Characterising the spatial overlap between liquid and ice in mixed-phase clouds

Evans, Matthew D., Abel, Steven J., Field, Paul R., Finney, Declan L., Lloyd, Gary, Cotton, Richard J., Smith, Daniel K. E., Murrary, Benjamin J. and Huang, Xinyi (2025) Characterising the spatial overlap between liquid and ice in mixed-phase clouds. Quarterly Journal of the Royal Meteorological Society. ISSN 0035-9009

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Abstract

Mixed-phase clouds are important for simulating precipitation formation and cloud radiative effects in numerical weather prediction (NWP) and climate models. One challenge to reduce model uncertainties is how best to represent the subgrid distribution of liquid and ice within a model grid box. This is poorly constrained by observations, yet is key for representing microphysical process rates that grow ice crystals at the expense of liquid droplets. This study uses in situ airborne observations from stratiform, shallow cumulus, deep convective, and frontal clouds to investigate the horizontal spatial overlap of liquid and ice phases on length-scales ~1km, which are appropriate for current regional NWP models. We place observational constraints on a simple parametrisation that describes the mixed-phase fraction as a function of subgrid liquid and ice cloud fractions and demonstrate that most of the observations show that, when ice and liquid are present, they are close to fully overlapped.

Item Type:	Article
Additional Information:	Data availability statement: Field campaign flight data from the FAAM aircraft are stored on the CEDA archive: ACAO at https://catalogue.ceda.ac.uk/uuid/01021a90c0c2481c909bdb145cb72398/; M-Phase at https://catalogue.ceda.ac.uk/uuid/6d7971a92d154bb29af3167dfb6f5a7e/; DCMEX at https://catalogue.ceda.ac.uk/uuid/b1211ad185e24b488d41dd98f957506c/; PICASSO at https://catalogue.ceda.ac.uk/uuid/400efba73c1d40c78f44918429ce9c99/. Cloud phase fractions calculated from Nevzorov and 2DS/CDP observations used for the analysis in this article can be found at https://doi.org/10.5281/zenodo.14526275. Funding information: Natural Environment Research Council, Grant/Award Numbers: NE/P012426/1, NE/T006404/1, NE/T006439/1, NE/T006463/1, NE/T00648X/1, NE/T006420/1
Uncontrolled Keywords:	airborne observations,cloud fractions,clouds,mixed-phase,parametrisation,phase overlap,atmospheric science,sdg 13 - climate action ,/dk/atira/pure/subjectarea/asjc/1900/1902
Faculty \ School:	Faculty of Science > School of Environmental Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	10 Oct 2025 15:32
Last Modified:	18 Oct 2025 16:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/100698
DOI:	10.1002/qj.5041

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