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Challenging and improving the simulation of mid-level mixed-phase clouds over the high-latitude Southern Ocean

Citation

Vignon, E and Alexander, SP and DeMott, PJ and Sotiropoulou, G and Gerber, F and Hill, TCJ and Marchand, R and Nenes, A and Berne, A, Challenging and improving the simulation of mid-level mixed-phase clouds over the high-latitude Southern Ocean, Journal of Geophysical Research-Atmospheres, 126, (7) Article e2020JD033490. ISSN 2169-897X (2021) [Refereed Article]


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DOI: doi:10.1029/2020JD033490

Abstract

Climate models exhibit major radiative biases over the Southern Ocean owing to a poor representation of mixed-phase clouds. This study uses the remote-sensing dataset from the Measurements of Aerosols, Radiation and Clouds over the Southern Ocean (MARCUS) campaign to assess the ability of the Weather Research and Forecasting (WRF) model to reproduce frontal clouds off Antarctica. It focuses on the modeling of thin mid-level supercooled liquid water layers which precipitate ice. The standard version of WRF produces almost fully glaciated clouds and cannot reproduce cloud top turbulence. Our work demonstrates the importance of adapting the ice nucleation parameterization to the pristine austral atmosphere to reproduce the supercooled liquid layers. Once simulated, droplets significantly impact the cloud radiative effect by increasing downwelling longwave fluxes and decreasing downwelling shortwave fluxes at the surface. The net radiative effect is a warming of snow and ice covered surfaces and a cooling of the ocean. Despite improvements in our simulations, the local turbulent circulation related to cloud-top radiative cooling is not properly reproduced, advocating for the need to develop a parameterization for top-down convection to capture the turbulence-microphysics interplay at cloud top.

Item Details

Item Type:Refereed Article
Keywords:Antarctica, ice nuclei particles, microphysics, mixed-phase clouds, Southern Ocean
Research Division:Earth Sciences
Research Group:Atmospheric sciences
Research Field:Cloud physics
Objective Division:Environmental Management
Objective Group:Air quality, atmosphere and weather
Objective Field:Atmospheric processes and dynamics
UTAS Author:Alexander, SP (Dr Simon Alexander)
ID Code:151755
Year Published:2021
Web of Science® Times Cited:9
Deposited By:Australian Antarctic Program Partnership
Deposited On:2022-08-04
Last Modified:2022-08-04
Downloads:0

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