Articles | Volume 36, issue 4
https://doi.org/10.5194/angeo-36-999-2018
© Author(s) 2018. 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-36-999-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
13 Jul 2018
Regular paper |
| 13 Jul 2018
| 13 Jul 2018
Semidiurnal solar tide differences between fall and spring transition times in the Northern Hemisphere
Leibniz Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Germany
Jorge L. Chau
Leibniz Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Germany
Fazlul I. Laskar
Leibniz Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Germany
Gunter Stober
Leibniz Institute of Atmospheric Physics, University of Rostock, Kühlungsborn, Germany
Hauke Schmidt
Max Planck Institute for Meteorology, Hamburg, Germany
Peter Brown
Department of Physics and Astronomy, Western University, London, Ontario, Canada
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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.
Witali Krochin, Axel Murk, and Gunter Stober
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2024-42, https://doi.org/10.5194/amt-2024-42, 2024
Preprint under review for AMT
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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 manuscript, 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 20–50 km at the geographical location of Payerne (Switzerland).
Guochun Shi, Witali Krochin, Eric Sauvageat, and Gunter Stober
EGUsphere, https://doi.org/10.5194/egusphere-2024-65, https://doi.org/10.5194/egusphere-2024-65, 2024
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In our study, we investigated ozone anomalies over polar regions during SSW and FSW events with ground-based microwave radiometers at polar latitudes, comparing them with reanalysis and satellite data. We document the underlying dynamical and chemical mechanisms that 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.
Hauke Schmidt, Sebastian Rast, Jiawei Bao, Amrit Cassim, Shih-Wei Fang, Diego Jimenez-de la Cuesta, Paul Keil, Lukas Kluft, Clarissa Kroll, Theresa Lang, Ulrike Niemeier, Andrea Schneidereit, Andrew I. L. Williams, and Bjorn Stevens
Geosci. Model Dev., 17, 1563–1584, https://doi.org/10.5194/gmd-17-1563-2024, https://doi.org/10.5194/gmd-17-1563-2024, 2024
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A recent development in numerical simulations of the global atmosphere is the increase in horizontal resolution to grid spacings of a few kilometers. However, the vertical grid spacing of these models has not been reduced at the same rate as the horizontal grid spacing. Here, we assess the effects of much finer vertical grid spacings, in particular the impacts on cloud quantities and the atmospheric energy balance.
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.
Moritz Günther, Hauke Schmidt, Claudia Timmreck, and Matthew Toohey
EGUsphere, https://doi.org/10.5194/egusphere-2024-429, https://doi.org/10.5194/egusphere-2024-429, 2024
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Stratospheric aerosol affects temperatures differently across the globe, with pronounced cooling in the tropical Indian and Western Pacific ocean. The aerosol also heats the stratosphere. Using a climate model, we show that the resulting circulation changes cause enhanced heat fluxes out of the tropical oceans, resulting in the pronounced local surface cooling. This highlights the importance of circulation adjustments and surface perspectives on forcing for understanding temperature responses.
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.
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.
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.
Sandra Wallis, Hauke Schmidt, and Christian von Savigny
Atmos. Chem. Phys., 23, 7001–7014, https://doi.org/10.5194/acp-23-7001-2023, https://doi.org/10.5194/acp-23-7001-2023, 2023
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Strong volcanic eruptions are able to alter the temperature and the circulation of the middle atmosphere. This study simulates the atmospheric response to an idealized strong tropical eruption and focuses on the impact on the mesosphere. The simulations show a warming of the polar summer mesopause in the first November after the eruption. Our study indicates that this is mainly due to dynamical coupling in the summer hemisphere with a potential contribution from interhemispheric coupling.
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).
Cathy Hohenegger, Peter Korn, Leonidas Linardakis, René Redler, Reiner Schnur, Panagiotis Adamidis, Jiawei Bao, Swantje Bastin, Milad Behravesh, Martin Bergemann, Joachim Biercamp, Hendryk Bockelmann, Renate Brokopf, Nils Brüggemann, Lucas Casaroli, Fatemeh Chegini, George Datseris, Monika Esch, Geet George, Marco Giorgetta, Oliver Gutjahr, Helmuth Haak, Moritz Hanke, Tatiana Ilyina, Thomas Jahns, Johann Jungclaus, Marcel Kern, Daniel Klocke, Lukas Kluft, Tobias Kölling, Luis Kornblueh, Sergey Kosukhin, Clarissa Kroll, Junhong Lee, Thorsten Mauritsen, Carolin Mehlmann, Theresa Mieslinger, Ann Kristin Naumann, Laura Paccini, Angel Peinado, Divya Sri Praturi, Dian Putrasahan, Sebastian Rast, Thomas Riddick, Niklas Roeber, Hauke Schmidt, Uwe Schulzweida, Florian Schütte, Hans Segura, Radomyra Shevchenko, Vikram Singh, Mia Specht, Claudia Christine Stephan, Jin-Song von Storch, Raphaela Vogel, Christian Wengel, Marius Winkler, Florian Ziemen, Jochem Marotzke, and Bjorn Stevens
Geosci. Model Dev., 16, 779–811, https://doi.org/10.5194/gmd-16-779-2023, https://doi.org/10.5194/gmd-16-779-2023, 2023
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Models of the Earth system used to understand climate and predict its change typically employ a grid spacing of about 100 km. Yet, many atmospheric and oceanic processes occur on much smaller scales. In this study, we present a new model configuration designed for the simulation of the components of the Earth system and their interactions at kilometer and smaller scales, allowing an explicit representation of the main drivers of the flow of energy and matter by solving the underlying equations.
Shih-Wei Fang, Claudia Timmreck, Johann Jungclaus, Kirstin Krüger, and Hauke Schmidt
Earth Syst. Dynam., 13, 1535–1555, https://doi.org/10.5194/esd-13-1535-2022, https://doi.org/10.5194/esd-13-1535-2022, 2022
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The early 19th century was the coldest period over the past 500 years, when strong tropical volcanic events and a solar minimum coincided. This study quantifies potential surface cooling from the solar and volcanic forcing in the early 19th century with large ensemble simulations, and identifies the regions that their impacts cannot be simply additive. The cooling perspective of Arctic amplification exists in both solar and post-volcano period with the albedo feedback as the main contribution.
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.
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.
Mohammad M. Khabbazan, Marius Stankoweit, Elnaz Roshan, Hauke Schmidt, and Hermann Held
Earth Syst. Dynam., 12, 1529–1542, https://doi.org/10.5194/esd-12-1529-2021, https://doi.org/10.5194/esd-12-1529-2021, 2021
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We ask for an optimal amount of solar radiation management (SRM) in conjunction with mitigation if global warming is limited to 2 °C and regional precipitation anomalies are confined to an amount ethically compatible with the 2 °C target. Then, compared to a scenario without regional targets, most of the SRM usage is eliminated from the portfolio even if transgressing regional targets are tolerated in terms of 1/10 of the standard deviation of natural variability.
Ryan Volz, Jorge L. Chau, Philip J. Erickson, Juha P. Vierinen, J. Miguel Urco, and Matthias Clahsen
Atmos. Meas. Tech., 14, 7199–7219, https://doi.org/10.5194/amt-14-7199-2021, https://doi.org/10.5194/amt-14-7199-2021, 2021
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We introduce a new way of estimating winds in the upper atmosphere (about 80 to 100 km in altitude) from the observed Doppler shift of meteor trails using a statistical method called Gaussian process regression. Wind estimates and, critically, the uncertainty of those estimates can be evaluated smoothly (i.e., not gridded) in space and time. The effective resolution is set by provided parameters, which are limited in practice by the number density of the observed meteors.
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.
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.
Fabio Vargas, Jorge L. Chau, Harikrishnan Charuvil Asokan, and Michael Gerding
Atmos. Chem. Phys., 21, 13631–13654, https://doi.org/10.5194/acp-21-13631-2021, https://doi.org/10.5194/acp-21-13631-2021, 2021
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We study large- and small-scale gravity wave cases observed in both airglow imagery and meteor radar data obtained during the SIMONe campaign carried out in early November 2018. We calculate the intrinsic features of several waves and estimate their impact in the mesosphere and lower thermosphere region via transferring energy and momentum to the atmosphere. We also associate cases of large-scale waves with secondary wave generation in the stratosphere.
Clarissa Alicia Kroll, Sally Dacie, Alon Azoulay, Hauke Schmidt, and Claudia Timmreck
Atmos. Chem. Phys., 21, 6565–6591, https://doi.org/10.5194/acp-21-6565-2021, https://doi.org/10.5194/acp-21-6565-2021, 2021
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Volcanic forcing is counteracted by stratospheric water vapor (SWV) entering the stratosphere as a consequence of aerosol-induced cold-point warming. We find that depending on the emission strength, aerosol profile height and season of the eruption, up to 4 % of the tropical aerosol forcing can be counterbalanced. A power function relationship between cold-point warming/SWV forcing and AOD in the yearly average is found, allowing us to estimate the SWV forcing for comparable eruptions.
Johann Stamm, Juha Vierinen, Juan M. Urco, Björn Gustavsson, and Jorge L. Chau
Ann. Geophys., 39, 119–134, https://doi.org/10.5194/angeo-39-119-2021, https://doi.org/10.5194/angeo-39-119-2021, 2021
Cathy W. Y. Li, Guy P. Brasseur, Hauke Schmidt, and Juan Pedro Mellado
Atmos. Chem. Phys., 21, 483–503, https://doi.org/10.5194/acp-21-483-2021, https://doi.org/10.5194/acp-21-483-2021, 2021
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Intense and localised emissions of pollutants are common in urban environments, in which turbulence cannot mix these segregated pollutants efficiently in the atmosphere. Despite their relatively high resolution, regional models cannot resolve such segregation and assume instantaneous mixing of these pollutants in their model grids, which potentially induces significant error in the subsequent chemical calculation, based on our calculation with a model that explicitly resolves turbulent motions.
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
Harikrishnan Charuvil Asokan, Jorge L. Chau, Raffaele Marino, Juha Vierinen, Fabio Vargas, Juan Miguel Urco, Matthias Clahsen, and Christoph Jacobi
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2020-974, https://doi.org/10.5194/acp-2020-974, 2020
Preprint withdrawn
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This paper explores the dynamics of gravity waves and turbulence present in the mesosphere and lower thermosphere (MLT) region. We utilized two different techniques on meteor radar observations and simulations to obtain power spectra at different horizontal scales. The techniques are applied to a special campaign conducted in northern Germany in November 2018. The study revealed the dominance of large-scale structures with horizontal scales larger than 500 km during the campaign period.
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
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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
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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
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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.
Katja Matthes, Arne Biastoch, Sebastian Wahl, Jan Harlaß, Torge Martin, Tim Brücher, Annika Drews, Dana Ehlert, Klaus Getzlaff, Fritz Krüger, Willi Rath, Markus Scheinert, Franziska U. Schwarzkopf, Tobias Bayr, Hauke Schmidt, and Wonsun Park
Geosci. Model Dev., 13, 2533–2568, https://doi.org/10.5194/gmd-13-2533-2020, https://doi.org/10.5194/gmd-13-2533-2020, 2020
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A new Earth system model, the Flexible Ocean and Climate Infrastructure (FOCI), is introduced, consisting of a high-top atmosphere, an ocean model, sea-ice and land surface model components. A unique feature of FOCI is the ability to explicitly resolve small-scale oceanic features, for example, the Agulhas Current and the Gulf Stream. It allows to study the evolution of the climate system on regional and seasonal to (multi)decadal scales and bridges the gap to coarse-resolution climate models.
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
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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
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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.
Sebastian Borchert, Guidi Zhou, Michael Baldauf, Hauke Schmidt, Günther Zängl, and Daniel Reinert
Geosci. Model Dev., 12, 3541–3569, https://doi.org/10.5194/gmd-12-3541-2019, https://doi.org/10.5194/gmd-12-3541-2019, 2019
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We present an upper-atmosphere extension of the ICOsahedral Non-hydrostatic (ICON) model.
This includes an extension of the model dynamics from a shallow to a deep atmosphere
and the implementation of upper-atmosphere physics parameterizations.
Idealized test cases and climate simulations are performed in order to evaluate this new configuration, named UA-ICON.
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
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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.
Maosheng He and Jorge Luis Chau
Atmos. Chem. Phys., 19, 5993–6006, https://doi.org/10.5194/acp-19-5993-2019, https://doi.org/10.5194/acp-19-5993-2019, 2019
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We propose an approach to resolve waves with multiple spatial scales at a given frequency using ground-based detectors from few longitudinal sectors. The approach is used to investigate near-12 h waves. Results suggest that broadly reported enhancements of two solar nonmigrating tides during sudden stratospheric warming events are just low-frequency-resolved signatures of two neighboring waves. The tides do not enhance.
Ina Tegen, David Neubauer, Sylvaine Ferrachat, Colombe Siegenthaler-Le Drian, Isabelle Bey, Nick Schutgens, Philip Stier, Duncan Watson-Parris, Tanja Stanelle, Hauke Schmidt, Sebastian Rast, Harri Kokkola, Martin Schultz, Sabine Schroeder, Nikos Daskalakis, Stefan Barthel, Bernd Heinold, and Ulrike Lohmann
Geosci. Model Dev., 12, 1643–1677, https://doi.org/10.5194/gmd-12-1643-2019, https://doi.org/10.5194/gmd-12-1643-2019, 2019
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We describe a new version of the aerosol–climate model ECHAM–HAM and show tests of the model performance by comparing different aspects of the aerosol distribution with different datasets. The updated version of HAM contains improved descriptions of aerosol processes, including updated emission fields and cloud processes. While there are regional deviations between the model and observations, the model performs well overall.
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
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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
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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.
Jorge Luis Chau, Juan Miguel Urco, Juha Pekka Vierinen, Ryan Andrew Volz, Matthias Clahsen, Nico Pfeffer, and Jörg Trautner
Atmos. Meas. Tech., 12, 2113–2127, https://doi.org/10.5194/amt-12-2113-2019, https://doi.org/10.5194/amt-12-2113-2019, 2019
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New systems to study the mesosphere are introduced. They result from the reengineering of previous systems, by making use of MIMO, spread-spectrum and compressed-sensing techniques that are widely used in telecommunications. The interferometer configuration is now implemented in transmission, making the location of meteor echoes possible with just one antenna on reception. Our novel concept makes the study of a mesosphere volume from different viewing points on the ground feasible and easy.
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
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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.
Juan Miguel Urco, Jorge Luis Chau, Tobias Weber, and Ralph Latteck
Atmos. Meas. Tech., 12, 955–969, https://doi.org/10.5194/amt-12-955-2019, https://doi.org/10.5194/amt-12-955-2019, 2019
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For decades, radar observations have been used to study complicated atmospheric dynamics. Previous observations of the mesosphere, between 80 and 90 km altitude, over polar regions have been limited to a spatial resolution of a few kilometers. In this work, we present a technique which allows 3-D radar observations of the mesospheric dynamics, with an unprecedented spatial resolution of ~ 900 m. We combine the concept of MIMO and high-resolution algorithms to improve the spatial resolution.
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
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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
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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.
Uwe Mikolajewicz, Florian Ziemen, Guido Cioni, Martin Claussen, Klaus Fraedrich, Marvin Heidkamp, Cathy Hohenegger, Diego Jimenez de la Cuesta, Marie-Luise Kapsch, Alexander Lemburg, Thorsten Mauritsen, Katharina Meraner, Niklas Röber, Hauke Schmidt, Katharina D. Six, Irene Stemmler, Talia Tamarin-Brodsky, Alexander Winkler, Xiuhua Zhu, and Bjorn Stevens
Earth Syst. Dynam., 9, 1191–1215, https://doi.org/10.5194/esd-9-1191-2018, https://doi.org/10.5194/esd-9-1191-2018, 2018
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Model experiments show that changing the sense of Earth's rotation has relatively little impact on the globally and zonally averaged energy budgets but leads to large shifts in continental climates and patterns of precipitation. The retrograde world is greener as the desert area shrinks. Deep water formation shifts from the North Atlantic to the North Pacific with subsequent changes in ocean overturning. Over large areas of the Indian Ocean, cyanobacteria dominate over bulk phytoplankton.
Ben Kravitz, Philip J. Rasch, Hailong Wang, Alan Robock, Corey Gabriel, Olivier Boucher, Jason N. S. Cole, Jim Haywood, Duoying Ji, Andy Jones, Andrew Lenton, John C. Moore, Helene Muri, Ulrike Niemeier, Steven Phipps, Hauke Schmidt, Shingo Watanabe, Shuting Yang, and Jin-Ho Yoon
Atmos. Chem. Phys., 18, 13097–13113, https://doi.org/10.5194/acp-18-13097-2018, https://doi.org/10.5194/acp-18-13097-2018, 2018
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Marine cloud brightening has been proposed as a means of geoengineering/climate intervention, or deliberately altering the climate system to offset anthropogenic climate change. In idealized simulations that highlight contrasts between land and ocean, we find that the globe warms, including the ocean due to transport of heat from land. This study reinforces that no net energy input into the Earth system does not mean that temperature will necessarily remain unchanged.
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
Amanda C. Maycock, Katja Matthes, Susann Tegtmeier, Hauke Schmidt, Rémi Thiéblemont, Lon Hood, Hideharu Akiyoshi, Slimane Bekki, Makoto Deushi, Patrick Jöckel, Oliver Kirner, Markus Kunze, Marion Marchand, Daniel R. Marsh, Martine Michou, David Plummer, Laura E. Revell, Eugene Rozanov, Andrea Stenke, Yousuke Yamashita, and Kohei Yoshida
Atmos. Chem. Phys., 18, 11323–11343, https://doi.org/10.5194/acp-18-11323-2018, https://doi.org/10.5194/acp-18-11323-2018, 2018
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The 11-year solar cycle is an important driver of climate variability. Changes in incoming solar ultraviolet radiation affect atmospheric ozone, which in turn influences atmospheric temperatures. Constraining the impact of the solar cycle on ozone is therefore important for understanding climate variability. This study examines the representation of the solar influence on ozone in numerical models used to simulate past and future climate. We highlight important differences among model datasets.
Jorge L. Chau, Derek McKay, Juha P. Vierinen, Cesar La Hoz, Thomas Ulich, Markku Lehtinen, and Ralph Latteck
Atmos. Chem. Phys., 18, 9547–9560, https://doi.org/10.5194/acp-18-9547-2018, https://doi.org/10.5194/acp-18-9547-2018, 2018
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Combining a phased-array power radar and a phased-array radio telescope, we have been able to identify and characterized horizontal structures and movement of noctilucent clouds, but at 3 m scales instead of optical scales. As a byproduct of our observations, we have studied their angular dependence. We show a new alternative to study these clouds on routine basis and therefore study the atmospheric dynamics that modulate them.
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
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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
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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
Martin G. Schultz, Scarlet Stadtler, Sabine Schröder, Domenico Taraborrelli, Bruno Franco, Jonathan Krefting, Alexandra Henrot, Sylvaine Ferrachat, Ulrike Lohmann, David Neubauer, Colombe Siegenthaler-Le Drian, Sebastian Wahl, Harri Kokkola, Thomas Kühn, Sebastian Rast, Hauke Schmidt, Philip Stier, Doug Kinnison, Geoffrey S. Tyndall, John J. Orlando, and Catherine Wespes
Geosci. Model Dev., 11, 1695–1723, https://doi.org/10.5194/gmd-11-1695-2018, https://doi.org/10.5194/gmd-11-1695-2018, 2018
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The chemistry–climate model ECHAM-HAMMOZ contains a detailed representation of tropospheric and stratospheric reactive chemistry and state-of-the-art parameterizations of aerosols. It thus allows for detailed investigations of chemical processes in the climate system. Evaluation of the model with various observational data yields good results, but the model has a tendency to produce too much OH in the tropics. This highlights the important interplay between atmospheric chemistry and dynamics.
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
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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
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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.
Katharina Meraner and Hauke Schmidt
Atmos. Chem. Phys., 18, 1079–1089, https://doi.org/10.5194/acp-18-1079-2018, https://doi.org/10.5194/acp-18-1079-2018, 2018
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Using a coupled Earth system model and radiative transfer modeling we show that the radiative forcing of a winter polar mesospheric ozone loss due to energetic particle precipitation is negligible. A climate impact of a mesospheric ozone loss as suggested by Andersson et al. (2014, Nature Communications) seems unlikely. A winter polar stratospheric ozone loss due to energetic particle precipitation leads to a small warming of the stratosphere, but only a few statistically significant changes.
Camilla W. Stjern, Helene Muri, Lars Ahlm, Olivier Boucher, Jason N. S. Cole, Duoying Ji, Andy Jones, Jim Haywood, Ben Kravitz, Andrew Lenton, John C. Moore, Ulrike Niemeier, Steven J. Phipps, Hauke Schmidt, Shingo Watanabe, and Jón Egill Kristjánsson
Atmos. Chem. Phys., 18, 621–634, https://doi.org/10.5194/acp-18-621-2018, https://doi.org/10.5194/acp-18-621-2018, 2018
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Marine cloud brightening (MCB) has been proposed to help limit global warming. We present here the first multi-model assessment of idealized MCB simulations from the Geoengineering Model Intercomparison Project. While all models predict a global cooling as intended, there is considerable spread between the models both in terms of radiative forcing and the climate response, largely linked to the substantial differences in the models' representation of clouds.
Ulrike Niemeier and Hauke Schmidt
Atmos. Chem. Phys., 17, 14871–14886, https://doi.org/10.5194/acp-17-14871-2017, https://doi.org/10.5194/acp-17-14871-2017, 2017
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An artificial stratospheric sulfur layer heats the lower stratosphere which impacts stratospheric dynamics and transport. The quasi-biennial oscillation shuts down due to the heated sulfur layer which impacts the meridional transport of the sulfate aerosols. The tropical confinement of the sulfate is stronger and the radiative forcing efficiency of the aerosol layer decreases compared to previous studies, as does the forcing when increasing the injection height.
Johann H. Jungclaus, Edouard Bard, Mélanie Baroni, Pascale Braconnot, Jian Cao, Louise P. Chini, Tania Egorova, Michael Evans, J. Fidel González-Rouco, Hugues Goosse, George C. Hurtt, Fortunat Joos, Jed O. Kaplan, Myriam Khodri, Kees Klein Goldewijk, Natalie Krivova, Allegra N. LeGrande, Stephan J. Lorenz, Jürg Luterbacher, Wenmin Man, Amanda C. Maycock, Malte Meinshausen, Anders Moberg, Raimund Muscheler, Christoph Nehrbass-Ahles, Bette I. Otto-Bliesner, Steven J. Phipps, Julia Pongratz, Eugene Rozanov, Gavin A. Schmidt, Hauke Schmidt, Werner Schmutz, Andrew Schurer, Alexander I. Shapiro, Michael Sigl, Jason E. Smerdon, Sami K. Solanki, Claudia Timmreck, Matthew Toohey, Ilya G. Usoskin, Sebastian Wagner, Chi-Ju Wu, Kok Leng Yeo, Davide Zanchettin, Qiong Zhang, and Eduardo Zorita
Geosci. Model Dev., 10, 4005–4033, https://doi.org/10.5194/gmd-10-4005-2017, https://doi.org/10.5194/gmd-10-4005-2017, 2017
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Climate model simulations covering the last millennium provide context for the evolution of the modern climate and for the expected changes during the coming centuries. They can help identify plausible mechanisms underlying palaeoclimatic reconstructions. Here, we describe the forcing boundary conditions and the experimental protocol for simulations covering the pre-industrial millennium. We describe the PMIP4 past1000 simulations as contributions to CMIP6 and additional sensitivity experiments.
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
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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
Bernd Funke, William Ball, Stefan Bender, Angela Gardini, V. Lynn Harvey, Alyn Lambert, Manuel López-Puertas, Daniel R. Marsh, Katharina Meraner, Holger Nieder, Sanna-Mari Päivärinta, Kristell Pérot, Cora E. Randall, Thomas Reddmann, Eugene Rozanov, Hauke Schmidt, Annika Seppälä, Miriam Sinnhuber, Timofei Sukhodolov, Gabriele P. Stiller, Natalia D. Tsvetkova, Pekka T. Verronen, Stefan Versick, Thomas von Clarmann, Kaley A. Walker, and Vladimir Yushkov
Atmos. Chem. Phys., 17, 3573–3604, https://doi.org/10.5194/acp-17-3573-2017, https://doi.org/10.5194/acp-17-3573-2017, 2017
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Simulations from eight atmospheric models have been compared to tracer and temperature observations from seven satellite instruments in order to evaluate the energetic particle indirect effect (EPP IE) during the perturbed northern hemispheric (NH) winter 2008/2009. Models are capable to reproduce the EPP IE in dynamically and geomagnetically quiescent NH winter conditions. The results emphasize the need for model improvements in the dynamical representation of elevated stratopause events.
Svenja Sommer and Jorge L. Chau
Ann. Geophys., 34, 1231–1241, https://doi.org/10.5194/angeo-34-1231-2016, https://doi.org/10.5194/angeo-34-1231-2016, 2016
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Radar echoes from mesospheric altitudes (80–90 km) are called polar mesospheric summer echoes (PMSEs). These echoes can be used to derive wind velocities and turbulence strength estimations in a region where measurements are hard to perform. The small-scale structure of PMSEs has not been analysed before but, as we will show, has a major influence on wind and turbulence measurements. We also present a method to improve these measurements by using software beam-steering methods.
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
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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
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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.
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
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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. Tilmes, M. J. Mills, U. Niemeier, H. Schmidt, A. Robock, B. Kravitz, J.-F. Lamarque, G. Pitari, and J. M. English
Geosci. Model Dev., 8, 43–49, https://doi.org/10.5194/gmd-8-43-2015, https://doi.org/10.5194/gmd-8-43-2015, 2015
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A new Geoengineering Model Intercomparison Project (GeoMIP) experiment “G4 specified stratospheric aerosols” (G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmosphere, chemistry, dynamics, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulfur dioxide (SO2) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments.
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
S. Studer, K. Hocke, A. Schanz, H. Schmidt, and N. Kämpfer
Atmos. Chem. Phys., 14, 5905–5919, https://doi.org/10.5194/acp-14-5905-2014, https://doi.org/10.5194/acp-14-5905-2014, 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
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
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: Terrestrial atmosphere and its relation to the sun | Keywords: Middle atmosphere dynamics
Propagating characteristics of mesospheric gravity waves observed by an OI 557.7 nm airglow all-sky camera at Mt. Bohyun (36.2° N, 128.9° E)
Modelling the residual mean meridional circulation at different stages of sudden stratospheric warming events
Stratospheric influence on the mesosphere–lower thermosphere over mid latitudes in winter observed by a Fabry–Perot interferometer
Migrating and non-migrating tides observed in the stratosphere from FORMOSAT-3/COSMIC temperature retrievals
Local stratopause temperature variabilities and their embedding in the global context
Relation between the interannual variability in the stratospheric Rossby wave forcing and zonal mean fields suggesting an interhemispheric link in the stratosphere
Impact of local gravity wave forcing in the lower stratosphere on the polar vortex stability: effect of longitudinal displacement
Stratospheric observations of noctilucent clouds: a new approach in studying middle- and large-scale mesospheric dynamics
High-resolution Beijing mesosphere–stratosphere–troposphere (MST) radar detection of tropopause structure and variability over Xianghe (39.75° N, 116.96° E), China
Effect of latitudinally displaced gravity wave forcing in the lower stratosphere on the polar vortex stability
Global analysis for periodic variations in gravity wave squared amplitudes and momentum fluxes in the middle atmosphere
Notes on the correlation between sudden stratospheric warmings and solar activity
Connection between the length of day and wind measurements in the mesosphere and lower thermosphere at mid- and high latitudes
Jun-Young Hwang, Young-Sook Lee, Yong Ha Kim, Hosik Kam, Seok-Min Song, Young-Sil Kwak, and Tae-Yong Yang
Ann. Geophys., 40, 247–257, https://doi.org/10.5194/angeo-40-247-2022, https://doi.org/10.5194/angeo-40-247-2022, 2022
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We analysed all-sky camera images observed at Mt. Bohyun observatory (36.2° N, 128.9° E) for the period of 2017–2019. We retrieved gravity wave parameters including horizontal wavelength, phase velocity and period from the image data. The horizontally propagating directions of the wave were biased according to their seasons, exerted with filtering effect by prevailing background winds. We also evaluated the nature of vertical propagation of the wave for each season.
Andrey V. Koval, Wen Chen, Ksenia A. Didenko, Tatiana S. Ermakova, Nikolai M. Gavrilov, Alexander I. Pogoreltsev, Olga N. Toptunova, Ke Wei, Anna N. Yarusova, and Anton S. Zarubin
Ann. Geophys., 39, 357–368, https://doi.org/10.5194/angeo-39-357-2021, https://doi.org/10.5194/angeo-39-357-2021, 2021
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Numerical modelling is used to simulate atmospheric circulation and calculate residual mean meridional circulation (RMC) during sudden stratospheric warming (SSW) events. Calculating the RMC is used to take into account wave effects on the transport of atmospheric quantities and gas species in the meridional plane. The results show that RMC undergoes significant changes at different stages of SSW and contributes to SSW development.
Olga S. Zorkaltseva and Roman V. Vasilyev
Ann. Geophys., 39, 267–276, https://doi.org/10.5194/angeo-39-267-2021, https://doi.org/10.5194/angeo-39-267-2021, 2021
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One of the fundamental tasks of atmospheric physics is the study of the processes of vertical interaction of atmospheric layers. We carried out observations with a Fabry–Perot interferometer at an altitude of 90–100 km. We have shown that sudden stratospheric warming and active planetary waves have an impact on the dynamics of the upper atmosphere. That is, the green line airglow decreases and the temperature rises. Major warming causes the reversal of the zonal wind in the upper atmosphere.
Uma Das, William E. Ward, Chen Jeih Pan, and Sanat Kumar Das
Ann. Geophys., 38, 421–435, https://doi.org/10.5194/angeo-38-421-2020, https://doi.org/10.5194/angeo-38-421-2020, 2020
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Temperatures obtained from FORMOSAT-3 and COSMIC observations in the stratosphere are analysed for tidal variations. It is seen that non-migrating tides are not very significant in the high-latitude winter stratosphere. It is shown that the observed amplitudes of these tides in earlier studies are most probably a result of aliasing and are not geophysical in nature. Thus, the process of non-linear interactions through which it was believed that they are produced seems to be unimportant.
Ronald Eixmann, Vivien Matthias, Josef Höffner, Gerd Baumgarten, and Michael Gerding
Ann. Geophys., 38, 373–383, https://doi.org/10.5194/angeo-38-373-2020, https://doi.org/10.5194/angeo-38-373-2020, 2020
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The aim of this study is to bring local variabilities into a global context. To qualitatively study the impact of global waves on local measurements in winter, we combine local lidar measurements with global MERRA-2 reanalysis data. Our results show that about 98 % of the local day-to-day variability can be explained by the variability of waves with zonal wave numbers 1, 2 and 3. Thus locally measured effects which are not based on global wave variability can be investigated much better.
Yuki Matsushita, Daiki Kado, Masashi Kohma, and Kaoru Sato
Ann. Geophys., 38, 319–329, https://doi.org/10.5194/angeo-38-319-2020, https://doi.org/10.5194/angeo-38-319-2020, 2020
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Interannual variabilities of the zonal mean wind and temperature related to the Rossby wave forcing in the winter stratosphere of the Southern Hemisphere are studied using 38-year reanalysis data. Correlation of the mean fields to the wave forcing is extended to the subtropics of the Northern Hemisphere. This interhemispheric link is caused by the wave forcing which reduces the meridional gradient of the angular momentum and drives the meridional circulation over the Equator in the stratosphere.
Nadja Samtleben, Aleš Kuchař, Petr Šácha, Petr Pišoft, and Christoph Jacobi
Ann. Geophys., 38, 95–108, https://doi.org/10.5194/angeo-38-95-2020, https://doi.org/10.5194/angeo-38-95-2020, 2020
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The additional transfer of momentum and energy induced by locally breaking gravity wave hotspots in the lower stratosphere may lead to a destabilization of the polar vortex, which is strongly dependent on the position of the hotspot. The simulations with a global circulation model show that hotspots located above Eurasia cause a total decrease in the stationary planetary wave (SPW) activity, while the impact of hotspots located in North America mostly increase the SPW activity.
Peter Dalin, Nikolay Pertsev, Vladimir Perminov, Denis Efremov, and Vitaly Romejko
Ann. Geophys., 38, 61–71, https://doi.org/10.5194/angeo-38-61-2020, https://doi.org/10.5194/angeo-38-61-2020, 2020
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A unique stratospheric balloon-borne observation of noctilucent clouds (NLCs) was performed at night on 5–6 July 2018. A sounding balloon, carrying the NLC camera, reached 20.4 km altitude. NLCs were observed from the stratosphere at large scales (100–1500 km) for the first time. Propagations of gravity waves of various scales were registered. This experiment is rather simple and can be reproduced by the broad geoscience community and amateurs, providing a new technique in NLC observations.
Feilong Chen, Gang Chen, Yufang Tian, Shaodong Zhang, Kaiming Huang, Chen Wu, and Weifan Zhang
Ann. Geophys., 37, 631–643, https://doi.org/10.5194/angeo-37-631-2019, https://doi.org/10.5194/angeo-37-631-2019, 2019
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Using the Beijing MST radar echo-power observations collected during the period November 2011–May 2017, the structure and variability of the tropopause over Xianghe, China (39.75° N, 116.96° E), was presented. Our comparison results showed a good agreement between the radar and thermal tropopauses during all seasons. In contrast, the consistency between the radar and dynamical tropopauses is poor during summer. Diurnal oscillation in tropopause height is commonly observed during all seasons.
Nadja Samtleben, Christoph Jacobi, Petr Pišoft, Petr Šácha, and Aleš Kuchař
Ann. Geophys., 37, 507–523, https://doi.org/10.5194/angeo-37-507-2019, https://doi.org/10.5194/angeo-37-507-2019, 2019
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Simulations of locally breaking gravity wave hot spots in the stratosphere show a suppression of wave propagation at midlatitudes, which is partly compensated for by additional wave propagation through the polar region. This leads to a displacement of the polar vortex towards lower latitudes. The effect is highly dependent on the position of the artificial gravity wave forcing. It is strongest (weakest) for hot spots at lower to middle latitudes (higher latitudes).
Dan Chen, Cornelia Strube, Manfred Ern, Peter Preusse, and Martin Riese
Ann. Geophys., 37, 487–506, https://doi.org/10.5194/angeo-37-487-2019, https://doi.org/10.5194/angeo-37-487-2019, 2019
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In this paper, for the first time, absolute gravity wave momentum flux (GWMF) on temporal scales from terannual variation up to solar cycle length is investigated. The systematic spectral analysis of SABER absolute GWMF is presented and physically interpreted. The various roles of filtering and oblique propagating are discussed, which is likely an important factor for MLT dynamics, and hence can be used as a stringent test bed of the reproduction of such features in global models.
Ekaterina Vorobeva
Ann. Geophys., 37, 375–380, https://doi.org/10.5194/angeo-37-375-2019, https://doi.org/10.5194/angeo-37-375-2019, 2019
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We investigated the statistical relationship between solar activity and the occurrence rate of major sudden stratospheric warmings (MSSWs). For this purpose, the 10.7 cm radio flux (F10.7) has been used as a proxy for solar activity. The calculations have been performed based on two datasets of central day (NCEP–NCAR-I and combined ERA) for the period from 1958 to 2013. The analysis revealed a positive correlation between MSSW events and solar activity.
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
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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.
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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.
Based on comparisons of meteor radar measurements with HAMMONIA model simulations, we show that...
