Articles | Volume 25, issue 13
https://doi.org/10.5194/acp-25-6843-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-25-6843-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Kinematic properties of regions that can involve persistent contrails over the North Atlantic and Europe during April and May 2024
Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Klaus Martin Gierens
Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
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Sina Maria Hofer and Klaus Martin Gierens
Atmos. Chem. Phys., 25, 9235–9247, https://doi.org/10.5194/acp-25-9235-2025, https://doi.org/10.5194/acp-25-9235-2025, 2025
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The climate effect of contrails depends on the contrail lifetime. Thus, it is important to know what constrains the lifetime. In this paper, we characterise the two most important contrail dissolution processes via their respective timescales. Both timescales are in the order of a couple of hours, depending on the synoptic situation and the size of the contrail ice crystals. The combined timescale, which combines both processes, is the harmonic mean of the two single timescales.
Sina Hofer, Klaus Gierens, and Susanne Rohs
Atmos. Chem. Phys., 24, 7911–7925, https://doi.org/10.5194/acp-24-7911-2024, https://doi.org/10.5194/acp-24-7911-2024, 2024
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We try to improve the forecast of ice supersaturation (ISS) and potential persistent contrails using data on dynamical quantities in addition to temperature and relative humidity in a modern kind of regression model. Although the results are improved, they are not good enough for flight routing. The origin of the problem is the strong overlap of probability densities conditioned on cases with and without ice-supersaturated regions (ISSRs) in the important range of 70–100 %.
Klaus Gierens, Lena Wilhelm, Sina Hofer, and Susanne Rohs
Atmos. Chem. Phys., 22, 7699–7712, https://doi.org/10.5194/acp-22-7699-2022, https://doi.org/10.5194/acp-22-7699-2022, 2022
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We are interested in the prediction of condensation trails, in particular strong ones. For this we need a good forecast of temperature and humidity in the levels where aircraft cruise. Unfortunately, the humidity forecast is quite difficult for these levels, in particular the ice supersaturation, which is needed for long-lasting contrails. We are thus seeking proxy variables that help distinguish situations where strong contrails can form, for instance the lapse rate.
Sina Maria Hofer and Klaus Martin Gierens
Atmos. Chem. Phys., 25, 9235–9247, https://doi.org/10.5194/acp-25-9235-2025, https://doi.org/10.5194/acp-25-9235-2025, 2025
Short summary
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The climate effect of contrails depends on the contrail lifetime. Thus, it is important to know what constrains the lifetime. In this paper, we characterise the two most important contrail dissolution processes via their respective timescales. Both timescales are in the order of a couple of hours, depending on the synoptic situation and the size of the contrail ice crystals. The combined timescale, which combines both processes, is the harmonic mean of the two single timescales.
Ziming Wang, Luca Bugliaro, Klaus Gierens, Michaela I. Hegglin, Susanne Rohs, Andreas Petzold, Stefan Kaufmann, and Christiane Voigt
Atmos. Chem. Phys., 25, 2845–2861, https://doi.org/10.5194/acp-25-2845-2025, https://doi.org/10.5194/acp-25-2845-2025, 2025
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Upper-tropospheric relative humidity bias in the ERA5 weather model is corrected by 10 % by an artificial neural network using aircraft in-service humidity data and thermodynamic and dynamical variables. The improved skills of the weather model will advance cirrus research, weather forecasts, and measures for contrail reduction.
Sina Hofer, Klaus Gierens, and Susanne Rohs
Atmos. Chem. Phys., 24, 7911–7925, https://doi.org/10.5194/acp-24-7911-2024, https://doi.org/10.5194/acp-24-7911-2024, 2024
Short summary
Short summary
We try to improve the forecast of ice supersaturation (ISS) and potential persistent contrails using data on dynamical quantities in addition to temperature and relative humidity in a modern kind of regression model. Although the results are improved, they are not good enough for flight routing. The origin of the problem is the strong overlap of probability densities conditioned on cases with and without ice-supersaturated regions (ISSRs) in the important range of 70–100 %.
Dario Sperber and Klaus Gierens
Atmos. Chem. Phys., 23, 15609–15627, https://doi.org/10.5194/acp-23-15609-2023, https://doi.org/10.5194/acp-23-15609-2023, 2023
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A significant share of aviation's climate impact is due to persistent contrails. Avoiding their creation is a step toward sustainable air transportation. For this purpose, a reliable forecast of so-called ice-supersaturated regions is needed, which then allows one to plan aircraft routes without persistent contrails. Here, we propose a method that leads to the better prediction of ice-supersaturated regions.
Klaus Gierens, Lena Wilhelm, Sina Hofer, and Susanne Rohs
Atmos. Chem. Phys., 22, 7699–7712, https://doi.org/10.5194/acp-22-7699-2022, https://doi.org/10.5194/acp-22-7699-2022, 2022
Short summary
Short summary
We are interested in the prediction of condensation trails, in particular strong ones. For this we need a good forecast of temperature and humidity in the levels where aircraft cruise. Unfortunately, the humidity forecast is quite difficult for these levels, in particular the ice supersaturation, which is needed for long-lasting contrails. We are thus seeking proxy variables that help distinguish situations where strong contrails can form, for instance the lapse rate.
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Short summary
Ice supersaturation is an immaterial feature that does not generally move with the wind that carries contrails and cirrus clouds. Here we analyse the different motions and show that ice supersaturated regions (ISSRs) on average move slower than the wind, the direction of movement is usually quite similar, and the distributions of both velocities follow Weibull distributions. The almost identical direction of the movements is beneficial for contrail lifetimes.
Ice supersaturation is an immaterial feature that does not generally move with the wind that...
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