Articles | Volume 22, issue 11
https://doi.org/10.5194/acp-22-7193-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-22-7193-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
03 Jun 2022
Research article |
| 03 Jun 2022
| 03 Jun 2022
Contribution of Asian emissions to upper tropospheric CO over the remote Pacific
Linda Smoydzin
CORRESPONDING AUTHOR
Institute for Atmospheric Physics, Johannes Gutenberg University, Mainz, Germany
Peter Hoor
Institute for Atmospheric Physics, Johannes Gutenberg University, Mainz, Germany
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Rodrigo J. Seguel, Charlie Opazo, Yann Cohen, Owen R. Cooper, Laura Gallardo, Björn-Martin Sinnhuber, Florian Obersteiner, Andreas Zahn, Peter Hoor, Susanne Rohs, and Andreas Marsing
Atmos. Chem. Phys., 25, 8553–8573, https://doi.org/10.5194/acp-25-8553-2025, https://doi.org/10.5194/acp-25-8553-2025, 2025
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We explored ozone differences between the Northern Hemisphere and Southern Hemispheres in the upper troposphere–lower stratosphere. We found lower ozone (with stratospheric origin) in the Southern Hemisphere, especially during years of severe ozone depletion. Sudden stratospheric warming events increased the ozone in each hemisphere, highlighting the relationship between stratospheric processes and ozone in the upper troposphere, where ozone is an important greenhouse gas.
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
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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.
Anna Breuninger, Philipp Joppe, Jonas Wilsch, Cornelis Schwenk, Heiko Bozem, Nicolas Emig, Laurin Merkel, Rainer Rossberg, Timo Keber, Arthur Kutschka, Philipp Waleska, Stefan Hofmann, Sarah Richter, Florian Ungeheuer, Konstantin Dörholt, Thorsten Hoffmann, Annette Miltenberger, Johannes Schneider, Peter Hoor, and Alexander L. Vogel
EGUsphere, https://doi.org/10.5194/egusphere-2025-3129, https://doi.org/10.5194/egusphere-2025-3129, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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This study investigates molecular organic aerosol composition in the upper troposphere and lower stratosphere from an airborne campaign over Central Europe in summer 2024. Via ultra-high-performance liquid chromatography and high-resolution mass spectrometry of tropospheric and stratospheric filter samples, we identified various organic compounds. Our findings underscore the significant cross-tropopause transport of biogenic secondary organic aerosol and anthropogenic pollutants.
Heiko Bozem, Philipp Joppe, Yun Li, Nicolas Emig, Armin Afchine, Anna Breuninger, Joachim Curtius, Stefan Hofmann, Sadath Ismayil, Konrad Kandler, Daniel Kunkel, Arthur Kutschka, Hans-Christoph Lachnitt, Andreas Petzold, Sarah Richter, Timo Röschenthaler, Christian Rolf, Lisa Schneider, Johannes Schneider, Alexander Vogel, and Peter Hoor
EGUsphere, https://doi.org/10.5194/egusphere-2025-3175, https://doi.org/10.5194/egusphere-2025-3175, 2025
This preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).
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Deployed on a Learjet as a tandem measurement platform during TPEx I (TropoPause composition gradients and mixing Experiment) campaign in June 2024, the new TPC-TOSS (TropoPause Composition Towed Sensor Shuttle) system delivers high-resolution in situ data on ozone, aerosol, clouds, and key weather parameters. Laboratory and in-flight tests confirmed its precision and stability. Observed gradients near the tropopause reveal active mixing and transport processes in the tropopause region.
Patrick Konjari, Christian Rolf, Martina Krämer, Armin Afchine, Nicole Spelten, Irene Bartolome Garcia, Annette Miltenberger, Nicolar Emig, Philipp Joppe, Johannes Schneider, Yun Li, Andreas Petzold, Heiko Bozem, and Peter Hoor
EGUsphere, https://doi.org/10.5194/egusphere-2025-2847, https://doi.org/10.5194/egusphere-2025-2847, 2025
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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We investigated how a powerful storm over southern Sweden in June 2024 transported ice particles and moist air into the normally dry stratosphere. We observed unusually high water vapor and ice levels up to 1.5 kilometers above the tropopause. Although the extra water vapor lasted only a few days to weeks, it shows how such storms can temporarily alter the upper atmosphere’s composition.
Philipp Joppe, Johannes Schneider, Jonas Wilsch, Heiko Bozem, Anna Breuninger, Joachim Curtius, Martin Ebert, Nicolas Emig, Peter Hoor, Sadath Ismayil, Konrad Kandler, Daniel Kunkel, Isabel Kurth, Hans-Christoph Lachnitt, Yun Li, Annette Miltenberger, Sarah Richter, Christian Rolf, Lisa Schneider, Cornelis Schwenk, Nicole Spelten, Alexander L. Vogel, Yafang Cheng, and Stephan Borrmann
EGUsphere, https://doi.org/10.5194/egusphere-2025-1346, https://doi.org/10.5194/egusphere-2025-1346, 2025
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We show measurements of a filament with biomass burning influence transported by a warm conveyor belt (WCB) into the tropopause region over Europe. The pollution originates from Canadian forest fires and is transported in the lower troposphere towards Europe. The WCB transport is followed by mixing with air masses of stratospheric chemical signatures. We hypothesize that this mixing leads to a change in the vertical gradient of the potential temperature.
Linda Ort, Andrea Pozzer, Peter Hoor, Florian Obersteiner, Andreas Zahn, Thomas B. Ryerson, Chelsea R. Thompson, Jeff Peischl, Róisín Commane, Bruce Daube, Ilann Bourgeois, Jos Lelieveld, and Horst Fischer
EGUsphere, https://doi.org/10.5194/egusphere-2025-1477, https://doi.org/10.5194/egusphere-2025-1477, 2025
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This study investigates the role of lightning emissions on the O3–CO ratio in the northern subtropics. We used in situ observations and a global circulation model to show an effect of up to 40 % onto the subtropical O3–CO ratio by tropical air masses transported via the Hadley cell. This influence of lightning emissions and its photochemistry has a global effect on trace and greenhouse gases and needs to be considered for global chemical distributions.
Sophie Bauchinger, Andreas Engel, Markus Jesswein, Timo Keber, Harald Bönisch, Florian Obersteiner, Andreas Zahn, Nicolas Emig, Peter Hoor, Hans-Christoph Lachnitt, Franziska Weyland, Linda Ort, and Tanja J. Schuck
EGUsphere, https://doi.org/10.5194/egusphere-2025-1589, https://doi.org/10.5194/egusphere-2025-1589, 2025
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We compared different ways to define the upper barrier of the troposphere in the extra-tropics, the “tropopause”. By analysing ozone distributions sorted by different definitions, we found that the traditional temperature-based tropopause works less well than dynamic or tracer-based definitions. We saw the strongest ozone gradients across the tropopause using a higher value of potential vorticity than often used and recommend this value for future studies of exchange processes in this region.
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
EGUsphere, https://doi.org/10.5194/egusphere-2025-1155, https://doi.org/10.5194/egusphere-2025-1155, 2025
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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.
Franziska Weyland, Peter Hoor, Daniel Kunkel, Thomas Birner, Felix Plöger, and Katharina Turhal
Atmos. Chem. Phys., 25, 1227–1252, https://doi.org/10.5194/acp-25-1227-2025, https://doi.org/10.5194/acp-25-1227-2025, 2025
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The lowermost stratosphere (LMS) plays an important role in the Earth's climate, containing strong gradients of ozone and water vapor. Our results indicate that the thermodynamic structure of the LMS was changing between 1979–2019 in response to anthropogenic climate change and the recovery of stratospheric ozone, also indicating large-scale circulation changes. We find that both the upper and the lower LMS boundaries show an (upward) trend, which has implications for the LMS mass.
Nicolas Emig, Annette K. Miltenberger, Peter M. Hoor, and Andreas Petzold
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This study presents in situ observations of cirrus occurrence from aircraft measurements in the extra-tropical transition layer (ExTL) using simultaneous measurements from two platforms. Lagrangian diagnostics based on high-resolution ICON simulations show long residence times of the cirrus in stratospheric air allowing to separate different diabatic processes during transit. The findings suggest that radiative diabatic cloud processes significantly impact the tropopause thermodynamic structure.
Johannes Schneider, Christiane Schulz, Florian Rubach, Anna Ludwig, Jonas Wilsch, Philipp Joppe, Christian Gurk, Sergej Molleker, Laurent Poulain, Florian Obersteiner, Torsten Gehrlein, Harald Bönisch, Andreas Zahn, Peter Hoor, Nicolas Emig, Heiko Bozem, Stephan Borrmann, and Markus Hermann
EGUsphere, https://doi.org/10.5194/egusphere-2024-3969, https://doi.org/10.5194/egusphere-2024-3969, 2025
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IAGOS-CARIBIC operates an instrumented container laboratory on commercial regular passenger flights to obtain a long-term representative data set on the composition of the upper troposphere and lowermost stratosphere. Here we report on the development on a fully automated aerosol mass spectrometer for this project. We present technical specifications, necessary modifications for the automation, instrument calibration and comparisons, detection limits, and first in-flight data.
Chun Hang Chau, Peter Hoor, and Holger Tost
EGUsphere, https://doi.org/10.5194/egusphere-2024-3805, https://doi.org/10.5194/egusphere-2024-3805, 2024
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This study examines how the turbulence in the upper troposphere/lower stratosphere could modify the tracer distribution under different situations. Using a multi-scale chemistry model, we find that both the pre-existing tracer gradient and the dynamical and thermodynamically forcing play a role in modifying the tracer distribution. These results allow further research on the UTLS turbulent mixing and its implications for the climate system.
Katharina Turhal, Felix Plöger, Jan Clemens, Thomas Birner, Franziska Weyland, Paul Konopka, and Peter Hoor
Atmos. Chem. Phys., 24, 13653–13679, https://doi.org/10.5194/acp-24-13653-2024, https://doi.org/10.5194/acp-24-13653-2024, 2024
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The tropopause separates the troposphere, where many greenhouse gases originate, from the stratosphere. This study examines a tropopause defined by potential vorticity – an analogue for angular momentum that changes sharply in the subtropics, creating a transport barrier. Between 1980 and 2017, this tropopause shifted poleward at lower altitudes and equatorward above, suggesting height-dependent changes in atmospheric circulation that may affect greenhouse gas distribution and global warming.
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
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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.
Niklas Karbach, Lisa Höhler, Peter Hoor, Heiko Bozem, Nicole Bobrowski, and Thorsten Hoffmann
Atmos. Meas. Tech., 17, 4081–4086, https://doi.org/10.5194/amt-17-4081-2024, https://doi.org/10.5194/amt-17-4081-2024, 2024
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The system presented here can accurately generate and reproduce a stable flow of gas mixtures of known concentrations over several days using ambient air as a dilution medium. In combination with the small size and low weight of the system, this enables the calibration of hydrogen sensors in the field, reducing the influence of matrix effects on the accuracy of the sensor. The system is inexpensive to assemble and easy to maintain, which is the key to reliable measurement results.
Philipp Joppe, Johannes Schneider, Katharina Kaiser, Horst Fischer, Peter Hoor, Daniel Kunkel, Hans-Christoph Lachnitt, Andreas Marsing, Lenard Röder, Hans Schlager, Laura Tomsche, Christiane Voigt, Andreas Zahn, and Stephan Borrmann
Atmos. Chem. Phys., 24, 7499–7522, https://doi.org/10.5194/acp-24-7499-2024, https://doi.org/10.5194/acp-24-7499-2024, 2024
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From aircraft measurements in the upper troposphere/lower stratosphere, we find a correlation between the ozone and particulate sulfate in the lower stratosphere. The correlation exhibits some variability over the measurement period exceeding the background sulfate-to-ozone correlation. From our analysis, we conclude that gas-to-particle conversion of volcanic sulfur dioxide leads to observed enhanced sulfate aerosol mixing ratios.
Tanja J. Schuck, Johannes Degen, Eric Hintsa, Peter Hoor, Markus Jesswein, Timo Keber, Daniel Kunkel, Fred Moore, Florian Obersteiner, Matt Rigby, Thomas Wagenhäuser, Luke M. Western, Andreas Zahn, and Andreas Engel
Atmos. Chem. Phys., 24, 689–705, https://doi.org/10.5194/acp-24-689-2024, https://doi.org/10.5194/acp-24-689-2024, 2024
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We study the interhemispheric gradient of sulfur hexafluoride (SF6), a strong long-lived greenhouse gas. Its emissions are stronger in the Northern Hemisphere; therefore, mixing ratios in the Southern Hemisphere lag behind. Comparing the observations to a box model, the model predicts air in the Southern Hemisphere to be older. For a better agreement, the emissions used as model input need to be increased (and their spatial pattern changed), and we need to modify north–south transport.
Frederik Harzer, Hella Garny, Felix Ploeger, Harald Bönisch, Peter Hoor, and Thomas Birner
Atmos. Chem. Phys., 23, 10661–10675, https://doi.org/10.5194/acp-23-10661-2023, https://doi.org/10.5194/acp-23-10661-2023, 2023
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We study the statistical relation between year-by-year fluctuations in winter-mean ozone and the strength of the stratospheric polar vortex. In the latitude–pressure plane, regression analysis shows that anomalously weak polar vortex years are associated with three pronounced local ozone maxima over the polar cap relative to the winter climatology. These response maxima primarily reflect the non-trivial combination of different ozone transport processes with varying relative contributions.
Luis F. Millán, Gloria L. Manney, Harald Boenisch, Michaela I. Hegglin, Peter Hoor, Daniel Kunkel, Thierry Leblanc, Irina Petropavlovskikh, Kaley Walker, Krzysztof Wargan, and Andreas Zahn
Atmos. Meas. Tech., 16, 2957–2988, https://doi.org/10.5194/amt-16-2957-2023, https://doi.org/10.5194/amt-16-2957-2023, 2023
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The determination of atmospheric composition trends in the upper troposphere and lower stratosphere (UTLS) is still highly uncertain. We present the creation of dynamical diagnostics to map several ozone datasets (ozonesondes, lidars, aircraft, and satellite measurements) in geophysically based coordinate systems. The diagnostics can also be used to analyze other greenhouse gases relevant to surface climate and UTLS chemistry.
Hans-Christoph Lachnitt, Peter Hoor, Daniel Kunkel, Martina Bramberger, Andreas Dörnbrack, Stefan Müller, Philipp Reutter, Andreas Giez, Thorsten Kaluza, and Markus Rapp
Atmos. Chem. Phys., 23, 355–373, https://doi.org/10.5194/acp-23-355-2023, https://doi.org/10.5194/acp-23-355-2023, 2023
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We present an analysis of high-resolution airborne measurements during a flight of the DEEPWAVE 2014 campaign in New Zealand. The focus of this flight was to study the effects of enhanced mountain wave activity over the Southern Alps. We discuss changes in the upstream and downstream distributions of N2O and CO and show that these changes are related to turbulence-induced trace gas fluxes which have persistent effects on the trace gas composition in the lower stratosphere.
Paul Konopka, Mengchu Tao, Marc von Hobe, Lars Hoffmann, Corinna Kloss, Fabrizio Ravegnani, C. Michael Volk, Valentin Lauther, Andreas Zahn, Peter Hoor, and Felix Ploeger
Geosci. Model Dev., 15, 7471–7487, https://doi.org/10.5194/gmd-15-7471-2022, https://doi.org/10.5194/gmd-15-7471-2022, 2022
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Pure trajectory-based transport models driven by meteorology derived from reanalysis products (ERA5) take into account only the resolved, advective part of transport. That means neither mixing processes nor unresolved subgrid-scale advective processes like convection are included. The Chemical Lagrangian Model of the Stratosphere (CLaMS) includes these processes. We show that isentropic mixing dominates unresolved transport. The second most important transport process is unresolved convection.
Helmut Ziereis, Peter Hoor, Jens-Uwe Grooß, Andreas Zahn, Greta Stratmann, Paul Stock, Michael Lichtenstern, Jens Krause, Vera Bense, Armin Afchine, Christian Rolf, Wolfgang Woiwode, Marleen Braun, Jörn Ungermann, Andreas Marsing, Christiane Voigt, Andreas Engel, Björn-Martin Sinnhuber, and Hermann Oelhaf
Atmos. Chem. Phys., 22, 3631–3654, https://doi.org/10.5194/acp-22-3631-2022, https://doi.org/10.5194/acp-22-3631-2022, 2022
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Airborne observations were conducted in the lowermost Arctic stratosphere during the winter of 2015/2016. The observed distribution of reactive nitrogen shows clear indications of nitrification in mid-winter and denitrification in late winter. This was caused by the formation of polar stratospheric cloud particles, which were observed during several flights. The sedimentation and evaporation of these particles and the descent of air masses cause a redistribution of reactive nitrogen.
Valentin Lauther, Bärbel Vogel, Johannes Wintel, Andrea Rau, Peter Hoor, Vera Bense, Rolf Müller, and C. Michael Volk
Atmos. Chem. Phys., 22, 2049–2077, https://doi.org/10.5194/acp-22-2049-2022, https://doi.org/10.5194/acp-22-2049-2022, 2022
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We show airborne in situ measurements of the very short-lived ozone-depleting substances CH2Cl2 and CHCl3, revealing particularly high concentrations of both species in the lower stratosphere. Back-trajectory calculations and 3D model simulations show that the air masses with high concentrations originated in the Asian boundary layer and were transported via the Asian summer monsoon. We also identify a fast transport pathway into the stratosphere via the North American monsoon and by hurricanes.
Markus Jesswein, Heiko Bozem, Hans-Christoph Lachnitt, Peter Hoor, Thomas Wagenhäuser, Timo Keber, Tanja Schuck, and Andreas Engel
Atmos. Chem. Phys., 21, 17225–17241, https://doi.org/10.5194/acp-21-17225-2021, https://doi.org/10.5194/acp-21-17225-2021, 2021
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This study presents and compares inorganic chlorine (Cly) derived from observations with the HALO research aircraft in the Antarctic late winter–early fall 2019 and the Arctic winter 2015–2016. Trend-corrected correlations from the Northern Hemisphere show excellent agreement with those from the Southern Hemisphere. After observation allocation inside and outside the vortex based on N2O measurements, results of the two campaigns reveal substantial differences in Cly within the respective vortex.
Meike K. Rotermund, Vera Bense, Martyn P. Chipperfield, Andreas Engel, Jens-Uwe Grooß, Peter Hoor, Tilman Hüneke, Timo Keber, Flora Kluge, Benjamin Schreiner, Tanja Schuck, Bärbel Vogel, Andreas Zahn, and Klaus Pfeilsticker
Atmos. Chem. Phys., 21, 15375–15407, https://doi.org/10.5194/acp-21-15375-2021, https://doi.org/10.5194/acp-21-15375-2021, 2021
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Airborne total bromine (Brtot) and tracer measurements suggest Brtot-rich air masses persistently protruded into the lower stratosphere (LS), creating a high Brtot region over the North Atlantic in fall 2017. The main source is via isentropic transport by the Asian monsoon and to a lesser extent transport across the extratropical tropopause as quantified by a Lagrange model. The transport of Brtot via Central American hurricanes is also observed. Lastly, the impact of Brtot on LS O3 is assessed.
Thorsten Kaluza, Daniel Kunkel, and Peter Hoor
Weather Clim. Dynam., 2, 631–651, https://doi.org/10.5194/wcd-2-631-2021, https://doi.org/10.5194/wcd-2-631-2021, 2021
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We present a 10-year analysis on the occurrence of strong wind shear in the Northern Hemisphere, focusing on the region around the transport barrier that separates the first two layers of the atmosphere. The major result of our analysis is that strong wind shear above a certain threshold occurs frequently and nearly exclusively in this region, which, as an indicator for turbulent mixing, might have major implications concerning the separation efficiency of the transport barrier.
Franziska Köllner, Johannes Schneider, Megan D. Willis, Hannes Schulz, Daniel Kunkel, Heiko Bozem, Peter Hoor, Thomas Klimach, Frank Helleis, Julia Burkart, W. Richard Leaitch, Amir A. Aliabadi, Jonathan P. D. Abbatt, Andreas B. Herber, and Stephan Borrmann
Atmos. Chem. Phys., 21, 6509–6539, https://doi.org/10.5194/acp-21-6509-2021, https://doi.org/10.5194/acp-21-6509-2021, 2021
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We present in situ observations of vertically resolved particle chemical composition in the summertime Arctic lower troposphere. Our analysis demonstrates the strong vertical contrast between particle properties within the boundary layer and aloft. Emissions from vegetation fires and anthropogenic sources in northern Canada, Europe, and East Asia influenced particle composition in the free troposphere. Organics detected in Arctic aerosol particles can partly be identified as dicarboxylic acids.
Johannes Schneider, Ralf Weigel, Thomas Klimach, Antonis Dragoneas, Oliver Appel, Andreas Hünig, Sergej Molleker, Franziska Köllner, Hans-Christian Clemen, Oliver Eppers, Peter Hoppe, Peter Hoor, Christoph Mahnke, Martina Krämer, Christian Rolf, Jens-Uwe Grooß, Andreas Zahn, Florian Obersteiner, Fabrizio Ravegnani, Alexey Ulanovsky, Hans Schlager, Monika Scheibe, Glenn S. Diskin, Joshua P. DiGangi, John B. Nowak, Martin Zöger, and Stephan Borrmann
Atmos. Chem. Phys., 21, 989–1013, https://doi.org/10.5194/acp-21-989-2021, https://doi.org/10.5194/acp-21-989-2021, 2021
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During five aircraft missions, we detected aerosol particles containing meteoric material in the lower stratosphere. The stratospheric measurements span a latitude range from 15 to 68° N, and we find that at potential temperature levels of more than 40 K above the tropopause; particles containing meteoric material occur at similar abundance fractions across latitudes and seasons. We conclude that meteoric material is efficiently distributed between high and low latitudes by isentropic mixing.
W. Richard Leaitch, John K. Kodros, Megan D. Willis, Sarah Hanna, Hannes Schulz, Elisabeth Andrews, Heiko Bozem, Julia Burkart, Peter Hoor, Felicia Kolonjari, John A. Ogren, Sangeeta Sharma, Meng Si, Knut von Salzen, Allan K. Bertram, Andreas Herber, Jonathan P. D. Abbatt, and Jeffrey R. Pierce
Atmos. Chem. Phys., 20, 10545–10563, https://doi.org/10.5194/acp-20-10545-2020, https://doi.org/10.5194/acp-20-10545-2020, 2020
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Black carbon is a factor in the warming of the Arctic atmosphere due to its ability to absorb light, but the uncertainty is high and few observations have been made in the high Arctic above 80° N. We combine airborne and ground-based observations in the springtime Arctic, at and above 80° N, with simulations from a global model to show that light absorption by black carbon may be much larger than modelled. However, the uncertainty remains high.
Marius Hauck, Harald Bönisch, Peter Hoor, Timo Keber, Felix Ploeger, Tanja J. Schuck, and Andreas Engel
Atmos. Chem. Phys., 20, 8763–8785, https://doi.org/10.5194/acp-20-8763-2020, https://doi.org/10.5194/acp-20-8763-2020, 2020
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This study features an extended inversion method that includes transport across the extratropical tropopause to derive age spectra in the lowermost stratosphere from in situ trace gas measurements. The refined method is validated in a model setup and applied to data gained with the HALO research aircraft. Results are congruent with the findings of previous studies so that the method provides a promising toolset for the analysis of stratospheric dynamics based on observations in the future.
Heiko Bozem, Peter Hoor, Daniel Kunkel, Franziska Köllner, Johannes Schneider, Andreas Herber, Hannes Schulz, W. Richard Leaitch, Amir A. Aliabadi, Megan D. Willis, Julia Burkart, and Jonathan P. D. Abbatt
Atmos. Chem. Phys., 19, 15049–15071, https://doi.org/10.5194/acp-19-15049-2019, https://doi.org/10.5194/acp-19-15049-2019, 2019
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We present airborne trace gas measurements in the European and Canadian Arctic for July 2014 and April 2015. Based on CO and CO2 in situ data as well as 10 d kinematic back trajectories, we characterize the prevailing transport regimes and derive a tracer-based diagnostic for the determination of the polar dome boundary. Using the tracer-derived boundary, an analysis of the recent transport history of air masses within the polar dome reveals significant differences between spring and summer.
Daniel Kunkel, Peter Hoor, Thorsten Kaluza, Jörn Ungermann, Björn Kluschat, Andreas Giez, Hans-Christoph Lachnitt, Martin Kaufmann, and Martin Riese
Atmos. Chem. Phys., 19, 12607–12630, https://doi.org/10.5194/acp-19-12607-2019, https://doi.org/10.5194/acp-19-12607-2019, 2019
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In this study we present a mixing process around the tropopause in extratropical baroclinic waves. We analyze airborne data from a flight during the WISE campaign in autumn 2017 over the North Atlantic. We use idealized experiments to study the mixing process. Although the process occurs on a small geographical scale, it might be of importance due to its relation to a frequent feature of the extratropical UTLS. The process is relevant for STE but is not fully included in climatologies.
Andreas Marsing, Tina Jurkat-Witschas, Jens-Uwe Grooß, Stefan Kaufmann, Romy Heller, Andreas Engel, Peter Hoor, Jens Krause, and Christiane Voigt
Atmos. Chem. Phys., 19, 10757–10772, https://doi.org/10.5194/acp-19-10757-2019, https://doi.org/10.5194/acp-19-10757-2019, 2019
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We study the partitioning of inorganic chlorine into active (ozone-depleting) and reservoir species in the lowermost stratosphere of the Arctic polar vortex, using novel in situ aircraft measurements in winter 2015/2016. We observe a change in recovery pathways of the reservoirs HCl and ClONO2 with increasing potential temperature. A comparison with the CLaMS model relates the observations to the vortex-wide evolution and confirms unresolved discrepancies in the mid-winter HCl distribution.
Thorsten Kaluza, Daniel Kunkel, and Peter Hoor
Atmos. Chem. Phys., 19, 6621–6636, https://doi.org/10.5194/acp-19-6621-2019, https://doi.org/10.5194/acp-19-6621-2019, 2019
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We present a comprehensive mean evolution of the tropopause inversion layer in mid-latitudes, an atmospheric feature that is located in the region that separates the well-mixed troposphere and the stably stratified stratosphere. We counter-intuitively find this region, which is expected to stabilise atmospheric flow, to exhibit favourable conditions for turbulent exchange between troposphere and stratosphere. This is an important result concerning the overall assessment of exchange processes.
Meng Si, Erin Evoy, Jingwei Yun, Yu Xi, Sarah J. Hanna, Alina Chivulescu, Kevin Rawlings, Daniel Veber, Andrew Platt, Daniel Kunkel, Peter Hoor, Sangeeta Sharma, W. Richard Leaitch, and Allan K. Bertram
Atmos. Chem. Phys., 19, 3007–3024, https://doi.org/10.5194/acp-19-3007-2019, https://doi.org/10.5194/acp-19-3007-2019, 2019
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We investigated the importance of mineral dust, sea spray aerosol, and anthropogenic aerosol to the ice-nucleating particle (INP) population in the Canadian Arctic during spring 2016. The results suggest that mineral dust transported from the Gobi Desert was a major source of the INP population studied, and that sea spray aerosol decreased the ice-nucleating ability of mineral dust. The results should be useful for testing and improving models used to predict INPs and climate in the Arctic.
Jonathan P. D. Abbatt, W. Richard Leaitch, Amir A. Aliabadi, Allan K. Bertram, Jean-Pierre Blanchet, Aude Boivin-Rioux, Heiko Bozem, Julia Burkart, Rachel Y. W. Chang, Joannie Charette, Jai P. Chaubey, Robert J. Christensen, Ana Cirisan, Douglas B. Collins, Betty Croft, Joelle Dionne, Greg J. Evans, Christopher G. Fletcher, Martí Galí, Roya Ghahreman, Eric Girard, Wanmin Gong, Michel Gosselin, Margaux Gourdal, Sarah J. Hanna, Hakase Hayashida, Andreas B. Herber, Sareh Hesaraki, Peter Hoor, Lin Huang, Rachel Hussherr, Victoria E. Irish, Setigui A. Keita, John K. Kodros, Franziska Köllner, Felicia Kolonjari, Daniel Kunkel, Luis A. Ladino, Kathy Law, Maurice Levasseur, Quentin Libois, John Liggio, Martine Lizotte, Katrina M. Macdonald, Rashed Mahmood, Randall V. Martin, Ryan H. Mason, Lisa A. Miller, Alexander Moravek, Eric Mortenson, Emma L. Mungall, Jennifer G. Murphy, Maryam Namazi, Ann-Lise Norman, Norman T. O'Neill, Jeffrey R. Pierce, Lynn M. Russell, Johannes Schneider, Hannes Schulz, Sangeeta Sharma, Meng Si, Ralf M. Staebler, Nadja S. Steiner, Jennie L. Thomas, Knut von Salzen, Jeremy J. B. Wentzell, Megan D. Willis, Gregory R. Wentworth, Jun-Wei Xu, and Jacqueline D. Yakobi-Hancock
Atmos. Chem. Phys., 19, 2527–2560, https://doi.org/10.5194/acp-19-2527-2019, https://doi.org/10.5194/acp-19-2527-2019, 2019
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The Arctic is experiencing considerable environmental change with climate warming, illustrated by the dramatic decrease in sea-ice extent. It is important to understand both the natural and perturbed Arctic systems to gain a better understanding of how they will change in the future. This paper summarizes new insights into the relationships between Arctic aerosol particles and climate, as learned over the past five or so years by a large Canadian research consortium, NETCARE.
Hannes Schulz, Marco Zanatta, Heiko Bozem, W. Richard Leaitch, Andreas B. Herber, Julia Burkart, Megan D. Willis, Daniel Kunkel, Peter M. Hoor, Jonathan P. D. Abbatt, and Rüdiger Gerdes
Atmos. Chem. Phys., 19, 2361–2384, https://doi.org/10.5194/acp-19-2361-2019, https://doi.org/10.5194/acp-19-2361-2019, 2019
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Aircraft vertical profiles of black carbon (BC) aerosol from the High Canadian Arctic have shown systematic variability in different levels of the cold, stably stratified polar dome. During spring and summer, efficiencies of BC supply by transport (often from gas flaring and wildfire-affected regions) were different in the lower dome than at higher levels, as apparent from changes in mean particle size and mixing ratios with CO. Summer BC concentrations were a factor of 10 lower than in spring.
Jens Krause, Peter Hoor, Andreas Engel, Felix Plöger, Jens-Uwe Grooß, Harald Bönisch, Timo Keber, Björn-Martin Sinnhuber, Wolfgang Woiwode, and Hermann Oelhaf
Atmos. Chem. Phys., 18, 6057–6073, https://doi.org/10.5194/acp-18-6057-2018, https://doi.org/10.5194/acp-18-6057-2018, 2018
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We present tracer measurements of CO and N2O measured during the POLSTRACC aircraft campaign in winter 2015–2016. We found enhanced CO values relative to N2O in the polar lower stratosphere in addition to the ageing of this region during winter. By using model simulations it was possible to link this enhancement to an increased mixing of the tropical tropopause. We thus conclude that the polar lower stratosphere in late winter is strongly influenced by quasi-isentropic mixing from the tropics.
Christian Rolf, Bärbel Vogel, Peter Hoor, Armin Afchine, Gebhard Günther, Martina Krämer, Rolf Müller, Stefan Müller, Nicole Spelten, and Martin Riese
Atmos. Chem. Phys., 18, 2973–2983, https://doi.org/10.5194/acp-18-2973-2018, https://doi.org/10.5194/acp-18-2973-2018, 2018
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The Asian monsoon is a pronounced circulation system linked to rapid vertical transport of surface air from India and east Asia in the summer months. We found, based on aircraft measurements, higher concentration of water vapor in the lowermost stratosphere caused by the Asian monsoon. Enrichment of water vapor concentrations in the lowermost stratosphere impacts the radiation budget and thus climate. Understanding those variations in water vapor is important for climate projections.
Franziska Köllner, Johannes Schneider, Megan D. Willis, Thomas Klimach, Frank Helleis, Heiko Bozem, Daniel Kunkel, Peter Hoor, Julia Burkart, W. Richard Leaitch, Amir A. Aliabadi, Jonathan P. D. Abbatt, Andreas B. Herber, and Stephan Borrmann
Atmos. Chem. Phys., 17, 13747–13766, https://doi.org/10.5194/acp-17-13747-2017, https://doi.org/10.5194/acp-17-13747-2017, 2017
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We conducted aircraft-based single particle chemical composition measurements in the Canadian high Arctic during summer. Our results provide evidence for a marine-biogenic influence on secondary formation of particulate trimethylamine in the Arctic boundary layer. Understanding emission sources and further processes controlling aerosol number concentration and chemical composition in the pristine Arctic summer is crucial for modeling future climate in the area.
Tilman Hüneke, Oliver-Alex Aderhold, Jannik Bounin, Marcel Dorf, Eric Gentry, Katja Grossmann, Jens-Uwe Grooß, Peter Hoor, Patrick Jöckel, Mareike Kenntner, Marvin Knapp, Matthias Knecht, Dominique Lörks, Sabrina Ludmann, Sigrun Matthes, Rasmus Raecke, Marcel Reichert, Jannis Weimar, Bodo Werner, Andreas Zahn, Helmut Ziereis, and Klaus Pfeilsticker
Atmos. Meas. Tech., 10, 4209–4234, https://doi.org/10.5194/amt-10-4209-2017, https://doi.org/10.5194/amt-10-4209-2017, 2017
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This paper describes a novel instrument for the aircraft-borne remote sensing of trace gases and liquid and solid water. Until recently, such measurements could only be evaluated under clear-sky conditions. We present a characterization and error assessment of the novel "scaling method", which allows for the retrieval of absolute trace gas concentrations under all sky conditions, significantly expanding the applicability of such measurements to study atmospheric photochemistry.
Marcus Klingebiel, André Ehrlich, Fanny Finger, Timo Röschenthaler, Suad Jakirlić, Matthias Voigt, Stefan Müller, Rolf Maser, Manfred Wendisch, Peter Hoor, Peter Spichtinger, and Stephan Borrmann
Atmos. Meas. Tech., 10, 3485–3498, https://doi.org/10.5194/amt-10-3485-2017, https://doi.org/10.5194/amt-10-3485-2017, 2017
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Microphysical and radiation measurements were collected with the unique AIRcraft TOwed Sensor Shuttle (AIRTOSS) – Learjet tandem platform. It is a combination of a Learjet 35A research aircraft and an instrumented aerodynamic bird, which can be detached from and retracted back to the aircraft during flight.
AIRTOSS and Learjet are equipped with radiative, cloud microphysical, trace gas,
and meteorological instruments to study cirrus clouds.
Andrea Mues, Maheswar Rupakheti, Christoph Münkel, Axel Lauer, Heiko Bozem, Peter Hoor, Tim Butler, and Mark G. Lawrence
Atmos. Chem. Phys., 17, 8157–8176, https://doi.org/10.5194/acp-17-8157-2017, https://doi.org/10.5194/acp-17-8157-2017, 2017
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Ceilometer measurements taken in the Kathmandu Valley, Nepal, were used to study the temporal and spatial evolution of the mixing layer height in the valley. This provides important information on the vertical structure of the atmosphere and can thus also help to understand the mixing of air pollutants (e.g. black carbon) in the valley. The seasonal and diurnal cycles of the mixing layer were found to be highly dependent on meteorology and mainly anticorrelated to black carbon concentrations.
Klaus-D. Gottschaldt, Hans Schlager, Robert Baumann, Heiko Bozem, Veronika Eyring, Peter Hoor, Patrick Jöckel, Tina Jurkat, Christiane Voigt, Andreas Zahn, and Helmut Ziereis
Atmos. Chem. Phys., 17, 6091–6111, https://doi.org/10.5194/acp-17-6091-2017, https://doi.org/10.5194/acp-17-6091-2017, 2017
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We present upper-tropospheric trace gas measurements in the Asian summer monsoon anticyclone, obtained with the HALO research aircraft in September 2012. The anticyclone is one of the largest atmospheric features on Earth, but many aspects of it are not well understood. With the help of model simulations we find that entrainments from the tropopause region and the lower troposphere, combined with photochemistry and dynamical instabilities, can explain the observations.
Julia Burkart, Megan D. Willis, Heiko Bozem, Jennie L. Thomas, Kathy Law, Peter Hoor, Amir A. Aliabadi, Franziska Köllner, Johannes Schneider, Andreas Herber, Jonathan P. D. Abbatt, and W. Richard Leaitch
Atmos. Chem. Phys., 17, 5515–5535, https://doi.org/10.5194/acp-17-5515-2017, https://doi.org/10.5194/acp-17-5515-2017, 2017
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Our aircraft study for the first time systematically investigates aerosol size distributions, including ultrafine particles (5–20 nm in diameter), in the Arctic summertime atmosphere. We find that ultrafine particles occur very frequently in the boundary layer and not aloft, suggesting a surface source of these particles. Understanding aerosol properties and sources is crucial to predict climate and especially important in the Arctic as this region responds extremely fast to climate change.
Johannes Wagner, Andreas Dörnbrack, Markus Rapp, Sonja Gisinger, Benedikt Ehard, Martina Bramberger, Benjamin Witschas, Fernando Chouza, Stephan Rahm, Christian Mallaun, Gerd Baumgarten, and Peter Hoor
Atmos. Chem. Phys., 17, 4031–4052, https://doi.org/10.5194/acp-17-4031-2017, https://doi.org/10.5194/acp-17-4031-2017, 2017
Bärbel Vogel, Gebhard Günther, Rolf Müller, Jens-Uwe Grooß, Armin Afchine, Heiko Bozem, Peter Hoor, Martina Krämer, Stefan Müller, Martin Riese, Christian Rolf, Nicole Spelten, Gabriele P. Stiller, Jörn Ungermann, and Andreas Zahn
Atmos. Chem. Phys., 16, 15301–15325, https://doi.org/10.5194/acp-16-15301-2016, https://doi.org/10.5194/acp-16-15301-2016, 2016
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The identification of transport pathways from the Asian monsoon anticyclone into the lower stratosphere is unclear. Global simulations with the CLaMS model demonstrate that source regions in Asia and in the Pacific Ocean have a significant impact on the chemical composition of the lower stratosphere of the Northern Hemisphere by flooding the extratropical lower stratosphere with young moist air masses. Two main horizontal transport pathways from the Asian monsoon anticyclone are identified.
W. Richard Leaitch, Alexei Korolev, Amir A. Aliabadi, Julia Burkart, Megan D. Willis, Jonathan P. D. Abbatt, Heiko Bozem, Peter Hoor, Franziska Köllner, Johannes Schneider, Andreas Herber, Christian Konrad, and Ralf Brauner
Atmos. Chem. Phys., 16, 11107–11124, https://doi.org/10.5194/acp-16-11107-2016, https://doi.org/10.5194/acp-16-11107-2016, 2016
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Thought to be mostly unimportant for summertime Arctic liquid-water clouds, airborne observations show that atmospheric aerosol particles 50 nm in diameter or smaller and most likely from natural sources are often involved in cloud formation in the pristine Arctic summer. The result expands the reference for aerosol forcing of climate. Further, for extremely low droplet concentrations, no evidence is found for a connection between cloud liquid water and aerosol particle concentrations.
Stefan Müller, Peter Hoor, Heiko Bozem, Ellen Gute, Bärbel Vogel, Andreas Zahn, Harald Bönisch, Timo Keber, Martina Krämer, Christian Rolf, Martin Riese, Hans Schlager, and Andreas Engel
Atmos. Chem. Phys., 16, 10573–10589, https://doi.org/10.5194/acp-16-10573-2016, https://doi.org/10.5194/acp-16-10573-2016, 2016
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In situ airborne measurements performed during TACTS/ESMVal 2012 were analysed to investigate the chemical compostion of the upper troposphere and lower stratosphere. N2O, CO and O3 data show an increase in tropospherically affected air masses within the extratropical stratosphere from August to September 2012, which originate from the Asian monsoon region. Thus, the Asian monsoon anticyclone significantly affected the chemical composition of the extratropical stratosphere during summer 2012.
Amir A. Aliabadi, Jennie L. Thomas, Andreas B. Herber, Ralf M. Staebler, W. Richard Leaitch, Hannes Schulz, Kathy S. Law, Louis Marelle, Julia Burkart, Megan D. Willis, Heiko Bozem, Peter M. Hoor, Franziska Köllner, Johannes Schneider, Maurice Levasseur, and Jonathan P. D. Abbatt
Atmos. Chem. Phys., 16, 7899–7916, https://doi.org/10.5194/acp-16-7899-2016, https://doi.org/10.5194/acp-16-7899-2016, 2016
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For the first time, ship emissions of an ice-breaker, the Amundsen, is characterized while breaking ice in the Canadian Arctic using the plume intercepts by the Polar 6 aircraft. The study is novel, estimating lower plume expansion rates over the stable Arctic marine boundary layer and different emissions factors for oxides of nitrogen, black carbon, and carbon monoxide, compared to plume intercept studies in mid latitudes. These results can inform policy making and emission inventory datasets.
Megan D. Willis, Julia Burkart, Jennie L. Thomas, Franziska Köllner, Johannes Schneider, Heiko Bozem, Peter M. Hoor, Amir A. Aliabadi, Hannes Schulz, Andreas B. Herber, W. Richard Leaitch, and Jonathan P. D. Abbatt
Atmos. Chem. Phys., 16, 7663–7679, https://doi.org/10.5194/acp-16-7663-2016, https://doi.org/10.5194/acp-16-7663-2016, 2016
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We present a case study focused on an aerosol growth event observed in the Canadian High Arctic during summer. Using measurements of aerosol chemical and physical properties we find evidence for aerosol growth into cloud condensation nuclei-active sizes, through marine-influenced secondary organic aerosol formation. Understanding the mechanisms that control the formation and growth of aerosol is crucial for our ability to predict cloud properties, and therefore radiative balance and climate.
Florian Berkes, Peter Hoor, Heiko Bozem, Daniel Kunkel, Michael Sprenger, and Stephan Henne
Atmos. Chem. Phys., 16, 6011–6025, https://doi.org/10.5194/acp-16-6011-2016, https://doi.org/10.5194/acp-16-6011-2016, 2016
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We presented airborne measurements of CO2 and O3 across the entrainment zone over a semi-remote environment in southwestern Germany in late summer 2011 .
For the first time CO2 and O3 were used as tracer to identify mixing through this transport barrier. We demonstrated that the tracer--tracer correlation of CO2 and O3 is a powerful tool to identify entrainment and mixing.
N. Sobanski, M. J. Tang, J. Thieser, G. Schuster, D. Pöhler, H. Fischer, W. Song, C. Sauvage, J. Williams, J. Fachinger, F. Berkes, P. Hoor, U. Platt, J. Lelieveld, and J. N. Crowley
Atmos. Chem. Phys., 16, 4867–4883, https://doi.org/10.5194/acp-16-4867-2016, https://doi.org/10.5194/acp-16-4867-2016, 2016
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The nitrate radical (NO3) is an important nocturnal oxidant. By measuring NO3, its precursors (nitrogen dioxide and ozone) and several trace gases with which it reacts, we examined the chemical and meteorological factors influencing the lifetime of NO3 at a semi-rural mountain site. Unexpectedly long lifetimes, approaching 1 h, were observed on several nights and were associated with a low-lying residual layer. We discuss the role of other reactions that convert NO2 to NO3.
D. Kunkel, P. Hoor, and V. Wirth
Atmos. Chem. Phys., 16, 541–560, https://doi.org/10.5194/acp-16-541-2016, https://doi.org/10.5194/acp-16-541-2016, 2016
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By conducting various simulations of dry and moist baroclinic life cycles, we aimed to improve the understanding of whether dynamical or diabatic processes are more relevant to form a tropopause inversion layer at midlatitudes. Most importantly, our experiments highlighted the role of different moisture related processes for the formation and evolution of the tropopause inversion layer with varying relevance and strength in different phases of the baroclinic life cycles.
Christiane Hofmann, Astrid Kerkweg, Peter Hoor, and Patrick Jöckel
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2015-949, https://doi.org/10.5194/acp-2015-949, 2016
Revised manuscript not accepted
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Ozone enhancements at the surface, caused by descending stratospheric air masses along deep tropopause folds, can be reproduced using the model system MECO(n). It is shown that stratosphere-troposphere-exchange (STE) in the vicinity of a tropopause fold occurs in regions of turbulence and diabatic processes. The efficiency of mixing is quantified, showing that almost all of the air masses originating in the tropopause fold are transported into the troposphere during the following two days.
C. Rolf, A. Afchine, H. Bozem, B. Buchholz, V. Ebert, T. Guggenmoser, P. Hoor, P. Konopka, E. Kretschmer, S. Müller, H. Schlager, N. Spelten, O. Sumińska-Ebersoldt, J. Ungermann, A. Zahn, and M. Krämer
Atmos. Chem. Phys., 15, 9143–9158, https://doi.org/10.5194/acp-15-9143-2015, https://doi.org/10.5194/acp-15-9143-2015, 2015
W. Frey, R. Schofield, P. Hoor, D. Kunkel, F. Ravegnani, A. Ulanovsky, S. Viciani, F. D'Amato, and T. P. Lane
Atmos. Chem. Phys., 15, 6467–6486, https://doi.org/10.5194/acp-15-6467-2015, https://doi.org/10.5194/acp-15-6467-2015, 2015
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This study examines the simulated downward transport and mixing of stratospheric air into the upper tropical troposphere as observed on a research flight during the SCOUT-O3 campaign in connection with a deep convective system, using the WRF model. Passive tracers are initialised to study the impact of the deep convection on the tracers and water vapour. We use the model to explain the processes causing the transport and also expose areas of inconsistencies between the model and observations.
R. Pommrich, R. Müller, J.-U. Grooß, P. Konopka, F. Ploeger, B. Vogel, M. Tao, C. M. Hoppe, G. Günther, N. Spelten, L. Hoffmann, H.-C. Pumphrey, S. Viciani, F. D'Amato, C. M. Volk, P. Hoor, H. Schlager, and M. Riese
Geosci. Model Dev., 7, 2895–2916, https://doi.org/10.5194/gmd-7-2895-2014, https://doi.org/10.5194/gmd-7-2895-2014, 2014
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A version of the chemical transport model CLaMS is presented, which features a simplified (numerically inexpensive) chemistry scheme. The model results using this version of CLaMS show a good representation of anomaly fields of CO, CH4, N2O, and CFC-11 in the lower stratosphere. CO measurements of three instruments (COLD, HAGAR, and Falcon-CO) in the lower tropical stratosphere (during the campaign TROCCINOX in 2005) have been compared and show a good agreement within the error bars.
B. Vogel, G. Günther, R. Müller, J.-U. Grooß, P. Hoor, M. Krämer, S. Müller, A. Zahn, and M. Riese
Atmos. Chem. Phys., 14, 12745–12762, https://doi.org/10.5194/acp-14-12745-2014, https://doi.org/10.5194/acp-14-12745-2014, 2014
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Enhanced tropospheric trace gases (e.g. pollutants) were measured in situ in
the lowermost stratosphere over Northern Europe on 26 September 2012
during the TACTS aircraft campaign. We found that the combination of rapid uplift by a typhoon and eastward eddy shedding from the Asian monsoon anticyclone is a novel fast transport pathway
that may carry boundary emissions from Southeast
Asia/western Pacific within approximately 5 weeks to the lowermost
stratosphere in Northern Europe.
M. Riese, H. Oelhaf, P. Preusse, J. Blank, M. Ern, F. Friedl-Vallon, H. Fischer, T. Guggenmoser, M. Höpfner, P. Hoor, M. Kaufmann, J. Orphal, F. Plöger, R. Spang, O. Suminska-Ebersoldt, J. Ungermann, B. Vogel, and W. Woiwode
Atmos. Meas. Tech., 7, 1915–1928, https://doi.org/10.5194/amt-7-1915-2014, https://doi.org/10.5194/amt-7-1915-2014, 2014
C. Liu, S. Beirle, T. Butler, P. Hoor, C. Frankenberg, P. Jöckel, M. Penning de Vries, U. Platt, A. Pozzer, M. G. Lawrence, J. Lelieveld, H. Tost, and T. Wagner
Atmos. Chem. Phys., 14, 1717–1732, https://doi.org/10.5194/acp-14-1717-2014, https://doi.org/10.5194/acp-14-1717-2014, 2014
J. Yoon, A. Pozzer, P. Hoor, D. Y. Chang, S. Beirle, T. Wagner, S. Schloegl, J. Lelieveld, and H. M. Worden
Atmos. Chem. Phys., 13, 11307–11316, https://doi.org/10.5194/acp-13-11307-2013, https://doi.org/10.5194/acp-13-11307-2013, 2013
Related subject area
Subject: Gases | Research Activity: Atmospheric Modelling and Data Analysis | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)
Natural surface emissions dominate anthropogenic emissions contributions to total gaseous mercury at Canadian rural sites
Modelling Arctic lower-tropospheric ozone: processes controlling seasonal variations
Influence of nitrogen oxides and volatile organic compounds emission changes on tropospheric ozone variability, trends and radiative effect
Tropospheric ozone trends and attributions over East and Southeast Asia in 1995–2019: an integrated assessment using statistical methods, machine learning models, and multiple chemical transport models
Characterization of reactive oxidized nitrogen in the global upper troposphere using recent and historic commercial and research aircraft campaigns and GEOS-Chem
Soil deposition of atmospheric hydrogen constrained using planetary-scale observations
Comparative ozone production sensitivity to NOx and VOCs in Quito, Ecuador, and Santiago, Chile
South Asia anthropogenic ammonia emission inversion through assimilating IASI observations
A new parameterization of photolysis rates for oxygenated volatile organic compounds (OVOCs)
Constraining the budget of NOx and volatile organic compounds at a remote tropical island using multi-platform observations and WRF-Chem model simulations
Multi-observational estimation of regional and sectoral emission contributions to the persistent high growth rate of atmospheric CH4 for 2020–2022
Representing improved tropospheric ozone distribution over the Northern Hemisphere by including lightning NOx emissions in CHIMERE
Assessing the ability to quantify the decrease in NOx anthropogenic emissions in 2019 compared to 2005 using OMI and TROPOMI satellite observations
Tracking daily NOx emissions from an urban agglomeration based on TROPOMI NO2 and a local ensemble transform Kalman filter
Evaluation of O3, H2O, CO, and NOy climatologies simulated by four global models in the upper troposphere–lower stratosphere with IAGOS measurements
Source contribution to ozone pollution during June 2021 fire events in Arizona: insights from WRF-Chem-tagged O3 and CO
High-resolution mapping of on-road vehicle emissions with real-time traffic datasets based on big data
Sensitivity of climate–chemistry model simulated atmospheric composition to the application of an inverse relationship between NOx emission and lightning flash frequency
Regional and sectoral contributions of NOx and reactive carbon emission sources to global trends in tropospheric ozone during the 2000–2018 period
Underappreciated contributions of biogenic volatile organic compounds from urban green spaces to ozone pollution
Chemistry–climate feedback of atmospheric methane in a methane-emission-flux-driven chemistry–climate model
Surface ozone trend variability across the United States and the impact of heat waves (1990–2023)
Influence of Various Criteria on Identifying the Springtime Tropospheric Ozone Depletion Events (ODEs) at Utqiagvik, Arctic
Sensitivity of climate effects of hydrogen to leakage size, location, and chemical background
Evaluating tropospheric nitrogen dioxide in UKCA using OMI satellite retrievals over south and east Asia
A technology-based global non-methane volatile organic compounds (NMVOC) emission inventory under the MEIC framework
The role of the tropical carbon balance in determining the large atmospheric CO2 growth rate in 2023
Shifts in global atmospheric oxidant chemistry from land cover change
Technical note: A comparative study of chemistry schemes for volcanic sulfur dioxide in Lagrangian transport simulations – a case study of the 2019 Raikoke eruption
Revisiting the high tropospheric ozone over southern Africa: role of biomass burning and anthropogenic emissions
Monoterpene oxidation pathways initiated by acyl peroxy radical addition
Local and transboundary contributions to NOy loadings across East Asia using CMAQ-ISAM and a GEMS-informed emission inventory during the winter–spring transition
Estimating the variability in NOx emissions from Wuhan with TROPOMI NO2 data during 2018 to 2023
Effects of enhancing nitrogen use efficiency in cropland and livestock systems on agricultural ammonia emissions and particulate matter air quality in China
Enhanced understanding of atmospheric blocking modulation on ozone dynamics within a high-resolution Earth system model
Tropospheric ozone responses to the El Niño-Southern Oscillation (ENSO): quantification of individual processes and future projections from multiple chemical models
Natural emissions of VOC and NOx over Africa constrained by TROPOMI HCHO and NO2 data using the MAGRITTEv1.1 model
Contributions of lightning to long-term trends and inter-annual variability in global atmospheric chemistry constrained by Schumann Resonance observations
Simulated photochemical response to observational constraints on aerosol vertical distribution over North China
Impacts of wildfire smoke aerosols on near-surface ozone photochemistry
Anthropogenic emission controls reduce summertime ozone–temperature sensitivity in the United States
Effectiveness of Emission Controls on Atmospheric Oxidation and Air Pollutant Concentrations: Uncertainties due to Chemical Mechanisms and Inventories
Investigating the response of China's surface ozone concentration to the future changes of multiple factors
The 21st-century wetting inhibits growing surface ozone in Northwestern China
Effects of different emission inventories on tropospheric ozone and methane lifetime
Assessing the relative impacts of satellite ozone and its precursor observations to improve global tropospheric ozone analysis using multiple chemical reanalysis systems
Evaluating present-day and future impacts of agricultural ammonia emissions on atmospheric chemistry and climate
Global atmospheric inversion of the NH3 emissions over 2019–2022 using the LMDZ-INCA chemistry-transport model and the IASI NH3 observations
Air-pollution-satellite-based CO2 emission inversion: system evaluation, sensitivity analysis, and future research direction
The impact of sea spray aerosol on photochemical ozone formation over eastern China: heterogeneous reaction of chlorine particles and radiative effect
Irene Cheng, Amanda Cole, Leiming Zhang, and Alexandra Steffen
Atmos. Chem. Phys., 25, 8591–8611, https://doi.org/10.5194/acp-25-8591-2025, https://doi.org/10.5194/acp-25-8591-2025, 2025
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Using the positive matrix factorization (PMF) model and observations, we showed that natural surface emission (wildfires and re-emitted Hg) dominated anthropogenic contributions to total gaseous mercury (TGM). Decreasing TGM was due to reduced shipping, local combustion, and regional emissions. Relative contributions from natural surface emissions increased by 0.3–1.8 % yr-1. Results showed Hg control measures have been effective, but greater attention is needed for monitoring surface re-emissions.
Wanmin Gong, Stephen R. Beagley, Kenjiro Toyota, Henrik Skov, Jesper Heile Christensen, Alex Lupu, Diane Pendlebury, Junhua Zhang, Ulas Im, Yugo Kanaya, Alfonso Saiz-Lopez, Roberto Sommariva, Peter Effertz, John W. Halfacre, Nis Jepsen, Rigel Kivi, Theodore K. Koenig, Katrin Müller, Claus Nordstrøm, Irina Petropavlovskikh, Paul B. Shepson, William R. Simpson, Sverre Solberg, Ralf M. Staebler, David W. Tarasick, Roeland Van Malderen, and Mika Vestenius
Atmos. Chem. Phys., 25, 8355–8405, https://doi.org/10.5194/acp-25-8355-2025, https://doi.org/10.5194/acp-25-8355-2025, 2025
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This study showed that the springtime O3 depletion plays a critical role in driving the surface O3 seasonal cycle in the central Arctic. The O3 depletion events, while occurring most notably within the lowest few hundred metres above the Arctic Ocean, can induce a 5–7 % loss in the pan-Arctic tropospheric O3 burden during springtime. The study also found enhancements in O3 and NOy (mostly peroxyacetyl nitrate) concentrations in the Arctic due to northern boreal wildfires, particularly at higher altitudes.
Suvarna Fadnavis, Yasin Elshorbany, Jerald Ziemke, Brice Barret, Alexandru Rap, P. R. Satheesh Chandran, Richard J. Pope, Vijay Sagar, Domenico Taraborrelli, Eric Le Flochmoen, Juan Cuesta, Catherine Wespes, Folkert Boersma, Isolde Glissenaar, Isabelle De Smedt, Michel Van Roozendael, Hervé Petetin, and Isidora Anglou
Atmos. Chem. Phys., 25, 8229–8254, https://doi.org/10.5194/acp-25-8229-2025, https://doi.org/10.5194/acp-25-8229-2025, 2025
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Satellites and model simulations show enhancement in tropospheric ozone, which is highly impacted by human-produced nitrous oxides compared to volatile organic compounds. The increased amount of ozone enhances ozone radiative forcing. The ozone enhancement and associated radiative forcing are the highest over South and East Asia. The emissions of nitrous oxides show a higher influence on shifting ozone photochemical regimes than volatile organic compounds.
Xiao Lu, Yiming Liu, Jiayin Su, Xiang Weng, Tabish Ansari, Yuqiang Zhang, Guowen He, Yuqi Zhu, Haolin Wang, Ganquan Zeng, Jingyu Li, Cheng He, Shuai Li, Teerachai Amnuaylojaroen, Tim Butler, Qi Fan, Shaojia Fan, Grant L. Forster, Meng Gao, Jianlin Hu, Yugo Kanaya, Mohd Talib Latif, Keding Lu, Philippe Nédélec, Peer Nowack, Bastien Sauvage, Xiaobin Xu, Lin Zhang, Ke Li, Ja-Ho Koo, and Tatsuya Nagashima
Atmos. Chem. Phys., 25, 7991–8028, https://doi.org/10.5194/acp-25-7991-2025, https://doi.org/10.5194/acp-25-7991-2025, 2025
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This study analyzes summertime ozone trends in East and Southeast Asia derived from a comprehensive observational database spanning from 1995 to 2019, incorporating aircraft observations, ozonesonde data, and measurements from 2500 surface sites. Multiple models are applied to attribute to changes in anthropogenic emissions and climate. The results highlight that increases in anthropogenic emissions are the primary driver of ozone increases both in the free troposphere and at the surface.
Nana Wei, Eloise A. Marais, Gongda Lu, Robert G. Ryan, and Bastien Sauvage
Atmos. Chem. Phys., 25, 7925–7940, https://doi.org/10.5194/acp-25-7925-2025, https://doi.org/10.5194/acp-25-7925-2025, 2025
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This study uses reactive nitrogen observations from NASA DC-8 research aircraft and the In-service Aircraft for a Global Observing System (IAGOS) campaigns to characterize reactive nitrogen seasonality and composition in the global upper troposphere and to diagnose the greatest knowledge gaps from comparison to a state-of-the-science model, GEOS-Chem, that need to be resolved for climate, nitrogen cycle, and air pollution assessments.
Alexander K. Tardito Chaudhri and David S. Stevenson
Atmos. Chem. Phys., 25, 7369–7385, https://doi.org/10.5194/acp-25-7369-2025, https://doi.org/10.5194/acp-25-7369-2025, 2025
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There remains a large uncertainty in the global warming potential of atmospheric hydrogen due to poor constraints on its soil deposition and, therefore, its lifetime. A new analysis of the latitudinal variation in the observed seasonality of hydrogen is used to constrain its surface fluxes. This is complemented with a simple latitude–height model where surface fluxes are adjusted from a prototype deposition scheme.
María Cazorla, Melissa Trujillo, Rodrigo Seguel, and Laura Gallardo
Atmos. Chem. Phys., 25, 7087–7109, https://doi.org/10.5194/acp-25-7087-2025, https://doi.org/10.5194/acp-25-7087-2025, 2025
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The current climate and environmental crises impose the need to take actions in cities to curb ozone as a pollutant and a climate forcer. This endeavor is challenging in understudied regions. In this work we analyze how reducing levels of precursor chemicals would affect ozone formation in Quito, Ecuador, and Santiago, Chile.
Ji Xia, Yi Zhou, Li Fang, Yingfei Qi, Dehao Li, Hong Liao, and Jianbing Jin
Atmos. Chem. Phys., 25, 7071–7086, https://doi.org/10.5194/acp-25-7071-2025, https://doi.org/10.5194/acp-25-7071-2025, 2025
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This study established an ammonia emission inventory for South Asia via an assimilation-based inversion system. The posterior emissions, calculated by integrating the anthropogenic inventory and satellite observations, showed significant improvement over the prior. Validation against various measurements supports our results. The study offers a deep understanding of ammonia emissions for policymakers and researchers aiming to develop air quality management and mitigation strategies for South Asia.
Yuwen Peng, Bin Yuan, Sihang Wang, Xin Song, Zhe Peng, Wenjie Wang, Suxia Yang, Jipeng Qi, Xianjun He, Yibo Huangfu, Xiao-Bing Li, and Min Shao
Atmos. Chem. Phys., 25, 7037–7052, https://doi.org/10.5194/acp-25-7037-2025, https://doi.org/10.5194/acp-25-7037-2025, 2025
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A structural-based parameterization for the photolysis rates of oxygenated volatile organic compounds (OVOCs) was integrated into an updated chemical mechanism. This method links photolysis rates to species' structure, bypassing limitations of insufficient quantum yield data. Box model results show that non-HCHO OVOCs, particularly multifunctional carbonyl compounds, significantly contribute to radical production, with alkene and aromatic oxidation products playing key roles.
Catalina Poraicu, Jean-François Müller, Trissevgeni Stavrakou, Crist Amelynck, Bert W. D. Verreyken, Niels Schoon, Corinne Vigouroux, Nicolas Kumps, Jérôme Brioude, Pierre Tulet, and Camille Mouchel-Vallon
Atmos. Chem. Phys., 25, 6903–6941, https://doi.org/10.5194/acp-25-6903-2025, https://doi.org/10.5194/acp-25-6903-2025, 2025
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We investigated the sources and impacts of nitrogen oxides and organic compounds over a remote tropical island. Simulations of the high-resolution Weather Research and Forecasting model coupled with chemistry (WRF-Chem) were evaluated using in situ Fourier transform infrared spectroscopy (FTIR) and satellite measurements. This work highlights gaps in current models, like missing sources of key organic compounds and inaccuracies in emission inventories, emphasizing the importance of improving chemical and dynamical processes in atmospheric modelling for budget estimates in tropical regions.
Yosuke Niwa, Yasunori Tohjima, Yukio Terao, Tazu Saeki, Akihiko Ito, Taku Umezawa, Kyohei Yamada, Motoki Sasakawa, Toshinobu Machida, Shin-Ichiro Nakaoka, Hideki Nara, Hiroshi Tanimoto, Hitoshi Mukai, Yukio Yoshida, Shinji Morimoto, Shinya Takatsuji, Kazuhiro Tsuboi, Yousuke Sawa, Hidekazu Matsueda, Kentaro Ishijima, Ryo Fujita, Daisuke Goto, Xin Lan, Kenneth Schuldt, Michal Heliasz, Tobias Biermann, Lukasz Chmura, Jarsolaw Necki, Irène Xueref-Remy, and Damiano Sferlazzo
Atmos. Chem. Phys., 25, 6757–6785, https://doi.org/10.5194/acp-25-6757-2025, https://doi.org/10.5194/acp-25-6757-2025, 2025
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This study estimated regional and sectoral emission contributions to the unprecedented surge of atmospheric methane for 2020–2022. The methane is the second most important greenhouse gas, and its emissions reduction is urgently required to mitigate global warming. Numerical modeling-based estimates with three different sets of atmospheric observations consistently suggested large contributions of biogenic emissions from South Asia and Southeast Asia to the surge of atmospheric methane.
Sanhita Ghosh, Arineh Cholakian, Sylvain Mailler, and Laurent Menut
Atmos. Chem. Phys., 25, 6273–6297, https://doi.org/10.5194/acp-25-6273-2025, https://doi.org/10.5194/acp-25-6273-2025, 2025
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In this study, we evaluate the present state of modelling lightning flashes over the Northern Hemisphere, using the classical CTH (cloud-top height) scheme and the ICEFLUX scheme with the CHIMERE model. Our study provides a comprehensive 3D comparison of model outputs to assess the robustness and applicability of these schemes. An improvement in O3 distribution in the tropical free troposphere is observed due to inclusion of LNOx (nitrogen oxide emissions from lightning) in the model. Inclusion of LNOx also reduces the lifetime of trace gas CH4.
Audrey Fortems-Cheiney, Grégoire Broquet, Elise Potier, Antoine Berchet, Isabelle Pison, Adrien Martinez, Robin Plauchu, Rimal Abeed, Aurélien Sicsik-Paré, Gaelle Dufour, Adriana Coman, Dilek Savas, Guillaume Siour, Henk Eskes, Hugo A. C. Denier van der Gon, and Stijn N. C. Dellaert
Atmos. Chem. Phys., 25, 6047–6068, https://doi.org/10.5194/acp-25-6047-2025, https://doi.org/10.5194/acp-25-6047-2025, 2025
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This study assesses the potential of the Ozone Monitoring Instrument (OMI) and the TROPOspheric Monitoring Instrument (TROPOMI) satellite observations to inform about the decrease in anthropogenic emissions of nitrogen oxides (NOx) in 2019 compared with 2005 at regional to national scales in Europe. Both the OMI and TROPOMI inversions show decreases in European NOx anthropogenic emission budgets in 2019 compared to 2005 but with different magnitudes.
Yawen Kong, Bo Zheng, and Yuxi Liu
Atmos. Chem. Phys., 25, 5959–5976, https://doi.org/10.5194/acp-25-5959-2025, https://doi.org/10.5194/acp-25-5959-2025, 2025
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Current high-resolution satellite remote sensing technologies provide a unique opportunity to derive timely high-resolution emission data. We developed an emission inversion system to assimilate satellite NO2 data to obtain daily kilometer-scale NOx emission inventories. Our results enhance inventory accuracy, allowing us to capture the effects of pollution control policies on daily emissions (e.g., during COVID-19 lockdowns) and improve fine-scale air quality modeling.
Yann Cohen, Didier Hauglustaine, Nicolas Bellouin, Marianne Tronstad Lund, Sigrun Matthes, Agnieszka Skowron, Robin Thor, Ulrich Bundke, Andreas Petzold, Susanne Rohs, Valérie Thouret, Andreas Zahn, and Helmut Ziereis
Atmos. Chem. Phys., 25, 5793–5836, https://doi.org/10.5194/acp-25-5793-2025, https://doi.org/10.5194/acp-25-5793-2025, 2025
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The chemical composition of the atmosphere near the tropopause is a key parameter for evaluating the climate impact of subsonic aviation pollutants. This study uses in situ data collected aboard passenger aircraft to assess the ability of four chemistry–climate models to reproduce (bi-)decadal climatologies of ozone, carbon monoxide, water vapour, and reactive nitrogen in this region. The models reproduce the very distinct ozone seasonality in the upper troposphere and in the lower stratosphere well.
Yafang Guo, Mohammad Amin Mirrezaei, Armin Sorooshian, and Avelino F. Arellano
Atmos. Chem. Phys., 25, 5591–5616, https://doi.org/10.5194/acp-25-5591-2025, https://doi.org/10.5194/acp-25-5591-2025, 2025
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We assess the contributions of fire and anthropogenic emissions to O3 levels in Phoenix, Arizona, during a period of intense heat and drought conditions. We find that fire exacerbates O3 pollution and that interactions between weather, climate, and air chemistry are important to consider. This has implications for activities related to formulating emission reduction strategies in areas that are currently understudied yet becoming relevant due to reports of increasing global aridity.
Yujia Wang, Hongbin Wang, Bo Zhang, Peng Liu, Xinfeng Wang, Shuchun Si, Likun Xue, Qingzhu Zhang, and Qiao Wang
Atmos. Chem. Phys., 25, 5537–5555, https://doi.org/10.5194/acp-25-5537-2025, https://doi.org/10.5194/acp-25-5537-2025, 2025
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This study established a bottom-up approach that employs real-time traffic flows and interpolation to obtain a spatially continuous on-road vehicle emission mapping for the main urban area of Jinan. The diurnal variation, spatial distribution, and emission hotspots were analyzed with clustering and hotspot analysis, showing unique fine-scale variation characteristics of on-road vehicle emissions. Future scenario analysis demonstrates remarkable benefits of electrification on emission reduction.
Francisco J. Pérez-Invernón, Francisco J. Gordillo-Vázquez, Heidi Huntrieser, Patrick Jöckel, and Eric J. Bucsela
Atmos. Chem. Phys., 25, 5557–5575, https://doi.org/10.5194/acp-25-5557-2025, https://doi.org/10.5194/acp-25-5557-2025, 2025
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Lightning plays a significant role in tropospheric chemistry by producing substantial amounts of nitrogen oxides. According to recent estimates, thunderstorms that produce a higher lightning frequency rate also produce less nitrogen oxide per flash. We implemented the dependency of nitrogen oxide production per flash on lightning flash frequency in a chemical atmospheric model.
Aditya Nalam, Aura Lupaşcu, Tabish Ansari, and Tim Butler
Atmos. Chem. Phys., 25, 5287–5311, https://doi.org/10.5194/acp-25-5287-2025, https://doi.org/10.5194/acp-25-5287-2025, 2025
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Tropospheric O3 molecules are labeled with the identity of their precursor source to simulate contributions from various emission sources to the global tropospheric O3 burden (TOB) and its trends. With an equatorward shift, anthropogenic NOx emissions become significantly more efficient at producing O3 and play a major role in driving TOB trends, mainly due to larger convection at the tropics effectively lifting O3 and its precursors to the free troposphere, where O3 lifetime is longer.
Haofan Wang, Yuejin Li, Yiming Liu, Xiao Lu, Yang Zhang, Qi Fan, Chong Shen, Senchao Lai, Yan Zhou, Tao Zhang, and Dingli Yue
Atmos. Chem. Phys., 25, 5233–5250, https://doi.org/10.5194/acp-25-5233-2025, https://doi.org/10.5194/acp-25-5233-2025, 2025
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This study explores how urban green spaces (UGSs) in Guangzhou influence ozone levels. By using advanced models, we found that natural emissions from these areas can significantly affect air quality. Our results suggest that the design and planning of UGSs should not only consider aesthetics and social factors but also their environmental impacts on air quality.
Laura Stecher, Franziska Winterstein, Patrick Jöckel, Michael Ponater, Mariano Mertens, and Martin Dameris
Atmos. Chem. Phys., 25, 5133–5158, https://doi.org/10.5194/acp-25-5133-2025, https://doi.org/10.5194/acp-25-5133-2025, 2025
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Methane, the second most important anthropogenic greenhouse gas, is chemically decomposed in the atmosphere. The chemical sink of atmospheric methane is not constant but depends on the temperature and on the abundance of its reaction partners. In this study, we use a global chemistry–climate model to assess the feedback of atmospheric methane induced by changes in the chemical sink in a warming climate and its implications for the chemical composition and the surface air temperature change.
Kai-Lan Chang, Brian C. McDonald, Colin Harkins, and Owen R. Cooper
Atmos. Chem. Phys., 25, 5101–5132, https://doi.org/10.5194/acp-25-5101-2025, https://doi.org/10.5194/acp-25-5101-2025, 2025
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Exposure to high levels of ozone can be harmful to human health. This study shows consistent and robust evidence of decreasing ozone extremes across much of the United States over the period from 1990 to 2023, previously attributed to ozone precursor emission controls. Nevertheless, we also show that the increasing heat wave frequencies are likely to contribute to additional ozone exceedances, slowing the progress of decreasing the frequency of ozone exceedances.
Xiaochun Zhu, Le Cao, Xin Yang, Simeng Li, Jiandong Wang, and Tianliang Zhao
EGUsphere, https://doi.org/10.5194/egusphere-2024-3873, https://doi.org/10.5194/egusphere-2024-3873, 2025
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We applied various criteria to identify springtime ODEs at Utqiagvik, Arctic, and investigated the influences of using different criteria on conclusions regarding the characteristics of ODEs. We found criteria using a constant threshold and using thresholds based on the monthly averaged ozone more suitable for identifying ODEs than the others. Applying a threshold varying with the monthly average or stricter thresholds also signifies a more significant reduction in the ODE occurrences.
Ragnhild Bieltvedt Skeie, Marit Sandstad, Srinath Krishnan, Gunnar Myhre, and Maria Sand
Atmos. Chem. Phys., 25, 4929–4942, https://doi.org/10.5194/acp-25-4929-2025, https://doi.org/10.5194/acp-25-4929-2025, 2025
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Hydrogen leakages can alter the amount of climate gases in the atmosphere and hence have a climate impact. In this study we investigate, using an atmospheric chemistry model, how this indirect climate effect differs with different amounts of leakages and with where the hydrogen leaks and if this effect changes in the future. The effect is largest for emissions far from areas where hydrogen is removed from the atmosphere by the soil, but these are not relevant locations for a future hydrogen economy.
Alok K. Pandey, David S. Stevenson, Alcide Zhao, Richard J. Pope, Ryan Hossaini, Krishan Kumar, and Martyn P. Chipperfield
Atmos. Chem. Phys., 25, 4785–4802, https://doi.org/10.5194/acp-25-4785-2025, https://doi.org/10.5194/acp-25-4785-2025, 2025
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Nitrogen dioxide is an air pollutant largely controlled by human activity that affects ozone, methane, and aerosols. Satellite instruments can quantify column NO2 and, by carefully matching the time and location of measurements, enable evaluation of model simulations. NO2 over south and east Asia is assessed, showing that the model captures not only many features of the measurements, but also important differences that suggest model deficiencies in representing several aspects of the atmospheric chemistry of NO2.
Ruochong Xu, Hanchen Ma, Jingxian Li, Dan Tong, Liu Yan, Lanyuan Wang, Xinying Qin, Qingyang Xiao, Xizhe Yan, Hanwen Hu, Yujia Fu, Nana Wu, Huaxuan Wang, Yuexuanzi Wang, Xiaodong Liu, Guannan Geng, Kebin He, and Qiang Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2025-1085, https://doi.org/10.5194/egusphere-2025-1085, 2025
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In this study, we developed a new global emission inventory for non-methane volatile organic compounds (NMVOC) for the period of 1970–2020, with a focus on improving the representation of NMVOC-emission-related technologies. Our analysis revealed that activity growth, technology advancements, and policy-driven emission controls were key driving forces of NMVOC emission changes, but their roles were different across sectors and regions.
Liang Feng, Paul Palmer, Luke Smallman, Jingfeng Xiao, Paulo Cristofanelli, Ove Hermansen, John Lee, Casper Labuschagne, Simonetta Montaguti, Steffen Noe, Stephen Platt, Xinrong Ren, Martin Steinbacher, and Irene Xueref-Remy
EGUsphere, https://doi.org/10.5194/egusphere-2025-1793, https://doi.org/10.5194/egusphere-2025-1793, 2025
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2023 saw an unexpectedly high global atmospheric CO2 growth. Satellite data reveal a role for increased emissions over the tropics. Larger emissions over eastern Brazil can be explained by warmer temperatures, while changes in rainfall and soil moisture play more of a role in emission increases elsewhere in the tropics.
Ryan Vella, Sergey Gromov, Clara M. Nussbaumer, Laura Stecher, Matthias Kohl, Samuel Ruhl, Holger Tost, Jos Lelieveld, and Andrea Pozzer
EGUsphere, https://doi.org/10.5194/egusphere-2025-1800, https://doi.org/10.5194/egusphere-2025-1800, 2025
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We evaluated how replacing forests with farmland and grazing areas affects atmospheric composition. Using a global climate-chemistry model, we found that deforestation reduces BVOCs, increases farming pollutants, and shifts ozone chemistry. These changes lead to a small cooling effect on the climate. Restoring natural vegetation could reverse some of these effects.
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
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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.
Yufen Wang, Ke Li, Xi Chen, Zhenjiang Yang, Minglong Tang, Pascoal M. D. Campos, Yang Yang, Xu Yue, and Hong Liao
Atmos. Chem. Phys., 25, 4455–4475, https://doi.org/10.5194/acp-25-4455-2025, https://doi.org/10.5194/acp-25-4455-2025, 2025
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The impacts of biomass burning and anthropogenic emissions on high tropospheric ozone levels are not well studied in southern Africa. We combined model simulations with recent observations at the surface and from space to quantify tropospheric ozone and its drivers in southern Africa. Our work focuses on the impact of emissions from different sources at different spatial scales, contributing to a comprehensive understanding of air pollution drivers and their uncertainties in southern Africa.
Dominika Pasik, Thomas Golin Almeida, Emelda Ahongshangbam, Siddharth Iyer, and Nanna Myllys
Atmos. Chem. Phys., 25, 4313–4331, https://doi.org/10.5194/acp-25-4313-2025, https://doi.org/10.5194/acp-25-4313-2025, 2025
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We used quantum chemistry methods to investigate the oxidation mechanisms of acyl peroxy radicals (APRs) with various monoterpenes. Our findings reveal unique oxidation pathways for different monoterpenes, leading to either chain-terminating products or highly reactive intermediates that can contribute to particle formation in the atmosphere. This research highlights APRs as potentially significant but underexplored atmospheric oxidants that may influence future approaches to modelling climate.
Jincheol Park, Yunsoo Choi, and Sagun Kayastha
Atmos. Chem. Phys., 25, 4291–4311, https://doi.org/10.5194/acp-25-4291-2025, https://doi.org/10.5194/acp-25-4291-2025, 2025
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We investigated NOx emission contributions to NOy loadings across five regions of East Asia during the 2022 winter–spring transition through chemical transport modeling informed by satellite data. As seasons progress, local contributions within each region to its NOy budget decreased from 32 %–43 % to 23 %–30 %, while transboundary contributions increased from 16 %–33 % to 27 %–37 %, driven by a shift in synoptic settings that allowed pollutants to spread more broadly across the regions.
Qianqian Zhang, K. Folkert Boersma, Chiel van der Laan, Alba Mols, Bin Zhao, Shengyue Li, and Yuepeng Pan
Atmos. Chem. Phys., 25, 3313–3326, https://doi.org/10.5194/acp-25-3313-2025, https://doi.org/10.5194/acp-25-3313-2025, 2025
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Accurate NOx emission estimates are required to better understand air pollution. This study investigates and demonstrates the ability of the superposition column model in combination with TROPOMI tropospheric NO2 column data to estimate city-scale NOx emissions and lifetimes and their variabilities. The results of this work nevertheless confirm the strength of the superposition column model in estimating urban NOx emissions with reasonable accuracy.
Biao Luo, Lei Liu, David H. Y. Yung, Tiangang Yuan, Jingwei Zhang, Leo T. H. Ng, and Amos P. K. Tai
EGUsphere, https://doi.org/10.5194/egusphere-2025-72, https://doi.org/10.5194/egusphere-2025-72, 2025
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Through a combination of emission models and air quality model, we aimed to address the pressing issue of poor nitrogen management while promoting sustainable food systems and public health in China. We discovered that improving nitrogen management of crop and livestock can substantially reduce air pollutant emissions, particularly in North China Plain. Our findings further provide the benefits of such interventions on PM2.5 reductions, offering valuable insights for policymakers.
Wenbin Kou, Yang Gao, Dan Tong, Xiaojie Guo, Xiadong An, Wenyu Liu, Mengshi Cui, Xiuwen Guo, Shaoqing Zhang, Huiwang Gao, and Lixin Wu
Atmos. Chem. Phys., 25, 3029–3048, https://doi.org/10.5194/acp-25-3029-2025, https://doi.org/10.5194/acp-25-3029-2025, 2025
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Unlike traditional numerical studies, we apply a high-resolution Earth system model, improving simulations of surface ozone and large-scale circulations such as atmospheric blocking. Besides local heat waves, we quantify the impact of atmospheric blocking on downstream ozone concentrations, which is closely associated with the blocking position. We identify three major pathways of Rossby wave propagation, stressing the critical role of large-scale circulation in regional air quality.
Jingyu Li, Haolin Wang, Qi Fan, and Xiao Lu
EGUsphere, https://doi.org/10.5194/egusphere-2025-782, https://doi.org/10.5194/egusphere-2025-782, 2025
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We use multiple global chemical models to quantify processes contributing the ozone response to ENSO. We find that changes in transport patterns are the dominant factor in the overall ozone-ENSO responses, with the opposing effects of chemical depletion and increased biomass burning on ozone largely offsetting each other. Models consistently project an increase in tropical ozone-ENSO response associated with strengthening anomalous circulation and more abundant water vapor with global warming.
Beata Opacka, Trissevgeni Stavrakou, Jean-François Müller, Isabelle De Smedt, Jos van Geffen, Eloise A. Marais, Rebekah P. Horner, Dylan B. Millet, Kelly C. Wells, and Alex B. Guenther
Atmos. Chem. Phys., 25, 2863–2894, https://doi.org/10.5194/acp-25-2863-2025, https://doi.org/10.5194/acp-25-2863-2025, 2025
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Vegetation releases biogenic volatile organic compounds, while soils and lightning contribute to the natural emissions of nitrogen oxides into the atmosphere. These gases interact in complex ways. Using satellite data and models, we developed a new method to simultaneously optimize these natural emissions over Africa in 2019. Our approach resulted in an increase in natural emissions, supported by independent data indicating that current estimates are underestimated.
Xiaobo Wang, Yuzhong Zhang, Tamás Bozóki, Ruosi Liang, Xinchun Xie, Shutao Zhao, Rui Wang, Yujia Zhao, and Shuai Sun
EGUsphere, https://doi.org/10.5194/egusphere-2025-370, https://doi.org/10.5194/egusphere-2025-370, 2025
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Schumann Resonance observations are used to parameterize lightning NOx emissions for better capturing global lightning trend and variability. Updated simulations reveal insignificant trend but greater variability in lightning NOx emissions, impacting tropospheric NOx, O3 and OH. Lightning generally counteracts non-lightning factors, reducing the inter-annua variability of tropospheric O3 and OH. Variations of global lightning play important role in understanding the atmospheric methane budget.
Xi Chen, Ke Li, Ting Yang, Xipeng Jin, Lei Chen, Yang Yang, Shuman Zhao, Bo Hu, Bin Zhu, Zifa Wang, and Hong Liao
EGUsphere, https://doi.org/10.5194/egusphere-2025-430, https://doi.org/10.5194/egusphere-2025-430, 2025
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Aerosol vertical distribution that plays a crucial role in aerosol-photolysis interaction (API) remains underrepresented in chemical models. We integrated lidar and radiosonde observations to constrain the simulated aerosol profiles over North China and quantified the photochemical responses. The increased photolysis rates in the lower layers led to increased ozone and accounted for a 36 %–56 % reduction in API effects, resulting in enhanced atmospheric oxidizing capacity and aerosol formation.
Jiaqi Shen, Ronald C. Cohen, Glenn M. Wolfe, and Xiaomeng Jin
EGUsphere, https://doi.org/10.5194/egusphere-2025-706, https://doi.org/10.5194/egusphere-2025-706, 2025
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This study shows large chemical and radiative effects of smoke aerosols from fires on near-surface ozone production. Aerosol loading and NOx levels are identified as the primary factors influencing these effects. Furthermore, we show that the surface PM2.5 to NO2 column ratio can be used as an indicator for identifying aerosol-dominated regimes, facilitating the assessments of aerosol impacts on ozone formation through satellite observations.
Shuai Li, Haolin Wang, and Xiao Lu
Atmos. Chem. Phys., 25, 2725–2743, https://doi.org/10.5194/acp-25-2725-2025, https://doi.org/10.5194/acp-25-2725-2025, 2025
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Summertime ozone–temperature sensitivity has decreased by 50 % from 3.0 ppbv per K in 1990 to 1.5 ppb per K in 2021 in the US. GEOS-Chem simulations show that anthropogenic nitrogen oxide emission reduction is the dominant driver of ozone–temperature sensitivity decline by influencing both temperature direct and temperature indirect processes. Reduced ozone–temperature sensitivity has decreased ozone enhancement from low to high temperatures by an average of 6.8 ppbv across the US.
Mingjie Kang, Hongliang Zhang, and Qi Ying
EGUsphere, https://doi.org/10.5194/egusphere-2025-255, https://doi.org/10.5194/egusphere-2025-255, 2025
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This study examines the impacts of reducing nitrogen oxides and volatile organic compounds on ozone (O3), secondary inorganic aerosols (SIA), and OH and NO3 radicals. The results show similar predictions for 8-h O3 but significant variability for SIA and radicals, with differences up to 30 % for SIA and 200 % for radicals across chemical mechanisms and inventories. The findings highlight that evaluating control strategies for SIA and atmospheric oxidation capacity requires an ensemble approach.
Jinya Yang, Yutong Wang, Lei Zhang, and Yu Zhao
Atmos. Chem. Phys., 25, 2649–2666, https://doi.org/10.5194/acp-25-2649-2025, https://doi.org/10.5194/acp-25-2649-2025, 2025
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We develop a modeling framework to predict future ozone concentrations (till the 2060s) in China following an IPCC scenario. We evaluate the contributions of climatic, anthropogenic, and biogenic factors by season and region. We find persistent emission controls will alter the nonlinear response of ozone to its precursors and dominate the declining ozone level. The outcomes highlight the importance of human actions, even with a climate penalty on air quality.
Xiaodong Zhang, Yu Yan, Ning Zhang, Wenpeng Wang, Huabing Suo, Xiaohu Jian, Chao Wang, Haibo Ma, Hong Gao, Zhaoli Yang, Tao Huang, and Jianmin Ma
EGUsphere, https://doi.org/10.5194/egusphere-2025-258, https://doi.org/10.5194/egusphere-2025-258, 2025
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This study performed comprehensive sensitivity model simulations to explore the surface O3 responses to historical and projected climate change in Northwestern China (NW). Our results reveal that substantial wetting trends since the 21st century have mitigated O3 growth in this region, with the influence of wetting on O3 evolution outweighing the warming effect. These findings should be taken into account in future policymaking aimed at scientifically reducing O3 pollution in NW.
Catherine Acquah, Laura Stecher, Mariano Mertens, and Patrick Jöckel
EGUsphere, https://doi.org/10.5194/egusphere-2025-294, https://doi.org/10.5194/egusphere-2025-294, 2025
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Short-lived ozone precursor species influence the formation of ozone and also the atmospheric lifetime of methane. Our study assesses the effect of two widely used emission inventories of these species on ozone and the methane lifetime. Our results indicate tropospheric ozone and methane lifetime differences of around 4 % even though both emission inventories aim at representing present-day conditions. We further attribute the differences to emissions of individual sectors, e.g. land traffic.
Takashi Sekiya, Emanuele Emili, Kazuyuki Miyazaki, Antje Inness, Zhen Qu, R. Bradley Pierce, Dylan Jones, Helen Worden, William Y. Y. Cheng, Vincent Huijnen, and Gerbrand Koren
Atmos. Chem. Phys., 25, 2243–2268, https://doi.org/10.5194/acp-25-2243-2025, https://doi.org/10.5194/acp-25-2243-2025, 2025
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Five global chemical reanalysis datasets were used to assess the relative impacts of assimilating satellite ozone and its precursor measurements on tropospheric ozone analyses for 2010. The multiple reanalysis system comparison allows an evaluation of the dependency of the impacts on different reanalysis systems. The results suggested the importance of satellite ozone and its precursor measurements for improving ozone analysis in the whole troposphere, with varying magnitudes among the systems.
Maureen Beaudor, Didier Hauglustaine, Juliette Lathière, Martin Van Damme, Lieven Clarisse, and Nicolas Vuichard
Atmos. Chem. Phys., 25, 2017–2046, https://doi.org/10.5194/acp-25-2017-2025, https://doi.org/10.5194/acp-25-2017-2025, 2025
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Agriculture is the biggest ammonia (NH3) source, impacting air quality, climate, and ecosystems. Because of food demand, NH3 emissions are projected to rise by 2100. Using a global model, we analyzed the impact of present and future NH3 emissions generated from a land model. Our results show improved ammonia patterns compared to a reference inventory. Future scenarios predict up to 70 % increase in global NH3 burden, with significant changes in radiative forcing that can greatly elevate N2O.
Pramod Kumar, Grégoire Broquet, Didier Hauglustaine, Maureen Beaudor, Lieven Clarisse, Martin Van Damme, Pierre Coheur, Anne Cozic, Bo Zheng, Beatriz Revilla Romero, Antony Delavois, and Philippe Ciais
EGUsphere, https://doi.org/10.5194/egusphere-2025-162, https://doi.org/10.5194/egusphere-2025-162, 2025
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Global maps of the NH3 emissions over 2019–2022 are derived using IASI NH3 spaceborne observations, the LMDZ-INCA chemistry-transport model at 1.27°×2.5° resolution and mass balance approach. The average global NH3 emissions over the period are ~98 Tg NH3 yr-1, which is significantly higher than three reference inventories. The analysis provides confidence in the seasonal variability and regional budgets, and provides new insights into NH3 emissions at global and regional scales.
Hui Li, Jiaxin Qiu, and Bo Zheng
Atmos. Chem. Phys., 25, 1949–1963, https://doi.org/10.5194/acp-25-1949-2025, https://doi.org/10.5194/acp-25-1949-2025, 2025
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We conduct a sensitivity analysis with 31 tests on various factors including prior emissions, model resolution, satellite constraint, and other system configurations to assess the vulnerability of emission estimates across temporal, sectoral, and regional dimensions. This reveals the robustness of emissions estimated by this air-pollution-satellite-based CO2 emission inversion system, with relative change between tests and base inversion below 4.0 % for national annual NOx and CO2 emissions.
Yingying Hong, Yuqi Zhu, Yuxuan Huang, Yiming Liu, Chuqi Xiong, and Qi Fan
EGUsphere, https://doi.org/10.5194/egusphere-2024-4132, https://doi.org/10.5194/egusphere-2024-4132, 2025
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This study investigates the impact of sea spray aerosol on ozone formation across Eastern China, highlighting its complex influence through both chemical reactions and radiative effects, which vary seasonally and geographically.
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Short summary
Our study presents a detailed analysis of the spatial and temporal distribution of elevated CO level in the upper troposphere over the Pacific using 20 years of MOPITT data. We create a climatology of severe pollution episodes and use trajectory calculations to link each particular pollution event detected in MOPITT satellite data with a distinct source region. Additionally, we analyse uplift mechanisms such as WCB-related upward transport.
Our study presents a detailed analysis of the spatial and temporal distribution of elevated CO...
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