we present the breadboard design of a newly developed radiometer, which will retrieve vertical profiles of middle atmospheric water vapor.
Chao Ban, Xin Fang, Wen Yi, Jie Zeng, Gunter Stober, Weilin Pan, Tao Li, and Xianghui Xue
Atmos. Meas. Tech., 19, 1697–1709, https://doi.org/10.5194/amt-19-1697-2026, https://doi.org/10.5194/amt-19-1697-2026, 2026
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This paper presents an intercomparison of zonal winds observed by a sodium fluorescence lidar and three types of meteor radars – a multistatic meteor radar, a conventional monostatic radar, and a forward remote receiver – located near Hefei, China. The multistatic meteor radar shows the best agreement with the lidar measurements, confirming the reliability of its wind retrievals in the mesosphere and lower thermosphere and highlighting its potential for future atmospheric dynamics studies.
Sina Mehrdad, Sajedeh Marjani, Dörthe Handorf, and Christoph Jacobi
Atmos. Chem. Phys., 26, 3391–3415, https://doi.org/10.5194/acp-26-3391-2026, https://doi.org/10.5194/acp-26-3391-2026, 2026
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We studied how strong wind disturbances caused by mountains can disturb the polar vortex, a large pool of cold air high above the North Pole. Using simulations, we boosted these wind disturbances over the Himalayas, North America, and East Asia. We found they can shift, weaken, and mix the vortex in different ways depending on the region. This helps explain how mountains influence the upper atmosphere and improve forecasts of extreme cold weather at the surface.
Florian Günzkofer, Anders Tjulin, Gang Lu, Hanli Liu, and Gunter Stober
EGUsphere, https://doi.org/10.5194/egusphere-2026-823, https://doi.org/10.5194/egusphere-2026-823, 2026
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Incoherent scatter radars (ISRs) are an important measurement tool for space weather research. However, ISR measurements require previous knowledge of the state of the ionosphere, especially the ratio of atomic oxygen ions (O+) to electrons. We present ISR measurements during the May 2024 "Mothers' Day Storm" and apply data assimilation-based O+ ratios, which should result in more accurate ISR measurements. The advantages and disadvantages of our method are compared to those of other approaches.
Ales Kuchar, Matthias Stocker, Alistair Bell, Bruno Lehner, Jessica Kult-Herdin, Gabriel Chiodo, Timofei Sukhodolov, Eugene Rozanov, Gunter Stober, and Harald E. Rieder
EGUsphere, https://doi.org/10.5194/egusphere-2026-406, https://doi.org/10.5194/egusphere-2026-406, 2026
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We investigated why the Northern Hemisphere winter polar vortex became unusually strong in the winter of 2024/2025. Using satellite and reanalysis datasets, and model simulations, we found that extra water erupted high in the atmosphere by the 2022 Hunga Tonga eruption led to cooling of polar latitudes of the upper atmosphere, helping the winds aloft intensify. This link suggests such volcanic eruptions can shape winters in the upper atmosphere for several years.
Louis Mirallie, Eliane Maillard Barras, Caroline Jonas, Corinne Vigouroux, Roeland Van Malderen, Irina Petropavlovskikh, Sophie Godin-Beekmann, Thierry Leblanc, Wolfgang Steinbrecht, Antoine Vadès, Rolf Ruefenach, Alexander Haefele, Gunter Stober, Peter Effertz, Julian Gröbner, Gerard Ancellet, María Cazorla, Petra Duff, Matthias Frey, Michael Gill, James W. Hannigan, Nicholas Jones, Rigel Kivi, Raphael Koehler, Bogumil Kois, Debra Kollonige, Emmanuel Mahieu, Glen McConville, Johan Mellqvist, Gary Morris, Isao Murata, Tomoo Nagahama, Gerald E. Nedoluha, Shin-Ya Ogino, Richard Querel, Ryan Stauffer, Wolfgang Stremme, Kimberly Strong, Ralf Sussmann, Anne Thompson, and Yana Virolainen
EGUsphere, https://doi.org/10.5194/egusphere-2026-113, https://doi.org/10.5194/egusphere-2026-113, 2026
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We present regional Bayesian composite of ground-based ozone records. Defining coherent regions via CAMS (Copernicus Atmosphere Monitoring Service) representativeness study and partial columns to be merged using the BASIC (BAyeSian Integrated and Consolidated, Ball et al., 2017) method, we reduce trends by 15.3 % compared to a weighted mean. Results confirm upper stratospheric recovery and reveal significant lower stratospheric decline in some regions.
Kian Sartipzadeh, Andreas Kvammen, Björn Gustavsson, Njål Gulbrandsen, Magnar G. Johnsen, Devin Huyghebaert, and Juha Vierinen
Ann. Geophys., 44, 85–107, https://doi.org/10.5194/angeo-44-85-2026, https://doi.org/10.5194/angeo-44-85-2026, 2026
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Knowledge of the charged environment in the upper atmosphere is essential for understanding space weather effects on satellites and radio communication. This environment is difficult to estimate at high latitudes, where aurora cause strong variability. We developed an artificial intelligence model to estimate this environment continuously. Our results show that the model provides reliable estimates even during auroral activity, improving monitoring of the polar upper atmosphere.
Sina Mehrdad, Sajedeh Marjani, Dörthe Handorf, and Christoph Jacobi
Weather Clim. Dynam., 6, 1491–1514, https://doi.org/10.5194/wcd-6-1491-2025, https://doi.org/10.5194/wcd-6-1491-2025, 2025
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Wind flowing over mountains creates wave-like patterns aloft that can influence the atmosphere higher up in the stratosphere and mesosphere. In this study, we intensified these waves over specific regions like the Himalayas and Rocky Mountains and examined the resulting climate effects. We found that this can shift global wind patterns and even impact extreme events near the poles, showing how small regional changes in stratospheric wind patterns can influence the broader climate system.
J. Federico Conte, Jorge L. Chau, Toralf Renkwitz, Ralph Latteck, Masaki Tsutsumi, Christoph Jacobi, Njål Gulbrandsen, and Satonori Nozawa
Ann. Geophys., 43, 603–619, https://doi.org/10.5194/angeo-43-603-2025, https://doi.org/10.5194/angeo-43-603-2025, 2025
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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.
Pekka T. Verronen, Akira Mizuno, Yoshizumi Miyoshi, Sandeep Kumar, Taku Nakajima, Shin-Ichiro Oyama, Tomoo Nagahama, Satonori Nozawa, Monika E. Szeląg, Tuomas Häkkilä, Niilo Kalakoski, Antti Kero, Esa Turunen, Satoshi Kasahara, Shoichiro Yokota, Kunihiro Keika, Tomoaki Hori, Takefumi Mitani, Takeshi Takashima, and Iku Shinohara
Ann. Geophys., 43, 561–578, https://doi.org/10.5194/angeo-43-561-2025, https://doi.org/10.5194/angeo-43-561-2025, 2025
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We use NO column density data from the Syowa station in Antarctica from 2012–2017. We compare these ground-based radiometer observations with results from a global atmosphere model to understand the year-to-year and day-to-day variability, shortcomings of current electron forcing, and how geomagnetic storms are driving the variability of NO. Our results demonstrate an underestimation in the magnitude of day-to-day variability in simulations, which calls for improved electron forcing in models.
Guochun Shi, Hanli Liu, Masaki Tsutsumi, Njål Gulbrandsen, Alexander Kozlovsky, Dimitry Pokhotelov, Mark Lester, Christoph Jacobi, Kun Wu, and Gunter Stober
Atmos. Chem. Phys., 25, 9403–9430, https://doi.org/10.5194/acp-25-9403-2025, https://doi.org/10.5194/acp-25-9403-2025, 2025
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Concerns about climate change are growing due to its widespread impacts, including rising temperatures, extreme weather events, and disruptions to ecosystems. To address these challenges, urgent global action is needed to monitor the distribution of trace gases and understand their effects on the atmosphere.
Ales Kuchar, Gunter Stober, Dimitry Pokhotelov, Huixin Liu, Han-Li Liu, Manfred Ern, Damian Murphy, Diego Janches, Tracy Moffat-Griffin, Nicholas Mitchell, and Christoph Jacobi
EGUsphere, https://doi.org/10.5194/egusphere-2025-2827, https://doi.org/10.5194/egusphere-2025-2827, 2025
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We studied how the healing of the Antarctic ozone layer is affecting winds high above the South Pole. Using ground-based radar, satellite data, and computer models, we found that winds in the upper atmosphere have become stronger over the past two decades. These changes appear to be linked to shifts in the lower atmosphere caused by ozone recovery. Our results show that human efforts to repair the ozone layer are also influencing climate patterns far above Earth’s surface.
Gabriel Augusto Giongo, Cristiano Max Wrasse, Pierre-Dominique Pautet, José Valentin Bageston, Prosper Kwamla Nyassor, Cosme Alexandre Oliveira Barros Figueiredo, Anderson Vestena Bilibio, Tracy Moffat-Griffin, Damian John Murphy, Toyese Tunde Ayorinde, Delano Gobbi, and Hisao Takahashi
EGUsphere, https://doi.org/10.5194/egusphere-2025-3114, https://doi.org/10.5194/egusphere-2025-3114, 2025
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This work analyzes the medium-scale atmospheric gravity waves observed by ground-based airglow imaging over the Antarctic continent. Medium-scale gravity waves refer to waves larger than 50 km of horizontal wavelength, and have not been analyzed in that region so far. Wave parameters and horizontal propagation characteristics were obtained by a recently improved methodology and are described thoroughly.
Florian Günzkofer, Gunter Stober, Johan Kero, David R. Themens, Anders Tjulin, Njål Gulbrandsen, Masaki Tsutsumi, and Claudia Borries
Ann. Geophys., 43, 331–348, https://doi.org/10.5194/angeo-43-331-2025, https://doi.org/10.5194/angeo-43-331-2025, 2025
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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.
Christoph Jacobi, Khalil Karami, Ales Kuchar, Manfred Ern, Toralf Renkwitz, Ralph Latteck, and Jorge L. Chau
Adv. Radio Sci., 23, 21–31, https://doi.org/10.5194/ars-23-21-2025, https://doi.org/10.5194/ars-23-21-2025, 2025
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Half-hourly mean winds have been obtained using ground-based low-frequency and very high frequency radio observations of the mesopause region at Collm, Germany, since 1984. Long-term changes of wind variances, which are proxies for short-period atmospheric gravity waves, have been analysed. Gravity wave amplitudes increase with time in winter, but mainly decrease in summer. The trends are consistent with mean wind changes according to wave theory.
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
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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
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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
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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
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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.
Natalie Kaifler, Bernd Kaifler, Markus Rapp, Guiping Liu, Diego Janches, Gerd Baumgarten, and Jose-Luis Hormaechea
Atmos. Chem. Phys., 24, 14029–14044, https://doi.org/10.5194/acp-24-14029-2024, https://doi.org/10.5194/acp-24-14029-2024, 2024
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Noctilucent clouds (NLCs) are silvery clouds that can be viewed during twilight and indicate atmospheric conditions like temperature and water vapor in the upper mesosphere. High-resolution measurements from a remote sensing laser instrument provide NLC height, brightness, and occurrence rate since 2017. Most observations occur in the morning hours, likely caused by strong tidal winds, and NLC ice particles are thus transported from elsewhere to the observing location in the Southern Hemisphere.
Sina Mehrdad, Dörthe Handorf, Ines Höschel, Khalil Karami, Johannes Quaas, Sudhakar Dipu, and Christoph Jacobi
Weather Clim. Dynam., 5, 1223–1268, https://doi.org/10.5194/wcd-5-1223-2024, https://doi.org/10.5194/wcd-5-1223-2024, 2024
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This study introduces a novel deep learning (DL) approach to analyze how regional radiative forcing in Europe impacts the Arctic climate. By integrating atmospheric poleward energy transport with DL-based clustering of atmospheric patterns and attributing anomalies to specific clusters, our method reveals crucial, nuanced interactions within the climate system, enhancing our understanding of intricate climate dynamics.
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
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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
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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).
Ales Kuchar, Maurice Öhlert, Roland Eichinger, and Christoph Jacobi
Weather Clim. Dynam., 5, 895–912, https://doi.org/10.5194/wcd-5-895-2024, https://doi.org/10.5194/wcd-5-895-2024, 2024
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Exploring the polar vortex's impact on climate, the study evaluates model simulations against the ERA5 reanalysis data. Revelations about model discrepancies in simulating disruptive stratospheric warmings and vortex behavior highlight the need for refined model simulations of past climate. By enhancing our understanding of these dynamics, the research contributes to more reliable climate projections of the polar vortex with the impact on surface climate.
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.
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
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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
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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.
Ralph Latteck and Damian J. Murphy
Ann. Geophys., 42, 55–68, https://doi.org/10.5194/angeo-42-55-2024, https://doi.org/10.5194/angeo-42-55-2024, 2024
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This paper gives an overview of continuous measurements of polar mesophere summer echoes (PMSE) by VHF radars at Andøya (69° N) and Davis (69° S). PMSE signal strengths are of the same order of magnitude; significantly fewer PMSE were observed in the Southern than the Northern Hemisphere. Compared to Andøya, the PMSE season over Davis starts ~7 d later and ends 9 d earlier; PMSE occur less frequently but with greater seasonal/diurnal occurrence variability, reaching higher peak altitudes.
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
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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
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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.
Christoph Jacobi, Ales Kuchar, Toralf Renkwitz, and Juliana Jaen
Adv. Radio Sci., 21, 111–121, https://doi.org/10.5194/ars-21-111-2023, https://doi.org/10.5194/ars-21-111-2023, 2023
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Middle atmosphere long-term changes show the signature of climate change. We analyse 43 years of mesopause region horizontal winds obtained at two sites in Germany. We observe mainly positive trends of the zonal prevailing wind throughout the year, while the meridional winds tend to decrease in magnitude in both summer and winter. Furthermore, there is a change in long-term trends around the late 1990s, which is most clearly visible in summer winds.
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
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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.
Olivia Linke, Johannes Quaas, Finja Baumer, Sebastian Becker, Jan Chylik, Sandro Dahlke, André Ehrlich, Dörthe Handorf, Christoph Jacobi, Heike Kalesse-Los, Luca Lelli, Sina Mehrdad, Roel A. J. Neggers, Johannes Riebold, Pablo Saavedra Garfias, Niklas Schnierstein, Matthew D. Shupe, Chris Smith, Gunnar Spreen, Baptiste Verneuil, Kameswara S. Vinjamuri, Marco Vountas, and Manfred Wendisch
Atmos. Chem. Phys., 23, 9963–9992, https://doi.org/10.5194/acp-23-9963-2023, https://doi.org/10.5194/acp-23-9963-2023, 2023
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Lapse rate feedback (LRF) is a major driver of the Arctic amplification (AA) of climate change. It arises because the warming is stronger at the surface than aloft. Several processes can affect the LRF in the Arctic, such as the omnipresent temperature inversion. Here, we compare multimodel climate simulations to Arctic-based observations from a large research consortium to broaden our understanding of these processes, find synergy among them, and constrain the Arctic LRF and AA.
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
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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.
Nobuo Matuura, Ryoichi Fujii, and Satonori Nozawa
Hist. Geo Space. Sci., 14, 61–69, https://doi.org/10.5194/hgss-14-61-2023, https://doi.org/10.5194/hgss-14-61-2023, 2023
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This paper describes the details of the Japan's participation in the EISCAT Radar Scientific Association as the 7th associate country approved in 1995, emphasizing strong collaboration with Norwegian scientists and the EISCAT Radar Scientific Association towards the realization of the Svalbard second antenna. Also described is a brief summary of Japanese EISCAT-related scientific achievement, comprehensive scientific collaborations so far between Japan and Europe, and hopes for EISCAT_3D.
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
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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).
Khalil Karami, Rolando Garcia, Christoph Jacobi, Jadwiga H. Richter, and Simone Tilmes
Atmos. Chem. Phys., 23, 3799–3818, https://doi.org/10.5194/acp-23-3799-2023, https://doi.org/10.5194/acp-23-3799-2023, 2023
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Alongside mitigation and adaptation efforts, stratospheric aerosol intervention (SAI) is increasingly considered a third pillar to combat dangerous climate change. We investigate the teleconnection between the quasi-biennial oscillation in the equatorial stratosphere and the Arctic stratospheric polar vortex under a warmer climate and an SAI scenario. We show that the Holton–Tan relationship weakens under both scenarios and discuss the physical mechanisms responsible for such changes.
Christoph Jacobi, Kanykei Kandieva, and Christina Arras
Adv. Radio Sci., 20, 85–92, https://doi.org/10.5194/ars-20-85-2023, https://doi.org/10.5194/ars-20-85-2023, 2023
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Sporadic E (Es) layers are thin regions of accumulated ions in the lower ionosphere. They can be observed by disturbances of GNSS links between low-Earth orbiting satellites and GNSS satellites. Es layers are influenced by neutral atmospheric tides and show the coupling between the neutral atmosphere and the ionosphere. Here we analyse migrating (sun-synchronous) and non-migrating tidal components in Es. The main signatures are migrating Es, but nonmigrating components are found as well.
Gerhard Georg Bruno Schmidtke, Raimund Brunner, and Christoph Jacobi
EGUsphere, https://doi.org/10.5194/egusphere-2023-139, https://doi.org/10.5194/egusphere-2023-139, 2023
Preprint withdrawn
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The instrument records annual changes in Spectral Outgoing Radiation from 200–1100 nm, with 60 photomultiplier tubes simultaneously providing spectrometer and photometer data. Using Total Solar Irradiance data with a stability of 0.01 Wm-2 per year to recalibrate the established instruments, stable data of ~0.1 Wm-2 over a solar cycle period is expected. Determination of the changes in the global green Earth coverage and mapping will also assess the impact of climate engineering actions.
Yuan Xia, Jing Jiao, Satonori Nozawa, Xuewu Cheng, Jihong Wang, Chunhua Shi, Lifang Du, Yajuan Li, Haoran Zheng, Faquan Li, and Guotao Yang
Atmos. Chem. Phys., 22, 13817–13831, https://doi.org/10.5194/acp-22-13817-2022, https://doi.org/10.5194/acp-22-13817-2022, 2022
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The layer of sodium atoms is generally located above 80 km. This study reports the significant enhancements of the sodium layer below 75 km where sodium atoms are short-lived. The neutral chemical reactions were suggested as making a critical contribution. The reported results provide clear observational evidence for the role of planetary waves in the variation of metal layers, and have implications for the response of the metal layers to perturbations in the lower atmosphere.
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
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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.
Neil P. Hindley, Nicholas J. Mitchell, Neil Cobbett, Anne K. Smith, Dave C. Fritts, Diego Janches, Corwin J. Wright, and Tracy Moffat-Griffin
Atmos. Chem. Phys., 22, 9435–9459, https://doi.org/10.5194/acp-22-9435-2022, https://doi.org/10.5194/acp-22-9435-2022, 2022
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We present observations of winds in the mesosphere and lower thermosphere (MLT) from a recently installed meteor radar on the remote island of South Georgia (54° S, 36° W). We characterise mean winds, tides, planetary waves, and gravity waves in the MLT at this location and compare our measured winds with a leading climate model. We find that the observed wintertime winds are unexpectedly reversed from model predictions, probably because of missing impacts of secondary gravity waves in the model.
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.
Ales Kuchar, Petr Sacha, Roland Eichinger, Christoph Jacobi, Petr Pisoft, and Harald Rieder
EGUsphere, https://doi.org/10.5194/egusphere-2022-474, https://doi.org/10.5194/egusphere-2022-474, 2022
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We focus on the impact of small-scale orographic gravity waves (OGWs) above the Himalayas. The interaction of GWs with the large-scale circulation in the stratosphere is not still well understood and can have implications on climate projections. We use a chemistry-climate model to show that these strong OGW events are associated with anomalously increased upward planetary-scale waves and in turn affect the circumpolar circulation and have the potential to alter ozone variability as well.
Jill Brouwer, Alexander D. Fraser, Damian J. Murphy, Pat Wongpan, Alberto Alberello, Alison Kohout, Christopher Horvat, Simon Wotherspoon, Robert A. Massom, Jessica Cartwright, and Guy D. Williams
The Cryosphere, 16, 2325–2353, https://doi.org/10.5194/tc-16-2325-2022, https://doi.org/10.5194/tc-16-2325-2022, 2022
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The marginal ice zone is the region where ocean waves interact with sea ice. Although this important region influences many sea ice, ocean and biological processes, it has been difficult to accurately measure on a large scale from satellite instruments. We present new techniques for measuring wave attenuation using the NASA ICESat-2 laser altimeter. By measuring how waves attenuate within the sea ice, we show that the marginal ice zone may be far wider than previously realised.
Matthew J. Griffith and Nicholas J. Mitchell
Ann. Geophys., 40, 327–358, https://doi.org/10.5194/angeo-40-327-2022, https://doi.org/10.5194/angeo-40-327-2022, 2022
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There is great scientific interest in extending atmospheric models, such as the Met Office’s Unified Model, upwards to include the upper atmosphere. Atmospheric tides are an important driver of circulation at these greater heights. This study provides a first in-depth analysis of the migrating and non-migrating components of these tides, examining important tidal properties. Our results show that the ExUM produces a rich spectrum of spatial components, with significant non-migrating components.
Phoebe Noble, Neil Hindley, Corwin Wright, Chihoko Cullens, Scott England, Nicholas Pedatella, Nicholas Mitchell, and Tracy Moffat-Griffin
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2022-150, https://doi.org/10.5194/acp-2022-150, 2022
Revised manuscript not accepted
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We use long term radar data and the WACCM-X model to study the impact of dynamical phenomena, including the 11-year solar cycle, ENSO, QBO and SAM, on Antarctic mesospheric winds. We find that in summer, the zonal wind (both observationally and in the model) is strongly correlated with the solar cycle. We also see important differences in the results from the other processes. In addition we find important and large biases in the winter model zonal winds relative to the observations.
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
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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
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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
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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
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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
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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
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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
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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
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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.
Rajesh Vaishnav, Christoph Jacobi, Jens Berdermann, Mihail Codrescu, and Erik Schmölter
Ann. Geophys., 39, 641–655, https://doi.org/10.5194/angeo-39-641-2021, https://doi.org/10.5194/angeo-39-641-2021, 2021
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We investigate the role of eddy diffusion in the delayed ionospheric response against solar flux changes in the solar rotation period using the CTIPe model. The study confirms that eddy diffusion is an important factor affecting the delay of the total electron content. An increase in eddy diffusion leads to faster transport processes and an increased loss rate, resulting in a decrease in the ionospheric delay.
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Short summary
This study focuses on a 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 wind measurements and MR winds shows good agreement. A TIDI–MR seasonal comparison and analysis of the altitude–latitude dependence for winds are performed. TIDI reproduces the mean circulation well when compared with MRs and may be a useful lower boundary for general circulation models.
This study focuses on a TIMED Doppler Interferometer (TIDI)–meteor radar (MR) comparison of...
