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150459 - Southern Ocean cloud properties derived from CAPRICORN and MARCUS data.pdf (4.56 MB)

Southern Ocean cloud properties derived from CAPRICORN and MARCUS data

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journal contribution
posted on 2023-05-21, 08:28 authored by Mace, GG, Alain ProtatAlain Protat, Humphries, RS, Simon AlexanderSimon Alexander, McRobert, IM, Ward, J, Selleck, P, Keywood, M, McFarquhar, GM

The properties of Southern Ocean (SO) liquid phase non precipitating clouds (hereafter clouds) are examined using shipborne data collected during the Measurements of Aerosols, Radiation and Clouds over the Southern Ocean and the Clouds Aerosols Precipitation Radiation and atmospheric Composition Over the SoutheRN ocean I and II campaigns that took place south of Australia during Autumn 2016 and Summer 2017–2018. Cloud properties are derived using data from W-band radars, lidars, and microwave radiometers using an optimal estimation algorithm. The SO clouds tended to have larger liquid water paths (LWP, 115 ± 117 g m−2), smaller effective radii (re, 8.7 ± 3 μm), and higher number concentrations (Nd, 90 ± 107 cm−3) than typical values of eastern ocean basin stratocumulus. The clouds demonstrated a tendency for the LWP to increase with Nd presumably due to precipitation suppression up to Nd of approximately 100 cm−3 when mean LWP decreased with increasing Nd. Due to higher optical depth, cloud albedos were less susceptible to changes in Nd compared to subtropical stratocumulus. The highest latitude clouds of the datasets, observed along and near the Antarctic coast, presented a distinctly bimodal character. One mode had the properties of marine clouds further north. The other mode occurred in an aerosol environment characterized by high cloud condensation nuclei concentrations and elevated sulfate aerosol without obvious continental aerosol markers. These regions of higher cloud condensation nuclei tended to have higher Nd, smaller re and higher LWP suggesting sensitivity of cloud properties to seasonal biogenic aerosol production in the high latitude SO.


Publication title

Journal of Geophysical Research: Atmospheres





Article number









Institute for Marine and Antarctic Studies


Wiley-Blackwell Publishing Inc.

Place of publication

United States

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© 2020. The Authors. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, ( which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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  • Open

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Expanding knowledge in the environmental sciences

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