Models are universally challenged to accurately predict the coupled microphysical, turbulent and radiative processes within widespread, long-lived marine cold-air outbreak (CAO) cloud fields, which leads to biases and uncertainties in atmospheric predictions over all time scales. Here we assemble a suite of ground-based and satellite measurements to initialize and constrain large-eddy simulations (LES) of cloud field evolution with distance downwind from the marginal ice zone during a strong, highly supercooled and convective CAO observed during the Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE). Detailed LES results are compared with large-scale models run in single-column model (SCM) mode, providing an observation-constrained framework for large-scale model evaluation and future improvements. All models reproduce rapid cloud formation off the ice edge, and a monotonic ascent of downwind cloud-top heights that is well correlated with time-integrated surface heat fluxes. LES generally reproduce domain-mean observational targets using a modest test domain (25 × 25 km²), and a larger domain (125 × 125 km²) enables better reproducing the observed growth of convective cell sizes. In realistic mixed-phase LES compared with liquid-only simulations, ice processes lead to thinner, broken cloud decks and substantially reduced cloud radiative effects on top-of-atmosphere longwave fluxes. By contrast, mixed-phase SCM simulations generally underpredict the impact of ice on radiative fluxes, primarily owing to insufficient reduction of cloud cover. Results indicate that cellular cloud structure is qualitatively captured by LES, and thus LES could provide guidance to improvement of large-scale model physics schemes. Follow-on work will extend these results to larger domains, apply objective analysis of mesoscale structure, and include prognostic aerosol properties for droplet and heterogeneous ice formation.
The Cold-Air Outbreaks in the Marine Boundary Layer Experiment model-observation intercomparison project (COMBLE-MIP), Part I: Model specification, observational constraints, and preliminary findings
Timothy W. Juliano1,
Florian Tornow2, 3,
Ann M. Fridlind3,
Andrew S. Ackerman3,
Gregory S. Elsaesser2, 3,
Bart Geerts4,
Christian P. Lackner4,
David Painemal5, 6,
Israel Silber7,
Mikhail Ovchinnikov7,
…
Gunilla Svensson8,
Michael Tjernström8,
Peng Wu7,
Alejandro Baró Pérez9,
Peter Bogenschutz19,
Dmitry Chechin10,
Kamal Kant Chandrakar1,
Jan Chylik11,
Andrey Debolskiy12, 20,
Rostislav Fadeev13,
Anu Gupta14,
Luisa Ickes9,
Michail Karalis9,
Martin Köhler15,
Branko Kosović16,
Peter Kuma17,
Weiwei Li1,
Evgeny Mortikov12, 20,
Hugh Morrison1,
Roel A. J. Neggers11,
Anna Possner17,
Tomi Raatikainen18,
Sami Romakkaniemi18,
Niklas Schnierstein11,
Shin-ichiro Shima14,
Nikita Silin12,
Mikhail Tolstykh13,
Lulin Xue1,
Meng Zhang19,
Xue Zheng19
1U.S. National Science Foundation (NSF) National Center for Atmospheric Research (NCAR), Boulder, CO, USA
11University of Cologne, Cologne, Germany
2Columbia University, New York, NY, USA
3National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies (GISS), New York, NY, USA
4University of Wyoming, Laramie, WY, USA
5NASA Langley Research Center, Hampton, VA, USA
6Science Systems and Applications, Inc., Hampton, VA, USA
7Pacific Northwest National Laboratory (PNNL), Richland, WA, USA
8Department of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
9Chalmers Technical University, Gothenburg, Sweden
10Obukhov Institute of Atmospheric Physics (IAP), Russian Academy of Sciences (RAS), Moscow, Russia
…
12Research Computing Center, Lomonosov Moscow State University, Moscow, Russia
13Institute of Numerical Mathematics (INM), RAS, and Hydrometcentre of Russia, Moscow, Russia
14Graduate School of Information Science, University of Hyogo, Kobe, Japan
15Deutscher Wetterdienst (DWD), Offenbach am Main, Germany
16Ralph O’Connor Sustainable Energy Institute, Johns Hopkins University, Baltimore, Maryland
17Goethe University, Frankfurt, Germany
18Finnish Meteorological Institute, Helsinki, Finland
19Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA
20Moscow Center of Fundamental and Applied Mathematics, Moscow, Russia
Abstract
- Note:
- in review in Geoscientific Model Development
- Journal:
- EGUsphere
- Volume:
- 2026
- Pages:
- 1–52
- DOI:
- 10.5194/egusphere-2025-6217
- Submitted:
- 12 December 2025
- License:
- Open access / Creative Commons Attribution 4.0 (CC BY 4.0)
BibTeX:
@article{juliano2026,
journal={EGUsphere},
year={2026},
note={in review in Geoscientific Model Development},
volume={2026},
pages={1-52},
doi={10.5194/egusphere-2025-6217},
url={https://doi.org/10.5194/egusphere-2025-6217},
author={Juliano, Timothy W. and Tornow, Florian and Fridlind, Ann M. and Ackerman, Andrew S. and Elsaesser, Gregory S. and Geerts, Bart and Lackner, Christian P. and Painemal, David and Silber, Israel and Ovchinnikov, Mikhail and Svensson, Gunilla and Tjernstr{\"o}m, Michael and Wu, Peng and Bar{\'o} P{\'e}rez, Alejandro and Bogenschutz, Peter and Chechin, Dmitry and Chandrakar, Kamal Kant and Chylik, Jan and Debolskiy, Andrey and Fadeev, Rostislav and Gupta, Anu and Ickes, Luisa and Karalis, Michail and K{\"o}hler, Martin and Kosovi{\'c}, Branko and Kuma, Peter and Li, Weiwei and Mortikov, Evgeny and Morrison, Hugh and Neggers, Roel A. J. and Possner, Anna and Raatikainen, Tomi and Romakkaniemi, Sami and Schnierstein, Niklas and Shima, Shin-ichiro and Silin, Nikita and Tolstykh, Mikhail and Xue, Lulin and Zhang, Meng and Zheng, Xue},
title={The Cold-Air Outbreaks in the Marine Boundary Layer Experiment model-observation intercomparison project (COMBLE-MIP), Part I: Model specification, observational constraints, and preliminary findings}
}
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