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A characterization of clouds and precipitation over the Southern Ocean from synoptic to micro scales during the CAPRICORN field campaigns
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  • Estefania Montoya Duque,
  • Yi HUANG,
  • Steven Siems,
  • Peter May,
  • Alain Protat,
  • Greg McFarquhar
Estefania Montoya Duque
University of Melbourne

Corresponding Author:emontoyaduqu@student.unimelb.edu.au

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The University of Melbourne
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Steven Siems
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Peter May
Monash University
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Alain Protat
Australian Bureau of Meteorology
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Greg McFarquhar
Cooperative Institutes for Mesoscale Meteorological Studies
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The persistent Southern Ocean (SO) shortwave radiation biases in climate models and reanalyses have been associated with the poor representation of clouds, precipitation, aerosols, the atmospheric boundary layer, and their intrinsic interactions. Capitalizing on shipborne observations collected during the Clouds Aerosols Precipitation Radiation and atmospheric Composition Over the Southern Ocean (CAPRICORN) 2016 and 2018 field campaigns, this research investigates and characterizes cloud and precipitation processes from synoptic to micro scales. Distinct cloud and precipitation regimes are found to correspond to the seven thermodynamic clusters established using a K-means clustering technique, while less distinctions are evident using the cyclone and (cold) front compositing methods. Cloud radar and disdrometer data reveal that light precipitation is common over the SO with higher intensities associated with cyclonic and warm frontal regions. While multiple microphysical processes and properties are present in several cloud regimes, ice aggregation appears to be dominant in deep precipitating clouds. Mixed phase, and in some cases, riming was detected in shallow convective clouds away from the frontal conditions. Two unique clusters with contrasting cloud and precipitation properties are observed over the high-latitude SO and coastal Antarctica, suggesting distinct physical processes therein. Through a single case study, in-situ and remote-sensing data collected by an overflight of the Southern Ocean Clouds Radiation Aerosol Transport Experimental Study (SOCRATES) were also evaluated and complement the ship-based analysis.