Articles | Volume 25, issue 2
https://doi.org/10.5194/acp-25-1227-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-25-1227-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
29 Jan 2025
Research article |
| 29 Jan 2025
| 29 Jan 2025
Long-term changes in the thermodynamic structure of the lowermost stratosphere inferred from reanalysis data
Franziska Weyland
CORRESPONDING AUTHOR
Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Mainz, Germany
Peter Hoor
Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Mainz, Germany
Daniel Kunkel
Institute for Atmospheric Physics, Johannes Gutenberg University Mainz, Mainz, Germany
Thomas Birner
Meteorological Institute, Ludwig-Maximilians-Universität München, Munich, Germany
Institute for Physics of the Atmosphere, Deutsches Zentrum für Luft- und Raumfahrt, Oberpfaffenhofen, Germany
Felix Plöger
Institute of Climate and Energy Systems, Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, Germany
Institute for Atmospheric and Environmental Research, University of Wuppertal, Wuppertal, Germany
Katharina Turhal
Institute of Climate and Energy Systems, Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, Germany
Institute for Atmospheric and Environmental Research, University of Wuppertal, Wuppertal, Germany
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Rasul Baikhadzhaev, Felix Ploeger, Peter Preusse, Manfred Ern, and Thomas Birner
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Chun Hang Chau, Peter Hoor, and Holger Tost
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Katharina Turhal, Felix Plöger, Jan Clemens, Thomas Birner, Franziska Weyland, Paul Konopka, and Peter Hoor
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Philip Rupp, Jonas Spaeth, Hilla Afargan-Gerstman, Dominik Büeler, Michael Sprenger, and Thomas Birner
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Philipp Joppe, Johannes Schneider, Katharina Kaiser, Horst Fischer, Peter Hoor, Daniel Kunkel, Hans-Christoph Lachnitt, Andreas Marsing, Lenard Röder, Hans Schlager, Laura Tomsche, Christiane Voigt, Andreas Zahn, and Stephan Borrmann
Atmos. Chem. Phys., 24, 7499–7522, https://doi.org/10.5194/acp-24-7499-2024, https://doi.org/10.5194/acp-24-7499-2024, 2024
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Cristina Peña-Ortiz, Nuria Pilar Plaza, David Gallego, and Felix Ploeger
Atmos. Chem. Phys., 24, 5457–5478, https://doi.org/10.5194/acp-24-5457-2024, https://doi.org/10.5194/acp-24-5457-2024, 2024
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Although water vapour (H2O) in the lower stratosphere is only a few molecules among 1 million air molecules, atmospheric radiative forcing and surface temperature are sensitive to changes in its concentration. Monsoon regions play a key role in H2O transport and its concentration in the lower stratosphere. We show how the quasi-biennial oscillation (QBO) has a major impact on H2O over the Asian monsoon during August through changes in temperature caused by QBO modulation of tropical clouds.
Martin Ebert, Ralf Weigel, Stephan Weinbruch, Lisa Schneider, Konrad Kandler, Stefan Lauterbach, Franziska Köllner, Felix Plöger, Gebhard Günther, Bärbel Vogel, and Stephan Borrmann
Atmos. Chem. Phys., 24, 4771–4788, https://doi.org/10.5194/acp-24-4771-2024, https://doi.org/10.5194/acp-24-4771-2024, 2024
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Particles were collected during the flight campaign StratoClim 2017 within the Asian tropopause aerosol layer (ATAL). Refractory particles from seven different flights were characterized by scanning and transmission electron microscopy (SEM, TEM). The most abundant refractory particles are silicates and non-volatile organics. The most important sources are combustion processes at the ground and the agitation of soil material. During one flight, small cinnabar particles (HgS) were also detected.
Felix Ploeger, Thomas Birner, Edward Charlesworth, Paul Konopka, and Rolf Müller
Atmos. Chem. Phys., 24, 2033–2043, https://doi.org/10.5194/acp-24-2033-2024, https://doi.org/10.5194/acp-24-2033-2024, 2024
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We present a novel mechanism of how regional anomalies in water vapour concentrations in the upper troposphere and lower stratosphere impact regional atmospheric circulation systems. These impacts include a displaced upper-level Asian monsoon circulation and strengthened prevailing westerlies in the Pacific region. Current climate models have biases in simulating these regional water vapour anomalies and circulation impacts, but the biases can be avoided by improving the model transport.
Jan Clemens, Bärbel Vogel, Lars Hoffmann, Sabine Griessbach, Nicole Thomas, Suvarna Fadnavis, Rolf Müller, Thomas Peter, and Felix Ploeger
Atmos. Chem. Phys., 24, 763–787, https://doi.org/10.5194/acp-24-763-2024, https://doi.org/10.5194/acp-24-763-2024, 2024
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The source regions of the Asian tropopause aerosol layer (ATAL) are debated. We use balloon-borne measurements of the layer above Nainital (India) in August 2016 and atmospheric transport models to find ATAL source regions. Most air originated from the Tibetan plateau. However, the measured ATAL was stronger when more air originated from the Indo-Gangetic Plain and weaker when more air originated from the Pacific. Hence, the results indicate important anthropogenic contributions to the ATAL.
Tanja J. Schuck, Johannes Degen, Eric Hintsa, Peter Hoor, Markus Jesswein, Timo Keber, Daniel Kunkel, Fred Moore, Florian Obersteiner, Matt Rigby, Thomas Wagenhäuser, Luke M. Western, Andreas Zahn, and Andreas Engel
Atmos. Chem. Phys., 24, 689–705, https://doi.org/10.5194/acp-24-689-2024, https://doi.org/10.5194/acp-24-689-2024, 2024
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We study the interhemispheric gradient of sulfur hexafluoride (SF6), a strong long-lived greenhouse gas. Its emissions are stronger in the Northern Hemisphere; therefore, mixing ratios in the Southern Hemisphere lag behind. Comparing the observations to a box model, the model predicts air in the Southern Hemisphere to be older. For a better agreement, the emissions used as model input need to be increased (and their spatial pattern changed), and we need to modify north–south transport.
Bärbel Vogel, C. Michael Volk, Johannes Wintel, Valentin Lauther, Jan Clemens, Jens-Uwe Grooß, Gebhard Günther, Lars Hoffmann, Johannes C. Laube, Rolf Müller, Felix Ploeger, and Fred Stroh
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Over the Indian subcontinent, polluted air is rapidly uplifted to higher altitudes during the Asian monsoon season. We present an assessment of vertical transport in this region using different wind data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF), as well as high-resolution aircraft measurements. In general, our findings confirm that the newest ECMWF reanalysis product, ERA5, yields a better representation of transport compared to the predecessor, ERA-Interim.
Paul Konopka, Christian Rolf, Marc von Hobe, Sergey M. Khaykin, Benjamin Clouser, Elisabeth Moyer, Fabrizio Ravegnani, Francesco D'Amato, Silvia Viciani, Nicole Spelten, Armin Afchine, Martina Krämer, Fred Stroh, and Felix Ploeger
Atmos. Chem. Phys., 23, 12935–12947, https://doi.org/10.5194/acp-23-12935-2023, https://doi.org/10.5194/acp-23-12935-2023, 2023
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We studied water vapor in a critical region of the atmosphere, the Asian summer monsoon anticyclone, using rare in situ observations. Our study shows that extremely high water vapor values observed in the stratosphere within the Asian monsoon anticyclone still undergo significant freeze-drying and that water vapor concentrations set by the Lagrangian dry point are a better proxy for the stratospheric water vapor budget than rare observations of enhanced water mixing ratios.
Frederik Harzer, Hella Garny, Felix Ploeger, Harald Bönisch, Peter Hoor, and Thomas Birner
Atmos. Chem. Phys., 23, 10661–10675, https://doi.org/10.5194/acp-23-10661-2023, https://doi.org/10.5194/acp-23-10661-2023, 2023
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We study the statistical relation between year-by-year fluctuations in winter-mean ozone and the strength of the stratospheric polar vortex. In the latitude–pressure plane, regression analysis shows that anomalously weak polar vortex years are associated with three pronounced local ozone maxima over the polar cap relative to the winter climatology. These response maxima primarily reflect the non-trivial combination of different ozone transport processes with varying relative contributions.
Luis F. Millán, Gloria L. Manney, Harald Boenisch, Michaela I. Hegglin, Peter Hoor, Daniel Kunkel, Thierry Leblanc, Irina Petropavlovskikh, Kaley Walker, Krzysztof Wargan, and Andreas Zahn
Atmos. Meas. Tech., 16, 2957–2988, https://doi.org/10.5194/amt-16-2957-2023, https://doi.org/10.5194/amt-16-2957-2023, 2023
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The determination of atmospheric composition trends in the upper troposphere and lower stratosphere (UTLS) is still highly uncertain. We present the creation of dynamical diagnostics to map several ozone datasets (ozonesondes, lidars, aircraft, and satellite measurements) in geophysically based coordinate systems. The diagnostics can also be used to analyze other greenhouse gases relevant to surface climate and UTLS chemistry.
Flossie Brown, Lauren Marshall, Peter H. Haynes, Rolando R. Garcia, Thomas Birner, and Anja Schmidt
Atmos. Chem. Phys., 23, 5335–5353, https://doi.org/10.5194/acp-23-5335-2023, https://doi.org/10.5194/acp-23-5335-2023, 2023
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Large-magnitude volcanic eruptions have the potential to alter large-scale circulation patterns, such as the quasi-biennial oscillation (QBO). The QBO is an oscillation of the tropical stratospheric zonal winds between easterly and westerly directions. Using a climate model, we show that large-magnitude eruptions can delay the progression of the QBO, with a much longer delay when the shear is easterly than when it is westerly. Such delays may affect weather and transport of atmospheric gases.
Felix Jäger, Philip Rupp, and Thomas Birner
Weather Clim. Dynam., 4, 49–60, https://doi.org/10.5194/wcd-4-49-2023, https://doi.org/10.5194/wcd-4-49-2023, 2023
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Mid-latitude weather is dominated by the growth, breaking and decay of baroclinic waves and associated jet shifts. A way to study this process is via idealised life-cycle simulations, which are often classified as LC1 (anticyclonic breaking, poleward shift) or LC2 (cyclonic breaking, equatorward shift), depending on details of the initial state. We show that all systems exhibit predominantly anticyclonic character and poleward net shifts if multiple wave modes are allowed to grow simultaneously.
Hans-Christoph Lachnitt, Peter Hoor, Daniel Kunkel, Martina Bramberger, Andreas Dörnbrack, Stefan Müller, Philipp Reutter, Andreas Giez, Thorsten Kaluza, and Markus Rapp
Atmos. Chem. Phys., 23, 355–373, https://doi.org/10.5194/acp-23-355-2023, https://doi.org/10.5194/acp-23-355-2023, 2023
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We present an analysis of high-resolution airborne measurements during a flight of the DEEPWAVE 2014 campaign in New Zealand. The focus of this flight was to study the effects of enhanced mountain wave activity over the Southern Alps. We discuss changes in the upstream and downstream distributions of N2O and CO and show that these changes are related to turbulence-induced trace gas fluxes which have persistent effects on the trace gas composition in the lower stratosphere.
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.
Paul Konopka, Mengchu Tao, Marc von Hobe, Lars Hoffmann, Corinna Kloss, Fabrizio Ravegnani, C. Michael Volk, Valentin Lauther, Andreas Zahn, Peter Hoor, and Felix Ploeger
Geosci. Model Dev., 15, 7471–7487, https://doi.org/10.5194/gmd-15-7471-2022, https://doi.org/10.5194/gmd-15-7471-2022, 2022
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Pure trajectory-based transport models driven by meteorology derived from reanalysis products (ERA5) take into account only the resolved, advective part of transport. That means neither mixing processes nor unresolved subgrid-scale advective processes like convection are included. The Chemical Lagrangian Model of the Stratosphere (CLaMS) includes these processes. We show that isentropic mixing dominates unresolved transport. The second most important transport process is unresolved convection.
Jonas Spaeth and Thomas Birner
Weather Clim. Dynam., 3, 883–903, https://doi.org/10.5194/wcd-3-883-2022, https://doi.org/10.5194/wcd-3-883-2022, 2022
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Past research has demonstrated robust stratosphere–troposphere dynamical coupling following stratospheric circulation extremes. Here, we use a large set of extended-range ensemble forecasts to robustly quantify the increased risk for tropospheric circulation extremes following stratospheric extreme events. In particular, we provide estimates of the fraction of tropospheric extremes that may be attributable to preceding stratospheric extremes.
Liubov Poshyvailo-Strube, Rolf Müller, Stephan Fueglistaler, Michaela I. Hegglin, Johannes C. Laube, C. Michael Volk, and Felix Ploeger
Atmos. Chem. Phys., 22, 9895–9914, https://doi.org/10.5194/acp-22-9895-2022, https://doi.org/10.5194/acp-22-9895-2022, 2022
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Brewer–Dobson circulation (BDC) controls the composition of the stratosphere, which in turn affects radiation and climate. As the BDC cannot be measured directly, it is necessary to infer its strength and trends indirectly. In this study, we test in the
model worlddifferent methods for estimating the mean age of air trends based on a combination of stratospheric water vapour and methane data. We also provide simple practical advice of a more reliable estimation of the mean age of air trends.
Linda Smoydzin and Peter Hoor
Atmos. Chem. Phys., 22, 7193–7206, https://doi.org/10.5194/acp-22-7193-2022, https://doi.org/10.5194/acp-22-7193-2022, 2022
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Our study presents a detailed analysis of the spatial and temporal distribution of elevated CO level in the upper troposphere over the Pacific using 20 years of MOPITT data. We create a climatology of severe pollution episodes and use trajectory calculations to link each particular pollution event detected in MOPITT satellite data with a distinct source region. Additionally, we analyse uplift mechanisms such as WCB-related upward transport.
Suvarna Fadnavis, Prashant Chavan, Akash Joshi, Sunil M. Sonbawne, Asutosh Acharya, Panuganti C. S. Devara, Alexandru Rap, Felix Ploeger, and Rolf Müller
Atmos. Chem. Phys., 22, 7179–7191, https://doi.org/10.5194/acp-22-7179-2022, https://doi.org/10.5194/acp-22-7179-2022, 2022
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We show that large amounts of anthropogenic aerosols are transported from South Asia to the northern Indian Ocean. These aerosols are then lifted into the UTLS by the ascending branch of the Hadley circulation. They are further transported to the Southern Hemisphere and downward via westerly ducts over the tropical Atlantic and Pacific. These aerosols increase tropospheric heating, resulting in an increase in water vapor, which is then transported to the UTLS.
Felix Ploeger and Hella Garny
Atmos. Chem. Phys., 22, 5559–5576, https://doi.org/10.5194/acp-22-5559-2022, https://doi.org/10.5194/acp-22-5559-2022, 2022
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We investigate hemispheric asymmetries in stratospheric circulation changes in the last 2 decades in model simulations and atmospheric observations. We find that observed trace gas changes can be explained by a structural circulation change related to a deepening circulation in the Northern Hemisphere relative to the Southern Hemisphere. As this asymmetric signal is small compared to internal variability observed circulation trends over the recent past are not in contradiction to climate models.
Jan Clemens, Felix Ploeger, Paul Konopka, Raphael Portmann, Michael Sprenger, and Heini Wernli
Atmos. Chem. Phys., 22, 3841–3860, https://doi.org/10.5194/acp-22-3841-2022, https://doi.org/10.5194/acp-22-3841-2022, 2022
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Highly polluted air flows from the surface to higher levels of the atmosphere during the Asian summer monsoon. At high levels, the air is trapped within eddies. Here, we study how air masses can leave the eddy within its cutoff, how they distribute, and how their chemical composition changes. We found evidence for transport from the eddy to higher latitudes over the North Pacific and even Alaska. During transport, trace gas concentrations within cutoffs changed gradually, showing steady mixing.
Helmut Ziereis, Peter Hoor, Jens-Uwe Grooß, Andreas Zahn, Greta Stratmann, Paul Stock, Michael Lichtenstern, Jens Krause, Vera Bense, Armin Afchine, Christian Rolf, Wolfgang Woiwode, Marleen Braun, Jörn Ungermann, Andreas Marsing, Christiane Voigt, Andreas Engel, Björn-Martin Sinnhuber, and Hermann Oelhaf
Atmos. Chem. Phys., 22, 3631–3654, https://doi.org/10.5194/acp-22-3631-2022, https://doi.org/10.5194/acp-22-3631-2022, 2022
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Airborne observations were conducted in the lowermost Arctic stratosphere during the winter of 2015/2016. The observed distribution of reactive nitrogen shows clear indications of nitrification in mid-winter and denitrification in late winter. This was caused by the formation of polar stratospheric cloud particles, which were observed during several flights. The sedimentation and evaporation of these particles and the descent of air masses cause a redistribution of reactive nitrogen.
Valentin Lauther, Bärbel Vogel, Johannes Wintel, Andrea Rau, Peter Hoor, Vera Bense, Rolf Müller, and C. Michael Volk
Atmos. Chem. Phys., 22, 2049–2077, https://doi.org/10.5194/acp-22-2049-2022, https://doi.org/10.5194/acp-22-2049-2022, 2022
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We show airborne in situ measurements of the very short-lived ozone-depleting substances CH2Cl2 and CHCl3, revealing particularly high concentrations of both species in the lower stratosphere. Back-trajectory calculations and 3D model simulations show that the air masses with high concentrations originated in the Asian boundary layer and were transported via the Asian summer monsoon. We also identify a fast transport pathway into the stratosphere via the North American monsoon and by hurricanes.
Markus Jesswein, Heiko Bozem, Hans-Christoph Lachnitt, Peter Hoor, Thomas Wagenhäuser, Timo Keber, Tanja Schuck, and Andreas Engel
Atmos. Chem. Phys., 21, 17225–17241, https://doi.org/10.5194/acp-21-17225-2021, https://doi.org/10.5194/acp-21-17225-2021, 2021
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This study presents and compares inorganic chlorine (Cly) derived from observations with the HALO research aircraft in the Antarctic late winter–early fall 2019 and the Arctic winter 2015–2016. Trend-corrected correlations from the Northern Hemisphere show excellent agreement with those from the Southern Hemisphere. After observation allocation inside and outside the vortex based on N2O measurements, results of the two campaigns reveal substantial differences in Cly within the respective vortex.
Meike K. Rotermund, Vera Bense, Martyn P. Chipperfield, Andreas Engel, Jens-Uwe Grooß, Peter Hoor, Tilman Hüneke, Timo Keber, Flora Kluge, Benjamin Schreiner, Tanja Schuck, Bärbel Vogel, Andreas Zahn, and Klaus Pfeilsticker
Atmos. Chem. Phys., 21, 15375–15407, https://doi.org/10.5194/acp-21-15375-2021, https://doi.org/10.5194/acp-21-15375-2021, 2021
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Airborne total bromine (Brtot) and tracer measurements suggest Brtot-rich air masses persistently protruded into the lower stratosphere (LS), creating a high Brtot region over the North Atlantic in fall 2017. The main source is via isentropic transport by the Asian monsoon and to a lesser extent transport across the extratropical tropopause as quantified by a Lagrange model. The transport of Brtot via Central American hurricanes is also observed. Lastly, the impact of Brtot on LS O3 is assessed.
Christoph Mahnke, Ralf Weigel, Francesco Cairo, Jean-Paul Vernier, Armin Afchine, Martina Krämer, Valentin Mitev, Renaud Matthey, Silvia Viciani, Francesco D'Amato, Felix Ploeger, Terry Deshler, and Stephan Borrmann
Atmos. Chem. Phys., 21, 15259–15282, https://doi.org/10.5194/acp-21-15259-2021, https://doi.org/10.5194/acp-21-15259-2021, 2021
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In 2017, in situ aerosol measurements were conducted aboard the M55 Geophysica in the Asian monsoon region. The vertical particle mixing ratio profiles show a distinct layer (15–18.5 km), the Asian tropopause aerosol layer (ATAL). The backscatter ratio (BR) was calculated based on the aerosol size distributions and compared with the BRs detected by a backscatter probe and a lidar aboard M55, and by the CALIOP lidar. All four methods show enhanced BRs in the ATAL altitude range (max. at 17.5 km).
Ralf Weigel, Christoph Mahnke, Manuel Baumgartner, Antonis Dragoneas, Bärbel Vogel, Felix Ploeger, Silvia Viciani, Francesco D'Amato, Silvia Bucci, Bernard Legras, Beiping Luo, and Stephan Borrmann
Atmos. Chem. Phys., 21, 11689–11722, https://doi.org/10.5194/acp-21-11689-2021, https://doi.org/10.5194/acp-21-11689-2021, 2021
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In July and August 2017, eight StratoClim mission flights of the Geophysica reached up to 20 km in the Asian monsoon anticyclone. New particle formation (NPF) was identified in situ by abundant nucleation-mode aerosols (6–15 nm in diameter) with mixing ratios of up to 50 000 mg−1. NPF occurred most frequently at 12–16 km with fractions of non-volatile residues of down to 15 %. Abundance and productivity of observed NPF indicate its ability to promote the Asian tropopause aerosol layer.
Thorsten Kaluza, Daniel Kunkel, and Peter Hoor
Weather Clim. Dynam., 2, 631–651, https://doi.org/10.5194/wcd-2-631-2021, https://doi.org/10.5194/wcd-2-631-2021, 2021
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We present a 10-year analysis on the occurrence of strong wind shear in the Northern Hemisphere, focusing on the region around the transport barrier that separates the first two layers of the atmosphere. The major result of our analysis is that strong wind shear above a certain threshold occurs frequently and nearly exclusively in this region, which, as an indicator for turbulent mixing, might have major implications concerning the separation efficiency of the transport barrier.
Lukas Krasauskas, Jörn Ungermann, Peter Preusse, Felix Friedl-Vallon, Andreas Zahn, Helmut Ziereis, Christian Rolf, Felix Plöger, Paul Konopka, Bärbel Vogel, and Martin Riese
Atmos. Chem. Phys., 21, 10249–10272, https://doi.org/10.5194/acp-21-10249-2021, https://doi.org/10.5194/acp-21-10249-2021, 2021
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A Rossby wave (RW) breaking event was observed over the North Atlantic during the WISE measurement campaign in October 2017. Infrared limb sounding measurements of trace gases in the lower stratosphere, including high-resolution 3-D tomographic reconstruction, revealed complex spatial structures in stratospheric tracers near the polar jet related to previous RW breaking events. Backward-trajectory analysis and tracer correlations were used to study mixing and stratosphere–troposphere exchange.
Nuria Pilar Plaza, Aurélien Podglajen, Cristina Peña-Ortiz, and Felix Ploeger
Atmos. Chem. Phys., 21, 9585–9607, https://doi.org/10.5194/acp-21-9585-2021, https://doi.org/10.5194/acp-21-9585-2021, 2021
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We study the role of different processes in setting the lower stratospheric water vapour. We find that mechanisms involving ice microphysics and small-scale mixing produce the strongest increase in water vapour, in particular over the Asian Monsoon. Small-scale mixing has a special relevance as it improves the agreement with observations at seasonal and intra-seasonal timescales, contrary to the North American Monsoon case, in which large-scale temperatures still dominate its variability.
Felix Ploeger, Mohamadou Diallo, Edward Charlesworth, Paul Konopka, Bernard Legras, Johannes C. Laube, Jens-Uwe Grooß, Gebhard Günther, Andreas Engel, and Martin Riese
Atmos. Chem. Phys., 21, 8393–8412, https://doi.org/10.5194/acp-21-8393-2021, https://doi.org/10.5194/acp-21-8393-2021, 2021
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We investigate the global stratospheric circulation (Brewer–Dobson circulation) in the new ECMWF ERA5 reanalysis based on age of air simulations, and we compare it to results from the preceding ERA-Interim reanalysis. Our results show a slower stratospheric circulation and higher age for ERA5. The age of air trend in ERA5 over the 1989–2018 period is negative throughout the stratosphere, related to multi-annual variability and a potential contribution from changes in the reanalysis system.
Mohamadou Diallo, Manfred Ern, and Felix Ploeger
Atmos. Chem. Phys., 21, 7515–7544, https://doi.org/10.5194/acp-21-7515-2021, https://doi.org/10.5194/acp-21-7515-2021, 2021
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Despite good agreement in the spatial structure, there are substantial differences in the strength of the Brewer–Dobson circulation (BDC) and its modulations in the UTLS and upper stratosphere. The tropical upwelling is generally weaker in ERA5 than in ERAI due to weaker planetary and gravity wave breaking in the UTLS. Analysis of the BDC trend shows an acceleration of the BDC of about 1.5 % decade-1 due to the long-term intensification in wave breaking, consistent with climate predictions.
Xiaolu Yan, Paul Konopka, Marius Hauck, Aurélien Podglajen, and Felix Ploeger
Atmos. Chem. Phys., 21, 6627–6645, https://doi.org/10.5194/acp-21-6627-2021, https://doi.org/10.5194/acp-21-6627-2021, 2021
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Inter-hemispheric transport is important for understanding atmospheric tracers because of the asymmetry in emissions between the Southern Hemisphere (SH) and Northern Hemisphere (NH). This study finds that the air masses from the NH extratropics to the atmosphere are about 5 times larger than those from the SH extratropics. The interplay between the Asian summer monsoon and westerly ducts triggers the cross-Equator transport from the NH to the SH in boreal summer and fall.
Franziska Köllner, Johannes Schneider, Megan D. Willis, Hannes Schulz, Daniel Kunkel, Heiko Bozem, Peter Hoor, Thomas Klimach, Frank Helleis, Julia Burkart, W. Richard Leaitch, Amir A. Aliabadi, Jonathan P. D. Abbatt, Andreas B. Herber, and Stephan Borrmann
Atmos. Chem. Phys., 21, 6509–6539, https://doi.org/10.5194/acp-21-6509-2021, https://doi.org/10.5194/acp-21-6509-2021, 2021
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We present in situ observations of vertically resolved particle chemical composition in the summertime Arctic lower troposphere. Our analysis demonstrates the strong vertical contrast between particle properties within the boundary layer and aloft. Emissions from vegetation fires and anthropogenic sources in northern Canada, Europe, and East Asia influenced particle composition in the free troposphere. Organics detected in Arctic aerosol particles can partly be identified as dicarboxylic acids.
Philip Rupp and Thomas Birner
Weather Clim. Dynam., 2, 111–128, https://doi.org/10.5194/wcd-2-111-2021, https://doi.org/10.5194/wcd-2-111-2021, 2021
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We use the simple framework of an idealised baroclinic life cycle to study the tropospheric eddy feedback to different stratospheric conditions and, hence, obtain insights into the fundamental processes of stratosphere–troposphere coupling – in particular, the processes involved in creating the robust equatorward shift in the tropospheric mid-latitude jet that has been observed following sudden stratospheric warming events.
Marc von Hobe, Felix Ploeger, Paul Konopka, Corinna Kloss, Alexey Ulanowski, Vladimir Yushkov, Fabrizio Ravegnani, C. Michael Volk, Laura L. Pan, Shawn B. Honomichl, Simone Tilmes, Douglas E. Kinnison, Rolando R. Garcia, and Jonathon S. Wright
Atmos. Chem. Phys., 21, 1267–1285, https://doi.org/10.5194/acp-21-1267-2021, https://doi.org/10.5194/acp-21-1267-2021, 2021
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The Asian summer monsoon (ASM) is known to foster transport of polluted tropospheric air into the stratosphere. To test and amend our picture of ASM vertical transport, we analyse distributions of airborne trace gas observations up to 20 km altitude near the main ASM vertical conduit south of the Himalayas. We also show that a new high-resolution version of the global chemistry climate model WACCM is able to reproduce the observations well.
Johannes Schneider, Ralf Weigel, Thomas Klimach, Antonis Dragoneas, Oliver Appel, Andreas Hünig, Sergej Molleker, Franziska Köllner, Hans-Christian Clemen, Oliver Eppers, Peter Hoppe, Peter Hoor, Christoph Mahnke, Martina Krämer, Christian Rolf, Jens-Uwe Grooß, Andreas Zahn, Florian Obersteiner, Fabrizio Ravegnani, Alexey Ulanovsky, Hans Schlager, Monika Scheibe, Glenn S. Diskin, Joshua P. DiGangi, John B. Nowak, Martin Zöger, and Stephan Borrmann
Atmos. Chem. Phys., 21, 989–1013, https://doi.org/10.5194/acp-21-989-2021, https://doi.org/10.5194/acp-21-989-2021, 2021
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During five aircraft missions, we detected aerosol particles containing meteoric material in the lower stratosphere. The stratospheric measurements span a latitude range from 15 to 68° N, and we find that at potential temperature levels of more than 40 K above the tropopause; particles containing meteoric material occur at similar abundance fractions across latitudes and seasons. We conclude that meteoric material is efficiently distributed between high and low latitudes by isentropic mixing.
Corinna Kloss, Gwenaël Berthet, Pasquale Sellitto, Felix Ploeger, Ghassan Taha, Mariam Tidiga, Maxim Eremenko, Adriana Bossolasco, Fabrice Jégou, Jean-Baptiste Renard, and Bernard Legras
Atmos. Chem. Phys., 21, 535–560, https://doi.org/10.5194/acp-21-535-2021, https://doi.org/10.5194/acp-21-535-2021, 2021
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The year 2019 was particularly rich for the stratospheric aerosol layer due to two volcanic eruptions (at Raikoke and Ulawun) and wildfire events. With satellite observations and models, we describe the exceptionally complex situation following the Raikoke eruption. The respective plume overwhelmed the Northern Hemisphere stratosphere in terms of aerosol load and resulted in the highest climate impact throughout the past decade.
Manuel Baumgartner, Ralf Weigel, Allan H. Harvey, Felix Plöger, Ulrich Achatz, and Peter Spichtinger
Atmos. Chem. Phys., 20, 15585–15616, https://doi.org/10.5194/acp-20-15585-2020, https://doi.org/10.5194/acp-20-15585-2020, 2020
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The potential temperature is routinely used in atmospheric science. We review its derivation and suggest a new potential temperature, based on a temperature-dependent parameterization of the dry air's specific heat capacity. Moreover, we compare the new potential temperature to the common one and discuss the differences which become more important at higher altitudes. Finally, we indicate some consequences of using the new potential temperature in typical applications.
Edward J. Charlesworth, Ann-Kristin Dugstad, Frauke Fritsch, Patrick Jöckel, and Felix Plöger
Atmos. Chem. Phys., 20, 15227–15245, https://doi.org/10.5194/acp-20-15227-2020, https://doi.org/10.5194/acp-20-15227-2020, 2020
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Modeling the stratosphere requires models with good representations of chemical transport. To do this, nearly all models divide the atmosphere into boxes. This creates some unwanted problems. However, the only other option is to divide the atmosphere into balloons, and this method is very complicated. Here, we use a model which uses this balloon-like method to estimate the impacts of this method on chemical transport. We find significant differences in sensitive regions of the stratosphere.
Hella Garny, Roland Walz, Matthias Nützel, and Thomas Birner
Geosci. Model Dev., 13, 5229–5257, https://doi.org/10.5194/gmd-13-5229-2020, https://doi.org/10.5194/gmd-13-5229-2020, 2020
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Numerical models of Earth's climate system have been gaining more and more complexity over the last decades. Therefore, it is important to establish simplified models to improve process understanding. In our study, we present and document the development of a new simplified model setup within the framework of a complex climate model system that uses the same routines to calculate atmospheric dynamics as the complex model but is simplified in the representation of clouds and radiation.
Lina Boljka and Thomas Birner
Weather Clim. Dynam., 1, 555–575, https://doi.org/10.5194/wcd-1-555-2020, https://doi.org/10.5194/wcd-1-555-2020, 2020
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This study addresses the origin and impacts of a source of large-scale atmospheric waves in the lower stratosphere, which have not been examined before. This wave source is caused by interactions of waves of smaller scales. Here we show that as it lies in the lower stratosphere, this wave source can precede extreme events in the stratosphere and that such events can then lead to a response of the tropospheric weather patterns several weeks later (potential for long-term forecasting).
W. Richard Leaitch, John K. Kodros, Megan D. Willis, Sarah Hanna, Hannes Schulz, Elisabeth Andrews, Heiko Bozem, Julia Burkart, Peter Hoor, Felicia Kolonjari, John A. Ogren, Sangeeta Sharma, Meng Si, Knut von Salzen, Allan K. Bertram, Andreas Herber, Jonathan P. D. Abbatt, and Jeffrey R. Pierce
Atmos. Chem. Phys., 20, 10545–10563, https://doi.org/10.5194/acp-20-10545-2020, https://doi.org/10.5194/acp-20-10545-2020, 2020
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Black carbon is a factor in the warming of the Arctic atmosphere due to its ability to absorb light, but the uncertainty is high and few observations have been made in the high Arctic above 80° N. We combine airborne and ground-based observations in the springtime Arctic, at and above 80° N, with simulations from a global model to show that light absorption by black carbon may be much larger than modelled. However, the uncertainty remains high.
Cited articles
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Short summary
The lowermost stratosphere (LMS) plays an important role in the Earth's climate, containing strong gradients of ozone and water vapor. Our results indicate that the thermodynamic structure of the LMS was changing between 1979–2019 in response to anthropogenic climate change and the recovery of stratospheric ozone, also indicating large-scale circulation changes. We find that both the upper and the lower LMS boundaries show an (upward) trend, which has implications for the LMS mass.
The lowermost stratosphere (LMS) plays an important role in the Earth's climate, containing...
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