Project Leader: Maximilian Maahn
Project ended in 2023
B08 is a project that was funded later than the other (AC)³ phase II projects and started in July 2021. The goal of B08 was to investigate the spatial variability of ice water content (IWC) and the corresponding snowfall formation processes in mixed-phase clouds (MPCs) based on the (AC)³ airborne campaigns. The PL Maximilian Maahn and PhD student Nina Maherndl participated in the HALO-(AC)³ field experiment that took part in March and April 2022 and operated remote sensing instruments on board the research aircraft Polar 5. Maximilian Maahn acted as mission principle investigator (PI) for research flight 5 of Polar 5 on March 28. Within the B08 project, we were particularly interested in joint flights of Polar 5 and Polar 6 to obtain spatially and temporally collocated radar and in–situ measurements of clouds. This flight strategy was successfully implemented in five flights, collecting about four hours of collocated in cloud measurements. Further, B08 set up and operated together with E02 a 2nd generation Video In Situ Snowfall Sensor (VISSS) in Ny–Ålesund. The main scientific results of phase II are presented below.
Hypothesis:
Spatial variability of ice water content (IWC) in and below MPCs is regulated by the spatial variability of surface properties and cloud top thermodynamic phase in addition to macrophysical properties such as cloud type, liquid water path, cloud depth, moisture availability and surface coupling. Correlating these properties to IWC variability will allow to identify the dominating processes.
In testing the hypothesis, we address the following overarching questions:
- How can we combine in situ and remote sensing aircraft measurements to obtain spatial variability of IWC in and below clouds with minimal uncertainties?
- What determines the vertical and horizontal gradients of IWC in the Arctic atmosphere and how do these gradients differ depending on the observed dominant ice formation processes and boundary conditions such as surface fluxes, cloud phase variability at cloud top or liquid water path?
- How do the observed IWC gradients and ice mass fluxes differ from those present in the ICON-LEM model for similar cloud types and forcing?
Role within (AC)³
Project Posters
| Phase III Evaluation poster 2023 | Phase II Evaluation poster 2019 | |
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Project Members
Publications
2026
2025
Klingebiel, M., Ehrlich, A., Gryschka, M., Risse, N., Maherndl, N., Schirmacher, I., Rosenburg, S., Hörnig, S., Moser, M., Jäkel, E., Schäfer, M., Deneke, H., Mech, M., Voigt, C., and Wendisch, M. , September 2025: Airborne observations of cloud properties during their evolution from organized streets to isotropic cloud structures along an Arctic cold-air outbreak. Atmospheric Chem. Phys., 25(17):9787–9801, doi:10.5194/acp-25-9787-2025
Maherndl, N., Battaglia, A., Kötsche, A., and Maahn, M. , July 2025: Riming-dependent snowfall rate and ice water content retrievals for W-band cloud radar. Atmospheric Meas. Tech., 18(14):3287–3304, doi:10.5194/amt-18-3287-2025
2024
Maherndl, N., Moser, M., Schirmacher, I., Bansemer, A., Lucke, J., Voigt, C., and Maahn, M. , December 2024: How does riming influence the observed spatial variability of ice water in mixed-phase clouds? Atmospheric Chem. Phys., 24(24):13935–13960, doi:10.5194/acp-24-13935-2024
Wendisch, M., Crewell, S., Ehrlich, A., Herber, A., Kirbus, B., Lüpkes, C., Mech, M., Abel, S. J., Akansu, E. F., Ament, F., Aubry, C., Becker, S., Borrmann, S., Bozem, H., Brückner, M., Clemen, H., Dahlke, S., Dekoutsidis, G., Delanoë, J., De La Torre Castro, E., Dorff, H., Dupuy, R., Eppers, O., Ewald, F., George, G., Gorodetskaya, I. V., Grawe, S., Groß, S., Hartmann, J., Henning, S., Hirsch, L., Jäkel, E., Joppe, P., Jourdan, O., Jurányi, Z., Karalis, M., Kellermann, M., Klingebiel, M., Lonardi, M., Lucke, J., Luebke, A. E., Maahn, M., Maherndl, N., Maturilli, M., Mayer, B., Mayer, J., Mertes, S., Michaelis, J., Michalkov, M., Mioche, G., Moser, M., Müller, H., Neggers, R., Ori, D., Paul, D., Paulus, F. M., Pilz, C., Pithan, F., Pöhlker, M., Pörtge, V., Ringel, M., Risse, N., Roberts, G. C., Rosenburg, S., Röttenbacher, J., Rückert, J., Schäfer, M., Schaefer, J., Schemann, V., Schirmacher, I., Schmidt, J., Schmidt, S., Schneider, J., Schnitt, S., Schwarz, A., Siebert, H., Sodemann, H., Sperzel, T., Spreen, G., Stevens, B., Stratmann, F., Svensson, G., Tatzelt, C., Tuch, T., Vihma, T., Voigt, C., Volkmer, L., Walbröl, A., Weber, A., Wehner, B., Wetzel, B., Wirth, M., and Zinner, T. , August 2024: Overview: Quasi-Lagrangian Observations of Arctic Air Mass Transformations – Introduction and Initial Results of the HALO–(A C)\textsuperscript3 Aircraft Campaign. Atmospheric Chem. Phys., 24(15):8865–8892, doi:10.5194/acp-24-8865-2024
Maherndl, N., Moser, M., Lucke, J., Mech, M., Risse, N., Schirmacher, I., and Maahn, M. , March 2024: Quantifying Riming from Airborne Data during the HALO-(AC)\textsuperscript3 Campaign. Atmospheric Meas. Tech., 17(5):1475–1495, doi:10.5194/amt-17-1475-2024
Maahn, M., Moisseev, D., Steinke, I., Maherndl, N., and Shupe, M. D. , February 2024: Introducing the Video In Situ Snowfall Sensor (VISSS). Atmospheric Meas. Tech., 17(2):899–919, doi:10.5194/amt-17-899-2024
2023
Maherndl, N., Maahn, M., Tridon, F., Leinonen, J., Ori, D., and Kneifel, S. , October 2023: A Riming-dependent Parameterization of Scattering by Snowflakes Using the Self-similar Rayleigh–Gans Approximation. Q. J. R. Meteorol. Soc., 149(757):3562–3581, doi:10.1002/qj.4573
Maherndl, N., Maahn, M., Moser, M., Lucke, J., Mech, M., and Risse, N. Airborne Observations of Riming in Arctic Mixed-Phase Clouds during HALO-(AC)3. May 2023. doi:10.5194/egusphere-egu23-5000.
2022
Maherndl, N., Maahn, M., Tridon, F., and Dupuy, R. Retrieving Riming in Arctic Mixed Phase Clouds from Collocated Remote Sensing and in Situ Aircraft Measurements during ACLOUD . March 2022. doi:10.5194/egusphere-egu22-13359.
2021
Maahn, M., Goren, T., Shupe, M. D., and de Boer, G. , September 2021: Liquid Containing Clouds at the North Slope of Alaska Demonstrate Sensitivity to Local Industrial Aerosol Emissions. Geophys. Res. Lett., 48(17):e2021GL094307, doi:10.1029/2021GL094307
