Articles | Volume 14, issue 22
https://doi.org/10.5194/acp-14-12479-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/acp-14-12479-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Stratospheric lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies
Jülich Supercomputing Centre, Forschungszentrum Jülich, Jülich, Germany
C. M. Hoppe
Institut für Energie- und Klimaforschung, Forschungszentrum Jülich, Jülich, Germany
R. Müller
Institut für Energie- und Klimaforschung, Forschungszentrum Jülich, Jülich, Germany
G. S. Dutton
NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, CO, USA
J. C. Gille
National Center for Atmospheric Research, Boulder, CO, USA
Center for Limb Atmospheric Sounding, University of Colorado, Boulder, CO, USA
S. Griessbach
Jülich Supercomputing Centre, Forschungszentrum Jülich, Jülich, Germany
A. Jones
Department of Physics, University of Toronto, Toronto, Canada
C. I. Meyer
Jülich Supercomputing Centre, Forschungszentrum Jülich, Jülich, Germany
Institut für Energie- und Klimaforschung, Forschungszentrum Jülich, Jülich, Germany
C. M. Volk
Bergische Universität Wuppertal, Fachbereich Physik, Wuppertal, Germany
K. A. Walker
Department of Physics, University of Toronto, Toronto, Canada
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
Related authors
Phoebe Noble, Haruka Okui, Joan Alexander, Manfred Ern, Neil P. Hindley, Lars Hoffmann, Laura Holt, Annelize van Niekerk, Riwal Plougonven, Inna Polichtchouk, Claudia C. Stephan, Martina Bramberger, Milena Corcos, William Putnam, Christopher Kruse, and Corwin J. Wright
Atmos. Chem. Phys., 26, 7607–7630, https://doi.org/10.5194/acp-26-7607-2026, https://doi.org/10.5194/acp-26-7607-2026, 2026
Short summary
Short summary
Gravity waves are small-scale processes that drive the circulation in the middle and upper atmosphere. In this work, we assess 3 new high-resolution (3-5km horizontal resolution) models against satellite data. Generally, models capture the spatial patterns and represent stratospheric northern hemisphere mountain generated waves well. However, they still underestimate amplitudes globally and struggle with the representation of southern hemispheric convective waves.
Yen-Sen Lu, Lars Hoffmann, Xue Wu, Corwin J. Wright, and Neil P. Hindley
EGUsphere, https://doi.org/10.5194/egusphere-2026-1469, https://doi.org/10.5194/egusphere-2026-1469, 2026
Short summary
Short summary
We studied how computer models represent atmospheric waves triggered by intense tropical cyclones. We used a real typhoon as a case study to test how different mathematical descriptions of the atmospheric model affect these wave patterns. We found that small changes in model settings significantly impact the predicted waves in the upper atmosphere. This research helps scientists choose better model configurations to improve weather forecasts and our understanding of atmospheric science.
Zhen Yang, Bärbel Vogel, Felix Plöger, Zhixuan Bai, Dan Li, Sabine Griessbach, Lars Hoffmann, Frank G. Wienhold, Elizabeth Asher, Alexandre A. Baron, Katie R. Smith, Troy Thornberry, Jianchun Bian, and Michaela I. Hegglin
Atmos. Chem. Phys., 26, 4749–4769, https://doi.org/10.5194/acp-26-4749-2026, https://doi.org/10.5194/acp-26-4749-2026, 2026
Short summary
Short summary
Balloon measurements over Lhasa, China, combined with satellite guided modelling, tracked aerosol from the 2019 Raikoke eruption through the Asian summer monsoon anticyclone. We find two altitude dependent routes into the anticyclone. It partly blocks transport but also allows entry and mixing, explaining the gradual weakening of the layers. Balloon measurements over Boulder, United States, outside the anticyclone, provide an independent check outside the region.
Peter G. Berthelemy, Corwin J. Wright, Neil P. Hindley, Phoebe E. Noble, and Lars Hoffmann
Atmos. Chem. Phys., 25, 17595–17611, https://doi.org/10.5194/acp-25-17595-2025, https://doi.org/10.5194/acp-25-17595-2025, 2025
Short summary
Short summary
Atmospheric gravity waves are one of the key mechanisms for moving energy upwards through the atmosphere. We use temperature data to see them from a satellite, and here have made a new method to automatically detect them. This works by seeing if points next to each other are from the same wave. This is useful for creating larger gravity wave datasets without noise, which can then be used by climate forecasters to improve their understanding of the atmosphere.
Arno Keppens, Daan Hubert, José Granville, Oindrila Nath, Jean-Christopher Lambert, Catherine Wespes, Pierre-François Coheur, Cathy Clerbaux, Anne Boynard, Richard Siddans, Barry Latter, Brian Kerridge, Serena Di Pede, Pepijn Veefkind, Juan Cuesta, Gaelle Dufour, Klaus-Peter Heue, Melanie Coldewey-Egbers, Diego Loyola, Andrea Orfanoz-Cheuquelaf, Swathi Maratt Satheesan, Kai-Uwe Eichmann, Alexei Rozanov, Viktoria F. Sofieva, Jerald R. Ziemke, Antje Inness, Roeland Van Malderen, and Lars Hoffmann
Atmos. Meas. Tech., 18, 6893–6916, https://doi.org/10.5194/amt-18-6893-2025, https://doi.org/10.5194/amt-18-6893-2025, 2025
Short summary
Short summary
The first Tropospheric Ozone Assessment Report (TOAR) encountered discrepancies between several satellite sensors’ estimates of the distribution and change of ozone in the free troposphere. Therefore, contributing to the second TOAR, we harmonise as much as possible the observational perspective of sixteen tropospheric ozone products from satellites. This only partially accounts for the observed discrepancies, with a reduction of 10–40 % of the inter-product dispersion upon harmonisation.
Farahnaz Khosrawi and Lars Hoffmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-3147, https://doi.org/10.5194/egusphere-2025-3147, 2025
Preprint archived
Short summary
Short summary
Computer performance has increased immensely in recent years, but the ability to store data has only increased slightly. This presents scientists with major challenges. Many compression methods have been developed in recent years with which data can be stored either lossless or lossy. Here we test three of these methods: two lossy compression methods and one lossless compressor. Our study shows that compression is a valuable tool to cope with the high demand of disk space from these data sets.
Mingzhao Liu, Lars Hoffmann, Jens-Uwe Grooß, Zhongyin Cai, Sabine Grießbach, and Yi Heng
Atmos. Chem. Phys., 25, 4403–4418, https://doi.org/10.5194/acp-25-4403-2025, https://doi.org/10.5194/acp-25-4403-2025, 2025
Short summary
Short summary
We studied the transport and chemical decomposition of volcanic SO2, focusing on the 2019 Raikoke event. By comparing two different chemistry modeling schemes, we found that including complex chemical reactions leads to a more accurate prediction of how long SO2 stays in the atmosphere. This research helps improve our understanding of volcanic pollution and its impact on air quality and climate, providing better tools for scientists to track and predict the movement of these pollutants.
Ling Zou, Reinhold Spang, Sabine Griessbach, Lars Hoffmann, Farahnaz Khosrawi, Rolf Müller, and Ines Tritscher
Atmos. Chem. Phys., 24, 11759–11774, https://doi.org/10.5194/acp-24-11759-2024, https://doi.org/10.5194/acp-24-11759-2024, 2024
Short summary
Short summary
This study provided estimates of the occurrence of ice polar stratospheric clouds (PSCs) observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and their connection with temperatures above the frost point (Tice) using a Lagrangian model derived from ERA5. We found that ice PSCs above Tice with temperature fluctuations along the backward trajectory are 33 % in the Arctic and 9 % in the Antarctic. This quantitative assessment enhances our understanding of ice PSCs.
Jan Clemens, Lars Hoffmann, Bärbel Vogel, Sabine Grießbach, and Nicole Thomas
Geosci. Model Dev., 17, 4467–4493, https://doi.org/10.5194/gmd-17-4467-2024, https://doi.org/10.5194/gmd-17-4467-2024, 2024
Short summary
Short summary
Lagrangian transport models simulate the transport of air masses in the atmosphere. For example, one model (CLaMS) is well suited to calculating transport as it uses a special coordinate system and special vertical wind. However, it only runs inefficiently on modern supercomputers. Hence, we have implemented the benefits of CLaMS into a new model (MPTRAC), which is already highly efficient on modern supercomputers. Finally, in extensive tests, we showed that CLaMS and MPTRAC agree very well.
Lars Hoffmann, Kaveh Haghighi Mood, Andreas Herten, Markus Hrywniak, Jiri Kraus, Jan Clemens, and Mingzhao Liu
Geosci. Model Dev., 17, 4077–4094, https://doi.org/10.5194/gmd-17-4077-2024, https://doi.org/10.5194/gmd-17-4077-2024, 2024
Short summary
Short summary
Lagrangian particle dispersion models are key for studying atmospheric transport but can be computationally intensive. To speed up simulations, the MPTRAC model was ported to graphics processing units (GPUs). Performance optimization of data structures and memory alignment resulted in runtime improvements of up to 75 % on NVIDIA A100 GPUs for ERA5-based simulations with 100 million particles. These optimizations make the MPTRAC model well suited for future high-performance computing systems.
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
Short summary
Short summary
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.
Abhiraj Bishnoi, Olaf Stein, Catrin I. Meyer, René Redler, Norbert Eicker, Helmuth Haak, Lars Hoffmann, Daniel Klocke, Luis Kornblueh, and Estela Suarez
Geosci. Model Dev., 17, 261–273, https://doi.org/10.5194/gmd-17-261-2024, https://doi.org/10.5194/gmd-17-261-2024, 2024
Short summary
Short summary
We enabled the weather and climate model ICON to run in a high-resolution coupled atmosphere–ocean setup on the JUWELS supercomputer, where the ocean and the model I/O runs on the CPU Cluster, while the atmosphere is running simultaneously on GPUs. Compared to a simulation performed on CPUs only, our approach reduces energy consumption by 45 % with comparable runtimes. The experiments serve as preparation for efficient computing of kilometer-scale climate models on future supercomputing systems.
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
Atmos. Chem. Phys., 24, 317–343, https://doi.org/10.5194/acp-24-317-2024, https://doi.org/10.5194/acp-24-317-2024, 2024
Short summary
Short summary
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.
Xue Wu, Lars Hoffmann, Corwin J. Wright, Neil P. Hindley, M. Joan Alexander, Silvio Kalisch, Xin Wang, Bing Chen, Yinan Wang, and Daren Lyu
EGUsphere, https://doi.org/10.5194/egusphere-2023-3008, https://doi.org/10.5194/egusphere-2023-3008, 2024
Preprint archived
Short summary
Short summary
This study identified a noteworthy time-lagged correlation between hurricane intensity and stratospheric gravity wave intensities during hurricane intensification. Meanwhile, the study reveals distinct frequencies, horizontal wavelengths, and vertical wavelengths in the inner core region during hurricane intensification, offering essential insights for monitoring hurricane intensity via satellite observations of stratospheric gravity waves.
Mingzhao Liu, Lars Hoffmann, Sabine Griessbach, Zhongyin Cai, Yi Heng, and Xue Wu
Geosci. Model Dev., 16, 5197–5217, https://doi.org/10.5194/gmd-16-5197-2023, https://doi.org/10.5194/gmd-16-5197-2023, 2023
Short summary
Short summary
We introduce new and revised chemistry and physics modules in the Massive-Parallel Trajectory Calculations (MPTRAC) Lagrangian transport model aiming to improve the representation of volcanic SO2 transport and depletion. We test these modules in a case study of the Ambae eruption in July 2018 in which the SO2 plume underwent wet removal and convection. The lifetime of SO2 shows highly variable and complex dependencies on the atmospheric conditions at different release heights.
Lars Hoffmann, Paul Konopka, Jan Clemens, and Bärbel Vogel
Atmos. Chem. Phys., 23, 7589–7609, https://doi.org/10.5194/acp-23-7589-2023, https://doi.org/10.5194/acp-23-7589-2023, 2023
Short summary
Short summary
Atmospheric convection plays a key role in tracer transport in the troposphere. Global meteorological forecasts and reanalyses typically have a coarse spatiotemporal resolution that does not adequately resolve the dynamics, transport, and mixing of air associated with storm systems or deep convection. We discuss the application of the extreme convection parameterization in a Lagrangian transport model to improve simulations of tracer transport from the boundary layer into the free troposphere.
Reimar Bauer, Jens-Uwe Grooß, Jörn Ungermann, May Bär, Markus Geldenhuys, and Lars Hoffmann
Geosci. Model Dev., 15, 8983–8997, https://doi.org/10.5194/gmd-15-8983-2022, https://doi.org/10.5194/gmd-15-8983-2022, 2022
Short summary
Short summary
The Mission Support System (MSS) is an open source software package that has been used for planning flight tracks of scientific aircraft in multiple measurement campaigns during the last decade. Here, we describe the MSS software and its use during the SouthTRAC measurement campaign in 2019. As an example for how the MSS software is used in conjunction with many datasets, we describe the planning of a single flight probing orographic gravity waves propagating up into the lower mesosphere.
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
Short summary
Short summary
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.
Zhongyin Cai, Sabine Griessbach, and Lars Hoffmann
Atmos. Chem. Phys., 22, 6787–6809, https://doi.org/10.5194/acp-22-6787-2022, https://doi.org/10.5194/acp-22-6787-2022, 2022
Short summary
Short summary
Using AIRS and TROPOMI sulfur dioxide retrievals and the Lagrangian transport model MPTRAC, we present an improved reconstruction of injection parameters of the 2019 Raikoke eruption. Reconstructions agree well between using AIRS nighttime and TROPOMI daytime retrievals, showing the potential of our approach to create a long-term volcanic sulfur dioxide inventory from nearly 20 years of AIRS retrievals.
Ling Zou, Sabine Griessbach, Lars Hoffmann, and Reinhold Spang
Atmos. Chem. Phys., 22, 6677–6702, https://doi.org/10.5194/acp-22-6677-2022, https://doi.org/10.5194/acp-22-6677-2022, 2022
Short summary
Short summary
Ice clouds in the stratosphere (SICs) greatly affect the water vapor balance and radiation budget in the upper troposphere and lower stratosphere (UTLS). We quantified the global SICs and analyzed their relationships with tropopause temperature, double tropopauses, UTLS clouds, gravity waves, and stratospheric aerosols. The correlations between SICs and all abovementioned processes indicate that the occurrence of and variability in SICs are spatiotemporally dependent on different processes.
Lars Hoffmann, Paul F. Baumeister, Zhongyin Cai, Jan Clemens, Sabine Griessbach, Gebhard Günther, Yi Heng, Mingzhao Liu, Kaveh Haghighi Mood, Olaf Stein, Nicole Thomas, Bärbel Vogel, Xue Wu, and Ling Zou
Geosci. Model Dev., 15, 2731–2762, https://doi.org/10.5194/gmd-15-2731-2022, https://doi.org/10.5194/gmd-15-2731-2022, 2022
Short summary
Short summary
We describe the new version (2.2) of the Lagrangian transport model MPTRAC, which has been ported for application on GPUs. The model was verified by comparing kinematic trajectories and synthetic tracer simulations for the free troposphere and stratosphere from GPUs and CPUs. Benchmarking showed a speed-up of a factor of 16 of GPU-enabled simulations compared to CPU-only runs, indicating the great potential of applying GPUs for Lagrangian transport simulations on upcoming HPC systems.
Lars Hoffmann and Reinhold Spang
Atmos. Chem. Phys., 22, 4019–4046, https://doi.org/10.5194/acp-22-4019-2022, https://doi.org/10.5194/acp-22-4019-2022, 2022
Short summary
Short summary
We present an intercomparison of 2009–2018 lapse rate tropopause characteristics as derived from ECMWF's ERA5 and ERA-Interim reanalyses. Large-scale features are similar, but ERA5 shows notably larger variability, which we mainly attribute to UTLS temperature fluctuations due to gravity waves being better resolved by ECMWF's IFS forecast model. Following evaluation with radiosondes and GPS data, we conclude ERA5 will be a more suitable asset for tropopause-related studies in future work.
Paul F. Baumeister and Lars Hoffmann
Geosci. Model Dev., 15, 1855–1874, https://doi.org/10.5194/gmd-15-1855-2022, https://doi.org/10.5194/gmd-15-1855-2022, 2022
Short summary
Short summary
The efficiency of the numerical simulation of radiative transport is shown on modern server-class graphics cards (GPUs). The low-cost prefactor on GPUs compared to general-purpose processors (CPUs) enables future large retrieval campaigns for multi-channel data from infrared sounders aboard low-orbit satellites. The validated research software JURASSIC is available in the public domain.
Zhipeng Qu, Cuong Nguyen, Paloma Borque, Alexei Korolev, Howard W. Barker, Keyvan Ranjbar, Lei Liu, Zen Mariani, Meriem Kacimi, Melissa Cholette, Ivan Heckman, Kenny Bala, Natalia Bliankinshtein, Leonid Nichman, Benjamin Riot-Bretêcher, Yi Huang, Jason N. S. Cole, Raphaël Peroni, Stephen Holden, Robert Reed, Robert Crawford, Daniel Michelson, Eve Bigras, Michael Wheeler, John Gyakum, Jason A. Milbrandt, Julie M. Thériault, Kaley A. Walker, Mengistu Wolde, Jean-Pierre Blanchet, Yann Blanchard, Jonas von Bismark, Rob Koopman, Montserrat Piñol Solé, Bernat Puigdomènech Treserras, Robin J. Hogan, and Shannon L. Mason
EGUsphere, https://doi.org/10.5194/egusphere-2026-5347, https://doi.org/10.5194/egusphere-2026-5347, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
The ECALOT campaign brought together aircraft and ground-based observations in the Ottawa–Montreal region to help evaluate the European Space Agency’s EarthCARE satellite, which studies clouds, aerosols, radiation, and their interactions. By comparing satellite measurements with multi-platform remote-sensing and in situ observations collected during the campaign, ECALOT provides an integrated approach to evaluating EarthCARE products at different stages of the data processing chain.
Florian Voet, Felix Ploeger, Johannes C. Laube, Laura N. Saunders, Patrick E. Sheese, Attahir Mainika, Peter Preusse, Jens-Uwe Grooß, Kaley A. Walker, Susann Tegtmeier, and Michaela Imelda Hegglin
EGUsphere, https://doi.org/10.5194/egusphere-2026-4647, https://doi.org/10.5194/egusphere-2026-4647, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
We developed a better way to estimate how long air remains in the upper atmosphere, because satellite estimates can be too noisy to show long-term changes. Using measurements of several gases from a satellite, we found that combining them cuts uncertainty by about half and gives estimates with about 0.3 years of average uncertainty. Results for 2004–2021 show older air in the Northern Hemisphere and younger air in the tropics and Southern Hemisphere, suggesting slower circulation in the north.
Laura N. Saunders, Kaley A. Walker, Gabriele P. Stiller, Piera Raspollini, Luis F. Millán, Marco Gai, Chris D. Boone, John Gille, Norbert Glatthor, Armin Kleinboehl, Anne Kleinert, Alyn Lambert, Donal Murtaugh, Patrick E. Sheese, Geoffrey C. Toon, and Gerald Wetzel
EGUsphere, https://doi.org/10.5194/egusphere-2026-4651, https://doi.org/10.5194/egusphere-2026-4651, 2026
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
Short summary
Short summary
We present a comprehensive evaluation of nitrous oxide (N2O) measurements taken during the 2002–2024 period from five limb-viewing satellite instruments: ACE-FTS, HIRDLS, MIPAS, Aura-MLS, and SMR. Coincident measurements are compared between satellite instruments and with independent reference data from balloon-borne instruments. We show that ACE-FTS, MIPAS, and SMR constitute an excellent 23-year record of N2O measurements that could be used to create an ESA-funded merged dataset in future.
Wolfgang Woiwode, Bärbel Vogel, Valentin Lauther, Jens-Uwe Grooß, Jeremy Harrison, Sören Johansson, Jörn Ungermann, Peter Braesicke, Markus Dick, Andreas Engel, Felix Friedl-Vallon, Norbert Glatthor, Thomas Gulde, Michael Höpfner, Markus Jesswein, Jan Kaumanns, Timo Keber, Anne Kleinert, Erik Kretschmer, Guido Maucher, Tom Neubert, Hans Nordmeyer, Christof Piesch, Felix Plöger, Peter Preusse, Markus Retzlaff, Sebastian Rhode, Heinz Rongen, Georg Schardt, Tanja Schuck, Björn-Martin Sinnhuber, Johannes Strobel, Franziska Trinkl, Ronja Van Luijt, Stefan Versick, C. Michael Volk, Gerald Wetzel, Peter Hoor, and Martin Riese
EGUsphere, https://doi.org/10.5194/egusphere-2026-3271, https://doi.org/10.5194/egusphere-2026-3271, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Filaments of CH2Cl2-rich air are revealed by airborne infrared limb-imaging observations in late summer 2023 above the North Pacific, Canada and Alaska and traced back to the Asian Summer Monsoon region. Involving new spectroscopic data, high CH2Cl2 levels were retrieved in the troposphere and moderate enhancements also in air masses with characteristics of the lowermost stratosphere. Mesoscale filaments are shown to transport substantial amounts of CH2Cl2 across the North Pacific.
Oleh Kachula, Bärbel Vogel, Gebhard Günther, Rolf Müller, and Felix Ploeger
EGUsphere, https://doi.org/10.5194/egusphere-2026-3509, https://doi.org/10.5194/egusphere-2026-3509, 2026
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
Short summary
Short summary
Locating the boundary of the Asian summer monsoon anticyclone (ASMA) in the upper atmosphere is important for understanding how this system distributes pollutants. We show that while different methodologies generally agree on the boundary's location and shape, certain methods are preferred under specific conditions. These findings will be of broad interest to researchers studying large-scale atmospheric circulations in upper atmosphere.
Monika E. Szelag, Viktoria F. Sofieva, Edward Malina, Pekka T. Verronen, Michelle L. Santee, Manuel López-Puertas, Bernd Funke, Gabriele Stiller, Alexandra Laeng, Kaley A. Walker, Patrick E. Sheese, Mark E. Hervig, and Benjamin T. Marshall
Atmos. Chem. Phys., 26, 7503–7522, https://doi.org/10.5194/acp-26-7503-2026, https://doi.org/10.5194/acp-26-7503-2026, 2026
Short summary
Short summary
We present a new global dataset of ozone profiles in the mesosphere and lower thermosphere, created by combining several satellite measurements covering more than three decades. Our results show that ozone is recovering in the stratosphere but decreasing in the mesosphere, with the strongest declines near the mesopause. This dataset provides a valuable resource for investigating long-term changes, improving model performance, and addressing an observational gap in the upper atmosphere.
Phoebe Noble, Haruka Okui, Joan Alexander, Manfred Ern, Neil P. Hindley, Lars Hoffmann, Laura Holt, Annelize van Niekerk, Riwal Plougonven, Inna Polichtchouk, Claudia C. Stephan, Martina Bramberger, Milena Corcos, William Putnam, Christopher Kruse, and Corwin J. Wright
Atmos. Chem. Phys., 26, 7607–7630, https://doi.org/10.5194/acp-26-7607-2026, https://doi.org/10.5194/acp-26-7607-2026, 2026
Short summary
Short summary
Gravity waves are small-scale processes that drive the circulation in the middle and upper atmosphere. In this work, we assess 3 new high-resolution (3-5km horizontal resolution) models against satellite data. Generally, models capture the spatial patterns and represent stratospheric northern hemisphere mountain generated waves well. However, they still underestimate amplitudes globally and struggle with the representation of southern hemispheric convective waves.
Shubhajyoti Roy, Satheesh P. R. Chandran, Suvarna Fadnavis, Vijay Sagar, Michaela I. Hegglin, Rolf Müller, and Prashant Chavan
Atmos. Chem. Phys., 26, 7047–7059, https://doi.org/10.5194/acp-26-7047-2026, https://doi.org/10.5194/acp-26-7047-2026, 2026
Short summary
Short summary
We show that stratospheric ozone intrusions associated with sudden stratospheric warming events occurring concurrent with the westerly phase of the Quasi-biennial oscillation enhance ozone in the upper troposphere and lower stratosphere over South Asia. The ozone enhancement increases ozone radiative forcing by 0.09±0.05 W m-2 over South Asia. This increase in ozone radiative forcing potentially exacerbates regional climate warming.
Bärbel Vogel, Valentin Lauther, Franziska Köllner, Fatih Ekinci, Christian Rolf, Johannes Strobel, Ronja van Luijt, C. Michael Volk, Stephan Borrmann, Antonis Dragoneas, Oliver Eppers, Sergej Molleker, Peter Hoor, Linda Ort, Franziska Weyland, Andreas Zahn, Jan Clemens, Gebhard Günther, Oleh Kachula, Rolf Müller, Felix Ploeger, and Martin Riese
Atmos. Chem. Phys., 26, 6283–6319, https://doi.org/10.5194/acp-26-6283-2026, https://doi.org/10.5194/acp-26-6283-2026, 2026
Short summary
Short summary
This work highlights the impact of the Asian summer monsoon on the chemical composition of the upper troposphere and lower stratosphere. Measurements of trace gases and aerosol particles uplifted by the Asian summer monsoon to higher altitudes are sparse. Here, we had the opportunity to use a whole suite of different measured trace gases and the chemical composition of aerosols, in combination with simulations, to better understand the complex transport and mixing processes in this region.
Yen-Sen Lu, Lars Hoffmann, Xue Wu, Corwin J. Wright, and Neil P. Hindley
EGUsphere, https://doi.org/10.5194/egusphere-2026-1469, https://doi.org/10.5194/egusphere-2026-1469, 2026
Short summary
Short summary
We studied how computer models represent atmospheric waves triggered by intense tropical cyclones. We used a real typhoon as a case study to test how different mathematical descriptions of the atmospheric model affect these wave patterns. We found that small changes in model settings significantly impact the predicted waves in the upper atmosphere. This research helps scientists choose better model configurations to improve weather forecasts and our understanding of atmospheric science.
Zhen Yang, Bärbel Vogel, Felix Plöger, Zhixuan Bai, Dan Li, Sabine Griessbach, Lars Hoffmann, Frank G. Wienhold, Elizabeth Asher, Alexandre A. Baron, Katie R. Smith, Troy Thornberry, Jianchun Bian, and Michaela I. Hegglin
Atmos. Chem. Phys., 26, 4749–4769, https://doi.org/10.5194/acp-26-4749-2026, https://doi.org/10.5194/acp-26-4749-2026, 2026
Short summary
Short summary
Balloon measurements over Lhasa, China, combined with satellite guided modelling, tracked aerosol from the 2019 Raikoke eruption through the Asian summer monsoon anticyclone. We find two altitude dependent routes into the anticyclone. It partly blocks transport but also allows entry and mixing, explaining the gradual weakening of the layers. Balloon measurements over Boulder, United States, outside the anticyclone, provide an independent check outside the region.
Rolf Müller, Bärbel Vogel, Martina Krämer, Christian Rolf, Nicole Spelten, and Fabrizio Ravegnani
Atmos. Chem. Phys., 26, 4359–4376, https://doi.org/10.5194/acp-26-4359-2026, https://doi.org/10.5194/acp-26-4359-2026, 2026
Short summary
Short summary
In the Asian summer monsoon anticyclone the lapse rate tropopause, and not the cold point, constitutes a good estimate of the upper boundary of the well mixed tropospheric air mass. For strong convection there is substantial dehydration at the cold point tropopause (in summer 2017). Above the cold point tropopause, under such conditions, neither ice particle occurrence, nor enhanced molar mixing ratios of water vapour (above ≲ 6 ppm) are observed.
Jiansheng Zou, C. Thomas McElroy, James R. Drummond, Kaley A. Walker, and Paul S. Jeffery
Atmos. Meas. Tech., 19, 1991–2008, https://doi.org/10.5194/amt-19-1991-2026, https://doi.org/10.5194/amt-19-1991-2026, 2026
Short summary
Short summary
Two decades of operations and performance for the MAESTRO instrument are reviewed. Topics addressed include: (a) occultation measurement schemes, (b) MAESTRO's field of view (FOV) on the Sun, (c) FOV changes on the solar disk during occultations and their impact on calculated transmittances, (d) the relation between the MAESTRO and ACE-FTS FOVs, (e) verification of wavelength assignment, and how it has been affected by thermal environment changes, and (f) the determination of MAESTRO tangent heights.
Ariana Elena Castillo, Marianna Linz, Eric Ray, Laura N. Saunders, Kaley A. Walker, Gabriele P. Stiller, Todd A. Mooring, and Stephen Bourguet
EGUsphere, https://doi.org/10.5194/egusphere-2026-1236, https://doi.org/10.5194/egusphere-2026-1236, 2026
Short summary
Short summary
In the stratosphere, transport strongly impacts the distribution of long-lived trace gases, and age of air is a measure of transport times in the stratosphere. We present two datasets that capture the structure and seasonality of stratospheric transport in both hemispheres: (1) latitude-varying empirical relationships of tracers to calculate a (2) 7-year timeseries of age of air. We lay groundwork for a multidecade timeseries of age to understand long-term transport in a warming climate.
Viktoria F. Sofieva, Alexandra Laeng, Thomas von Clarmann, Gabriele Stiller, Michael Kiefer, Johanna Tamminen, Alexey Rozanov, Carlo Arosio, Nathaniel Livesey, Robert Damadeo, Patrick Sheese, Kaley A. Walker, Doug Degenstein, Daniel Zawada, Natalya A. Kramarova, and Arno Keppens
Atmos. Meas. Tech., 19, 1837–1852, https://doi.org/10.5194/amt-19-1837-2026, https://doi.org/10.5194/amt-19-1837-2026, 2026
Short summary
Short summary
For satellite measurements of atmospheric composition, the random uncertainty estimates provided by retrieval algorithms might be imperfect due to various approximations used in the retrievals or presence of unknown error sources. This paper presents an overview of the methods used for validation of random uncertainty estimates. All methods discussed in this study are categorized, and assumptions and limitations of each method are discussed.
Paul Konopka, Felix Ploeger, Francesco D'Amato, Teresa Campos, Marc von Hobe, Shawn B. Honomichl, Peter Hoor, Laura L. Pan, Michelle L. Santee, Silvia Viciani, Kaley A. Walker, and Michaela I. Hegglin
Atmos. Chem. Phys., 25, 17973–17996, https://doi.org/10.5194/acp-25-17973-2025, https://doi.org/10.5194/acp-25-17973-2025, 2025
Short summary
Short summary
We present an improved version of the Chemical Lagrangian Model of the Stratosphere (CLaMS-3.0), which better represents transport from the lower atmosphere to the upper troposphere and lower stratosphere. By refining grid resolution and improving convection representation, the model more accurately simulates carbon monoxide transport. Comparisons with satellite and in situ observations highlight its ability to capture seasonal variations and improve our understanding of atmospheric transport.
Peter G. Berthelemy, Corwin J. Wright, Neil P. Hindley, Phoebe E. Noble, and Lars Hoffmann
Atmos. Chem. Phys., 25, 17595–17611, https://doi.org/10.5194/acp-25-17595-2025, https://doi.org/10.5194/acp-25-17595-2025, 2025
Short summary
Short summary
Atmospheric gravity waves are one of the key mechanisms for moving energy upwards through the atmosphere. We use temperature data to see them from a satellite, and here have made a new method to automatically detect them. This works by seeing if points next to each other are from the same wave. This is useful for creating larger gravity wave datasets without noise, which can then be used by climate forecasters to improve their understanding of the atmosphere.
Arno Keppens, Daan Hubert, José Granville, Oindrila Nath, Jean-Christopher Lambert, Catherine Wespes, Pierre-François Coheur, Cathy Clerbaux, Anne Boynard, Richard Siddans, Barry Latter, Brian Kerridge, Serena Di Pede, Pepijn Veefkind, Juan Cuesta, Gaelle Dufour, Klaus-Peter Heue, Melanie Coldewey-Egbers, Diego Loyola, Andrea Orfanoz-Cheuquelaf, Swathi Maratt Satheesan, Kai-Uwe Eichmann, Alexei Rozanov, Viktoria F. Sofieva, Jerald R. Ziemke, Antje Inness, Roeland Van Malderen, and Lars Hoffmann
Atmos. Meas. Tech., 18, 6893–6916, https://doi.org/10.5194/amt-18-6893-2025, https://doi.org/10.5194/amt-18-6893-2025, 2025
Short summary
Short summary
The first Tropospheric Ozone Assessment Report (TOAR) encountered discrepancies between several satellite sensors’ estimates of the distribution and change of ozone in the free troposphere. Therefore, contributing to the second TOAR, we harmonise as much as possible the observational perspective of sixteen tropospheric ozone products from satellites. This only partially accounts for the observed discrepancies, with a reduction of 10–40 % of the inter-product dispersion upon harmonisation.
Sujan Khanal, Matthew Toohey, Adam Bourassa, C. Thomas McElroy, Christopher Sioris, and Kaley A. Walker
Atmos. Meas. Tech., 18, 6835–6852, https://doi.org/10.5194/amt-18-6835-2025, https://doi.org/10.5194/amt-18-6835-2025, 2025
Short summary
Short summary
Measurements of stratospheric aerosol from the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (MAESTRO) instrument are compared to other measurements to assess their scientific value. We find that medians of MAESTRO measurements binned by month and latitude show reasonable correlation with other data sets, with notable increases after volcanic eruptions, and that biases in the data can be alleviated through a simple correction technique. Used with care, MAESTRO aerosol measurements provide information that can complement other data sets.
Oleh Kachula, Bärbel Vogel, Gebhard Günther, and Rolf Müller
Atmos. Chem. Phys., 25, 15171–15195, https://doi.org/10.5194/acp-25-15171-2025, https://doi.org/10.5194/acp-25-15171-2025, 2025
Short summary
Short summary
We propose a novel method to define the boundary of the Asian summer monsoon anticyclone (ASMA) and provide the inter-annual and intra-seasonal analyses based on 44 years (1980–2023) and highlight individual years – 2017, 2022 and 2023 during which aircraft campaigns StratoClim, ACCLIP and PHILEAS took place respectively. Our method shows consistent results with previous studies but also provide new information about possible bimodality of the ASMA and inter-annual decrease of the ASMA area.
Martina Krämer, Nicole Spelten, Christian Rolf, and Reinhold Spang
Atmos. Chem. Phys., 25, 13563–13583, https://doi.org/10.5194/acp-25-13563-2025, https://doi.org/10.5194/acp-25-13563-2025, 2025
Short summary
Short summary
The size and number of cirrus ice crystals is one parameter influencing the still uncertain effect of cirrus clouds on climate. Here, the occurrence of ice particle sizes and concentrations with varying temperature and cloud microphysical thickness is analyzed as well as whether they formed in-situ or were transported upwards as frozen droplets from further below. The analyses are based on a large database of airborne measurements and extensive simulations.
Rolf Müller, Lennart Bengtsson, John Birks, John Burrows, Ruprecht Jaenicke, and Richard S. Stolarski
Hist. Geo Space. Sci., 16, 31–40, https://doi.org/10.5194/hgss-16-31-2025, https://doi.org/10.5194/hgss-16-31-2025, 2025
Short summary
Short summary
This paper reports a few anecdotes from the life of Paul J. Crutzen that were contributed by friends and colleagues. Taken together, these anecdotes should shed some light on the person that Paul was, as this is perhaps sometimes obscured when focusing solely on his many scientific achievements.
Markus Jesswein, Valentin Lauther, Nicolas Emig, Peter Hoor, Timo Keber, Hans-Christoph Lachnitt, Linda Ort, Tanja Schuck, Johannes Strobel, Ronja Van Luijt, C. Michael Volk, Franziska Weyland, and Andreas Engel
Atmos. Chem. Phys., 25, 8107–8126, https://doi.org/10.5194/acp-25-8107-2025, https://doi.org/10.5194/acp-25-8107-2025, 2025
Short summary
Short summary
The study investigates transport within the Asian Summer Monsoon, focusing on how CH2Cl2 reaches the subarctic tropopause region. Using data from the PHILEAS campaign in 2023, events with increased mixing ratios were detected. Their origin, the transport paths to the tropopause region, and the potential entry into the stratosphere were analyzed. The East Asian Summer Monsoon was identified as the main transport pathway, with only a small contribution to the stratosphere in the following days.
Jasna V. Pittman, Bruce C. Daube, Steven C. Wofsy, Elliot L. Atlas, Maria A. Navarro, Eric J. Hintsa, Fred L. Moore, Geoff S. Dutton, James W. Elkins, Troy D. Thornberry, Andrew W. Rollins, Eric J. Jensen, Thaopaul Bui, Jonathan Dean-Day, and Leonhard Pfister
Atmos. Chem. Phys., 25, 7543–7562, https://doi.org/10.5194/acp-25-7543-2025, https://doi.org/10.5194/acp-25-7543-2025, 2025
Short summary
Short summary
Biomass fires emit aerosols and precursors that can provide a novel environment for initiating stratospheric ozone loss. The Airborne Tropical TRopopause EXperiment campaign sampled the western Pacific, the dominant longitudes for surface air lofted by convection to enter the global stratosphere. Aircraft measurements over multiple flights revealed persistent layers of biomass burning pollutants entering the lower stratosphere and originating from fires as far away as Africa and Indonesia.
Farahnaz Khosrawi and Lars Hoffmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-3147, https://doi.org/10.5194/egusphere-2025-3147, 2025
Preprint archived
Short summary
Short summary
Computer performance has increased immensely in recent years, but the ability to store data has only increased slightly. This presents scientists with major challenges. Many compression methods have been developed in recent years with which data can be stored either lossless or lossy. Here we test three of these methods: two lossy compression methods and one lossless compressor. Our study shows that compression is a valuable tool to cope with the high demand of disk space from these data sets.
Patrick E. Sheese, Kaley A. Walker, Chris D. Boone, and David A. Plummer
Atmos. Chem. Phys., 25, 5199–5213, https://doi.org/10.5194/acp-25-5199-2025, https://doi.org/10.5194/acp-25-5199-2025, 2025
Short summary
Short summary
Observations from Atmospheric Chemistry Experiment–Fourier Transform Spectrometer (ACE-FTS) are used to examine global stratospheric water vapour trends for 2004–2021. The satellite measurements are used to quantify trend contributions arising from changes in tropical tropopause temperatures, general circulation patterns, and methane concentrations. While most of the observed trends can be explained by these changes, there remains an unaccounted-for and increasing source of water vapour in the lower mid-stratosphere at mid-latitudes, which is discussed.
Mingzhao Liu, Lars Hoffmann, Jens-Uwe Grooß, Zhongyin Cai, Sabine Grießbach, and Yi Heng
Atmos. Chem. Phys., 25, 4403–4418, https://doi.org/10.5194/acp-25-4403-2025, https://doi.org/10.5194/acp-25-4403-2025, 2025
Short summary
Short summary
We studied the transport and chemical decomposition of volcanic SO2, focusing on the 2019 Raikoke event. By comparing two different chemistry modeling schemes, we found that including complex chemical reactions leads to a more accurate prediction of how long SO2 stays in the atmosphere. This research helps improve our understanding of volcanic pollution and its impact on air quality and climate, providing better tools for scientists to track and predict the movement of these pollutants.
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
Short summary
Short summary
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.
Astrid Kerkweg, Timo Kirfel, Duong H. Do, Sabine Griessbach, Patrick Jöckel, and Domenico Taraborrelli
Geosci. Model Dev., 18, 1265–1286, https://doi.org/10.5194/gmd-18-1265-2025, https://doi.org/10.5194/gmd-18-1265-2025, 2025
Short summary
Short summary
Normally, the Modular Earth Submodel System (MESSy) is linked to complete dynamic models to create chemical climate models. However, the modular concept of MESSy and the newly developed DWARF component presented here make it possible to create simplified models that contain only one or a few process descriptions. This is very useful for technical optimisation, such as porting to GPUs, and can be used to create less complex models, such as a chemical box model.
Prashant Chavan, Suvarna Fadnavis, Anton Laakso, Jean-Paul Vernier, Simone Tilmes, and Rolf Müller
EGUsphere, https://doi.org/10.5194/egusphere-2024-3825, https://doi.org/10.5194/egusphere-2024-3825, 2025
Preprint archived
Short summary
Short summary
Our simulations with volcanoes, when compared without volcanoes, show that volcanic aerosol precursors enter the tropical stratosphere, propagating upward and enhancing sulphate aerosol and heating. This stratospheric heating caused by the volcanoes reduces the amplitude of the QBO and disrupts its phases. Since QBO also modulates tropical convection and weather, we suggest including volcanic emissions and the QBO in the weather prediction model for a better forecast.
Paul S. Jeffery, James R. Drummond, C. Thomas McElroy, Kaley A. Walker, and Jiansheng Zou
Atmos. Meas. Tech., 18, 569–602, https://doi.org/10.5194/amt-18-569-2025, https://doi.org/10.5194/amt-18-569-2025, 2025
Short summary
Short summary
The MAESTRO instrument has been monitoring ozone and NO2 since February 2004. A new version of these data products has recently been released; however, these new products must be validated against other datasets to ensure their validity. This study presents such an assessment, using measurements from 11 satellite instruments to characterize the new MAESTRO products. In the stratosphere, good agreement is found for ozone and acceptable agreement is found for NO2 with these other datasets.
Kimberlee Dubé, Susann Tegtmeier, Felix Ploeger, and Kaley A. Walker
Atmos. Chem. Phys., 25, 1433–1447, https://doi.org/10.5194/acp-25-1433-2025, https://doi.org/10.5194/acp-25-1433-2025, 2025
Short summary
Short summary
The transport rate of air in the stratosphere has changed in response to human emissions of greenhouse gases and ozone-depleting substances. This transport rate can be approximated using measurements of long-lived trace gases. We use observations and model results to derive anomalies and trends in the mean rate of stratospheric air transport. We find that air in the Northern Hemisphere aged by up to 0.3 years per decade relative to air in the Southern Hemisphere over 2004–2017.
Jiansheng Zou, Kaley A. Walker, Patrick E. Sheese, Chris D. Boone, Ryan M. Stauffer, Anne M. Thompson, and David W. Tarasick
Atmos. Meas. Tech., 17, 6983–7005, https://doi.org/10.5194/amt-17-6983-2024, https://doi.org/10.5194/amt-17-6983-2024, 2024
Short summary
Short summary
Ozone measurements from the ACE-FTS satellite instrument have been compared to worldwide balloon-borne ozonesonde profiles using pairs of closely spaced profiles and monthly averaged profiles. ACE-FTS typically measures more ozone in the stratosphere by up to 10 %. The long-term stability of the ACE-FTS ozone data is good, exhibiting small (but non-significant) drifts of less than 3 % per decade in the stratosphere. Lower in the profiles, the calculated drifts are larger (up to 10 % per decade).
Yiran Zhang-Liu, Rolf Müller, Jens-Uwe Grooß, Sabine Robrecht, Bärbel Vogel, Abdul Mannan Zafar, and Ralph Lehmann
Atmos. Chem. Phys., 24, 12557–12574, https://doi.org/10.5194/acp-24-12557-2024, https://doi.org/10.5194/acp-24-12557-2024, 2024
Short summary
Short summary
HCl null cycles in Antarctica are important for maintaining high values of ozone-destroying chlorine in Antarctic spring. These HCl null cycles are not affected by (1) using the most recent recommendations of chemical kinetics (compared to older recommendations), (2) accounting for dehydration in the Antarctic winter vortex, and (3) considering the observed (but unexplained) depletion of HCl in mid-winter in the Antarctic vortex throughout Antarctic winter.
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
Short summary
Short summary
In this study we describe new techniques to derive age of air from multiple simultaneous measurements of long-lived trace gases in order to improve the fidelity of the age-of-air estimates and to be able to compare age of air from measurements taken from different instruments, platforms and decades. This technique also allows new transport information to be obtained from the measurements such as the primary source latitude that can also be compared to models.
Ling Zou, Reinhold Spang, Sabine Griessbach, Lars Hoffmann, Farahnaz Khosrawi, Rolf Müller, and Ines Tritscher
Atmos. Chem. Phys., 24, 11759–11774, https://doi.org/10.5194/acp-24-11759-2024, https://doi.org/10.5194/acp-24-11759-2024, 2024
Short summary
Short summary
This study provided estimates of the occurrence of ice polar stratospheric clouds (PSCs) observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and their connection with temperatures above the frost point (Tice) using a Lagrangian model derived from ERA5. We found that ice PSCs above Tice with temperature fluctuations along the backward trajectory are 33 % in the Arctic and 9 % in the Antarctic. This quantitative assessment enhances our understanding of ice PSCs.
Cynthia D. Nevison, Qing Liang, Paul A. Newman, Britton B. Stephens, Geoff Dutton, Xin Lan, Roisin Commane, Yenny Gonzalez, and Eric Kort
Atmos. Chem. Phys., 24, 10513–10529, https://doi.org/10.5194/acp-24-10513-2024, https://doi.org/10.5194/acp-24-10513-2024, 2024
Short summary
Short summary
This study examines the drivers of interannual variability in tropospheric N2O. New insights are obtained from aircraft data and a chemistry–climate model that explicitly simulates stratospheric N2O. The stratosphere is found to be the dominant driver of N2O variability in the Northern Hemisphere, while both the stratosphere and El Niño cycles are important in the Southern Hemisphere. These results are consistent with known atmospheric dynamics and differences between the hemispheres.
Luis F. Millán, Peter Hoor, Michaela I. Hegglin, Gloria L. Manney, Harald Boenisch, Paul Jeffery, Daniel Kunkel, Irina Petropavlovskikh, Hao Ye, Thierry Leblanc, and Kaley Walker
Atmos. Chem. Phys., 24, 7927–7959, https://doi.org/10.5194/acp-24-7927-2024, https://doi.org/10.5194/acp-24-7927-2024, 2024
Short summary
Short summary
In the Observed Composition Trends And Variability in the UTLS (OCTAV-UTLS) Stratosphere-troposphere Processes And their Role in Climate (SPARC) activity, we have mapped multiplatform ozone datasets into coordinate systems to systematically evaluate the influence of these coordinates on binned climatological variability. This effort unifies the work of studies that focused on individual coordinate system variability. Our goal was to create the most comprehensive assessment of this topic.
Jayanarayanan Kuttippurath, Gopalakrishna Pillai Gopikrishnan, Rolf Müller, Sophie Godin-Beekmann, and Jerome Brioude
Atmos. Chem. Phys., 24, 6743–6756, https://doi.org/10.5194/acp-24-6743-2024, https://doi.org/10.5194/acp-24-6743-2024, 2024
Short summary
Short summary
The current understanding and observational evidence do not provide any support for the possibility of an ozone hole occurring outside Antarctica today with respect to the present-day stratospheric halogen levels.
Hanqin Tian, Naiqing Pan, Rona L. Thompson, Josep G. Canadell, Parvadha Suntharalingam, Pierre Regnier, Eric A. Davidson, Michael Prather, Philippe Ciais, Marilena Muntean, Shufen Pan, Wilfried Winiwarter, Sönke Zaehle, Feng Zhou, Robert B. Jackson, Hermann W. Bange, Sarah Berthet, Zihao Bian, Daniele Bianchi, Alexander F. Bouwman, Erik T. Buitenhuis, Geoffrey Dutton, Minpeng Hu, Akihiko Ito, Atul K. Jain, Aurich Jeltsch-Thömmes, Fortunat Joos, Sian Kou-Giesbrecht, Paul B. Krummel, Xin Lan, Angela Landolfi, Ronny Lauerwald, Ya Li, Chaoqun Lu, Taylor Maavara, Manfredi Manizza, Dylan B. Millet, Jens Mühle, Prabir K. Patra, Glen P. Peters, Xiaoyu Qin, Peter Raymond, Laure Resplandy, Judith A. Rosentreter, Hao Shi, Qing Sun, Daniele Tonina, Francesco N. Tubiello, Guido R. van der Werf, Nicolas Vuichard, Junjie Wang, Kelley C. Wells, Luke M. Western, Chris Wilson, Jia Yang, Yuanzhi Yao, Yongfa You, and Qing Zhu
Earth Syst. Sci. Data, 16, 2543–2604, https://doi.org/10.5194/essd-16-2543-2024, https://doi.org/10.5194/essd-16-2543-2024, 2024
Short summary
Short summary
Atmospheric concentrations of nitrous oxide (N2O), a greenhouse gas 273 times more potent than carbon dioxide, have increased by 25 % since the preindustrial period, with the highest observed growth rate in 2020 and 2021. This rapid growth rate has primarily been due to a 40 % increase in anthropogenic emissions since 1980. Observed atmospheric N2O concentrations in recent years have exceeded the worst-case climate scenario, underscoring the importance of reducing anthropogenic N2O emissions.
Karen De Los Ríos, Paulina Ordoñez, Gabriele P. Stiller, Piera Raspollini, Marco Gai, Kaley A. Walker, Cristina Peña-Ortiz, and Luis Acosta
Atmos. Meas. Tech., 17, 3401–3418, https://doi.org/10.5194/amt-17-3401-2024, https://doi.org/10.5194/amt-17-3401-2024, 2024
Short summary
Short summary
This study examines newer versions of H2O and HDO retrievals from Envisat/MIPAS and SCISAT/ACE-FTS. Results reveal a better agreement in stratospheric H2O profiles than in HDO profiles. The H2O tape recorder signal is consistent across databases, but δD tape recorder composites show differences that impact the interpretation of water vapour transport. These findings enhance the need for intercomparisons to refine our insights.
Jan Clemens, Lars Hoffmann, Bärbel Vogel, Sabine Grießbach, and Nicole Thomas
Geosci. Model Dev., 17, 4467–4493, https://doi.org/10.5194/gmd-17-4467-2024, https://doi.org/10.5194/gmd-17-4467-2024, 2024
Short summary
Short summary
Lagrangian transport models simulate the transport of air masses in the atmosphere. For example, one model (CLaMS) is well suited to calculating transport as it uses a special coordinate system and special vertical wind. However, it only runs inefficiently on modern supercomputers. Hence, we have implemented the benefits of CLaMS into a new model (MPTRAC), which is already highly efficient on modern supercomputers. Finally, in extensive tests, we showed that CLaMS and MPTRAC agree very well.
Xin Yang, Kimberly Strong, Alison S. Criscitiello, Marta Santos-Garcia, Kristof Bognar, Xiaoyi Zhao, Pierre Fogal, Kaley A. Walker, Sara M. Morris, and Peter Effertz
Atmos. Chem. Phys., 24, 5863–5886, https://doi.org/10.5194/acp-24-5863-2024, https://doi.org/10.5194/acp-24-5863-2024, 2024
Short summary
Short summary
This study uses snow samples collected from a Canadian high Arctic site, Eureka, to demonstrate that surface snow in early spring is a net sink of atmospheric bromine and nitrogen. Surface snow bromide and nitrate are significantly correlated, indicating the oxidation of reactive nitrogen is accelerated by reactive bromine. In addition, we show evidence that snow photochemical release of reactive bromine is very weak, and its emission flux is much smaller than the deposition flux of bromide.
Lars Hoffmann, Kaveh Haghighi Mood, Andreas Herten, Markus Hrywniak, Jiri Kraus, Jan Clemens, and Mingzhao Liu
Geosci. Model Dev., 17, 4077–4094, https://doi.org/10.5194/gmd-17-4077-2024, https://doi.org/10.5194/gmd-17-4077-2024, 2024
Short summary
Short summary
Lagrangian particle dispersion models are key for studying atmospheric transport but can be computationally intensive. To speed up simulations, the MPTRAC model was ported to graphics processing units (GPUs). Performance optimization of data structures and memory alignment resulted in runtime improvements of up to 75 % on NVIDIA A100 GPUs for ERA5-based simulations with 100 million particles. These optimizations make the MPTRAC model well suited for future high-performance computing systems.
Felicia Kolonjari, Patrick E. Sheese, Kaley A. Walker, Chris D. Boone, David A. Plummer, Andreas Engel, Stephen A. Montzka, David E. Oram, Tanja Schuck, Gabriele P. Stiller, and Geoffrey C. Toon
Atmos. Meas. Tech., 17, 2429–2449, https://doi.org/10.5194/amt-17-2429-2024, https://doi.org/10.5194/amt-17-2429-2024, 2024
Short summary
Short summary
The Canadian Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) satellite instrument is currently providing the only vertically resolved chlorodifluoromethane (HCFC-22) measurements from space. This study assesses the most current ACE-FTS HCFC-22 data product in the upper troposphere and lower stratosphere, as well as modelled HCFC-22 from a 39-year run of the Canadian Middle Atmosphere Model (CMAM39) in the same region.
Paul S. Jeffery, James R. Drummond, Jiansheng Zou, and Kaley A. Walker
Atmos. Chem. Phys., 24, 4253–4263, https://doi.org/10.5194/acp-24-4253-2024, https://doi.org/10.5194/acp-24-4253-2024, 2024
Short summary
Short summary
The MOPITT instrument has been monitoring carbon monoxide (CO) since March 2000. This dataset has been used for many applications; however, episodic emission events, which release large amounts of CO into the atmosphere, are a major source of uncertainty. This study presents a method for identifying these events by determining measurements that are unlikely to have typically arisen. The distribution and frequency of these flagged measurements in the MOPITT dataset are presented and discussed.
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
Short summary
Short summary
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.
Irene Bartolomé García, Odran Sourdeval, Reinhold Spang, and Martina Krämer
Atmos. Chem. Phys., 24, 1699–1716, https://doi.org/10.5194/acp-24-1699-2024, https://doi.org/10.5194/acp-24-1699-2024, 2024
Short summary
Short summary
How many ice crystals of each size are in a cloud is a key parameter for the retrieval of cloud properties. The distribution of ice crystals is obtained from in situ measurements and used to create parameterizations that can be used when analyzing the remote-sensing data. Current parameterizations are based on data sets that do not include reliable measurements of small crystals, but in our study we use a data set that includes very small ice crystals to improve these parameterizations.
Reinhold Spang, Rolf Müller, and Alexandru Rap
Atmos. Chem. Phys., 24, 1213–1230, https://doi.org/10.5194/acp-24-1213-2024, https://doi.org/10.5194/acp-24-1213-2024, 2024
Short summary
Short summary
Cirrus clouds play an important role in the radiation budget of the Earth. Despite recent progress in their observation, the radiative impact of ultra-thin cirrus clouds (UTC) in the tropopause region and in the lowermost stratosphere remains poorly constrained. Sensitivity model simulations with different ice parameters provide an uncertainty range for the radiative effect of UTCs. There is a need for better observed UTCs to enable the simulation of their potentially large effect on climate.
Victoria A. Flood, Kimberly Strong, Cynthia H. Whaley, Kaley A. Walker, Thomas Blumenstock, James W. Hannigan, Johan Mellqvist, Justus Notholt, Mathias Palm, Amelie N. Röhling, Stephen Arnold, Stephen Beagley, Rong-You Chien, Jesper Christensen, Makoto Deushi, Srdjan Dobricic, Xinyi Dong, Joshua S. Fu, Michael Gauss, Wanmin Gong, Joakim Langner, Kathy S. Law, Louis Marelle, Tatsuo Onishi, Naga Oshima, David A. Plummer, Luca Pozzoli, Jean-Christophe Raut, Manu A. Thomas, Svetlana Tsyro, and Steven Turnock
Atmos. Chem. Phys., 24, 1079–1118, https://doi.org/10.5194/acp-24-1079-2024, https://doi.org/10.5194/acp-24-1079-2024, 2024
Short summary
Short summary
It is important to understand the composition of the Arctic atmosphere and how it is changing. Atmospheric models provide simulations that can inform policy. This study examines simulations of CH4, CO, and O3 by 11 models. Model performance is assessed by comparing results matched in space and time to measurements from five high-latitude ground-based infrared spectrometers. This work finds that models generally underpredict the concentrations of these gases in the Arctic troposphere.
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
Short summary
Short summary
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.
Abhiraj Bishnoi, Olaf Stein, Catrin I. Meyer, René Redler, Norbert Eicker, Helmuth Haak, Lars Hoffmann, Daniel Klocke, Luis Kornblueh, and Estela Suarez
Geosci. Model Dev., 17, 261–273, https://doi.org/10.5194/gmd-17-261-2024, https://doi.org/10.5194/gmd-17-261-2024, 2024
Short summary
Short summary
We enabled the weather and climate model ICON to run in a high-resolution coupled atmosphere–ocean setup on the JUWELS supercomputer, where the ocean and the model I/O runs on the CPU Cluster, while the atmosphere is running simultaneously on GPUs. Compared to a simulation performed on CPUs only, our approach reduces energy consumption by 45 % with comparable runtimes. The experiments serve as preparation for efficient computing of kilometer-scale climate models on future supercomputing systems.
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
Atmos. Chem. Phys., 24, 317–343, https://doi.org/10.5194/acp-24-317-2024, https://doi.org/10.5194/acp-24-317-2024, 2024
Short summary
Short summary
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.
Xue Wu, Lars Hoffmann, Corwin J. Wright, Neil P. Hindley, M. Joan Alexander, Silvio Kalisch, Xin Wang, Bing Chen, Yinan Wang, and Daren Lyu
EGUsphere, https://doi.org/10.5194/egusphere-2023-3008, https://doi.org/10.5194/egusphere-2023-3008, 2024
Preprint archived
Short summary
Short summary
This study identified a noteworthy time-lagged correlation between hurricane intensity and stratospheric gravity wave intensities during hurricane intensification. Meanwhile, the study reveals distinct frequencies, horizontal wavelengths, and vertical wavelengths in the inner core region during hurricane intensification, offering essential insights for monitoring hurricane intensity via satellite observations of stratospheric gravity waves.
Andrea Pazmiño, Florence Goutail, Sophie Godin-Beekmann, Alain Hauchecorne, Jean-Pierre Pommereau, Martyn P. Chipperfield, Wuhu Feng, Franck Lefèvre, Audrey Lecouffe, Michel Van Roozendael, Nis Jepsen, Georg Hansen, Rigel Kivi, Kimberly Strong, and Kaley A. Walker
Atmos. Chem. Phys., 23, 15655–15670, https://doi.org/10.5194/acp-23-15655-2023, https://doi.org/10.5194/acp-23-15655-2023, 2023
Short summary
Short summary
The vortex-averaged ozone loss over the last 3 decades is evaluated for both polar regions using the passive ozone tracer of the chemical transport model TOMCAT/SLIMCAT and total ozone observations from the SAOZ network and MSR2 reanalysis. Three metrics were developed to compute ozone trends since 2000. The study confirms the ozone recovery in the Antarctic and shows a potential sign of quantitative detection of ozone recovery in the Arctic that needs to be robustly confirmed in the future.
Rolf Müller, Ulrich Pöschl, Thomas Koop, Thomas Peter, and Ken Carslaw
Atmos. Chem. Phys., 23, 15445–15453, https://doi.org/10.5194/acp-23-15445-2023, https://doi.org/10.5194/acp-23-15445-2023, 2023
Short summary
Short summary
Paul J. Crutzen was a pioneer in atmospheric sciences and a kind-hearted, humorous person with empathy for the private lives of his colleagues and students. He made fundamental scientific contributions to a wide range of scientific topics in all parts of the atmosphere. Paul was among the founders of the journal Atmospheric Chemistry and Physics. His work will continue to be a guide for generations of scientists and environmental policymakers to come.
Kimberlee Dubé, Susann Tegtmeier, Adam Bourassa, Daniel Zawada, Douglas Degenstein, Patrick E. Sheese, Kaley A. Walker, and William Randel
Atmos. Chem. Phys., 23, 13283–13300, https://doi.org/10.5194/acp-23-13283-2023, https://doi.org/10.5194/acp-23-13283-2023, 2023
Short summary
Short summary
This paper presents a technique for understanding the causes of long-term changes in stratospheric composition. By using N2O as a proxy for stratospheric circulation in the model used to calculated trends, it is possible to separate the effects of dynamics and chemistry on observed trace gas trends. We find that observed HCl increases are due to changes in the stratospheric circulation, as are O3 decreases above 30 hPa in the Northern Hemisphere.
Michael Kiefer, Dale F. Hurst, Gabriele P. Stiller, Stefan Lossow, Holger Vömel, John Anderson, Faiza Azam, Jean-Loup Bertaux, Laurent Blanot, Klaus Bramstedt, John P. Burrows, Robert Damadeo, Bianca Maria Dinelli, Patrick Eriksson, Maya García-Comas, John C. Gille, Mark Hervig, Yasuko Kasai, Farahnaz Khosrawi, Donal Murtagh, Gerald E. Nedoluha, Stefan Noël, Piera Raspollini, William G. Read, Karen H. Rosenlof, Alexei Rozanov, Christopher E. Sioris, Takafumi Sugita, Thomas von Clarmann, Kaley A. Walker, and Katja Weigel
Atmos. Meas. Tech., 16, 4589–4642, https://doi.org/10.5194/amt-16-4589-2023, https://doi.org/10.5194/amt-16-4589-2023, 2023
Short summary
Short summary
We quantify biases and drifts (and their uncertainties) between the stratospheric water vapor measurement records of 15 satellite-based instruments (SATs, with 31 different retrievals) and balloon-borne frost point hygrometers (FPs) launched at 27 globally distributed stations. These comparisons of measurements during the period 2000–2016 are made using robust, consistent statistical methods. With some exceptions, the biases and drifts determined for most SAT–FP pairs are < 10 % and < 1 % yr−1.
Suvarna Fadnavis, Bernd Heinold, T. P. Sabin, Anne Kubin, Katty Huang, Alexandru Rap, and Rolf Müller
Atmos. Chem. Phys., 23, 10439–10449, https://doi.org/10.5194/acp-23-10439-2023, https://doi.org/10.5194/acp-23-10439-2023, 2023
Short summary
Short summary
The influence of the COVID-19 lockdown on the Himalayas caused increases in snow cover and a decrease in runoff, ultimately leading to an enhanced snow water equivalent. Our findings highlight that, out of the two processes causing a retreat of Himalayan glaciers – (1) slow response to global climate change and (2) fast response to local air pollution – a policy action on the latter is more likely to be within the reach of possible policy action to help billions of people in southern Asia.
Mingzhao Liu, Lars Hoffmann, Sabine Griessbach, Zhongyin Cai, Yi Heng, and Xue Wu
Geosci. Model Dev., 16, 5197–5217, https://doi.org/10.5194/gmd-16-5197-2023, https://doi.org/10.5194/gmd-16-5197-2023, 2023
Short summary
Short summary
We introduce new and revised chemistry and physics modules in the Massive-Parallel Trajectory Calculations (MPTRAC) Lagrangian transport model aiming to improve the representation of volcanic SO2 transport and depletion. We test these modules in a case study of the Ambae eruption in July 2018 in which the SO2 plume underwent wet removal and convection. The lifetime of SO2 shows highly variable and complex dependencies on the atmospheric conditions at different release heights.
Lars Hoffmann, Paul Konopka, Jan Clemens, and Bärbel Vogel
Atmos. Chem. Phys., 23, 7589–7609, https://doi.org/10.5194/acp-23-7589-2023, https://doi.org/10.5194/acp-23-7589-2023, 2023
Short summary
Short summary
Atmospheric convection plays a key role in tracer transport in the troposphere. Global meteorological forecasts and reanalyses typically have a coarse spatiotemporal resolution that does not adequately resolve the dynamics, transport, and mixing of air associated with storm systems or deep convection. We discuss the application of the extreme convection parameterization in a Lagrangian transport model to improve simulations of tracer transport from the boundary layer into the free troposphere.
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
Short summary
Short summary
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.
Jianghanyang Li, Bianca C. Baier, Fred Moore, Tim Newberger, Sonja Wolter, Jack Higgs, Geoff Dutton, Eric Hintsa, Bradley Hall, and Colm Sweeney
Atmos. Meas. Tech., 16, 2851–2863, https://doi.org/10.5194/amt-16-2851-2023, https://doi.org/10.5194/amt-16-2851-2023, 2023
Short summary
Short summary
Monitoring a suite of trace gases in the stratosphere will help us better understand the stratospheric circulation and its impact on the earth's radiation balance. However, such measurements are rare and usually expensive. We developed an instrument that can measure stratospheric trace gases using a low-cost sampling platform (AirCore). The results showed expected agreement with aircraft measurements, demonstrating this technique provides a low-cost and robust way to observe the stratosphere.
Viktoria F. Sofieva, Monika Szelag, Johanna Tamminen, Carlo Arosio, Alexei Rozanov, Mark Weber, Doug Degenstein, Adam Bourassa, Daniel Zawada, Michael Kiefer, Alexandra Laeng, Kaley A. Walker, Patrick Sheese, Daan Hubert, Michel van Roozendael, Christian Retscher, Robert Damadeo, and Jerry D. Lumpe
Atmos. Meas. Tech., 16, 1881–1899, https://doi.org/10.5194/amt-16-1881-2023, https://doi.org/10.5194/amt-16-1881-2023, 2023
Short summary
Short summary
The paper presents the updated SAGE-CCI-OMPS+ climate data record of monthly zonal mean ozone profiles. This dataset covers the stratosphere and combines measurements by nine limb and occultation satellite instruments (SAGE II, OSIRIS, MIPAS, SCIAMACHY, GOMOS, ACE-FTS, OMPS-LP, POAM III, and SAGE III/ISS). The update includes new versions of MIPAS, ACE-FTS, and OSIRIS datasets and introduces data from additional sensors (POAM III and SAGE III/ISS) and retrieval processors (OMPS-LP).
Nasrin Mostafavi Pak, Jacob K. Hedelius, Sébastien Roche, Liz Cunningham, Bianca Baier, Colm Sweeney, Coleen Roehl, Joshua Laughner, Geoffrey Toon, Paul Wennberg, Harrison Parker, Colin Arrowsmith, Joseph Mendonca, Pierre Fogal, Tyler Wizenberg, Beatriz Herrera, Kimberly Strong, Kaley A. Walker, Felix Vogel, and Debra Wunch
Atmos. Meas. Tech., 16, 1239–1261, https://doi.org/10.5194/amt-16-1239-2023, https://doi.org/10.5194/amt-16-1239-2023, 2023
Short summary
Short summary
Ground-based remote sensing instruments in the Total Carbon Column Observing Network (TCCON) measure greenhouse gases in the atmosphere. Consistency between TCCON measurements is crucial to accurately infer changes in atmospheric composition. We use portable remote sensing instruments (EM27/SUN) to evaluate biases between TCCON stations in North America. We also improve the retrievals of EM27/SUN instruments and evaluate the previous (GGG2014) and newest (GGG2020) retrieval algorithms.
Joshua L. Laughner, Sébastien Roche, Matthäus Kiel, Geoffrey C. Toon, Debra Wunch, Bianca C. Baier, Sébastien Biraud, Huilin Chen, Rigel Kivi, Thomas Laemmel, Kathryn McKain, Pierre-Yves Quéhé, Constantina Rousogenous, Britton B. Stephens, Kaley Walker, and Paul O. Wennberg
Atmos. Meas. Tech., 16, 1121–1146, https://doi.org/10.5194/amt-16-1121-2023, https://doi.org/10.5194/amt-16-1121-2023, 2023
Short summary
Short summary
Observations using sunlight to measure surface-to-space total column of greenhouse gases in the atmosphere need an initial guess of the vertical distribution of those gases to start from. We have developed an approach to provide those initial guess profiles that uses readily available meteorological data as input. This lets us make these guesses without simulating them with a global model. The profiles generated this way match independent observations well.
Lei Hu, Deborah Ottinger, Stephanie Bogle, Stephen A. Montzka, Philip L. DeCola, Ed Dlugokencky, Arlyn Andrews, Kirk Thoning, Colm Sweeney, Geoff Dutton, Lauren Aepli, and Andrew Crotwell
Atmos. Chem. Phys., 23, 1437–1448, https://doi.org/10.5194/acp-23-1437-2023, https://doi.org/10.5194/acp-23-1437-2023, 2023
Short summary
Short summary
Effective mitigation of greenhouse gas (GHG) emissions relies on an accurate understanding of emissions. Here we demonstrate the added value of using inventory- and atmosphere-based approaches for estimating US emissions of SF6, the most potent GHG known. The results suggest a large decline in US SF6 emissions, shed light on the possible processes causing the differences between the independent estimates, and identify opportunities for substantial additional emission reductions.
Reimar Bauer, Jens-Uwe Grooß, Jörn Ungermann, May Bär, Markus Geldenhuys, and Lars Hoffmann
Geosci. Model Dev., 15, 8983–8997, https://doi.org/10.5194/gmd-15-8983-2022, https://doi.org/10.5194/gmd-15-8983-2022, 2022
Short summary
Short summary
The Mission Support System (MSS) is an open source software package that has been used for planning flight tracks of scientific aircraft in multiple measurement campaigns during the last decade. Here, we describe the MSS software and its use during the SouthTRAC measurement campaign in 2019. As an example for how the MSS software is used in conjunction with many datasets, we describe the planning of a single flight probing orographic gravity waves propagating up into the lower mesosphere.
Ali Jalali, Kaley A. Walker, Kimberly Strong, Rebecca R. Buchholz, Merritt N. Deeter, Debra Wunch, Sébastien Roche, Tyler Wizenberg, Erik Lutsch, Erin McGee, Helen M. Worden, Pierre Fogal, and James R. Drummond
Atmos. Meas. Tech., 15, 6837–6863, https://doi.org/10.5194/amt-15-6837-2022, https://doi.org/10.5194/amt-15-6837-2022, 2022
Short summary
Short summary
This study validates MOPITT version 8 carbon monoxide measurements over the Canadian high Arctic for the period 2006 to 2019. The MOPITT products from different detector pixels and channels are compared with ground-based measurements from the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Nunavut, Canada. These results show good consistency between the satellite and ground-based measurements and provide guidance on the usage of these MOPITT data at high latitudes.
Paul S. Jeffery, Kaley A. Walker, Chris E. Sioris, Chris D. Boone, Doug Degenstein, Gloria L. Manney, C. Thomas McElroy, Luis Millán, David A. Plummer, Niall J. Ryan, Patrick E. Sheese, and Jiansheng Zou
Atmos. Chem. Phys., 22, 14709–14734, https://doi.org/10.5194/acp-22-14709-2022, https://doi.org/10.5194/acp-22-14709-2022, 2022
Short summary
Short summary
The upper troposphere–lower stratosphere is one of the most variable regions in the atmosphere. To improve our understanding of water vapour and ozone concentrations in this region, climatologies have been developed from 14 years of measurements from three Canadian satellite instruments. Horizontal and vertical coordinates have been chosen to minimize the effects of variability. To aid in analysis, model simulations have been used to characterize differences between instrument climatologies.
Kimberlee Dubé, Daniel Zawada, Adam Bourassa, Doug Degenstein, William Randel, David Flittner, Patrick Sheese, and Kaley Walker
Atmos. Meas. Tech., 15, 6163–6180, https://doi.org/10.5194/amt-15-6163-2022, https://doi.org/10.5194/amt-15-6163-2022, 2022
Short summary
Short summary
Satellite observations are important for monitoring changes in atmospheric composition. Here we describe an improved version of the NO2 retrieval for the Optical Spectrograph and InfraRed Imager System. The resulting NO2 profiles are compared to those from the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer and the Stratospheric Aerosol and Gas Experiment III on the International Space Station. All datasets agree within 20 % throughout the stratosphere.
Xin Yang, Kimberly Strong, Alison S. Criscitiello, Marta Santos-Garcia, Kristof Bognar, Xiaoyi Zhao, Pierre Fogal, Kaley A. Walker, Sara M. Morris, and Peter Effertz
EGUsphere, https://doi.org/10.5194/egusphere-2022-696, https://doi.org/10.5194/egusphere-2022-696, 2022
Preprint archived
Short summary
Short summary
Snow pack in high Arctic plays a key role in polar atmospheric chemistry, especially in spring when photochemistry becomes active. By sampling surface snow from a Canadian high Arctic location at Eureka, Nunavut (80° N, 86° W), we demonstrate that surface snow is a net sink rather than a source of atmospheric reactive bromine and nitrate. This finding is new and opposite to previous conclusions that snowpack is a large and direct source of reactive bromine in polar spring.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
William G. Read, Gabriele Stiller, Stefan Lossow, Michael Kiefer, Farahnaz Khosrawi, Dale Hurst, Holger Vömel, Karen Rosenlof, Bianca M. Dinelli, Piera Raspollini, Gerald E. Nedoluha, John C. Gille, Yasuko Kasai, Patrick Eriksson, Christopher E. Sioris, Kaley A. Walker, Katja Weigel, John P. Burrows, and Alexei Rozanov
Atmos. Meas. Tech., 15, 3377–3400, https://doi.org/10.5194/amt-15-3377-2022, https://doi.org/10.5194/amt-15-3377-2022, 2022
Short summary
Short summary
This paper attempts to provide an assessment of the accuracy of 21 satellite-based instruments that remotely measure atmospheric humidity in the upper troposphere of the Earth's atmosphere. The instruments made their measurements from 1984 to the present time; however, most of these instruments began operations after 2000, and only a few are still operational. The objective of this study is to quantify the accuracy of each satellite humidity data set.
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
Short summary
Short summary
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.
Zhongyin Cai, Sabine Griessbach, and Lars Hoffmann
Atmos. Chem. Phys., 22, 6787–6809, https://doi.org/10.5194/acp-22-6787-2022, https://doi.org/10.5194/acp-22-6787-2022, 2022
Short summary
Short summary
Using AIRS and TROPOMI sulfur dioxide retrievals and the Lagrangian transport model MPTRAC, we present an improved reconstruction of injection parameters of the 2019 Raikoke eruption. Reconstructions agree well between using AIRS nighttime and TROPOMI daytime retrievals, showing the potential of our approach to create a long-term volcanic sulfur dioxide inventory from nearly 20 years of AIRS retrievals.
Ling Zou, Sabine Griessbach, Lars Hoffmann, and Reinhold Spang
Atmos. Chem. Phys., 22, 6677–6702, https://doi.org/10.5194/acp-22-6677-2022, https://doi.org/10.5194/acp-22-6677-2022, 2022
Short summary
Short summary
Ice clouds in the stratosphere (SICs) greatly affect the water vapor balance and radiation budget in the upper troposphere and lower stratosphere (UTLS). We quantified the global SICs and analyzed their relationships with tropopause temperature, double tropopauses, UTLS clouds, gravity waves, and stratospheric aerosols. The correlations between SICs and all abovementioned processes indicate that the occurrence of and variability in SICs are spatiotemporally dependent on different processes.
Cynthia H. Whaley, Rashed Mahmood, Knut von Salzen, Barbara Winter, Sabine Eckhardt, Stephen Arnold, Stephen Beagley, Silvia Becagli, Rong-You Chien, Jesper Christensen, Sujay Manish Damani, Xinyi Dong, Konstantinos Eleftheriadis, Nikolaos Evangeliou, Gregory Faluvegi, Mark Flanner, Joshua S. Fu, Michael Gauss, Fabio Giardi, Wanmin Gong, Jens Liengaard Hjorth, Lin Huang, Ulas Im, Yugo Kanaya, Srinath Krishnan, Zbigniew Klimont, Thomas Kühn, Joakim Langner, Kathy S. Law, Louis Marelle, Andreas Massling, Dirk Olivié, Tatsuo Onishi, Naga Oshima, Yiran Peng, David A. Plummer, Olga Popovicheva, Luca Pozzoli, Jean-Christophe Raut, Maria Sand, Laura N. Saunders, Julia Schmale, Sangeeta Sharma, Ragnhild Bieltvedt Skeie, Henrik Skov, Fumikazu Taketani, Manu A. Thomas, Rita Traversi, Kostas Tsigaridis, Svetlana Tsyro, Steven Turnock, Vito Vitale, Kaley A. Walker, Minqi Wang, Duncan Watson-Parris, and Tahya Weiss-Gibbons
Atmos. Chem. Phys., 22, 5775–5828, https://doi.org/10.5194/acp-22-5775-2022, https://doi.org/10.5194/acp-22-5775-2022, 2022
Short summary
Short summary
Air pollutants, like ozone and soot, play a role in both global warming and air quality. Atmospheric models are often used to provide information to policy makers about current and future conditions under different emissions scenarios. In order to have confidence in those simulations, in this study we compare simulated air pollution from 18 state-of-the-art atmospheric models to measured air pollution in order to assess how well the models perform.
Merritt Deeter, Gene Francis, John Gille, Debbie Mao, Sara Martínez-Alonso, Helen Worden, Dan Ziskin, James Drummond, Róisín Commane, Glenn Diskin, and Kathryn McKain
Atmos. Meas. Tech., 15, 2325–2344, https://doi.org/10.5194/amt-15-2325-2022, https://doi.org/10.5194/amt-15-2325-2022, 2022
Short summary
Short summary
The MOPITT (Measurements of Pollution in the Troposphere) satellite instrument uses remote sensing to obtain retrievals (measurements) of carbon monoxide (CO) in the atmosphere. This paper describes the latest MOPITT data product, Version 9. Globally, the number of daytime MOPITT retrievals over land has increased by 30 %–40 % compared to the previous product. The reported improvements in the MOPITT product should benefit a wide variety of applications including studies of pollution sources.
Lars Hoffmann, Paul F. Baumeister, Zhongyin Cai, Jan Clemens, Sabine Griessbach, Gebhard Günther, Yi Heng, Mingzhao Liu, Kaveh Haghighi Mood, Olaf Stein, Nicole Thomas, Bärbel Vogel, Xue Wu, and Ling Zou
Geosci. Model Dev., 15, 2731–2762, https://doi.org/10.5194/gmd-15-2731-2022, https://doi.org/10.5194/gmd-15-2731-2022, 2022
Short summary
Short summary
We describe the new version (2.2) of the Lagrangian transport model MPTRAC, which has been ported for application on GPUs. The model was verified by comparing kinematic trajectories and synthetic tracer simulations for the free troposphere and stratosphere from GPUs and CPUs. Benchmarking showed a speed-up of a factor of 16 of GPU-enabled simulations compared to CPU-only runs, indicating the great potential of applying GPUs for Lagrangian transport simulations on upcoming HPC systems.
Lars Hoffmann and Reinhold Spang
Atmos. Chem. Phys., 22, 4019–4046, https://doi.org/10.5194/acp-22-4019-2022, https://doi.org/10.5194/acp-22-4019-2022, 2022
Short summary
Short summary
We present an intercomparison of 2009–2018 lapse rate tropopause characteristics as derived from ECMWF's ERA5 and ERA-Interim reanalyses. Large-scale features are similar, but ERA5 shows notably larger variability, which we mainly attribute to UTLS temperature fluctuations due to gravity waves being better resolved by ECMWF's IFS forecast model. Following evaluation with radiosondes and GPS data, we conclude ERA5 will be a more suitable asset for tropopause-related studies in future work.
Patrick E. Sheese, Kaley A. Walker, Chris D. Boone, Adam E. Bourassa, Doug A. Degenstein, Lucien Froidevaux, C. Thomas McElroy, Donal Murtagh, James M. Russell III, and Jiansheng Zou
Atmos. Meas. Tech., 15, 1233–1249, https://doi.org/10.5194/amt-15-1233-2022, https://doi.org/10.5194/amt-15-1233-2022, 2022
Short summary
Short summary
This study analyzes the quality of two versions (v3.6 and v4.1) of ozone concentration measurements from the ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer), by comparing with data from five satellite instruments between 2004 and 2020. It was found that although the v3.6 data exhibit a better agreement than v4.1 with respect to the other instruments, v4.1 exhibits much better stability over time than v3.6. The stability of v4.1 makes it suitable for ozone trend studies.
Paul F. Baumeister and Lars Hoffmann
Geosci. Model Dev., 15, 1855–1874, https://doi.org/10.5194/gmd-15-1855-2022, https://doi.org/10.5194/gmd-15-1855-2022, 2022
Short summary
Short summary
The efficiency of the numerical simulation of radiative transport is shown on modern server-class graphics cards (GPUs). The low-cost prefactor on GPUs compared to general-purpose processors (CPUs) enables future large retrieval campaigns for multi-channel data from infrared sounders aboard low-orbit satellites. The validated research software JURASSIC is available in the public domain.
Lei Hu, Stephen A. Montzka, Fred Moore, Eric Hintsa, Geoff Dutton, M. Carolina Siso, Kirk Thoning, Robert W. Portmann, Kathryn McKain, Colm Sweeney, Isaac Vimont, David Nance, Bradley Hall, and Steven Wofsy
Atmos. Chem. Phys., 22, 2891–2907, https://doi.org/10.5194/acp-22-2891-2022, https://doi.org/10.5194/acp-22-2891-2022, 2022
Short summary
Short summary
The unexpected increase in CFC-11 emissions between 2012 and 2017 resulted in concerns about delaying the stratospheric ozone recovery. Although the subsequent decline of CFC-11 emissions indicated a mitigation in part to this problem, the regions fully responsible for these large emission changes were unclear. Here, our new estimate, based on atmospheric measurements from two global campaigns and from NOAA, suggests Asia primarily contributed to the global CFC-11 emission rise during 2012–2017.
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
Short summary
Short summary
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.
Heba S. Marey, James R. Drummond, Dylan B. A. Jones, Helen Worden, Merritt N. Deeter, John Gille, and Debbie Mao
Atmos. Meas. Tech., 15, 701–719, https://doi.org/10.5194/amt-15-701-2022, https://doi.org/10.5194/amt-15-701-2022, 2022
Short summary
Short summary
In this study, an analysis has been performed to understand the improvements in observational coverage over Canada in the new MOPITT V9 product. Temporal and spatial analysis of V9 indicates a general coverage gain of 15–20 % relative to V8, which varies regionally and seasonally; e.g., the number of successful MOPITT retrievals in V9 was doubled over Canada in winter. Also, comparison with the corresponding IASI instrument indicated generally good agreement, with about a 5–10 % positive bias.
Dina Khordakova, Christian Rolf, Jens-Uwe Grooß, Rolf Müller, Paul Konopka, Andreas Wieser, Martina Krämer, and Martin Riese
Atmos. Chem. Phys., 22, 1059–1079, https://doi.org/10.5194/acp-22-1059-2022, https://doi.org/10.5194/acp-22-1059-2022, 2022
Short summary
Short summary
Extreme storms transport humidity from the troposphere to the stratosphere. Here it has a strong impact on the climate. With ongoing global warming, we expect more storms and, hence, an enhancement of this effect. A case study was performed in order to measure the impact of the direct injection of water vapor into the lower stratosphere. The measurements displayed a significant transport of water vapor into the lower stratosphere, and this was supported by satellite and reanalysis data.
Tyler Wizenberg, Kimberly Strong, Kaley Walker, Erik Lutsch, Tobias Borsdorff, and Jochen Landgraf
Atmos. Meas. Tech., 14, 7707–7728, https://doi.org/10.5194/amt-14-7707-2021, https://doi.org/10.5194/amt-14-7707-2021, 2021
Short summary
Short summary
CO is an important atmospheric gas that influences both air quality and the climate. Here, we compare CO measurements from TROPOMI with those from ACE-FTS and an Arctic ground-based FTS at Eureka, Nunavut, to further characterize the accuracy of TROPOMI measurements. CO columns from the instruments agree well but show larger differences at high latitudes. Despite this, the results fall within the TROPOMI accuracy target, indicating good data quality at high latitudes.
Eric J. Hintsa, Fred L. Moore, Dale F. Hurst, Geoff S. Dutton, Bradley D. Hall, J. David Nance, Ben R. Miller, Stephen A. Montzka, Laura P. Wolton, Audra McClure-Begley, James W. Elkins, Emrys G. Hall, Allen F. Jordan, Andrew W. Rollins, Troy D. Thornberry, Laurel A. Watts, Chelsea R. Thompson, Jeff Peischl, Ilann Bourgeois, Thomas B. Ryerson, Bruce C. Daube, Yenny Gonzalez Ramos, Roisin Commane, Gregory W. Santoni, Jasna V. Pittman, Steven C. Wofsy, Eric Kort, Glenn S. Diskin, and T. Paul Bui
Atmos. Meas. Tech., 14, 6795–6819, https://doi.org/10.5194/amt-14-6795-2021, https://doi.org/10.5194/amt-14-6795-2021, 2021
Short summary
Short summary
We built UCATS to study atmospheric chemistry and transport. It has measured trace gases including CFCs, N2O, SF6, CH4, CO, and H2 with gas chromatography, as well as ozone and water vapor. UCATS has been part of missions to study the tropical tropopause; transport of air into the stratosphere; greenhouse gases, transport, and chemistry in the troposphere; and ozone chemistry, on both piloted and unmanned aircraft. Its design, capabilities, and some results are shown and described here.
Nathaniel J. Livesey, William G. Read, Lucien Froidevaux, Alyn Lambert, Michelle L. Santee, Michael J. Schwartz, Luis F. Millán, Robert F. Jarnot, Paul A. Wagner, Dale F. Hurst, Kaley A. Walker, Patrick E. Sheese, and Gerald E. Nedoluha
Atmos. Chem. Phys., 21, 15409–15430, https://doi.org/10.5194/acp-21-15409-2021, https://doi.org/10.5194/acp-21-15409-2021, 2021
Short summary
Short summary
The Microwave Limb Sounder (MLS), an instrument on NASA's Aura mission launched in 2004, measures vertical profiles of the temperature and composition of Earth's "middle atmosphere" (the region from ~12 to ~100 km altitude). We describe how, among the 16 trace gases measured by MLS, the measurements of water vapor (H2O) and nitrous oxide (N2O) have started to drift since ~2010. The paper also discusses the origins of this drift and work to ameliorate it in a new version of the MLS dataset.
Prashant Chavan, Suvarna Fadnavis, Tanusri Chakroborty, Christopher E. Sioris, Sabine Griessbach, and Rolf Müller
Atmos. Chem. Phys., 21, 14371–14384, https://doi.org/10.5194/acp-21-14371-2021, https://doi.org/10.5194/acp-21-14371-2021, 2021
Short summary
Short summary
Biomass burning (BB) over Asia is a strong source of carbonaceous aerosols during spring. Here, we show an outflow of Asian BB carbonaceous aerosols into the UTLS. These aerosols enhance atmospheric heating and produce circulation changes that lead to the enhancement of water vapor in the UTLS over the tropics. In the stratosphere, water vapor is further transported to the South Pole by the Brewer–Dobson circulation. Enhancement of water vapor in the UTLS has implications for climate change.
Jayanarayanan Kuttippurath, Wuhu Feng, Rolf Müller, Pankaj Kumar, Sarath Raj, Gopalakrishna Pillai Gopikrishnan, and Raina Roy
Atmos. Chem. Phys., 21, 14019–14037, https://doi.org/10.5194/acp-21-14019-2021, https://doi.org/10.5194/acp-21-14019-2021, 2021
Short summary
Short summary
The Arctic winter/spring 2020 was one of the coldest with a strong and long-lasting vortex, high chlorine activation, severe denitrification, and unprecedented ozone loss. The loss was even equal to the levels of some of the warm Antarctic winters. Total column ozone values below 220 DU for several weeks and ozone loss saturation were observed during the period. These results show an unusual meteorology and warrant dedicated studies on the impact of climate change on ozone loss.
Cited articles
Becker, G., Grooss, J.-U., McKenna, D., and Müller, R.: Stratospheric Photolysis Frequencies: Impact of an Improved Numerical Solution of the Radiative Transfer Equation, J. Atmos. Chem., 37, 217–229, https://doi.org/10.1023/A:1006468926530, 2000.
Bernath, P. F.: Atmospheric chemistry experiment (ACE): Analytical chemistry from orbit, TRAC-Trend. Anal. Chem., 25, 647–654, 2006.
Bernath, P. F., McElroy, C. T., Abrams, M. C., Boone, C. D., Butler, M., Camy-Peyret, C., Carleer, M., Clerbaux, C., Coheur, P. ., Colin, R., DeCola, P., DeMazière, M., Drummond, J. R., Dufour, D., Evans, W. F. J., Fast, H., Fussen, D., Gilbert, K., Jennings, D. E., Llewellyn, E. J., Lowe, R. P., Mahieu, E., McConnell, J. C., McHugh, M., McLeod, S. D., Michaud, R., Midwinter, C., Nassar, R., Nichitiu, F., Nowlan, C., Rinsland, C. P., Rochon, Y. J., Rowlands, N., Semeniuk, K., Simon, P., Skelton, R., Sloan, J. J., Soucy, M., Strong, K., Tremblay, P., Turnbull, D., Walker, K. A., Walkty, I., Wardle, D. A., Wehrle, V., Zander, R., and Zou, J.: Atmospheric chemistry experiment (ACE): Mission overview, Geophys. Res. Lett., 32, L15S01, https://doi.org/10.1029/2005GL022386, 2005.
Bingham, G. E., Zhou, D. K., Bartschi, B. Y., Anderson, G. P., Smith, D. R., Chetwynd, J. H., and Nadile, R. M.: Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS 1A) Earth limb spectral measurements, calibration, and atmospheric O3, HNO3, CFC-12, and CFC-11 profile retrieval, J. Geophys. Res., 102, 3547–3558, 1997.
Brown, A. T., Volk, C. M., Schoeberl, M. R., Boone, C. D., and Bernath, P. F.: Stratospheric lifetimes of CFC-12, CCl4, CH4, CH3Cl and N2O from measurements made by the Atmospheric Chemistry Experiment–Fourier Transform Spectrometer (ACE-FTS), Atmos. Chem. Phys., 13, 6921–6950, https://doi.org/10.5194/acp-13-6921-2013, 2013.
Chipperfield, M. P., Liang, Q., Strahan, S. E., Morgenstern, O., Dhomse, S. S., Abraham, N. L., Archibald, A. T., Bekki, S., Braesicke, P., Di Genova, G., Fleming, E. L., Hardiman, S. C., Iachetti, D., Jackman, C. H., Kinnison, D. E., Marchand, M., Pitari, G., Pyle, J. A., Rozanov, E., Stenke, A., and Tummon, F.: Multimodel estimates of atmospheric lifetimes of long-lived ozone-depleting substances: Present and future, J. Geophys. Res., 119, 2555–2573, https://doi.org/10.1002/2013JD021097, 2014.
Dinelli, B. M., Arnone, E., Brizzi, G., Carlotti, M., Castelli, E., Magnani, L., Papandrea, E., Prevedelli, M., and Ridolfi, M.: The MIPAS2D database of MIPAS/ENVISAT measurements retrieved with a multi-target 2-dimensional tomographic approach, Atmos. Meas. Tech., 3, 355–374, https://doi.org/10.5194/amt-3-355-2010, 2010.
Douglass, A. R., Stolarski, R. S., Schoeberl, M. R., Jackman, C. H., Gupta, M. L., Newman, P. A., Nielsen, J. E., and Fleming, E. L.: Relationship of loss, mean age of air and the distribution of CFCs to stratospheric circulation and implications for atmospheric lifetimes, J. Geophys. Res., 113, D14309, https://doi.org/10.1029/2007JD009575, 2008.
Elkins, J. W., Thompson, T. M., Swanson, T. H., Butler, J. H., Hall, B. D., Cummings, S. O., Fisher, D. A., and Raffo, A. G.: Decrease of growth rates of atmospheric chlorofluorocarbons 11 and 12, Nature, 364, 780–783, 1993.
Eyring, V., Harris, N. R. P., Rex, M., Shepherd, T. G., Fahey, D. W., Amanatidis, G. T., Austin, J., Chipperfield, M. P., Dameris, M., Forster, P. M. D. F., Gettelman, A., Graf, H. F., Nagashima, T., Newman, P. A., Pawson, S., Prather, M. J., Pyle, J. A., Salawitch, R. J., Santer, B. D., and Waugh, D. W.: A strategy for process-oriented validation of coupled chemistry-climate models, B. Am. Meteorol. Soc., 86, 1117–1133, 2005.
Fischer, H., Birk, M., Blom, C., Carli, B., Carlotti, M., von Clarmann, T., Delbouille, L., Dudhia, A., Ehhalt, D., Endemann, M., Flaud, J. M., Gessner, R., Kleinert, A., Koopman, R., Langen, J., López-Puertas, M., Mosner, P., Nett, H., Oelhaf, H., Perron, G., Remedios, J., Ridolfi, M., Stiller, G., and Zander, R.: MIPAS: an instrument for atmospheric and climate research, Atmos. Chem. Phys., 8, 2151–2188, https://doi.org/10.5194/acp-8-2151-2008, 2008.
Gille, J., Barnett, J., Arter, P., Barker, M., Bernath, P., Boone, C., Cavanaugh, C., Chow, J., Coffey, M., Craft, J., Craig, C., Dials, M., Dean, V., Eden, T., Edwards, D. P., Francis, G., Halvorson, C., Harvey, L., Hepplewhite, C., Khosravi, R., Kinnison, D., Krinsky, C., Lambert, A., Lee, H., Lyjak, L., Loh, J., Mankin, W., Massie, S., McInerney, J., Moorhouse, J., Nardi, B., Packman, D., Randall, C., Reburn, J., Rudolf, W., Schwartz, M., Serafin, J., Stone, K., Torpy, B., Walker, K., Waterfall, A., Watkins, R., Whitney, J., Woodard, D., and Young, G.: High Resolution Dynamics Limb Sounder: Experiment overview, recovery, and validation of initial temperature data, J. Geophys. Res., 113, D16S43, https://doi.org/10.1029/2007JD008824, 2008.
Gille, J., Gray, L., Cavanaugh, C., Coffey, M., Dean, V., Halvorson, C., Karol, S., Khosravi, R., Kinnison, D., Massie, S., Nardi, B., Rivas, M. B., Smith, L., Torpy, B., Waterfall, A., and Wright, C.: High Resolution Dynamics Limb Sounder, Earth Observing System (EOS), Data Description and Quality, Version 7 (V7), Tech. rep., National Center for Atmospheric Research, Boulder, Colorado, USA, http://www.eos.ucar.edu/hirdls/data/products/HIRDLS-DQD_V7-1.pdf (last access: 21 June 2014), 2013.
Gille, J. C., Barnett, J. J., Whitney, J. G., Dials, M. A., Woodard, D., Rudolf, W. P., Lambert, A., and Mankin, W.: The High-Resolution Dynamics Limb Sounder (HIRDLS) experiment on AURA, Proc. SPIE, 5152, 161–171, 2003.
Grooß, J.-U., Günther, G., Konopka, P., Müller, R., McKenna, D. S., Stroh, F., Vogel, B., Engel, A., Müller, M., Hoppel, K., Bevilacqua, R., Richard, E., Webster, C. R., Elkins, J. W., Hurst, D. F., Romashkin, P. A., and Baumgardner, D. G.: Simulation of ozone depletion in spring 2000 with the Chemical Lagrangian Model of the Stratosphere (CLaMS), J. Geophys. Res., 107, 8295, https://doi.org/10.1029/2001JD000456, 2002.
Hodnebrog, Ø., Etminan, M., Fuglestvedt, J. S., Marston, G., Myhre, G., Nielsen, C. J., Shine, K. P., and Wallington, T. J.: Global warming potentials and radiative efficiencies of halocarbons and related compounds: A comprehensive review, Rev. Geophys., 51, 300–378, 2013.
Hoffmann, L., Spang, R., and Riese, M.: Retrieval of chlorofluorocarbon distributions from Envisat MIPAS measurements, Proc. SPIE, 5571, 193–204, 2004.
Hoffmann, L., Spang, R., Kaufmann, M., and Riese, M.: Retrieval of CFC-11 and CFC-12 from Envisat MIPAS observations by means of rapid radiative transfer calculations, Adv. Space Res., 36, 915–921, 2005.
Hoffmann, L., Kaufmann, M., Spang, R., Müller, R., Remedios, J. J., Moore, D. P., Volk, C. M., von Clarmann, T., and Riese, M.: Envisat MIPAS measurements of CFC-11: retrieval, validation, and climatology, Atmos. Chem. Phys., 8, 3671–3688, https://doi.org/10.5194/acp-8-3671-2008, 2008.
Holton, J. R., Haynes, P. H., McIntyre, M. E., Douglass, A. R., Rood, R. B., and Pfister, L.: Stratosphere-Troposphere Exchange, Rev. Geophys., 33, 403–439, 1995.
Hoppe, C. M., Hoffmann, L., Konopka, P., Grooß, J.-U., Ploeger, F., Günther, G., Jöckel, P., and Müller, R.: The implementation of the CLaMS Lagrangian transport core into the chemistry climate model EMAC 2.40.1: application on age of air and transport of long-lived trace species, Geosci. Model Dev. Discuss., 7, 1759–1790, https://doi.org/10.5194/gmdd-7-1759-2014, 2014.
Hurrell, J. W., Hack, J. J., Shea, D., Caron, J. M., and Rosinski, J.: A New Sea Surface Temperature and Sea Ice Boundary Dataset for the Community Atmosphere Model, J. Clim., 21, 5145–5153, 2008.
IPCC: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2013.
Jöckel, P., Kerkweg, A., Buchholz-Dietsch, J., Tost, H., Sander, R., and Pozzer, A.: Technical Note: Coupling of chemical processes with the Modular Earth Submodel System (MESSy) submodel TRACER, Atmos. Chem. Phys., 8, 1677–1687, https://doi.org/10.5194/acp-8-1677-2008, 2008.
Jöckel, P., Kerkweg, A., Pozzer, A., Sander, R., Tost, H., Riede, H., Baumgaertner, A., Gromov, S., and Kern, B.: Development cycle 2 of the Modular Earth Submodel System (MESSy2), Geosci. Model Dev., 3, 717–752, https://doi.org/10.5194/gmd-3-717-2010, 2010.
Jones, A., Walker, K. A., Jin, J. J., Taylor, J. R., Boone, C. D., Bernath, P. F., Brohede, S., Manney, G. L., McLeod, S., Hughes, R., and Daffer, W. H.: Technical Note: A trace gas climatology derived from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) data set, Atmos. Chem. Phys., 12, 5207–5220, https://doi.org/10.5194/acp-12-5207-2012, 2012.
Kellmann, S., von Clarmann, T., Stiller, G. P., Eckert, E., Glatthor, N., Höpfner, M., Kiefer, M., Orphal, J., Funke, B., Grabowski, U., Linden, A., Dutton, G. S., and Elkins, J. W.: Global CFC-11 (CCl3F) and CFC-12 (CCl2F2) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends, Atmos. Chem. Phys., 12, 11857–11875, https://doi.org/10.5194/acp-12-11857-2012, 2012.
Khosrawi, F., Müller, R., Irie, H., Engel, A., Toon, G. C., Sen, B., Aoki, S., Nakazawa, T., Traub, W. A., Jucks, K. W., Johnson, D. G., Oelhaf, H., Wetzel, G., Sugita, T., Kanzawa, H., Yokota, T., Nakajima, H., and Sasano, Y.: Validation of CFC-12 measurements from the Improved Limb Atmospheric Spectrometer (ILAS) with the version 6.0 retrieval algorithm, J. Geophys. Res., 109, D06311, https://doi.org/10.1029/2003JD004325, 2004.
Konopka, P., Steinhorst, H.-M., Grooß, J.-U., Günther, G., Müller, R., Elkins, J. W., Jost, H.-J., Richard, E., Schmidt, U., Toon, G., and McKenna, D. S.: Mixing and ozone loss in the 1999–2000 Arctic vortex: Simulations with the three-dimensional Chemical Lagrangian Model of the Stratosphere (CLaMS), J. Geophys. Res., 109, D02315, https://doi.org/10.1029/2003JD003792, 2004.
Konopka, P., Günther, G., Müller, R., dos Santos, F. H. S., Schiller, C., Ravegnani, F., Ulanovsky, A., Schlager, H., Volk, C. M., Viciani, S., Pan, L. L., McKenna, D.-S., and Riese, M.: Contribution of mixing to upward transport across the tropical tropopause layer (TTL), Atmos. Chem. Phys., 7, 3285–3308, https://doi.org/10.5194/acp-7-3285-2007, 2007.
Kuell, V., Offermann, D., Jarisch, M., Schaeler, B., Engel, A., Claude, G., Smit, H. G. J., Ebel, A., and Feldmann, H.: Tropopause region temperatures and CFC 11 mixing ratios from CRISTA 2, J. Geophys. Res., 110, D16104, https://doi.org/10.1029/2004JD005592, 2005.
Laube, J. C., Keil, A., Bönisch, H., Engel, A., Röckmann, T., Volk, C. M., and Sturges, W. T.: Observation-based assessment of stratospheric fractional release, lifetimes, and ozone depletion potentials of ten important source gases, Atmos. Chem. Phys., 13, 2779–2791, https://doi.org/10.5194/acp-13-2779-2013, 2013.
Lin, S. J. and Rood, R. B.: Multidimensional flux-form semi-Lagrangian transport schemes, Mon. Weather Rev., 124, 2046–2070, 1996.
Mahieu, E., Duchatelet, P., Demoulin, P., Walker, K. A., Dupuy, E., Froidevaux, L., Randall, C., Catoire, V., Strong, K., Boone, C. D., Bernath, P. F., Blavier, J.-F., Blumenstock, T., Coffey, M., De Mazière, M., Griffith, D., Hannigan, J., Hase, F., Jones, N., Jucks, K. W., Kagawa, A., Kasai, Y., Mebarki, Y., Mikuteit, S., Nassar, R., Notholt, J., Rinsland, C. P., Robert, C., Schrems, O., Senten, C., Smale, D., Taylor, J., Tétard, C., Toon, G. C., Warneke, T., Wood, S. W., Zander, R., and Servais, C.: Validation of ACE-FTS v2.2 measurements of HCl, HF, CCl3F and CCl2F2 using space-, balloon- and ground-based instrument observations, Atmos. Chem. Phys., 8, 6199–6221, https://doi.org/10.5194/acp-8-6199-2008, 2008.
Mahowald, N. M., Plumb, R. A., Rasch, P. J., del Corral, J., Sassi, F., and Heres, W.: Stratospheric transport in a three-dimensional isentropic coordinate model, J. Geophys. Res., 107, ACH 3-1–ACH 3-14, https://doi.org/10.1029/2001JD001313, 2002.
McGillen, M. R., Fleming, E. L., Jackman, C. H., and Burkholder, J. B.: CFCl3 (CFC-11): UV absorption spectrum temperature dependence measurements and the impact on its atmospheric lifetime and uncertainty, Geophys. Res. Lett., 40, 4772–4776, 2013.
McKenna, D. S., Grooß, J.-U., Günther, G., Konopka, P., Müller, R., Carver, G., and Sasano, Y.: A new Chemical Lagrangian Model of the Stratosphere (CLaMS) 2. Formulation of chemistry scheme and initialization, J. Geophys. Res., 107, ACH 4-1–ACH 4-14, https://doi.org/10.1029/2000JD000113, 2002a.
McKenna, D. S., Konopka, P., Grooß, J.-U., Günther, G., Müller, R., Spang, R., Offermann, D., and Orsolini, Y.: A new Chemical Lagrangian Model of the Stratosphere (CLaMS) 1. Formulation of advection and mixing, J. Geophys. Res., 107, ACH 15-1–ACH 15-15, https://doi.org/10.1029/2000JD000114, 2002b.
Minschwaner, K., Hoffmann, L., Brown, A., Riese, M., Müller, R., and Bernath, P. F.: Stratospheric loss and atmospheric lifetimes of CFC-11 and CFC-12 derived from satellite observations, Atmos. Chem. Phys., 13, 4253–4263, https://doi.org/10.5194/acp-13-4253-2013, 2013.
Molina, M. J. and Rowland, F. S.: Stratospheric sink for chlorofluoromethanes: chlorine atom-catalyzed destruction of ozone, Nature, 249, 810–812, 1974.
Morgenstern, O., Pyle, J. A., Iwi, A. M., Norton, W. A., Elkins, J. W., Hurst, D. F., and Romashkin, P. A.: Diagnosis of mixing between middle latitudes and the polar vortex from tracer-tracer correlations, J. Geophys. Res., 107, 4321, https://doi.org/10.1029/2001JD001224, 2002.
Morgenstern, O., Lee, A. M., and Pyle, J. A.: Cumulative mixing inferred from stratospheric tracer relationships, J. Geophys. Res., 108, 8321, https://doi.org/10.1029/2002JD002098, 2003.
Müller, R., Crutzen, P. J., Grooß, J.-U., Brühl, C., Russell III, J. M., and Tuck, A. F.: Chlorine activation and ozone depletion in the Arctic vortex: Observations by the Halogen Occultation Experiment on the Upper Atmosphere Research Satellite, J. Geophys. Res., 101, 12531–12554, 1996.
Müller, R., McKenna, D. S., Schmidt, U., Engel, A., and Proffitt, M. H.: The O3–N2O relationship from balloon-borne observations as a measure of Arctic ozone loss in 1991/92, Q. J. Roy. Meteor. Soc., 127, 1389–1412, 2001.
Müller, R., Tilmes, S., Konopka, P., Grooß, J.-U., and Jost, H.-J.: Impact of mixing and chemical change on ozone-tracer relations in the polar vortex, Atmos. Chem. Phys., 5, 3139–3151, https://doi.org/10.5194/acp-5-3139-2005, 2005.
Neu, J. L. and Plumb, R. A.: Age of air in a "leaky pipe" model of stratospheric transport, J. Geophys. Res., 104, 19243–19255, 1999.
Plumb, R. A.: A "tropical pipe" model of stratospheric transport, J. Geophys. Res., 101, 3957–3972, 1996.
Plumb, R. A.: Stratospheric Transport, J. Met. Soc. Japan, 80, 793–809, 2002.
Plumb, R. A.: Tracer interrelationships in the stratosphere, Rev. Geophys., 45, RG4005, https://doi.org/10.1029/2005RG000179, 2007.
Plumb, R. A. and Ko, M. K. W.: Interrelationships between mixing ratios of long-lived stratospheric constituents, J. Geophys. Res., 97, 10145–10156, 1992.
Plumb, R. A., Waugh, D. W., and Chipperfield, M. P.: The effects of mixing on tracer relationships in the polar vortices, J. Geophys. Res., 105, 10047–10062, 2000.
Pommrich, R., Müller, R., Grooß, J.-U., Konopka, P., Ploeger, F., Vogel, B., Tao, M., Hoppe, C. M., Günther, G., Spelten, N., Hoffmann, L., Pumphrey, H.-C., Viciani, S., D'Amato, F., Volk, C. M., Hoor, P., Schlager, H., and Riese, M.: Tropical troposphere to stratosphere transport of carbon monoxide and long-lived trace species in the Chemical Lagrangian Model of the Stratosphere (CLaMS), Geosci. Model Dev. Discuss., 7, 5087–5139, https://doi.org/10.5194/gmdd-7-5087-2014, 2014.
Raspollini, P., Carli, B., Carlotti, M., Ceccherini, S., Dehn, A., Dinelli, B. M., Dudhia, A., Flaud, J.-M., López-Puertas, M., Niro, F., Remedios, J. J., Ridolfi, M., Sembhi, H., Sgheri, L., and von Clarmann, T.: Ten years of MIPAS measurements with ESA Level 2 processor V6 – Part 1: Retrieval algorithm and diagnostics of the products, Atmos. Meas. Tech., 6, 2419–2439, https://doi.org/10.5194/amt-6-2419-2013, 2013.
Riese, M., Spang, R., Preusse, P., Ern, M., Jarisch, M., Offermann, D., and Grossmann, K. U.: Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) data processing and atmospheric temperature and trace gas retrieval, J. Geophys. Res., 104, 16349–16367, 1999.
Rigby, M., Prinn, R. G., O'Doherty, S., Montzka, S. A., McCulloch, A., Harth, C. M., Mühle, J., Salameh, P. K., Weiss, R. F., Young, D., Simmonds, P. G., Hall, B. D., Dutton, G. S., Nance, D., Mondeel, D. J., Elkins, J. W., Krummel, P. B., Steele, L. P., and Fraser, P. J.: Re-evaluation of the lifetimes of the major CFCs and CH3CCl3 using atmospheric trends, Atmos. Chem. Phys., 13, 2691–2702, https://doi.org/10.5194/acp-13-2691-2013, 2013.
Rind, D., Lerner, J., Jonas, J., and McLinden, C.: Effects of resolution and model physics on tracer transports in the NASA Goddard Institute for Space Studies general circulation models, J. Geophys. Res., 112, D09315, https://doi.org/10.1029/2006JD007476, 2007.
Roeckner, E., Brokopf, R., Esch, M., Giorgetta, M., Hagemann, S., Kornblueh, L., Manzini, E., Schlese, U., and Schulzweida, U.: Sensitivity of simulated climate to horizontal and vertical resolution in the ECHAM5 atmosphere model, J. Clim., 19, 3771–3791, 2006.
Schoeberl, M. R., Douglass, A. R., Polansky, B., Boone, C., Walker, K. A., and Bernath, P.: Estimation of stratospheric age spectrum from chemical tracers, J. Geophys. Res., 110, D21303, https://doi.org/10.1029/2005JD006125, 2005.
Solomon, S.: Stratospheric ozone depletion: A review of concepts and history, Rev. Geophys., 37, 275–316, 1999.
SPARC: SPARC report on the lifetimes of stratospheric ozone-depleting substances, Their Replacements, and Related Species, SPARC Report No. 6, WCRP-15/2013, http://www.sparc-climate.org/publications/sparc-reports/sparc-report-no6/ (last access: 21 June 2014), 2013.
Velders, G. J. M., Andersen, S. O., Daniel, J. S., Fahey, D. W., and McFarland, M.: The importance of the Montreal Protocol in protecting climate, Proc. Natl. Acad. Sci. USA, 104, 4814–4819, 2007.
Volk, C. M., Elkins, J. W., Fahey, D. W., Salawitch, R. J., Dutton, G. S., Gilligan, J. M., Proffitt, M. H., Loewenstein, M., Podolske, J. R., Minschwaner, K., Margitan, J. J., and Chan, K. R.: Quantifying transport between the tropical and mid-latitude lower stratosphere, Science, 272, 1763–1768, 1996.
Volk, C. M., Elkins, J. W., Fahey, D. W., Dutton, G. S., Gilligan, J. M., Loewenstein, M., Podolske, J. R., Chan, K. R., and Gunson, M. R.: Evaluation of source gas lifetimes from stratospheric observations, J. Geophys. Res., 102, 25543–25564, 1997.
Waugh, D. W.: Mixing of polar vortex air into middle latitudes as revealed by tracer-tracer scatterplots, J. Geophys. Res., 102, 13119–13134, 1997.
Waugh, D. W., Hall, T. M., and Haine, T. W. N.: Relationships among tracer ages, J. Geophys. Res., 108, 3138, https://doi.org/10.1029/2002JC001325, 2003.
WMO: Scientific Assessment of Ozone Depletion, Global Ozone Research and Monitoring Project, Report No. 44, Geneva, Switzerland, 1999.
WMO: Scientific Assessment of Ozone Depletion: 2010, Global Ozone Research and Monitoring Project, Report No. 52, Geneva, Switzerland, 2011.
Yokota, T., Nakajima, H., Sugita, T., Tsubaki, H., Itou, Y., Kaji, M., Suzuki, M., Kanzawa, H., Park, J. H., and Sasano, Y.: Improved Limb Atmospheric Spectrometer (ILAS) data retrieval algorithm for Version 5.20 gas profile products, J. Geophys. Res., 107, 8216, https://doi.org/10.1029/2001JD000628, 2002.
Short summary
Stratospheric lifetimes determine the global warming and ozone depletion potentials of chlorofluorocarbons. We present new estimates of the CFC-11/CFC-12 lifetime ratio from satellite and model data (ACE-FTS, HIRDLS, MIPAS, and EMAC/CLaMS). Our estimates of 0.46+/-0.04 (satellites) and 0.48+/-0.07 (model) are in excellent agreement with the recent SPARC reassessment. Having smaller uncertainties than other studies, our results can help to better constrain future CFC lifetime recommendations.
Stratospheric lifetimes determine the global warming and ozone depletion potentials of...
Altmetrics
Final-revised paper
Preprint