01 Dec 2023
| 01 Dec 2023
Long-term trends of midlatitude horizontal mesosphere/lower thermosphere winds over four decades
Institute for Meteorology, Leipzig University, Stephanstr. 3, 04159 Leipzig, Germany
Ales Kuchar
Institute for Meteorology, Leipzig University, Stephanstr. 3, 04159 Leipzig, Germany
Toralf Renkwitz
Leibniz-Institute of Atmospheric Physics e.V. at the University Rostock, Schloßstraße 6, 18225 Kühlungsborn, Germany
Juliana Jaen
Leibniz-Institute of Atmospheric Physics e.V. at the University Rostock, Schloßstraße 6, 18225 Kühlungsborn, Germany
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Guochun Shi, Hanli Liu, Masaki Tsutsumi, Njål Gulbrandsen, Alexander Kozlovsky, Dimitry Pokhotelov, Mark Lester, Christoph Jacobi, Kun Wu, and Gunter Stober
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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.
Sina Mehrdad, Sajedeh Marjani, Dörthe Handorf, and Christoph Jacobi
EGUsphere, https://doi.org/10.5194/egusphere-2025-3005, https://doi.org/10.5194/egusphere-2025-3005, 2025
Short summary
Short summary
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.
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
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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 (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.
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
Short summary
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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.
Ales Kuchar, Timofei Sukhodolov, Gabriel Chiodo, Andrin Jörimann, Jessica Kult-Herdin, Eugene Rozanov, and Harald H. Rieder
Atmos. Chem. Phys., 25, 3623–3634, https://doi.org/10.5194/acp-25-3623-2025, https://doi.org/10.5194/acp-25-3623-2025, 2025
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In January 2022, the Hunga Tonga–Hunga Ha'apai (HTHH) volcano erupted, sending massive amounts of water vapour into the atmosphere. This event had a significant impact on stratospheric and lower-mesospheric chemical composition. Two years later, stratospheric conditions were disturbed during so-called sudden stratospheric warmings. Here we simulate a novel pathway by which this water-rich eruption may have contributed to conditions during these events and consequently impacted the surface climate.
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.
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
Short summary
Short summary
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.
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.
Jennifer Hartisch, Jorge L. Chau, Ralph Latteck, Toralf Renkwitz, and Marius Zecha
Ann. Geophys., 42, 29–43, https://doi.org/10.5194/angeo-42-29-2024, https://doi.org/10.5194/angeo-42-29-2024, 2024
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Scientists are studying the mesosphere and lower thermosphere using radar in northern Norway. They found peculiar events with strong upward and downward air movements, happening frequently (up to 2.5 % per month) from 2015 to 2021. Over 700 such events were noted, lasting around 20 min and expanding the studied layer. A total of 17 % of these events had extreme vertical speeds, showing their unique nature.
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.
Roland Eichinger, Sebastian Rhode, Hella Garny, Peter Preusse, Petr Pisoft, Aleš Kuchař, Patrick Jöckel, Astrid Kerkweg, and Bastian Kern
Geosci. Model Dev., 16, 5561–5583, https://doi.org/10.5194/gmd-16-5561-2023, https://doi.org/10.5194/gmd-16-5561-2023, 2023
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The columnar approach of gravity wave (GW) schemes results in dynamical model biases, but parallel decomposition makes horizontal GW propagation computationally unfeasible. In the global model EMAC, we approximate it by GW redistribution at one altitude using tailor-made redistribution maps generated with a ray tracer. More spread-out GW drag helps reconcile the model with observations and close the 60°S GW gap. Polar vortex dynamics are improved, enhancing climate model credibility.
Toralf Renkwitz, Mani Sivakandan, Juliana Jaen, and Werner Singer
Atmos. Chem. Phys., 23, 10823–10834, https://doi.org/10.5194/acp-23-10823-2023, https://doi.org/10.5194/acp-23-10823-2023, 2023
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The paper focuses on remote sensing of the lowermost part of the ionosphere (D region) between ca. 50 and 90 km altitude, which overlaps widely with the mesosphere. We present a climatology of electron density over northern Norway, covering solar-maximum and solar-minimum conditions (2014–2022). Excluding detected energetic particle precipitation events, we derived a quiet-profile climatology. We also found a spring–fall asymmetry, while a symmetric solar zenith angle dependence was expected.
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.
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.
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.
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
Preprint archived
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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.
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, 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.
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.
Rajesh Vaishnav, Erik Schmölter, Christoph Jacobi, Jens Berdermann, and Mihail Codrescu
Ann. Geophys., 39, 341–355, https://doi.org/10.5194/angeo-39-341-2021, https://doi.org/10.5194/angeo-39-341-2021, 2021
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We investigate the delayed ionospheric response using the observed and CTIPe-model-simulated TEC against the solar EUV flux. The ionospheric delay estimated using model-simulated TEC is in good agreement with the delay estimated for observed TEC. The study confirms the model's capabilities to reproduce the delayed ionospheric response against the solar EUV flux. Results also indicate that the average delay is higher in the Northern Hemisphere as compared to the Southern Hemisphere.
Arseniy Karagodin-Doyennel, Eugene Rozanov, Ales Kuchar, William Ball, Pavle Arsenovic, Ellis Remsberg, Patrick Jöckel, Markus Kunze, David A. Plummer, Andrea Stenke, Daniel Marsh, Doug Kinnison, and Thomas Peter
Atmos. Chem. Phys., 21, 201–216, https://doi.org/10.5194/acp-21-201-2021, https://doi.org/10.5194/acp-21-201-2021, 2021
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The solar signal in the mesospheric H2O and CO was extracted from the CCMI-1 model simulations and satellite observations using multiple linear regression (MLR) analysis. MLR analysis shows a pronounced and statistically robust solar signal in both H2O and CO. The model results show a general agreement with observations reproducing a negative/positive solar signal in H2O/CO. The pattern of the solar signal varies among the considered models, reflecting some differences in the model setup.
Cited articles
Akmaev, R.: Modeling the cooling due to CO2 increases in the mesosphere and lower thermosphere, Phys. Chem. Earth A/B/C, 27, 521–528, https://doi.org/10.1016/S1474-7065(02)00033-5, 2002. a
Beig, G.: Long-term trends in the temperature of the mesosphere/lower thermosphere region: 2. Solar response, J. Geophys. Res.-Space, 116, A00H12, https://doi.org/10.1029/2011JA016766, 2011. a
Beig, G., Keckhut, P., Lowe, R. P., Roble, R. G., Mlynczak, M. G., Scheer, J., Fomichev, V. I., Offermann, D., French, W. J. R., Shepherd, M. G., Semenov, A. I., Remsberg, E. E., She, C. Y., Lübken, F. J., Bremer, J., Clemesha, B. R., Stegman, J., Sigernes, F., and Fadnavis, S.: Review of mesospheric temperature trends, Rev. Geophys., 41, 1015, https://doi.org/10.1029/2002RG000121, 2003. a
Bremer, J.: Long-term trends in the ionospheric E and F1 regions, Ann. Geophys., 26, 1189–1197, https://doi.org/10.5194/angeo-26-1189-2008, 2008. a
Bremer, J. and Berger, U.: Mesospheric temperature trends derived from ground-based LF phase-height observations at mid-latitudes: comparison with model simulations, J. Atmos. Sol.-Terr. Phys., 64, 805–816, https://doi.org/10.1016/S1364-6826(02)00073-1, 2002. a, b
Bremer, J., Schminder, R., Greisiger, K., Hoffmann, P., Kürschner, D., and Singer, W.: Solar cycle dependence and long-term trends in the wind field of the mesosphere/lower thermosphere, J. Atmos. Sol.-Terr. Phys., 59, 497–509, https://doi.org/10.1016/S1364-6826(96)00032-6, 1997. a
Charlton, A. J. and Polvani, L. M.: A new look at stratospheric sudden warmings. Part I: Climatology and modeling benchmarks, J. Climate, 20, 449–469, https://doi.org/10.1175/JCLI3996.1, 2007. a
Emmert, J. T.: Altitude and solar activity dependence of 1967–2005 thermospheric density trends derived from orbital drag, J. Geophys. Res.-Space, 120, 2940–2950, https://doi.org/10.1002/2015JA021047, 2015. a
Emmert, J. T., Picone, J. M., and Meier, R. R.: Thermospheric global average density trends, 1967–2007, derived from orbits of 5000 near-Earth objects, Geophys. Res. Lett., 35, L05101, https://doi.org/10.1029/2007GL032809, 2008. a
Ermakova, T. S., Aniskina, O. G., Statnaia, I. A., Motsakov, M. A., and Pogoreltsev, A. I.: Simulation of the ENSO influence on the extra-tropical middle atmosphere, Earth Planets Space, 71, 8, https://doi.org/10.1186/s40623-019-0987-9, 2019. a
Hoffmann, P., Singer, W., Keuer, D., Hocking, W., Kunze, M., and Murayama, Y.: Latitudinal and longitudinal variability of mesospheric winds and temperatures during stratospheric warming events, J. Atmos. Sol.-Terr. Phys., 69, 2355–2366, https://doi.org/10.1016/j.jastp.2007.06.010, 2007. a
Hoffmann, P., Becker, E., Singer, W., and Placke, M.: Seasonal variation of mesospheric waves at northern middle and high latitudes, J. Atmos. Sol.-Terr. Phys., 72, 1068–1079, https://doi.org/10.1016/j.jastp.2010.07.002, 2010. a
Hoffmann, P., Rapp, M., Singer, W., and Keuer, D.: Trends of mesospheric gravity waves at northern middle latitudes during summer, J. Geophys. Res.-Atmos., 116, D00P08, https://doi.org/10.1029/2011JD015717, 2011. a, b
Jacobi, C.: Meteor radar measurements of mean winds and tides over Collm (51.3∘ N, 13∘ E) and comparison with LF drift measurements 2005–2007, Adv. Radio Sci., 9, 335–341, https://doi.org/10.5194/ars-9-335-2011, 2011. a
Jacobi, C. and Beckmann, B.: On the connection between upper atmospheric dynamics and tropospheric parameters: Correlations between mesopause region winds and the North Atlantic Oscillation, Climatic Change, 43, 629–643, https://doi.org/10.1023/A:1005451227975, 1999. a
Jacobi, C. and Kürschner, D.: Long-term trends of MLT region winds over Central Europe, Phys. Chem. Earth A/B/C, 31, 16–21, https://doi.org/10.1016/j.pce.2005.01.004, 2006. a, b, c
Jacobi, C., Fröhlich, K., Viehweg, C., Stober, G., and Kürschner, D.: Midlatitude mesosphere/lower thermosphere meridional winds and temperatures measured with meteor radar, Adv. Space Res., 39, 1278–1283, https://doi.org/10.1016/j.asr.2007.01.003, 2007. a
Jacobi, C., Hoffmann, P., and Kürschner, D.: Trends in MLT region winds and planetary waves, Collm (52∘ N, 15∘ E), Ann. Geophys., 26, 1221–1232, https://doi.org/10.5194/angeo-26-1221-2008, 2008. a
Jacobi, C., Arras, C., Kürschner, D., Singer, W., Hoffmann, P., and Keuer, D.: Comparison of mesopause region meteor radar winds, medium frequency radar winds and low frequency drifts over Germany, Adv. Space Res., 43, 247–252, https://doi.org/10.1016/j.asr.2008.05.009, 2009a. a, b
Jacobi, C., Hoffmann, P., Liu, R., Križan, P., Laštovička, J., Merzlyakov, E., Solovjova, T., and Portnyagin, Y.: Midlatitude mesopause region winds and waves and comparison with stratospheric variability, J. Atmos. Sol.-Terr. Phys., 71, 1540–1546, https://doi.org/10.1016/j.jastp.2009.05.004, 2009b. a
Jacobi, C., Lilienthal, F., Stober, G., Korotyshkin, D., and Merzlyakov, E.: Mesosphere/lower thermosphere winds measured with nearby SKiYMET meteor radars at Collm and Juliusruh, and comparison with Kazan winds, 2019 Kleinheubach Conference, 23–25 September 2019, Miltenberg, Germany, IEEE, https://ieeexplore.ieee.org/document/8890153 (last access: 15 December 2022), 2019. a
Jaen, J., Renkwitz, T., Chau, J. L., He, M., Hoffmann, P., Yamazaki, Y., Jacobi, C., Tsutsumi, M., Matthias, V., and Hall, C.: Long-term studies of mesosphere and lower-thermosphere summer length definitions based on mean zonal wind features observed for more than one solar cycle at middle and high latitudes in the Northern Hemisphere, Ann. Geophys., 40, 23–35, https://doi.org/10.5194/angeo-40-23-2022, 2022. a, b, c
Jakowski, N., Hoque, M., Mielich, J., and Hall, C.: Equivalent slab thickness of the ionosphere over Europe as an indicator of long-term temperature changes in the thermosphere, J. Atmos. Sol.-Terr. Phys., 163, 91–102, https://doi.org/10.1016/j.jastp.2017.04.008, 2017. a
Kashcheyev, B. and Oleynikov, A.: Dynamic regime of the mesopause–lower thermosphere at mid-latitudes of the northern hemisphere by radio meteor observations, J. Atmos. Sol.-Terr. Phys., 56, 1197–1207, https://doi.org/10.1016/0021-9169(94)90057-4, 1994. a
Keuer, D., Hoffmann, P., Singer, W., and Bremer, J.: Long-term variations of the mesospheric wind field at mid-latitudes, Ann. Geophys., 25, 1779–1790, https://doi.org/10.5194/angeo-25-1779-2007, 2007. a, b
Koval, A. V., Gavrilov, N. M., Pogoreltsev, A. I., and Kandieva, K. K.: Dynamical impacts of stratospheric QBO on the global circulation up to the lower thermosphere, J. Geophys. Res.-Atmos., 127, e2021JD036095, https://doi.org/10.1029/2021JD036095, 2022. a
Kürschner, D. and Jacobi, C.: Quasi-biennial and decadal variability obtained from long-term measurements of nighttime radio wave reflection heights over Central Europe, Adv. Space Res., 32, 1701–1706, https://doi.org/10.1016/S0273-1177(03)90465-0, 2003. a
Kürschner, D. and Schminder, R.: High-atmosphere wind profiles for altitudes between 90 and 110 km obtained from D1 LF measurements over Central Europe in 1983/1984, J. Atmos. Sol.-Terr. Phys., 48, 447–453, https://doi.org/10.1016/0021-9169(86)90121-2, 1986. a
Kürschner, D., Schminder, R., Singer, W., and Bremer, J.: Ein neues Verfahren zur Realisierung absoluter Reflexionshöhenmessungen an Raumwellen amplitudenmodulierter Rundfunksender bei Schrägeinfall im Langwellenbereich als Hilfsmittel zur Ableitung von Windprofilen in der oberen Mesopausenregion, Z. Meteorol., 37, 322–332, 1987. a
Laštovička, J. and Jelínek, Š.: Problems in calculating long-term trends in the upper atmosphere, J. Atmos. Sol.-Terr. Phys., 189, 80–86, https://doi.org/10.1016/j.jastp.2019.04.011, 2019. a
Laštovička, J., Akmaev, R. A., Beig, G., Bremer, J., and Emmert, J. T.: Global Change in the Upper Atmosphere, Science, 314, 1253–1254, https://doi.org/10.1126/science.1135134, 2006. a
Laštovička, J., Akmaev, R. A., Beig, G., Bremer, J., Emmert, J. T., Jacobi, C., Jarvis, M. J., Nedoluha, G., Portnyagin, Yu. I., and Ulich, T.: Emerging pattern of global change in the upper atmosphere and ionosphere, Ann. Geophys., 26, 1255–1268, https://doi.org/10.5194/angeo-26-1255-2008, 2008. a
Laštovička, J., Solomon, S. C., and Qian, L.: Trends in the neutral and ionized upper atmosphere, Space Sci. Rev., 168, 113–145, https://doi.org/10.1007/s11214-011-9799-3, 2012. a
Lilienthal, F., Yiğit, E., Samtleben, N., and Jacobi, C.: Variability of gravity wave effects on the zonal mean circulation and migrating terdiurnal tide as studied with the Middle and Upper Atmosphere Model (MUAM2019) using a nonlinear gravity wave scheme, Front. Astron. Space Sci., 7, 588956, https://doi.org/10.3389/fspas.2020.588956, 2020. a
Lima, L., Araújo, L., Alves, E., Batista, P., and Clemesha, B.: Variations in meteor heights at 22.7∘ S during solar cycle 23, J. Atmos. Sol.-Terr. Phys., 133, 139–144, https://doi.org/10.1016/j.jastp.2015.08.015, 2015. a
Liu, H., Tao, C., Jin, H., and Nakamoto, Y.: Circulation and tides in a cooler upper atmosphere: dynamical effects of CO2 doubling, Geophys. Res. Lett., 47, e2020GL087413, https://doi.org/10.1029/2020GL087413, 2020. a
Liu, H., Tao, C., Jin, H., and Abe, T.: Geomagnetic activity effects on CO2-driven trend in the thermosphere and ionosphere: ideal model experiments with GAIA, J. Geophys. Res.-Space, 126, e2020JA028607, https://doi.org/10.1029/2020JA028607, 2021. a
Liu, L., Liu, H., Chen, Y., Le, H., Sun, Y.-Y., Ning, B., Hu, L., and Wan, W.: Variations of the meteor echo heights at Beijing and Mohe, China, J. Geophys. Res.-Space, 122, 1117–1127, https://doi.org/10.1002/2016JA023448, 2017. a
Liu, R. Q., Jacobi, C., Hoffmann, P., Stober, G., and Merzlyakov, E. G.: A piecewise linear model for detecting climatic trends and their structural changes with application to mesosphere/lower thermosphere winds over Collm, Germany, J. Geophys. Res.-Atmos., 115, 588956, https://doi.org/10.1029/2010JD014080, 2010. a
Lübken, F.-J., Berger, U., and Baumgarten, G.: Temperature trends in the midlatitude summer mesosphere, J. Geophys. Res.-Atmos., 118, 13347–13360, https://doi.org/10.1002/2013JD020576, 2013. a
Manson, A. and Meek, C.: Winds and tidal oscillations in the upper middle atmosphere at Saskatoon (52∘ N, 107∘ W, L=4.3) during the year June 1982–May 1983, Planet. Space Sci., 32, 1087–1099, https://doi.org/10.1016/0032-0633(84)90134-X, 1984. a
Manson, A. H. and Meek, C. E.: Climatologies of mean winds and tides observed by medium frequency radars at Tromsø (70∘ N) and Saskatoon (52∘ N) during 1987–1989, Can. J. Phys., 69, 966–975, https://doi.org/10.1139/p91-152, 1991. a
Mielich, J. and Bremer, J.: Long-term trends in the ionospheric F2 region with different solar activity indices, Ann. Geophys., 31, 291–303, https://doi.org/10.5194/angeo-31-291-2013, 2013. a
Miyoshi, Y., Fujiwara, H., Jin, H., and Shinagawa, H.: Impacts of sudden stratospheric warming on general circulation of the thermosphere, J. Geophys. Res.-Space, 120, 10897–10912, https://doi.org/10.1002/2015JA021894, 2015. a
Peters, D. H., Entzian, G., and Keckhut, P.: Mesospheric temperature trends derived from standard phase-height measurements, J. Atmos. Sol.-Terr. Phys., 163, 23–30, https://doi.org/10.1016/j.jastp.2017.04.007, 2017. a
Pisoft, P., Sacha, P., Polvani, L. M., Añel, J. A., de la Torre, L., Eichinger, R., Foelsche, U., Huszar, P., Jacobi, C., Karlicky, J., Kuchar, A., Miksovsky, J., Zak, M., and Rieder, H. E.: Stratospheric contraction caused by increasing greenhouse gases, Environ. Res. Lett., 16, 064038, https://doi.org/10.1088/1748-9326/abfe2b, 2021. a
Schminder, R., Kürschner, D., Singer, W., Hoffmann, P., Keuer, D., and Bremer, J.: Representative height-time cross-sections of the upper atmosphere wind field over Central Europe 1990–1996, J. Atmos. Sol.-Terr. Phys., 59, 2177–2184, https://doi.org/10.1016/S1364-6826(97)00062-X, 1997. a
She, C.-Y., Berger, U., Yan, Z.-A., Yuan, T., Lübken, F.-J., Krueger, D. A., and Hu, X.: Solar Response and Long-Term Trend of Midlatitude Mesopause Region Temperature Based on 28 Years (1990–2017) of Na Lidar Observations, J. Geophys. Res.-Space, 124, 7140–7156, https://doi.org/10.1029/2019JA026759, 2019. a
Shepherd, M. G., Meek, C. E., Hocking, W. K., Hall, C. M., Partamies, N., Sigernes, F., Manson, A. H., and Ward, W. E.: Multi-instrument study of the mesosphere-lower thermosphere dynamics at 80∘ N during the major SSW in January 2019, J. Atmos. Sol.-Terr. Phys., 210, 105427, https://doi.org/10.1016/j.jastp.2020.105427, 2020. a
Smith, A. K., Garcia, R. R., Marsh, D. R., Kinnison, D. E., and Richter, J. H.: Simulations of the response of mesospheric circulation and temperature to the Antarctic ozone hole, Geophys. Res. Lett., 37, L22803, https://doi.org/10.1029/2010GL045255, 2010. a
Sprenger, K. and Schminder, R.: Results of ten years' ionospheric drift measurements in the l.f. range, J. Atmos. Sol.-Terr. Phys., 29, 183–199, https://doi.org/10.1016/0021-9169(67)90132-8, 1967. a, b
Sridharan, S., Tsuda, T., and Gurubaran, S.: Long-term tendencies in the mesosphere/lower thermosphere mean winds and tides as observed by medium-frequency radar at Tirunelveli (8.7∘ N, 77.8∘ E), J. Geophys. Res.-Atmos., 115, D08109, https://doi.org/10.1029/2008JD011609, 2010. a
Stober, G., Matthias, V., Brown, P., and Chau, J. L.: Neutral density variation from specular meteor echo observations spanning one solar cycle, Geophys. Res. Lett., 41, 6919–6925, https://doi.org/10.1002/2014GL061273, 2014. 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, 2021. a
Taubenheim, J., Entzian, G., and Berendorf, K.: Long-term decrease of mesospheric temperature, 1963–1995, inferred from radiowave reflection heights, Adv. Space Res., 20, 2059–2063, https://doi.org/10.1016/S0273-1177(97)00596-6, 1997. a
Wendisch, M., Brückner, M., Crewell, S., Ehrlich, A., Notholt, J., Lüpkes, C., Macke, A., Burrows, J. P., Rinke, A., Quaas, J., Maturilli, M., Schemann, V., Shupe, M. D., Akansu, E. F., Barrientos-Velasco, C., Bärfuss, K., Blechschmidt, A.-M., Block, K., Bougoudis, I., Bozem, H., Böckmann, C., Bracher, A., Bresson, H., Bretschneider, L., Buschmann, M., Chechin, D. G., Chylik, J., Dahlke, S., Deneke, H., Dethloff, K., Donth, T., Dorn, W., Dupuy, R., Ebell, K., Egerer, U., Engelmann, R., Eppers, O., Gerdes, R., Gierens, R., Gorodetskaya, I. V., Gottschalk, M., Griesche, H., Gryanik, V. M., Handorf, D., Harm-Altstädter, B., Hartmann, J., Hartmann, M., Heinold, B., Herber, A., Herrmann, H., Heygster, G., Höschel, I., Hofmann, Z., Hölemann, J., Hünerbein, A., Jafariserajehlou, S., Jäkel, E., Jacobi, C., Janout, M., Jansen, F., Jourdan, O., Jurányi, Z., Kalesse-Los, H., Kanzow, T., Käthner, R., Kliesch, L. L., Klingebiel, M., Knudsen, E. M., Kovács, T., Körtke, W., Krampe, D., Kretzschmar, J., Kreyling, D., Kulla, B., Kunkel, D., Lampert, A., Lauer, M., Lelli, L., von Lerber, A., Linke, O., Löhnert, U., Lonardi, M., Losa, S. N., Losch, M., Maahn, M., Mech, M., Mei, L., Mertes, S., Metzner, E., Mewes, D., Michaelis, J., Mioche, G., Moser, M., Nakoudi, K., Neggers, R., Neuber, R., Nomokonova, T., Oelker, J., Papakonstantinou-Presvelou, I., Pätzold, F., Pefanis, V., Pohl, C., van Pinxteren, M., Radovan, A., Rhein, M., Rex, M., Richter, A., Risse, N., Ritter, C., Rostosky, P., Rozanov, V. V., Donoso, E. R., Saavedra-Garfias, P., Salzmann, M., Schacht, J., Schäfer, M., Schneider, J., Schnierstein, N., Seifert, P., Seo, S., Siebert, H., Soppa, M. A., Spreen, G., Stachlewska, I. S., Stapf, J., Stratmann, F., Tegen, I., Viceto, C., Voigt, C., Vountas, M., Walbröl, A., Walter, M., Wehner, B., Wex, H., Willmes, S., Zanatta, M., and Zeppenfeld, S.: Atmospheric and Surface Processes, and Feedback Mechanisms Determining Arctic Amplification: A Review of First Results and Prospects of the (AC)3 Project, B. Am. Meteorol. Soc., 104, E208–E242, https://doi.org/10.1175/BAMS-D-21-0218.1, 2023. a
Yiğit, E. and Medvedev, A. S.: Internal wave coupling processes in Earth’s atmosphere, Adv. Space Res., 55, 983–1003, https://doi.org/10.1016/j.asr.2014.11.020, 2015. a
Short summary
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.
Middle atmosphere long-term changes show the signature of climate change. We analyse 43 years of...
