Articles | Volume 20, issue 4
https://doi.org/10.5194/acp-20-2367-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-20-2367-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
28 Feb 2020
Research article |
| 28 Feb 2020
| 28 Feb 2020
First measurements of tides in the stratosphere and lower mesosphere by ground-based Doppler microwave wind radiometry
Institute of Applied Physics, University of Bern, Bern, Switzerland
Klemens Hocke
Institute of Applied Physics, University of Bern, Bern, Switzerland
Gunter Stober
Institute of Applied Physics, University of Bern, Bern, Switzerland
Simon Pfreundschuh
Department of Space, Earth and Environment, Chalmers University of Technology, Gothenburg, Sweden
Axel Murk
Institute of Applied Physics, University of Bern, Bern, Switzerland
Niklaus Kämpfer
Institute of Applied Physics, University of Bern, Bern, Switzerland
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Atmos. Meas. Tech., 17, 4337–4368, https://doi.org/10.5194/amt-17-4337-2024, https://doi.org/10.5194/amt-17-4337-2024, 2024
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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).
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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
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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.
Adrià Amell, Patrick Eriksson, and Simon Pfreundschuh
Atmos. Meas. Tech., 15, 5701–5717, https://doi.org/10.5194/amt-15-5701-2022, https://doi.org/10.5194/amt-15-5701-2022, 2022
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Geostationary satellites continuously image a given location on Earth, a feature that satellites designed to characterize atmospheric ice lack. However, the relationship between geostationary images and atmospheric ice is complex. Machine learning is used here to leverage such images to characterize atmospheric ice throughout the day in a probabilistic manner. Using structural information from the image improves the characterization, and this approach compares favourably to traditional methods.
Simon Pfreundschuh, Paula J. Brown, Christian D. Kummerow, Patrick Eriksson, and Teodor Norrestad
Atmos. Meas. Tech., 15, 5033–5060, https://doi.org/10.5194/amt-15-5033-2022, https://doi.org/10.5194/amt-15-5033-2022, 2022
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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.
Simon Pfreundschuh, Stuart Fox, Patrick Eriksson, David Duncan, Stefan A. Buehler, Manfred Brath, Richard Cotton, and Florian Ewald
Atmos. Meas. Tech., 15, 677–699, https://doi.org/10.5194/amt-15-677-2022, https://doi.org/10.5194/amt-15-677-2022, 2022
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We test a novel method to remotely measure ice particles in clouds. This is important because such measurements are required to improve climate and weather models. The method combines a radar with newly developed sensors measuring microwave radiation at very short wavelengths. We use observations made from aircraft flying above the cloud and compare them to real measurements from inside the cloud. This works well given that one can model the ice particles in the cloud sufficiently well.
Christoph Jacobi, Friederike Lilienthal, Dmitry Korotyshkin, Evgeny Merzlyakov, and Gunter Stober
Adv. Radio Sci., 19, 185–193, https://doi.org/10.5194/ars-19-185-2021, https://doi.org/10.5194/ars-19-185-2021, 2021
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We compare winds and tidal amplitudes in the upper mesosphere/lower thermosphere region for cases with disturbed and undisturbed geomagnetic conditions. The zonal winds in both the mesosphere and lower thermosphere tend to be weaker during disturbed conditions. The summer equatorward meridional wind jet is weaker for disturbed geomagnetic conditions. The effect of geomagnetic variability on tidal amplitudes, except for the semidiurnal tide, is relatively small.
Gunter Stober, Alexander Kozlovsky, Alan Liu, Zishun Qiao, Masaki Tsutsumi, Chris Hall, Satonori Nozawa, Mark Lester, Evgenia Belova, Johan Kero, Patrick J. Espy, Robert E. Hibbins, and Nicholas Mitchell
Atmos. Meas. Tech., 14, 6509–6532, https://doi.org/10.5194/amt-14-6509-2021, https://doi.org/10.5194/amt-14-6509-2021, 2021
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Wind observations at the edge to space, 70–110 km altitude, are challenging. Meteor radars have become a widely used instrument to obtain mean wind profiles above an instrument for these heights. We describe an advanced mathematical concept and present a tomographic analysis using several meteor radars located in Finland, Sweden and Norway, as well as Chile, to derive the three-dimensional flow field. We show an example of a gravity wave decelerating the mean flow.
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.
Inderpreet Kaur, Patrick Eriksson, Simon Pfreundschuh, and David Ian Duncan
Atmos. Meas. Tech., 14, 2957–2979, https://doi.org/10.5194/amt-14-2957-2021, https://doi.org/10.5194/amt-14-2957-2021, 2021
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Currently, cloud contamination in microwave humidity channels is addressed using filtering schemes. We present an approach to correct the cloud-affected microwave humidity radiances using a Bayesian machine learning technique. The technique combines orthogonal information from microwave channels to obtain a probabilistic prediction of the clear-sky radiances. With this approach, we are able to predict bias-free clear-sky radiances with well-represented case-specific uncertainty estimates.
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
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.
Simon Pfreundschuh, Patrick Eriksson, Stefan A. Buehler, Manfred Brath, David Duncan, Richard Larsson, and Robin Ekelund
Atmos. Meas. Tech., 13, 4219–4245, https://doi.org/10.5194/amt-13-4219-2020, https://doi.org/10.5194/amt-13-4219-2020, 2020
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The next generation of European operational weather satellites will carry a novel microwave sensor, the Ice Cloud Imager (ICI), which will provide observations of clouds at microwave frequencies that were not available before. We investigate the potential benefits of combining observations from ICI with that of a radar. We find that such combined observations provide additional information on the properties of the cloud and help to reduce uncertainties in retrieved mass and number densities.
Eliane Maillard Barras, Alexander Haefele, Liliane Nguyen, Fiona Tummon, William T. Ball, Eugene V. Rozanov, Rolf Rüfenacht, Klemens Hocke, Leonie Bernet, Niklaus Kämpfer, Gerald Nedoluha, and Ian Boyd
Atmos. Chem. Phys., 20, 8453–8471, https://doi.org/10.5194/acp-20-8453-2020, https://doi.org/10.5194/acp-20-8453-2020, 2020
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To determine the part of the variability of the long-term ozone profile trends coming from measurement timing, we estimate microwave radiometer trends for each hour of the day with a multiple linear regression model. The variation in the trend with local solar time is not significant at the 95 % confidence level either in the stratosphere or in the low mesosphere. We conclude that systematic sampling differences between instruments cannot explain significant differences in trend estimates.
Christine Aebi, Julian Gröbner, Stelios Kazadzis, Laurent Vuilleumier, Antonis Gkikas, and Niklaus Kämpfer
Atmos. Meas. Tech., 13, 907–923, https://doi.org/10.5194/amt-13-907-2020, https://doi.org/10.5194/amt-13-907-2020, 2020
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Clouds are one of the largest sources of uncertainties in climate models. The current study estimates the cloud optical thickness (COT), the effective droplet radius and the single scattering albedo of stratus–altostratus and cirrus–cirrostratus clouds in Payerne, Switzerland, by combining ground- and satellite-based measurements and radiative transfer models. The estimated values are thereafter compared with data retrieved from other methods. The mean COT is distinct for different seasons.
Robin Ekelund, Patrick Eriksson, and Simon Pfreundschuh
Atmos. Meas. Tech., 13, 501–520, https://doi.org/10.5194/amt-13-501-2020, https://doi.org/10.5194/amt-13-501-2020, 2020
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Atmospheric ice particles (e.g. snow and ice crystals) are an important part of weather, climate, and the hydrological cycle. This study investigates whether combined satellite measurements by radar and radiometers at microwave wavelengths can be used to find the most likely shape of such ice particles. The method was limited when using only currently operating sensors (CloudSat radar and the GPM Microwave Imager) but shows promise if the upcoming Ice Cloud Imager is also considered.
David Ian Duncan, Patrick Eriksson, and Simon Pfreundschuh
Atmos. Meas. Tech., 12, 6341–6359, https://doi.org/10.5194/amt-12-6341-2019, https://doi.org/10.5194/amt-12-6341-2019, 2019
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The overlapping beams of some satellite observations contain spatial information that is discarded by most data processing techniques. This study applies an established technique in a new way to improve the spatial resolution of retrieval targets, effectively using the overlapping information to achieve a higher ultimate resolution. It is argued that this is a more optimal use of the total information available from current microwave sensors, using AMSR2 as an example.
Klemens Hocke, Leonie Bernet, Jonas Hagen, Axel Murk, Matthias Renker, and Christian Mätzler
Atmos. Chem. Phys., 19, 12083–12090, https://doi.org/10.5194/acp-19-12083-2019, https://doi.org/10.5194/acp-19-12083-2019, 2019
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The Tropospheric Water Radiometer (TROWARA) observed an enhanced intensity of short-term integrated water vapour (IWV) fluctuations during daytime in summer. These IWV fluctuations are possibly related to latent heat flux and thermal convective activity in the lower troposphere. The observed climatology and spectra of IWV fluctuations might be useful for modelling studies of water vapour convection in the atmospheric boundary layer at mid latitudes.
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.
Franziska Schranz, Brigitte Tschanz, Rolf Rüfenacht, Klemens Hocke, Mathias Palm, and Niklaus Kämpfer
Atmos. Chem. Phys., 19, 9927–9947, https://doi.org/10.5194/acp-19-9927-2019, https://doi.org/10.5194/acp-19-9927-2019, 2019
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The dynamics of the Arctic middle atmosphere above Ny-Ålesund, Svalbard (79° N, 12° E) is investigated using 3 years of H2O and O3 measurements from ground-based microwave radiometers. We found the signals of atmospheric phenomena like sudden stratospheric warmings, polar vortex shifts, effective descent rates of water vapour and periodicities in our data. Additionally, a comprehensive intercomparison is performed with models and measurements from ground-based, in situ and satellite instruments.
Klemens Hocke, Jonas Hagen, Franziska Schranz, and Leonie Bernet
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2019-630, https://doi.org/10.5194/acp-2019-630, 2019
Preprint withdrawn
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The dense sampling of geopotential height (GPH) profiles of the microwave limb sounder (MLS) on NASA's satellite Aura is appropriate for detection of mesospheric gravity waves. Up to now, the global distribution of mesospheric gravity wave activity is relatively unknown. The study focuses on the relation of mesospheric gravity waves to major sudden stratospheric warmings.
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.
David Ian Duncan, Patrick Eriksson, Simon Pfreundschuh, Christian Klepp, and Daniel C. Jones
Atmos. Chem. Phys., 19, 6969–6984, https://doi.org/10.5194/acp-19-6969-2019, https://doi.org/10.5194/acp-19-6969-2019, 2019
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Raindrop size distributions have not been systematically studied over the oceans but are significant for remotely sensing, assimilating, and modeling rain. Here we investigate raindrop populations with new global in situ data, compare them against satellite estimates, and explore a new technique to classify the shapes of these distributions. The results indicate the inadequacy of a commonly assumed shape in some regions and the sizable impact of shape variability on satellite measurements.
Martin Lainer, Klemens Hocke, Ellen Eckert, and Niklaus Kämpfer
Atmos. Chem. Phys., 19, 6611–6620, https://doi.org/10.5194/acp-19-6611-2019, https://doi.org/10.5194/acp-19-6611-2019, 2019
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A middle atmospheric water vapor time series of more than 11 years (April 2007 to May 2018) from the NDACC microwave remote sensing site at Bern (Switzerland) is investigated to estimate the trend by means of a robust multilinear parametric trend model. Between 61 and 72 km altitude a significant decline in water vapor could be detected. The reduction of water vapor maximizes to about −12 % per decade at 72 km altitude.
Jinghua Li, Guanyi Ma, Klemens Hocke, Qingtao Wan, Jiangtao Fan, and Xiaolan Wang
Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2019-64, https://doi.org/10.5194/angeo-2019-64, 2019
Revised manuscript not accepted
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Local occurrence rate (LOR) is defined to clarify the characteristics of ionospheric irregularities together with monthly occurrence rate (MOR) at 20–29° N in solar minimum, medium and maximum years of 2008, 2003 and 2014. MOR of irregularities in May/June is larger than that in equinoxes, which is different with the equatorial plasma bubbles. LOR shows that the irregularities at 26–29° N in May/June are more frequently happened and have smaller spatiotemporal scales than those at lower latitudes.
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.
Klemens Hocke, Huixin Liu, Nicholas Pedatella, and Guanyi Ma
Ann. Geophys., 37, 235–242, https://doi.org/10.5194/angeo-37-235-2019, https://doi.org/10.5194/angeo-37-235-2019, 2019
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The GPS radio occultation data of the COSMIC-FORMOSAT-3 mission are used to visualize the global distribution of ionospheric irregularities in the F2 region during a geomagnetic storm, at solar minimum, and at solar maximum.
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.
Leonie Bernet, Thomas von Clarmann, Sophie Godin-Beekmann, Gérard Ancellet, Eliane Maillard Barras, René Stübi, Wolfgang Steinbrecht, Niklaus Kämpfer, and Klemens Hocke
Atmos. Chem. Phys., 19, 4289–4309, https://doi.org/10.5194/acp-19-4289-2019, https://doi.org/10.5194/acp-19-4289-2019, 2019
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After severe ozone depletion, upper stratospheric ozone has started to recover in recent years. However, stratospheric ozone trends from various data sets still show differences. To partly explain such differences, we investigate how the trends are affected by different factors, for example, anomalies in the data. We show how trend estimates can be improved by considering such anomalies and present updated stratospheric ozone trends from ground data measured in central Europe.
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.
Christine Aebi, Julian Gröbner, and Niklaus Kämpfer
Atmos. Meas. Tech., 11, 5549–5563, https://doi.org/10.5194/amt-11-5549-2018, https://doi.org/10.5194/amt-11-5549-2018, 2018
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A newly developed hemispherical thermal infrared cloud camera (IRCCAM) is presented. The IRCCAM allows automatic cloud detection during the day and at night-time. The cloud fraction determined from the IRCCAM is compared with the cloud fraction determined from other instruments over a time period of 2 years. The IRCCAM has an agreement of +/- 2 oktas cloud fraction in 90 % of the data compared to other instruments. There are no significant differences between seasons or different times of day.
Jonas Hagen, Axel Murk, Rolf Rüfenacht, Sergey Khaykin, Alain Hauchecorne, and Niklaus Kämpfer
Atmos. Meas. Tech., 11, 5007–5024, https://doi.org/10.5194/amt-11-5007-2018, https://doi.org/10.5194/amt-11-5007-2018, 2018
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
Martin Lainer, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 18, 12061–12074, https://doi.org/10.5194/acp-18-12061-2018, https://doi.org/10.5194/acp-18-12061-2018, 2018
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A long continuous record (in total 7 years) of middle atmospheric water vapor at the midlatitude NDACC station in Bern is investigated to study quasi 2-day wave oscillations (Q2DWs). We present monthly climatologies of the wave amplitudes and show the periods that the Q2DWs developed. What we observe is very-high-frequency variability. An autobicoherence analysis revealed nonlinear phase couplings between Q2DWs and other atmospheric waves. Our results are useful for model validation purposes.
Simon Pfreundschuh, Patrick Eriksson, David Duncan, Bengt Rydberg, Nina Håkansson, and Anke Thoss
Atmos. Meas. Tech., 11, 4627–4643, https://doi.org/10.5194/amt-11-4627-2018, https://doi.org/10.5194/amt-11-4627-2018, 2018
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A novel neural-network-based retrieval method is proposed that combines the flexibility and computational efficiency of machine learning retrievals with the consistent treatment of uncertainties of Bayesian methods. Numerical experiments are presented that show the consistency of the proposed method with the Bayesian formulation as well as its ability to represent non-Gaussian retrieval errors. With this, the proposed method overcomes important limitations of traditional methods.
J. Federico Conte, Jorge L. Chau, Fazlul I. Laskar, Gunter Stober, Hauke Schmidt, and Peter Brown
Ann. Geophys., 36, 999–1008, https://doi.org/10.5194/angeo-36-999-2018, https://doi.org/10.5194/angeo-36-999-2018, 2018
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Based on comparisons of meteor radar measurements with HAMMONIA model simulations, we show that the differences exhibited by the semidiurnal solar tide (S2) observed at middle and high latitudes of the Northern Hemisphere between equinox times are mainly due to distinct behaviors of the migrating semidiurnal (SW2) and the non-migrating westward-propagating wave number 1 semidiurnal (SW1) tidal components.
Dimitry Pokhotelov, Erich Becker, Gunter Stober, and Jorge L. Chau
Ann. Geophys., 36, 825–830, https://doi.org/10.5194/angeo-36-825-2018, https://doi.org/10.5194/angeo-36-825-2018, 2018
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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
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.
Franziska Schranz, Susana Fernandez, Niklaus Kämpfer, and Mathias Palm
Atmos. Chem. Phys., 18, 4113–4130, https://doi.org/10.5194/acp-18-4113-2018, https://doi.org/10.5194/acp-18-4113-2018, 2018
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We present 1 year of ozone measurements form two ground-based microwave radiometers located at Ny-Ålesund, Svalbard. The ozone measurements cover an altitude range of 25–70 km altitude and have a high time resolution of 1–2 h. With these datasets and model data a comprehensive analysis of the ozone diurnal cycle in the Arctic is performed for the different insolation conditions throughout the year. In the stratosphere we find a diurnal cycle which persists over the whole polar day.
Martin Lainer, Klemens Hocke, Rolf Rüfenacht, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 14905–14917, https://doi.org/10.5194/acp-17-14905-2017, https://doi.org/10.5194/acp-17-14905-2017, 2017
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We report on middle-atmospheric water vapor measurements above Bern from the ground-based microwave radiometer MIAWARA (NDACC affiliated) during two winter periods of 6 months. Quasi 18 h oscillations of mesospheric water vapor above 0.1 hPa are observed. Further, the 18 h wave is seen in a zonal wind data set from the Doppler wind radiometer WIRA. Inertia-gravity-wave-induced fluctuations or a nonlinear coupling between tides and quasi 2-day waves are considered as possible drivers.
Gerald E. Nedoluha, Michael Kiefer, Stefan Lossow, R. Michael Gomez, Niklaus Kämpfer, Martin Lainer, Peter Forkman, Ole Martin Christensen, Jung Jin Oh, Paul Hartogh, John Anderson, Klaus Bramstedt, Bianca M. Dinelli, Maya Garcia-Comas, Mark Hervig, Donal Murtagh, Piera Raspollini, William G. Read, Karen Rosenlof, Gabriele P. Stiller, and Kaley A. Walker
Atmos. Chem. Phys., 17, 14543–14558, https://doi.org/10.5194/acp-17-14543-2017, https://doi.org/10.5194/acp-17-14543-2017, 2017
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As part of the second SPARC (Stratosphere–troposphere Processes And their Role in Climate) water vapor assessment (WAVAS-II), we present measurements taken from or coincident with seven sites from which ground-based microwave instruments measure water vapor in the middle atmosphere. In the lower mesosphere, we quantify instrumental differences in the observed trends and annual variations at six sites. We then present a range of observed trends in water vapor over the past 20 years.
Christine Aebi, Julian Gröbner, Niklaus Kämpfer, and Laurent Vuilleumier
Atmos. Meas. Tech., 10, 4587–4600, https://doi.org/10.5194/amt-10-4587-2017, https://doi.org/10.5194/amt-10-4587-2017, 2017
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The current study analyses the cloud radiative effect during the daytime depending on cloud fraction and cloud type at two stations in Switzerland over a time period of 3–5 years. Information about fractional cloud coverage and cloud type is retrieved from images taken by visible all-sky cameras. Cloud cover, cloud type and other atmospheric parameters have an influence on the magnitude of the longwave cloud effect as well as on the shortwave.
Francisco Navas-Guzmán, Niklaus Kämpfer, Franziska Schranz, Wolfgang Steinbrecht, and Alexander Haefele
Atmos. Chem. Phys., 17, 14085–14104, https://doi.org/10.5194/acp-17-14085-2017, https://doi.org/10.5194/acp-17-14085-2017, 2017
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The paper presents assessment of the stratospheric measurements of a relatively new temperature radiometer (TEMPERA) at 60 GHz. The temperature profiles from TEMPERA have been compared with measurements from different techniques such as radiosondes, MLS satellite and Rayleigh lidar and with the temperature outputs from the SD-WACCM model. The results showed absolute biases and standard deviations lower than 2 K for most of the altitudes and comparisons, proving the good performance of TEMPERA.
Leonie Bernet, Francisco Navas-Guzmán, and Niklaus Kämpfer
Atmos. Meas. Tech., 10, 4421–4437, https://doi.org/10.5194/amt-10-4421-2017, https://doi.org/10.5194/amt-10-4421-2017, 2017
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Microwave radiometry is a suitable technique to measure atmospheric temperature profiles during clear sky and cloudy conditions. However clouds can influence the temperature measurements. In this study we analyse the influence of clouds on temperature measurements in the troposphere from a microwave radiometer. We found that the effect of clouds on the temperature measurements is important and that the measurements can be improved substantially by considering clouds in the retrieval process.
Klemens Hocke, Francisco Navas-Guzmán, Lorena Moreira, Leonie Bernet, and Christian Mätzler
Atmos. Chem. Phys., 17, 12121–12131, https://doi.org/10.5194/acp-17-12121-2017, https://doi.org/10.5194/acp-17-12121-2017, 2017
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We derive the annual and semi-annual oscillations in cloud fraction (CF), integrated liquid water (ILW) and integrated water vapour (IWV) from the long-term measurements of the TROWARA radiometer in Bern, Switzerland. Further, we find a weekly cycle of CF and ILW from June to September with increased values on Saturday, Sunday and Monday.
Wolfgang Steinbrecht, Lucien Froidevaux, Ryan Fuller, Ray Wang, John Anderson, Chris Roth, Adam Bourassa, Doug Degenstein, Robert Damadeo, Joe Zawodny, Stacey Frith, Richard McPeters, Pawan Bhartia, Jeannette Wild, Craig Long, Sean Davis, Karen Rosenlof, Viktoria Sofieva, Kaley Walker, Nabiz Rahpoe, Alexei Rozanov, Mark Weber, Alexandra Laeng, Thomas von Clarmann, Gabriele Stiller, Natalya Kramarova, Sophie Godin-Beekmann, Thierry Leblanc, Richard Querel, Daan Swart, Ian Boyd, Klemens Hocke, Niklaus Kämpfer, Eliane Maillard Barras, Lorena Moreira, Gerald Nedoluha, Corinne Vigouroux, Thomas Blumenstock, Matthias Schneider, Omaira García, Nicholas Jones, Emmanuel Mahieu, Dan Smale, Michael Kotkamp, John Robinson, Irina Petropavlovskikh, Neil Harris, Birgit Hassler, Daan Hubert, and Fiona Tummon
Atmos. Chem. Phys., 17, 10675–10690, https://doi.org/10.5194/acp-17-10675-2017, https://doi.org/10.5194/acp-17-10675-2017, 2017
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Thanks to the 1987 Montreal Protocol and its amendments, ozone-depleting chlorine (and bromine) in the stratosphere has declined slowly since the late 1990s. Improved and extended long-term ozone profile observations from satellites and ground-based stations confirm that ozone is responding as expected and has increased by about 2 % per decade since 2000 in the upper stratosphere, around 40 km altitude. At lower altitudes, however, ozone has not changed significantly since 2000.
Lorena Moreira, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 10259–10268, https://doi.org/10.5194/acp-17-10259-2017, https://doi.org/10.5194/acp-17-10259-2017, 2017
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GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has provided ozone profiles for the Network for the Detection of Atmospheric Composition Change since 1994. A new retrieval version for ozone profiles aims to improve the altitude range of profiles. We performed a comparison between coincident profiles of GROMOS and Aura MLS, resulting in agreement within 2% in
the mid- and upper stratosphere from 2009 to 2016. We also observed extensions of the tertiary ozone maximum at midlatitudes.
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
Klemens Hocke, Franziska Schranz, Eliane Maillard Barras, Lorena Moreira, and Niklaus Kämpfer
Atmos. Chem. Phys., 17, 3445–3452, https://doi.org/10.5194/acp-17-3445-2017, https://doi.org/10.5194/acp-17-3445-2017, 2017
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Observation and simulation show an Atlantic ozone streamer along the edge region of the polar vortex in the northern middle stratosphere during winter. The Atlantic streamer has wind speeds of about 100 m/s and turns equatorward at a vortex erosion region. We compare the fields of stratospheric ozone and water vapour from ground- and space-based microwave radiometry and SD-WACCM simulations for a better understanding of non-linear transport processes in the middle atmosphere.
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.
Francisco Navas-Guzmán, Niklaus Kämpfer, and Alexander Haefele
Atmos. Meas. Tech., 9, 4587–4600, https://doi.org/10.5194/amt-9-4587-2016, https://doi.org/10.5194/amt-9-4587-2016, 2016
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The paper presents the assessment of the tropospheric measurements of a new temperature radiometer (TEMPERA) at 60 GHz. The temperature profiles from TEMPERA are compared with independent in situ radiosonde measurements. The TEMPERA performance is also compared with that of a commercial microwave radiometer (HATPRO). In addition, the brightness temperatures from both microwave radiometers are compared with the ones simulated using a radiative transfer model, ARTS.
Klemens Hocke, Martin Lainer, Lorena Moreira, Jonas Hagen, Susana Fernandez Vidal, and Franziska Schranz
Ann. Geophys., 34, 781–788, https://doi.org/10.5194/angeo-34-781-2016, https://doi.org/10.5194/angeo-34-781-2016, 2016
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The dense horizontal sampling of atmospheric temperature profiles by the microwave limb sounder MLS on the NASA satellite AURA permit the estimation of global distributions of inertia-gravity waves (IGWs) in the middle atmosphere. We present and discuss the estimated global distributions of IGWs for July 2015 and January 2016. A dependence on the zonal wind distribution is obvious. The distributions of IGWs are a bit similar to the global distributions of small-scale gravity waves.
Lorena Moreira, Klemens Hocke, Francisco Navas-Guzmán, Ellen Eckert, Thomas von Clarmann, and Niklaus Kämpfer
Atmos. Chem. Phys., 16, 10455–10467, https://doi.org/10.5194/acp-16-10455-2016, https://doi.org/10.5194/acp-16-10455-2016, 2016
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The GROMOS radiometer in Bern has been part of the NDACC since 1994. Our time series of stratospheric ozone profiles allow the assessment of natural oscillations, which are essential for the evaluation of detected stratospheric ozone trends. Among our new findings are the link between the upper stratospheric O3-SAO and the polar stratopause warmings in winter. We have also detected a strong peak amplitude of 5 % related to the solar activity cycle and the ENSO effect in ozone at midlatitudes.
Susana Fernandez, Rolf Rüfenacht, Niklaus Kämpfer, Thierry Portafaix, Françoise Posny, and Guillaume Payen
Atmos. Chem. Phys., 16, 7531–7543, https://doi.org/10.5194/acp-16-7531-2016, https://doi.org/10.5194/acp-16-7531-2016, 2016
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We present a new ground based microwave radiometer for campaigns, GROMOS-C. It measures the vertical distribution of ozone in the middle atmosphere by observing spectra at 110.836 GHz. The paper presents a validation campaign that took place on La Réunion Island. The ozone retrieved profiles are validated against ozone profiles from the Microwave Limb Sounder, the ozone lidar located in the observatory, ozone profiles from weekly radiosondes and with ECMWF model data.
Rolf Rüfenacht, Klemens Hocke, and Niklaus Kämpfer
Atmos. Chem. Phys., 16, 4915–4925, https://doi.org/10.5194/acp-16-4915-2016, https://doi.org/10.5194/acp-16-4915-2016, 2016
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We quantitatively analyze oscillations with periods from 5 to 50 days in horizontal wind profiles between mid-stratosphere and mesopause based on more than 44 months of data from high, mid- and low latitudes measured by a novel instrument. For the first time, long time series of continuous wind measurements allow direct observations of dynamics throughout this altitude range. The observations agree remarkably well with the ECMWF model in the stratosphere but discrepancies exist in the mesosphere.
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
L. Moreira, K. Hocke, E. Eckert, T. von Clarmann, and N. Kämpfer
Atmos. Chem. Phys., 15, 10999–11009, https://doi.org/10.5194/acp-15-10999-2015, https://doi.org/10.5194/acp-15-10999-2015, 2015
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GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has provided ozone profiles for the NDACC (Network for the Detection of Atmospheric Composition Change) at Bern since 1994. We performed a trend analysis of our 20-year time series of stratospheric ozone profiles with a multilinear parametric trend estimation method. With our estimated ozone trends we are able to support the stratospheric ozone turnaround, besides a statistically significant negative trend in the lower mesosphere.
M. Lainer, N. Kämpfer, B. Tschanz, G. E. Nedoluha, S. Ka, and J. J. Oh
Atmos. Chem. Phys., 15, 9711–9730, https://doi.org/10.5194/acp-15-9711-2015, https://doi.org/10.5194/acp-15-9711-2015, 2015
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We use water vapor profiles from ground-based microwave radiometers at five locations distributed over the Northern Hemisphere and operated in the frame of NDACC (Network for the Detection of Atmospheric Composition Change) to generate hemispheric water vapor maps based on the so-called trajectory mapping technique. The novelty is to show that a mini network of instruments is capable of providing information about the hemispheric distribution of water vapor under most conditions.
S. Fernandez, A. Murk, and N. Kämpfer
Atmos. Meas. Tech., 8, 2649–2662, https://doi.org/10.5194/amt-8-2649-2015, https://doi.org/10.5194/amt-8-2649-2015, 2015
K. Hocke, M. Lainer, and A. Schanz
Ann. Geophys., 33, 783–788, https://doi.org/10.5194/angeo-33-783-2015, https://doi.org/10.5194/angeo-33-783-2015, 2015
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The composite analysis of major sudden stratospheric warmings (SSW) showed changes in atmospheric parameters at mid-latitudes about 1-2 months before the central date of the SSW. Polar ozone is enhanced during the half year after the SSW event.
B. Tschanz and N. Kämpfer
Atmos. Chem. Phys., 15, 5099–5108, https://doi.org/10.5194/acp-15-5099-2015, https://doi.org/10.5194/acp-15-5099-2015, 2015
F. Navas-Guzmán, N. Kämpfer, A. Murk, R. Larsson, S. A. Buehler, and P. Eriksson
Atmos. Meas. Tech., 8, 1863–1874, https://doi.org/10.5194/amt-8-1863-2015, https://doi.org/10.5194/amt-8-1863-2015, 2015
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In this work we study the Zeeman effect on stratospheric O2 using ground-based microwave radiometer measurements. The interaction of the Earth magnetic field with the oxygen dipole leads to a splitting of O2 energy states which polarizes the emission spectra. A special campaign was carried out in order to measure for the first time the polarization state of the radiation due to the Zeeman effect in the main isotopologue of oxygen from ground-based microwave measurements.
A. Schanz, K. Hocke, N. Kämpfer, S. Chabrillat, A. Inness, M. Palm, J. Notholt, I. Boyd, A. Parrish, and Y. Kasai
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acpd-14-32667-2014, https://doi.org/10.5194/acpd-14-32667-2014, 2014
Revised manuscript not accepted
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The manuscript describes novel findings in the diurnal variation of stratospheric ozone by means of the MACC reanalysis, the ERA-Interim reanalysis and the WACCM model. The diurnal variation in ozone has dynamical and photochemical origins which lead to substantial amplitudes especially in the polar, stratospheric regions. The unprecedented, global view on diurnal ozone variation strengthens the implication to correct diurnally sampled satellite observations used for ozone trend estimates.
R. Rüfenacht, A. Murk, N. Kämpfer, P. Eriksson, and S. A. Buehler
Atmos. Meas. Tech., 7, 4491–4505, https://doi.org/10.5194/amt-7-4491-2014, https://doi.org/10.5194/amt-7-4491-2014, 2014
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Only very few techniques for wind measurements in the upper stratosphere and lower mesosphere exist. Moreover, none of these instruments is running on a continuous basis. This paper describes the development of ground-based microwave Doppler radiometry. Time series of daily wind profile measurements from four different locations at polar, mid- and tropical latitudes are presented. The agreement with ECMWF model data is good in the stratosphere, but discrepancies were found in the mesosphere.
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
A. Schanz, K. Hocke, and N. Kämpfer
Atmos. Chem. Phys., 14, 7645–7663, https://doi.org/10.5194/acp-14-7645-2014, https://doi.org/10.5194/acp-14-7645-2014, 2014
D. Scheiben, B. Tschanz, K. Hocke, N. Kämpfer, S. Ka, and J. J. Oh
Atmos. Chem. Phys., 14, 6511–6522, https://doi.org/10.5194/acp-14-6511-2014, https://doi.org/10.5194/acp-14-6511-2014, 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
F. Navas-Guzmán, O. Stähli, and N. Kämpfer
Atmos. Meas. Tech., 7, 1619–1628, https://doi.org/10.5194/amt-7-1619-2014, https://doi.org/10.5194/amt-7-1619-2014, 2014
F. Cossu and K. Hocke
Geosci. Model Dev., 7, 147–160, https://doi.org/10.5194/gmd-7-147-2014, https://doi.org/10.5194/gmd-7-147-2014, 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
O. Stähli, A. Murk, N. Kämpfer, C. Mätzler, and P. Eriksson
Atmos. Meas. Tech., 6, 2477–2494, https://doi.org/10.5194/amt-6-2477-2013, https://doi.org/10.5194/amt-6-2477-2013, 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
D. Scheiben, A. Schanz, B. Tschanz, and N. Kämpfer
Atmos. Chem. Phys., 13, 6877–6886, https://doi.org/10.5194/acp-13-6877-2013, https://doi.org/10.5194/acp-13-6877-2013, 2013
B. Tschanz, C. Straub, D. Scheiben, K. A. Walker, G. P. Stiller, and N. Kämpfer
Atmos. Meas. Tech., 6, 1725–1745, https://doi.org/10.5194/amt-6-1725-2013, https://doi.org/10.5194/amt-6-1725-2013, 2013
S. Studer, K. Hocke, M. Pastel, S. Godin-Beekmann, and N. Kämpfer
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amtd-6-6097-2013, https://doi.org/10.5194/amtd-6-6097-2013, 2013
Revised manuscript has not been submitted
K. Hocke, S. Studer, O. Martius, D. Scheiben, and N. Kämpfer
Ann. Geophys., 31, 755–764, https://doi.org/10.5194/angeo-31-755-2013, https://doi.org/10.5194/angeo-31-755-2013, 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: Dynamics | Research Activity: Remote Sensing | Altitude Range: Stratosphere | Science Focus: Physics (physical properties and processes)
Observational perspective on sudden stratospheric warmings and blocking from Eliassen–Palm fluxes
Aeolus wind lidar observations of the 2019/2020 quasi-biennial oscillation disruption with comparison to radiosondes and reanalysis
Convective gravity wave events during summer near 54° N, present in both AIRS and Rayleigh–Mie–Raman (RMR) lidar observations
Signatures of the Madden–Julian oscillation in middle-atmosphere zonal mean temperature: triggering the interhemispheric coupling pattern
The quasi-biennial oscillation (QBO) and global-scale tropical waves in Aeolus wind observations, radiosonde data, and reanalyses
Vertical structure of the lower-stratospheric moist bias in the ERA5 reanalysis and its connection to mixing processes
Intermittency of gravity wave potential energies and absolute momentum fluxes derived from infrared limb sounding satellite observations
The evolution and dynamics of the Hunga Tonga–Hunga Ha'apai sulfate aerosol plume in the stratosphere
Stratospheric water vapour and ozone response to the quasi-biennial oscillation disruptions in 2016 and 2020
A new methodology for measuring traveling quasi-5-day oscillations during sudden stratospheric warming events based on satellite observations
The middle atmospheric meridional circulation for 2002–2012 derived from MIPAS observations
Stratospheric gravity waves over the mountainous island of South Georgia: testing a high-resolution dynamical model with 3-D satellite observations and radiosondes
Smoke-charged vortices in the stratosphere generated by wildfires and their behaviour in both hemispheres: comparing Australia 2020 to Canada 2017
Using a network of temperature lidars to identify temperature biases in the upper stratosphere in ECMWF reanalyses
Direct inversion of circulation from tracer measurements – Part 2: Sensitivity studies and model recovery tests
Record low ozone values over the Arctic in boreal spring 2020
New insights into Rossby wave packet properties in the extratropical UTLS using GNSS radio occultations
Superposition of gravity waves with different propagation characteristics observed by airborne and space-borne infrared sounders
Gravity waves in the winter stratosphere over the Southern Ocean: high-resolution satellite observations and 3-D spectral analysis
Comparison of equatorial wave activity in the tropical tropopause layer and stratosphere represented in reanalyses
Investigation of Arctic middle-atmospheric dynamics using 3 years of H2O and O3 measurements from microwave radiometers at Ny-Ålesund
Influence of ENSO and MJO on the zonal structure of tropical tropopause inversion layer using high-resolution temperature profiles retrieved from COSMIC GPS Radio Occultation
How well do stratospheric reanalyses reproduce high-resolution satellite temperature measurements?
First tomographic observations of gravity waves by the infrared limb imager GLORIA
Shift of subtropical transport barriers explains observed hemispheric asymmetry of decadal trends of age of air
Exploring gravity wave characteristics in 3-D using a novel S-transform technique: AIRS/Aqua measurements over the Southern Andes and Drake Passage
A decadal satellite record of gravity wave activity in the lower stratosphere to study polar stratospheric cloud formation
Evolution of the eastward shift in the quasi-stationary minimum of the Antarctic total ozone column
Tropical temperature variability and Kelvin-wave activity in the UTLS from GPS RO measurements
The major stratospheric final warming in 2016: dispersal of vortex air and termination of Arctic chemical ozone loss
The tropical tropopause inversion layer: variability and modulation by equatorial waves
Satellite observations of middle atmosphere gravity wave absolute momentum flux and of its vertical gradient during recent stratospheric warmings
Stratospheric gravity waves at Southern Hemisphere orographic hotspots: 2003–2014 AIRS/Aqua observations
Global temperature response to the major volcanic eruptions in multiple reanalysis data sets
Reassessment of MIPAS age of air trends and variability
Enhanced internal gravity wave activity and breaking over the northeastern Pacific–eastern Asian region
Global distributions of overlapping gravity waves in HIRDLS data
The southern stratospheric gravity wave hot spot: individual waves and their momentum fluxes measured by COSMIC GPS-RO
Methane as a diagnostic tracer of changes in the Brewer–Dobson circulation of the stratosphere
The influence of the North Atlantic Oscillation and El Niño–Southern Oscillation on mean and extreme values of column ozone over the United States
Short vertical-wavelength inertia-gravity waves generated by a jet–front system at Arctic latitudes – VHF radar, radiosondes and numerical modelling
A climatology of the diurnal variations in stratospheric and mesospheric ozone over Bern, Switzerland
Long-term changes in the upper stratospheric ozone at Syowa, Antarctica
Estimates of turbulent diffusivities and energy dissipation rates from satellite measurements of spectra of stratospheric refractivity perturbations
Observations of filamentary structures near the vortex edge in the Arctic winter lower stratosphere
Impact of land convection on temperature diurnal variation in the tropical lower stratosphere inferred from COSMIC GPS radio occultations
Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010
Variability in the speed of the Brewer–Dobson circulation as observed by Aura/MLS
Simultaneous occurrence of polar stratospheric clouds and upper-tropospheric clouds caused by blocking anticyclones in the Southern Hemisphere
Quantification of structural uncertainty in climate data records from GPS radio occultation
Kamilya Yessimbet, Andrea K. Steiner, Florian Ladstädter, and Albert Ossó
Atmos. Chem. Phys., 24, 10893–10919, https://doi.org/10.5194/acp-24-10893-2024, https://doi.org/10.5194/acp-24-10893-2024, 2024
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Major sudden stratospheric warmings (SSWs) and atmospheric blocking can markedly influence winter extratropical surface weather. To study the relationship between SSWs and blocking, we examine dynamic stratosphere–troposphere coupling using vertically highly resolved observations from global navigation satellite system radio occultation for 2007–2019. Our results provide a purely observational view of the evolution of major SSWs, their link to blocking, and their effect on the polar tropopause.
Timothy P. Banyard, Corwin J. Wright, Scott M. Osprey, Neil P. Hindley, Gemma Halloran, Lawrence Coy, Paul A. Newman, Neal Butchart, Martina Bramberger, and M. Joan Alexander
Atmos. Chem. Phys., 24, 2465–2490, https://doi.org/10.5194/acp-24-2465-2024, https://doi.org/10.5194/acp-24-2465-2024, 2024
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In 2019/2020, the tropical stratospheric wind phenomenon known as the quasi-biennial oscillation (QBO) was disrupted for only the second time in the historical record. This was poorly forecasted, and we want to understand why. We used measurements from the first Doppler wind lidar in space, Aeolus, to observe the disruption in an unprecedented way. Our results reveal important differences between Aeolus and the ERA5 reanalysis that affect the timing of the disruption's onset and its evolution.
Eframir Franco-Diaz, Michael Gerding, Laura Holt, Irina Strelnikova, Robin Wing, Gerd Baumgarten, and Franz-Josef Lübken
Atmos. Chem. Phys., 24, 1543–1558, https://doi.org/10.5194/acp-24-1543-2024, https://doi.org/10.5194/acp-24-1543-2024, 2024
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We use satellite, lidar, and ECMWF data to study storm-related waves that propagate above Kühlungsborn, Germany, during summer. Although these events occur in roughly half of the years of the satellite data we analyzed, we focus our study on two case study years (2014 and 2015). These events could contribute significantly to middle atmospheric circulation and are not accounted for in weather and climate models.
Christoph G. Hoffmann, Lena G. Buth, and Christian von Savigny
Atmos. Chem. Phys., 23, 12781–12799, https://doi.org/10.5194/acp-23-12781-2023, https://doi.org/10.5194/acp-23-12781-2023, 2023
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The Madden–Julian oscillation is an important feature of weather in the tropics. Although it is mainly active in the troposphere, we show that it systematically influences the air temperature in the layers above, up to about 100 km altitude and from pole to pole. We have linked this to another known far-reaching process, interhemispheric coupling. This is basic research on atmospheric couplings and variability but might also be of interest for intraseasonal weather forecasting models.
Manfred Ern, Mohamadou A. Diallo, Dina Khordakova, Isabell Krisch, Peter Preusse, Oliver Reitebuch, Jörn Ungermann, and Martin Riese
Atmos. Chem. Phys., 23, 9549–9583, https://doi.org/10.5194/acp-23-9549-2023, https://doi.org/10.5194/acp-23-9549-2023, 2023
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Quasi-biennial oscillation (QBO) of the stratospheric tropical winds is an important mode of climate variability but is not well reproduced in free-running climate models. We use the novel global wind observations by the Aeolus satellite and radiosondes to show that the QBO is captured well in three modern reanalyses (ERA-5, JRA-55, and MERRA-2). Good agreement is also found also between Aeolus and reanalyses for large-scale tropical wave modes in the upper troposphere and lower stratosphere.
Konstantin Krüger, Andreas Schäfler, Martin Wirth, Martin Weissmann, and George C. Craig
Atmos. Chem. Phys., 22, 15559–15577, https://doi.org/10.5194/acp-22-15559-2022, https://doi.org/10.5194/acp-22-15559-2022, 2022
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A comprehensive data set of airborne lidar water vapour profiles is compared with ERA5 reanalyses for a robust characterization of the vertical structure of the mid-latitude lower-stratospheric moist bias. We confirm a moist bias of up to 55 % at 1.3 km altitude above the tropopause and uncover a decreasing bias beyond. Collocated O3 and H2O observations reveal a particularly strong bias in the mixing layer, indicating insufficiently modelled transport processes fostering the bias.
Manfred Ern, Peter Preusse, and Martin Riese
Atmos. Chem. Phys., 22, 15093–15133, https://doi.org/10.5194/acp-22-15093-2022, https://doi.org/10.5194/acp-22-15093-2022, 2022
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Based on data from the HIRDLS and SABER infrared limb sounding satellite instruments, we investigate the intermittency of global distributions of gravity wave (GW) potential energies and GW momentum fluxes in the stratosphere and mesosphere using probability distribution functions (PDFs) and Gini coefficients. We compare GW intermittency in different regions, seasons, and altitudes. These results can help to improve GW parameterizations and the distributions of GWs resolved in models.
Bernard Legras, Clair Duchamp, Pasquale Sellitto, Aurélien Podglajen, Elisa Carboni, Richard Siddans, Jens-Uwe Grooß, Sergey Khaykin, and Felix Ploeger
Atmos. Chem. Phys., 22, 14957–14970, https://doi.org/10.5194/acp-22-14957-2022, https://doi.org/10.5194/acp-22-14957-2022, 2022
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The long-duration atmospheric impact of the Tonga eruption in January 2022 is a plume of water and sulfate aerosols in the stratosphere that persisted for more than 6 months. We study this evolution using several satellite instruments and analyse the unusual behaviour of this plume as sulfates and water first moved down rapidly and then separated into two layers. We also report the self-organization in compact and long-lived patches.
Mohamadou A. Diallo, Felix Ploeger, Michaela I. Hegglin, Manfred Ern, Jens-Uwe Grooß, Sergey Khaykin, and Martin Riese
Atmos. Chem. Phys., 22, 14303–14321, https://doi.org/10.5194/acp-22-14303-2022, https://doi.org/10.5194/acp-22-14303-2022, 2022
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The quasi-biennial oacillation disruption events in both 2016 and 2020 decreased lower-stratospheric water vapour and ozone. Differences in the strength and depth of the anomalous lower-stratospheric circulation and ozone are due to differences in tropical upwelling and cold-point temperature induced by lower-stratospheric planetary and gravity wave breaking. The differences in water vapour are due to higher cold-point temperature in 2020 induced by Australian wildfire.
Zheng Ma, Yun Gong, Shaodong Zhang, Qiao Xiao, Chunming Huang, and Kaiming Huang
Atmos. Chem. Phys., 22, 13725–13737, https://doi.org/10.5194/acp-22-13725-2022, https://doi.org/10.5194/acp-22-13725-2022, 2022
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We present a novel method to measure the amplitudes of traveling quasi-5-day oscillations (Q5DOs) in the middle atmosphere during sudden stratospheric warming events based on satellite observations. Simulations and observations demonstrate that the previously reported traveling Q5DOs might be contaminated by stationary planetary waves (SPWs). The new fitting method is developed by inhibiting the effect of a rapid and large change in SPWs.
Thomas von Clarmann, Udo Grabowski, Gabriele P. Stiller, Beatriz M. Monge-Sanz, Norbert Glatthor, and Sylvia Kellmann
Atmos. Chem. Phys., 21, 8823–8843, https://doi.org/10.5194/acp-21-8823-2021, https://doi.org/10.5194/acp-21-8823-2021, 2021
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Measurements of long-lived trace gases (SF6, CFC-11, CFC-12, HCFC-12, CCl4, N2O, CH4, H2O, and CO) performed with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have been used to infer the stratospheric and mesospheric meridional circulation. The MIPAS data set covers the time period from July 2002 to April 2012. The method used for this purpose was the direct inversion of the two-dimensional continuity equation. Multiannual monthly mean circulation fields are presented.
Neil P. Hindley, Corwin J. Wright, Alan M. Gadian, Lars Hoffmann, John K. Hughes, David R. Jackson, John C. King, Nicholas J. Mitchell, Tracy Moffat-Griffin, Andrew C. Moss, Simon B. Vosper, and Andrew N. Ross
Atmos. Chem. Phys., 21, 7695–7722, https://doi.org/10.5194/acp-21-7695-2021, https://doi.org/10.5194/acp-21-7695-2021, 2021
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One limitation of numerical atmospheric models is spatial resolution. For atmospheric gravity waves (GWs) generated over small mountainous islands, the driving effect of these waves on atmospheric circulations can be underestimated. Here we use a specialised high-resolution model over South Georgia island to compare simulated stratospheric GWs to colocated 3-D satellite observations. We find reasonable model agreement with observations, with some GW amplitudes much larger than expected.
Hugo Lestrelin, Bernard Legras, Aurélien Podglajen, and Mikail Salihoglu
Atmos. Chem. Phys., 21, 7113–7134, https://doi.org/10.5194/acp-21-7113-2021, https://doi.org/10.5194/acp-21-7113-2021, 2021
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Following the 2020 Australian fires, it was recently discovered that stratospheric wildfire smoke plumes self-organize as anticyclonic vortices that persist for months and rise by 10 km due to the radiative heating from the absorbing smoke. In this study, we show that smoke-charged vortices previously occurred in the aftermath of the 2017 Canadian fires. We use meteorological analysis to characterize this new object in geophysical fluid dynamics, which likely impacts radiation and climate.
Graeme Marlton, Andrew Charlton-Perez, Giles Harrison, Inna Polichtchouk, Alain Hauchecorne, Philippe Keckhut, Robin Wing, Thierry Leblanc, and Wolfgang Steinbrecht
Atmos. Chem. Phys., 21, 6079–6092, https://doi.org/10.5194/acp-21-6079-2021, https://doi.org/10.5194/acp-21-6079-2021, 2021
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A network of Rayleigh lidars have been used to infer the upper-stratosphere temperature bias in ECMWF ERA-5 and ERA-Interim reanalyses during 1990–2017. Results show that ERA-Interim exhibits a cold bias of −3 to −4 K between 10 and 1 hPa. Comparisons with ERA-5 found a smaller bias of 1 K which varies between cold and warm between 10 and 3 hPa, indicating a good thermal representation of the atmosphere to 3 hPa. These biases must be accounted for in stratospheric studies using these reanalyses.
Thomas von Clarmann and Udo Grabowski
Atmos. Chem. Phys., 21, 2509–2526, https://doi.org/10.5194/acp-21-2509-2021, https://doi.org/10.5194/acp-21-2509-2021, 2021
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The direct inversion of the 2D continuity equation allows us to infer the effective meridional transport velocity of trace gases in the middle stratosphere. This method exploits the information both given by the displacement of patterns in measured trace gas distributions and by the approximate balance between sinks and horizontal as well as vertical advection. The robustness of this method has been tested and characterized using model recovery tests and sensitivity studies.
Martin Dameris, Diego G. Loyola, Matthias Nützel, Melanie Coldewey-Egbers, Christophe Lerot, Fabian Romahn, and Michel van Roozendael
Atmos. Chem. Phys., 21, 617–633, https://doi.org/10.5194/acp-21-617-2021, https://doi.org/10.5194/acp-21-617-2021, 2021
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Record low ozone values were observed in March 2020. Dynamical and chemical circumstances leading to low ozone values in spring 2020 are discussed and are compared to similar dynamical conditions in the Northern Hemisphere in 1996/1997 and 2010/2011. 2019/2020 showed an unusual persistent polar vortex with low stratospheric temperatures, which were permanently below 195 K at 50 hPa. This enabled enhanced formation of polar stratospheric clouds and a subsequent clear reduction of total ozone.
Robin Pilch Kedzierski, Katja Matthes, and Karl Bumke
Atmos. Chem. Phys., 20, 11569–11592, https://doi.org/10.5194/acp-20-11569-2020, https://doi.org/10.5194/acp-20-11569-2020, 2020
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Rossby wave packet (RWP) dynamics are crucial for weather forecasting, climate change projections and stratosphere–troposphere interactions. Our study is a first attempt to describe RWP behavior in the UTLS with global coverage directly from observations, using GNSS-RO data. Our novel results show an interesting relation of RWP vertical propagation with sudden stratospheric warmings and provide very useful information to improve RWP diagnostics in models and reanalysis.
Isabell Krisch, Manfred Ern, Lars Hoffmann, Peter Preusse, Cornelia Strube, Jörn Ungermann, Wolfgang Woiwode, and Martin Riese
Atmos. Chem. Phys., 20, 11469–11490, https://doi.org/10.5194/acp-20-11469-2020, https://doi.org/10.5194/acp-20-11469-2020, 2020
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In 2016, a scientific research flight above Scandinavia acquired various atmospheric data (temperature, gas composition, etc.). Through advanced 3-D reconstruction methods, a superposition of multiple gravity waves was identified. An in-depth analysis enabled the characterisation of these waves as well as the identification of their sources. This work will enable a better understanding of atmosphere dynamics and could lead to improved climate projections.
Neil P. Hindley, Corwin J. Wright, Nathan D. Smith, Lars Hoffmann, Laura A. Holt, M. Joan Alexander, Tracy Moffat-Griffin, and Nicholas J. Mitchell
Atmos. Chem. Phys., 19, 15377–15414, https://doi.org/10.5194/acp-19-15377-2019, https://doi.org/10.5194/acp-19-15377-2019, 2019
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In this study, a 3–D Stockwell transform is applied to AIRS–Aqua satellite observations in the first extended 3–D study of stratospheric gravity waves over the Southern Ocean during winter. A dynamic environment is revealed that contains some of the most intense gravity wave sources on Earth. A particularly striking result is a large–scale meridional convergence of gravity wave momentum flux towards latitudes near 60 °S, something which is not normally considered in model parameterisations.
Young-Ha Kim, George N. Kiladis, John R. Albers, Juliana Dias, Masatomo Fujiwara, James A. Anstey, In-Sun Song, Corwin J. Wright, Yoshio Kawatani, François Lott, and Changhyun Yoo
Atmos. Chem. Phys., 19, 10027–10050, https://doi.org/10.5194/acp-19-10027-2019, https://doi.org/10.5194/acp-19-10027-2019, 2019
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Reanalyses are widely used products of meteorological variables, generated using observational data and assimilation systems. We compare six modern reanalyses, with focus on their representation of equatorial waves which are important in stratospheric variability and stratosphere–troposphere exchange. Agreement/spreads among the reanalyses in the spectral properties and spatial distributions of the waves are examined, and satellite impacts on the wave representation in reanalyses are discussed.
Franziska Schranz, Brigitte Tschanz, Rolf Rüfenacht, Klemens Hocke, Mathias Palm, and Niklaus Kämpfer
Atmos. Chem. Phys., 19, 9927–9947, https://doi.org/10.5194/acp-19-9927-2019, https://doi.org/10.5194/acp-19-9927-2019, 2019
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The dynamics of the Arctic middle atmosphere above Ny-Ålesund, Svalbard (79° N, 12° E) is investigated using 3 years of H2O and O3 measurements from ground-based microwave radiometers. We found the signals of atmospheric phenomena like sudden stratospheric warmings, polar vortex shifts, effective descent rates of water vapour and periodicities in our data. Additionally, a comprehensive intercomparison is performed with models and measurements from ground-based, in situ and satellite instruments.
Noersomadi, Toshitaka Tsuda, and Masatomo Fujiwara
Atmos. Chem. Phys., 19, 6985–7000, https://doi.org/10.5194/acp-19-6985-2019, https://doi.org/10.5194/acp-19-6985-2019, 2019
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Characteristics of static stability (N2) in the tropical tropopause are analyzed using 0.1 km vertical resolution temperature profiles retrieved from COSMIC GNSS-RO. We define the tropopause inversion layer (TIL) by the sharp increase in N2 across the cold point tropopause (CPT) and the thickness of the enhanced peak in N2 just above the CPT. We investigated the TIL at the intraseasonal to interannual timescales above the Maritime Continent and Pacific Ocean with different land–sea distribution.
Corwin J. Wright and Neil P. Hindley
Atmos. Chem. Phys., 18, 13703–13731, https://doi.org/10.5194/acp-18-13703-2018, https://doi.org/10.5194/acp-18-13703-2018, 2018
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Reanalyses (RAs) are models which assimilate observations and are widely used as proxies for the true atmospheric state. Here, we resample six leading RAs using the weighting functions of four high-res satellite instruments, allowing a like-for-like comparison. We find that the RAs generally reproduce the satellite data well, except at high altitudes and in the tropics. However, we also find that the RAs more tightly correlate with each other than with observations, even those they assimilate.
Isabell Krisch, Peter Preusse, Jörn Ungermann, Andreas Dörnbrack, Stephen D. Eckermann, Manfred Ern, Felix Friedl-Vallon, Martin Kaufmann, Hermann Oelhaf, Markus Rapp, Cornelia Strube, and Martin Riese
Atmos. Chem. Phys., 17, 14937–14953, https://doi.org/10.5194/acp-17-14937-2017, https://doi.org/10.5194/acp-17-14937-2017, 2017
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Using the infrared limb imager GLORIA, the 3-D structure of mesoscale gravity waves in the lower stratosphere was measured for the first time, allowing for a complete 3-D characterization of the waves. This enables the precise determination of the sources of the waves in the mountain regions of Iceland with backward ray tracing. Forward ray tracing shows oblique propagation, an effect generally neglected in global atmospheric models.
Gabriele P. Stiller, Federico Fierli, Felix Ploeger, Chiara Cagnazzo, Bernd Funke, Florian J. Haenel, Thomas Reddmann, Martin Riese, and Thomas von Clarmann
Atmos. Chem. Phys., 17, 11177–11192, https://doi.org/10.5194/acp-17-11177-2017, https://doi.org/10.5194/acp-17-11177-2017, 2017
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The discrepancy between modelled and observed 25-year trends of the strength of the stratospheric Brewer–Dobson circulation (BDC) is still not resolved. With our paper we trace the observed hemispheric dipole structure of age of air trends back to natural variability in shorter-term (decadal) time frames. Beyond this we demonstrate that after correction for the decadal natural variability the remaining trend for the first decade of the 21st century is consistent with model simulations.
Corwin J. Wright, Neil P. Hindley, Lars Hoffmann, M. Joan Alexander, and Nicholas J. Mitchell
Atmos. Chem. Phys., 17, 8553–8575, https://doi.org/10.5194/acp-17-8553-2017, https://doi.org/10.5194/acp-17-8553-2017, 2017
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We introduce a novel 3-D method of measuring atmospheric gravity waves, based around a 3-D Stockwell transform. Our method lets us measure new properties, including wave intrinsic frequencies and phase and group velocities. We apply it to data from the AIRS satellite instrument over the Southern Andes for two consecutive winters. Our results show clear evidence that the waves measured are primarily orographic in origin, and that their group velocity vectors are focused into the polar night jet.
Lars Hoffmann, Reinhold Spang, Andrew Orr, M. Joan Alexander, Laura A. Holt, and Olaf Stein
Atmos. Chem. Phys., 17, 2901–2920, https://doi.org/10.5194/acp-17-2901-2017, https://doi.org/10.5194/acp-17-2901-2017, 2017
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We introduce a 10-year record (2003–2012) of AIRS/Aqua observations of gravity waves in the polar lower stratosphere. The data set was optimized to study the impact of gravity waves on the formation of polar stratospheric clouds (PSCs). We discuss the temporal and spatial patterns of gravity wave activity, validate explicitly resolved small-scale temperature fluctuations in the ECMWF data, and present a survey of gravity-wave-induced PSC formation events using joint AIRS and MIPAS observations.
Asen Grytsai, Andrew Klekociuk, Gennadi Milinevsky, Oleksandr Evtushevsky, and Kane Stone
Atmos. Chem. Phys., 17, 1741–1758, https://doi.org/10.5194/acp-17-1741-2017, https://doi.org/10.5194/acp-17-1741-2017, 2017
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Twenty years ago we discovered that the ozone hole shape is asymmetric. This asymmetry is minimum over the Weddell Sea region and maximum over the Ross Sea area. Later we detected that the position of the ozone minimum is shifting east. We have continued to follow this event, and a couple years ago we revealed that the shift is slowing down and starting to move back. We connect all this movement with ozone hole increase; since 2000 the ozone layer has been stabilizing and recently recovering.
Barbara Scherllin-Pirscher, William J. Randel, and Joowan Kim
Atmos. Chem. Phys., 17, 793–806, https://doi.org/10.5194/acp-17-793-2017, https://doi.org/10.5194/acp-17-793-2017, 2017
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Tropical temperature variability and associated Kelvin-wave activity are investigated from 10 km to 30 km using 13 years of high-resolution observational data. Strongest temperature variability is found in the tropical tropopause region between about 16 km and 20 km, where peaks of Kelvin-wave activity are irregularly distributed in time. Detailed knowledge of dynamical processes in the tropical tropopause region is an essential part of better understanding climate variability and change.
Gloria L. Manney and Zachary D. Lawrence
Atmos. Chem. Phys., 16, 15371–15396, https://doi.org/10.5194/acp-16-15371-2016, https://doi.org/10.5194/acp-16-15371-2016, 2016
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The 2015/16 Arctic winter stratosphere was the coldest on record through late February, raising the possibility of extensive chemical ozone loss. However, a major final sudden stratospheric warming in early March curtailed ozone destruction. We used Aura MLS satellite trace gas data and MERRA-2 meteorological data to show the details of transport, mixing, and dispersal of chemically processed air during the major final warming, and how these processes limited Arctic chemical ozone loss.
Robin Pilch Kedzierski, Katja Matthes, and Karl Bumke
Atmos. Chem. Phys., 16, 11617–11633, https://doi.org/10.5194/acp-16-11617-2016, https://doi.org/10.5194/acp-16-11617-2016, 2016
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This study provides a detailed overview of the daily variability of the tropopause inversion layer (TIL) in the tropics, where TIL research had focused little. The vertical and horizontal structures of this atmospheric layer are described and linked to near-tropopause horizontal wind divergence, the QBO and especially to equatorial waves. Our results increase the knowledge about the observed properties of the tropical TIL, mainly using satellite GPS radio-occultation measurements.
Manfred Ern, Quang Thai Trinh, Martin Kaufmann, Isabell Krisch, Peter Preusse, Jörn Ungermann, Yajun Zhu, John C. Gille, Martin G. Mlynczak, James M. Russell III, Michael J. Schwartz, and Martin Riese
Atmos. Chem. Phys., 16, 9983–10019, https://doi.org/10.5194/acp-16-9983-2016, https://doi.org/10.5194/acp-16-9983-2016, 2016
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Sudden stratospheric warmings (SSWs) influence the atmospheric circulation over a large range of altitudes and latitudes. We investigate the global distribution of small-scale gravity waves (GWs) during SSWs as derived from 13 years of satellite observations.
We find that GWs may play an important role for triggering SSWs by preconditioning the polar vortex, as well as during long-lasting vortex recovery phases after SSWs. The GW distribution during SSWs displays strong day-to-day variability.
Lars Hoffmann, Alison W. Grimsdell, and M. Joan Alexander
Atmos. Chem. Phys., 16, 9381–9397, https://doi.org/10.5194/acp-16-9381-2016, https://doi.org/10.5194/acp-16-9381-2016, 2016
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We present a 12-year record (2003-2014) of stratospheric gravity wave activity at Southern Hemisphere orographic hotspots as observed by the AIRS/Aqua satellite instrument. We introduce a method to discriminate between gravity waves from orographic or other sources and propose a simple model to predict the occurrence of mountain waves using zonal wind thresholds. The prediction model can help to disentangle upper level wind effects from low level source and other influences.
M. Fujiwara, T. Hibino, S. K. Mehta, L. Gray, D. Mitchell, and J. Anstey
Atmos. Chem. Phys., 15, 13507–13518, https://doi.org/10.5194/acp-15-13507-2015, https://doi.org/10.5194/acp-15-13507-2015, 2015
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This paper evaluates the temperature response in the troposphere and the stratosphere to the three major volcanic eruptions between the 1960s and the 1990s by comparing nine reanalysis data sets. It was found that the volcanic temperature response patterns differ among the major eruptions and that in general, more recent reanalysis data sets show a more consistent response pattern.
F. J. Haenel, G. P. Stiller, T. von Clarmann, B. Funke, E. Eckert, N. Glatthor, U. Grabowski, S. Kellmann, M. Kiefer, A. Linden, and T. Reddmann
Atmos. Chem. Phys., 15, 13161–13176, https://doi.org/10.5194/acp-15-13161-2015, https://doi.org/10.5194/acp-15-13161-2015, 2015
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Stratospheric circulation is thought to change as a consequence of climate change. Empirical evidence, however, is sparse. In this paper we present latitude- and altitude-resolved trends of the mean age of stratospheric air as derived from SF6 measurements performed by the MIPAS satellite instrument. The mean of the age of stratospheric air is a measure of the intensity of the Brewer-Dobson circulation. In this paper we discuss differences with respect to a preceding analysis by Stiller et al.
P. Šácha, A. Kuchař, C. Jacobi, and P. Pišoft
Atmos. Chem. Phys., 15, 13097–13112, https://doi.org/10.5194/acp-15-13097-2015, https://doi.org/10.5194/acp-15-13097-2015, 2015
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In this study, we present a discovery of an internal gravity wave activity and breaking hotspot collocated with an area of anomalously low annual cycle amplitude and specific dynamics in the stratosphere over the Northeastern Pacific/Eastern Asia coastal region. The reasons why this particular IGW activity hotspot was not discovered before nor the specific dynamics of this region pointed out are discussed together with possible consequences on the middle atmospheric dynamics and transport.
C. J. Wright, S. M. Osprey, and J. C. Gille
Atmos. Chem. Phys., 15, 8459–8477, https://doi.org/10.5194/acp-15-8459-2015, https://doi.org/10.5194/acp-15-8459-2015, 2015
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Data from the HIRDLS instrument are used to study the numerical variability of gravity waves. Observed distributions are dominated by long-vertical-short-horizontal-wavelength waves, with a similar spectral form at all locations. We further divide our data into subspecies by wavelength, and investigate variation in these subspecies in time and space. We show that the variations associated with particular phenomena arise due to changes in specific parts of the spectrum.
N. P. Hindley, C. J. Wright, N. D. Smith, and N. J. Mitchell
Atmos. Chem. Phys., 15, 7797–7818, https://doi.org/10.5194/acp-15-7797-2015, https://doi.org/10.5194/acp-15-7797-2015, 2015
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In nearly all GCMs, unresolved gravity wave (GW) drag may cause the southern stratospheric winter polar vortex to break down too late. Here, we characterise GWs in this region of the atmosphere using GPS radio occultation. We find GWs may propagate into the region from other latitudes. We develop a new quantitative wave identification method to learn about regional wave populations. We also find intense GW momentum fluxes over the southern Andes and Antarctic Peninsula GW hot spot.
E. E. Remsberg
Atmos. Chem. Phys., 15, 3739–3754, https://doi.org/10.5194/acp-15-3739-2015, https://doi.org/10.5194/acp-15-3739-2015, 2015
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Time series of the satellite-observed stratospheric tracer, CH4, are analyzed to see whether they indicate a significant trend for the hemispheric Brewer--Dobson circulation (BDC) for 1992-2005. Trends in CH4 for the lower stratosphere are generally positive and equivalent to those of the troposphere. However, the Northern Hemisphere BDC is clearly accelerated in the mid-stratosphere (20 to 7hPa). Corresponding trends for the Southern Hemisphere are smaller and less significant.
I. Petropavlovskikh, R. Evans, G. McConville, G. L. Manney, and H. E. Rieder
Atmos. Chem. Phys., 15, 1585–1598, https://doi.org/10.5194/acp-15-1585-2015, https://doi.org/10.5194/acp-15-1585-2015, 2015
A. Réchou, S. Kirkwood, J. Arnault, and P. Dalin
Atmos. Chem. Phys., 14, 6785–6799, https://doi.org/10.5194/acp-14-6785-2014, https://doi.org/10.5194/acp-14-6785-2014, 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
K. Miyagawa, I. Petropavlovskikh, R. D. Evans, C. Long, J. Wild, G. L. Manney, and W. H. Daffer
Atmos. Chem. Phys., 14, 3945–3968, https://doi.org/10.5194/acp-14-3945-2014, https://doi.org/10.5194/acp-14-3945-2014, 2014
N. M. Gavrilov
Atmos. Chem. Phys., 13, 12107–12116, https://doi.org/10.5194/acp-13-12107-2013, https://doi.org/10.5194/acp-13-12107-2013, 2013
C. Kalicinsky, J.-U. Grooß, G. Günther, J. Ungermann, J. Blank, S. Höfer, L. Hoffmann, P. Knieling, F. Olschewski, R. Spang, F. Stroh, and M. Riese
Atmos. Chem. Phys., 13, 10859–10871, https://doi.org/10.5194/acp-13-10859-2013, https://doi.org/10.5194/acp-13-10859-2013, 2013
S. M. Khaykin, J.-P. Pommereau, and A. Hauchecorne
Atmos. Chem. Phys., 13, 6391–6402, https://doi.org/10.5194/acp-13-6391-2013, https://doi.org/10.5194/acp-13-6391-2013, 2013
P. Baron, D. P. Murtagh, J. Urban, H. Sagawa, S. Ochiai, Y. Kasai, K. Kikuchi, F. Khosrawi, H. Körnich, S. Mizobuchi, K. Sagi, and M. Yasui
Atmos. Chem. Phys., 13, 6049–6064, https://doi.org/10.5194/acp-13-6049-2013, https://doi.org/10.5194/acp-13-6049-2013, 2013
T. Flury, D. L. Wu, and W. G. Read
Atmos. Chem. Phys., 13, 4563–4575, https://doi.org/10.5194/acp-13-4563-2013, https://doi.org/10.5194/acp-13-4563-2013, 2013
M. Kohma and K. Sato
Atmos. Chem. Phys., 13, 3849–3864, https://doi.org/10.5194/acp-13-3849-2013, https://doi.org/10.5194/acp-13-3849-2013, 2013
A. K. Steiner, D. Hunt, S.-P. Ho, G. Kirchengast, A. J. Mannucci, B. Scherllin-Pirscher, H. Gleisner, A. von Engeln, T. Schmidt, C. Ao, S. S. Leroy, E. R. Kursinski, U. Foelsche, M. Gorbunov, S. Heise, Y.-H. Kuo, K. B. Lauritsen, C. Marquardt, C. Rocken, W. Schreiner, S. Sokolovskiy, S. Syndergaard, and J. Wickert
Atmos. Chem. Phys., 13, 1469–1484, https://doi.org/10.5194/acp-13-1469-2013, https://doi.org/10.5194/acp-13-1469-2013, 2013
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Short summary
The middle atmosphere (30 to 70 km altitude) is stratified and, despite very strong horizontal winds, there is less mixing between the horizontal layers. An important driver for the energy exchange between the layers in this regime is atmospheric tides, which are waves that are driven by the diurnal cycle of solar heating. We measure these tides in the wind field for the first time using a ground-based passive instrument. Ultimately, such measurements could be used to improve atmospheric models.
The middle atmosphere (30 to 70 km altitude) is stratified and, despite very strong horizontal...
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