Articles | Volume 13, issue 11
https://doi.org/10.5194/gmd-13-5229-2020
© 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/gmd-13-5229-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Model description paper
| 
03 Nov 2020
Model description paper |
| 03 Nov 2020
| 03 Nov 2020
Extending the Modular Earth Submodel System (MESSy v2.54) model hierarchy: the ECHAM/MESSy IdeaLized (EMIL) model setup
Hella Garny
CORRESPONDING AUTHOR
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Ludwig Maximilians University of Munich, Meteorological Institute Munich, Munich, Germany
Roland Walz
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Matthias Nützel
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Thomas Birner
Ludwig Maximilians University of Munich, Meteorological Institute Munich, Munich, Germany
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Transport circulation in the stratosphere is important for the distribution of tracers, but its strength is hard to measure. Mean transport times can be inferred from observations of trace gases with certain properties, such as sulfur hexafluoride (SF6). However, this gas has a chemical sink in the high atmosphere, which can lead to substantial biases in inferred transport times. In this paper we present a method to correct mean transport times derived from SF6 for the effects of chemical sinks.
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This preprint is open for discussion and under review for Geoscientific Model Development (GMD).
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Marta Abalos, Thomas Birner, Andreas Chrysanthou, Sean Davis, Alvaro de la Cámara, Sandip Dhomse, Hella Garny, Michaela I. Hegglin, Daan Hubert, Oksana Ivaniha, James Keeble, Marianna Linz, Daniele Minganti, Jessica Neu, David Plummer, Laura Saunders, Kasturi Shah, Gabriele Stiller, Kleareti Tourpali, Darryn Waugh, Nathan Luke Abraham, Hideharu Akiyoshi, Martyn P. Chipperfield, Patrick Jöckel, Béatrice Josse, Marion Marchand, Patrick Martineau, Olaf Morgenstern, Timofei Sukhodolov, Shingo Watanabe, and Yousuke Yamashita
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Frederik Harzer, Hella Garny, Felix Ploeger, J. Moritz Menken, and Thomas Birner
Atmos. Chem. Phys., 25, 14909–14921, https://doi.org/10.5194/acp-25-14909-2025, https://doi.org/10.5194/acp-25-14909-2025, 2025
Short summary
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We study ozone transport in the extratropical lowermost stratosphere using potential temperature as vertical coordinate, thereby distinguishing adiabatic and diabatic processes. We find that on top of known dominant transport processes (quasi-horizontal mixing, slow diabatic descent) vertical mixing plays an important role near the tropopause. Our findings are relevant for understanding ozone's role in climate including its imprint on tropospheric ozone via stratosphere-troposphere air exchange.
Rasul Baikhadzhaev, Felix Ploeger, Peter Preusse, Manfred Ern, and Thomas Birner
Atmos. Chem. Phys., 25, 12753–12777, https://doi.org/10.5194/acp-25-12753-2025, https://doi.org/10.5194/acp-25-12753-2025, 2025
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Across four reanalyses, the shallow branch of the stratospheric overturning circulation was found to be driven by planetary waves 1 to 3, and the deep branch of the circulation was found to be driven by smaller-scale waves (wave 4 and higher). However, the height of the level separating the branches is dependent on the reanalysis considered. Thus, using the appropriate separation levels in model inter-comparisons could reduce the spread between models regarding climatology and trends in the circulation.
William J. Collins, Fiona M. O'Connor, Rachael E. Byrom, Øivind Hodnebrog, Patrick Jöckel, Mariano Mertens, Gunnar Myhre, Matthias Nützel, Dirk Olivié, Ragnhild Bieltvedt Skeie, Laura Stecher, Larry W. Horowitz, Vaishali Naik, Gregory Faluvegi, Ulas Im, Lee T. Murray, Drew Shindell, Kostas Tsigaridis, Nathan Luke Abraham, and James Keeble
Atmos. Chem. Phys., 25, 9031–9060, https://doi.org/10.5194/acp-25-9031-2025, https://doi.org/10.5194/acp-25-9031-2025, 2025
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We used 7 climate models that include atmospheric chemistry and find that in a scenario with weak controls on air quality, the warming effects (over 2015 to 2050) of decreases in ozone-depleting substances and increases in air quality pollutants are approximately equal and would make ozone the second highest contributor to warming over this period. We find that for stratospheric ozone recovery, the standard measure of climate effects underestimates a more comprehensive measure.
Laura N. Saunders, Kaley A. Walker, Gabriele P. Stiller, Thomas von Clarmann, Florian Haenel, Hella Garny, Harald Bönisch, Chris D. Boone, Ariana E. Castillo, Andreas Engel, Johannes C. Laube, Marianna Linz, Felix Ploeger, David A. Plummer, Eric A. Ray, and Patrick E. Sheese
Atmos. Chem. Phys., 25, 4185–4209, https://doi.org/10.5194/acp-25-4185-2025, https://doi.org/10.5194/acp-25-4185-2025, 2025
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We present a 17-year stratospheric age-of-air dataset derived from ACE-FTS satellite measurements of sulfur hexafluoride. This is the longest continuous, global, and vertically resolved age of air time series available to date. In this paper, we show that this dataset agrees well with age-of-air datasets based on measurements from other instruments. We also present trends in the midlatitude lower stratosphere that indicate changes in the global circulation that are predicted by climate models.
Franziska Weyland, Peter Hoor, Daniel Kunkel, Thomas Birner, Felix Plöger, and Katharina Turhal
Atmos. Chem. Phys., 25, 1227–1252, https://doi.org/10.5194/acp-25-1227-2025, https://doi.org/10.5194/acp-25-1227-2025, 2025
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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.
Katharina Turhal, Felix Plöger, Jan Clemens, Thomas Birner, Franziska Weyland, Paul Konopka, and Peter Hoor
Atmos. Chem. Phys., 24, 13653–13679, https://doi.org/10.5194/acp-24-13653-2024, https://doi.org/10.5194/acp-24-13653-2024, 2024
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The tropopause separates the troposphere, where many greenhouse gases originate, from the stratosphere. This study examines a tropopause defined by potential vorticity – an analogue for angular momentum that changes sharply in the subtropics, creating a transport barrier. Between 1980 and 2017, this tropopause shifted poleward at lower altitudes and equatorward above, suggesting height-dependent changes in atmospheric circulation that may affect greenhouse gas distribution and global warming.
Eric A. Ray, Fred L. Moore, Hella Garny, Eric J. Hintsa, Bradley D. Hall, Geoff S. Dutton, David Nance, James W. Elkins, Steven C. Wofsy, Jasna Pittman, Bruce Daube, Bianca C. Baier, Jianghanyang Li, and Colm Sweeney
Atmos. Chem. Phys., 24, 12425–12445, https://doi.org/10.5194/acp-24-12425-2024, https://doi.org/10.5194/acp-24-12425-2024, 2024
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Philip Rupp, Jonas Spaeth, Hilla Afargan-Gerstman, Dominik Büeler, Michael Sprenger, and Thomas Birner
Weather Clim. Dynam., 5, 1287–1298, https://doi.org/10.5194/wcd-5-1287-2024, https://doi.org/10.5194/wcd-5-1287-2024, 2024
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We quantify the occurrence of strong synoptic storms as contributing about 20 % to the uncertainty of subseasonal geopotential height forecasts over northern Europe. We further show that North Atlantic storms are less frequent, weaker and shifted southward following sudden stratospheric warming events, leading to a reduction in northern European forecast uncertainty.
Matthias Nützel, Laura Stecher, Patrick Jöckel, Franziska Winterstein, Martin Dameris, Michael Ponater, Phoebe Graf, and Markus Kunze
Geosci. Model Dev., 17, 5821–5849, https://doi.org/10.5194/gmd-17-5821-2024, https://doi.org/10.5194/gmd-17-5821-2024, 2024
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We extended the infrastructure of our modelling system to enable the use of an additional radiation scheme. After calibrating the model setups to the old and the new radiation scheme, we find that the simulation with the new scheme shows considerable improvements, e.g. concerning the cold-point temperature and stratospheric water vapour. Furthermore, perturbations of radiative fluxes associated with greenhouse gas changes, e.g. of methane, tend to be improved when the new scheme is employed.
Masatomo Fujiwara, Patrick Martineau, Jonathon S. Wright, Marta Abalos, Petr Šácha, Yoshio Kawatani, Sean M. Davis, Thomas Birner, and Beatriz M. Monge-Sanz
Atmos. Chem. Phys., 24, 7873–7898, https://doi.org/10.5194/acp-24-7873-2024, https://doi.org/10.5194/acp-24-7873-2024, 2024
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A climatology of the major variables and terms of the transformed Eulerian-mean (TEM) momentum and thermodynamic equations from four global atmospheric reanalyses is evaluated. The spread among reanalysis TEM momentum balance terms is around 10 % in Northern Hemisphere winter and up to 50 % in Southern Hemisphere winter. The largest uncertainties in the thermodynamic equation (about 50 %) are in the vertical advection, which does not show a structure consistent with the differences in heating.
Hella Garny, Roland Eichinger, Johannes C. Laube, Eric A. Ray, Gabriele P. Stiller, Harald Bönisch, Laura Saunders, and Marianna Linz
Atmos. Chem. Phys., 24, 4193–4215, https://doi.org/10.5194/acp-24-4193-2024, https://doi.org/10.5194/acp-24-4193-2024, 2024
Short summary
Short summary
Transport circulation in the stratosphere is important for the distribution of tracers, but its strength is hard to measure. Mean transport times can be inferred from observations of trace gases with certain properties, such as sulfur hexafluoride (SF6). However, this gas has a chemical sink in the high atmosphere, which can lead to substantial biases in inferred transport times. In this paper we present a method to correct mean transport times derived from SF6 for the effects of chemical sinks.
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.
Ryan S. Williams, Michaela I. Hegglin, Patrick Jöckel, Hella Garny, and Keith P. Shine
Atmos. Chem. Phys., 24, 1389–1413, https://doi.org/10.5194/acp-24-1389-2024, https://doi.org/10.5194/acp-24-1389-2024, 2024
Short summary
Short summary
During winter, a brief but abrupt reversal of the mean stratospheric westerly flow (~30 km high) around the Arctic occurs ~6 times a decade. Using a chemistry–climate model, about half of these events are shown to induce large anomalies in Arctic ozone (>25 %) and water vapour (>±25 %) around ~8–12 km altitude for up to 2–3 months, important for weather forecasting. We also calculate a doubling to trebling of the risk in breaches of mid-latitude surface air quality (ozone) standards (~60 ppbv).
Roland Eichinger, Sebastian Rhode, Hella Garny, Peter Preusse, Petr Pisoft, Aleš Kuchař, Patrick Jöckel, Astrid Kerkweg, and Bastian Kern
Geosci. Model Dev., 16, 5561–5583, https://doi.org/10.5194/gmd-16-5561-2023, https://doi.org/10.5194/gmd-16-5561-2023, 2023
Short summary
Short summary
The columnar approach of gravity wave (GW) schemes results in dynamical model biases, but parallel decomposition makes horizontal GW propagation computationally unfeasible. In the global model EMAC, we approximate it by GW redistribution at one altitude using tailor-made redistribution maps generated with a ray tracer. More spread-out GW drag helps reconcile the model with observations and close the 60°S GW gap. Polar vortex dynamics are improved, enhancing climate model credibility.
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
Short summary
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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.
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.
Matthias Nützel, Sabine Brinkop, Martin Dameris, Hella Garny, Patrick Jöckel, Laura L. Pan, and Mijeong Park
Atmos. Chem. Phys., 22, 15659–15683, https://doi.org/10.5194/acp-22-15659-2022, https://doi.org/10.5194/acp-22-15659-2022, 2022
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During the Asian summer monsoon season, a large high-pressure system is present at levels close to the tropopause above Asia. We analyse how air masses are transported from surface levels to this high-pressure system, which shows distinct features from the surrounding air masses. To this end, we employ multiannual data from two complementary models that allow us to analyse the climatology as well as the interannual and intraseasonal variability of these transport pathways.
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.
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.
Sheena Loeffel, Roland Eichinger, Hella Garny, Thomas Reddmann, Frauke Fritsch, Stefan Versick, Gabriele Stiller, and Florian Haenel
Atmos. Chem. Phys., 22, 1175–1193, https://doi.org/10.5194/acp-22-1175-2022, https://doi.org/10.5194/acp-22-1175-2022, 2022
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SF6-derived trends of stratospheric AoA from observations and model simulations disagree in sign. SF6 experiences chemical degradation, which we explicitly integrate in a global climate model. In our simulations, the AoA trend changes sign when SF6 sinks are considered; thus, the process has the potential to reconcile simulated with observed AoA trends. We show that the positive AoA trend is due to the SF6 sinks themselves and provide a first approach for a correction to account for SF6 loss.
Marta Abalos, Natalia Calvo, Samuel Benito-Barca, Hella Garny, Steven C. Hardiman, Pu Lin, Martin B. Andrews, Neal Butchart, Rolando Garcia, Clara Orbe, David Saint-Martin, Shingo Watanabe, and Kohei Yoshida
Atmos. Chem. Phys., 21, 13571–13591, https://doi.org/10.5194/acp-21-13571-2021, https://doi.org/10.5194/acp-21-13571-2021, 2021
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The stratospheric Brewer–Dobson circulation (BDC), responsible for transporting mass, tracers and heat globally in the stratosphere, is evaluated in a set of state-of-the-art climate models. The acceleration of the BDC in response to increasing greenhouse gases is most robust in the lower stratosphere. At higher levels, the well-known inconsistency between model and observational BDC trends can be partly reconciled by accounting for limited sampling and large uncertainties in the observations.
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Short summary
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.
Numerical models of Earth's climate system have been gaining more and more complexity over the...
