Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar
Mixed-phase clouds (MPCs), composed of both liquid and ice, are prevalent in Southern Ocean cyclones. A characterization of these clouds on fine vertical scales is required in order to understand the microphysical processes within these clouds, and for model and satellite evaluations over this regio...
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ftinfoscience:oai:infoscience.epfl.ch:287043 2023-05-15T13:44:32+02:00 Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar Alexander, S. P. McFarquhar, G. M. Marchand, R. Protat, A. Vignon, E. Mace, G. G. Klekociuk, A. R. 2021-07-03T00:24:02Z https://doi.org/10.1029/2020JD033626 http://infoscience.epfl.ch/record/287043 unknown doi:10.1029/2020JD033626 isi:000664863900003 http://infoscience.epfl.ch/record/287043 http://infoscience.epfl.ch/record/287043 Text 2021 ftinfoscience https://doi.org/10.1029/2020JD033626 2023-02-13T23:05:50Z Mixed-phase clouds (MPCs), composed of both liquid and ice, are prevalent in Southern Ocean cyclones. A characterization of these clouds on fine vertical scales is required in order to understand the microphysical processes within these clouds, and for model and satellite evaluations over this region. We investigated three examples of cloud systems collected by ship-mounted remote-sensing instruments adjacent to East Antarctica at latitudes between 64 degrees S and 69 degrees S. These cases allow us to examine the properties of midlevel MPCs, with cloud tops between 2 and 6 km. Midlevel MPCs contain multiple layers of supercooled liquid water (SLW) embedded within ice during the passage of cyclones. SLW layers are capped by strong temperature inversions and are observed at temperatures as low as -31 degrees C. Convective generating cells (GCs) are present inside supercooled liquid-topped midlevel MPCs. The horizontal extent, vertical extent, and maximum upward Doppler velocity of these GCs were 0.6-3.6 km, 0.7-1.0 km, and 0.5-1.0 m s(-1), respectively, and are consistent with observations from previous lower-latitude studies. Ice precipitation is nearly ubiquitous, except in the thinnest clouds at the trailing end of the observed systems. Seeding of lower SLW layers from above leads to periods with either larger ice particles or greater ice precipitation rates. Periods of supercooled drizzle lasting up to 2 h were observed toward the end of two of the three cyclone systems. This supercooled drizzle turns into predominantly ice precipitation as the result of seeding by ice clouds located above the precipitating SLW layer. Text Antarc* Antarctica East Antarctica Southern Ocean EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) Southern Ocean East Antarctica Journal of Geophysical Research: Atmospheres 126 8 |
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EPFL Infoscience (Ecole Polytechnique Fédérale Lausanne) |
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ftinfoscience |
language |
unknown |
description |
Mixed-phase clouds (MPCs), composed of both liquid and ice, are prevalent in Southern Ocean cyclones. A characterization of these clouds on fine vertical scales is required in order to understand the microphysical processes within these clouds, and for model and satellite evaluations over this region. We investigated three examples of cloud systems collected by ship-mounted remote-sensing instruments adjacent to East Antarctica at latitudes between 64 degrees S and 69 degrees S. These cases allow us to examine the properties of midlevel MPCs, with cloud tops between 2 and 6 km. Midlevel MPCs contain multiple layers of supercooled liquid water (SLW) embedded within ice during the passage of cyclones. SLW layers are capped by strong temperature inversions and are observed at temperatures as low as -31 degrees C. Convective generating cells (GCs) are present inside supercooled liquid-topped midlevel MPCs. The horizontal extent, vertical extent, and maximum upward Doppler velocity of these GCs were 0.6-3.6 km, 0.7-1.0 km, and 0.5-1.0 m s(-1), respectively, and are consistent with observations from previous lower-latitude studies. Ice precipitation is nearly ubiquitous, except in the thinnest clouds at the trailing end of the observed systems. Seeding of lower SLW layers from above leads to periods with either larger ice particles or greater ice precipitation rates. Periods of supercooled drizzle lasting up to 2 h were observed toward the end of two of the three cyclone systems. This supercooled drizzle turns into predominantly ice precipitation as the result of seeding by ice clouds located above the precipitating SLW layer. |
format |
Text |
author |
Alexander, S. P. McFarquhar, G. M. Marchand, R. Protat, A. Vignon, E. Mace, G. G. Klekociuk, A. R. |
spellingShingle |
Alexander, S. P. McFarquhar, G. M. Marchand, R. Protat, A. Vignon, E. Mace, G. G. Klekociuk, A. R. Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar |
author_facet |
Alexander, S. P. McFarquhar, G. M. Marchand, R. Protat, A. Vignon, E. Mace, G. G. Klekociuk, A. R. |
author_sort |
Alexander, S. P. |
title |
Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar |
title_short |
Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar |
title_full |
Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar |
title_fullStr |
Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar |
title_full_unstemmed |
Mixed-Phase Clouds and Precipitation in Southern Ocean Cyclones and Cloud Systems Observed Poleward of 64 degrees S by Ship-Based Cloud Radar and Lidar |
title_sort |
mixed-phase clouds and precipitation in southern ocean cyclones and cloud systems observed poleward of 64 degrees s by ship-based cloud radar and lidar |
publishDate |
2021 |
url |
https://doi.org/10.1029/2020JD033626 http://infoscience.epfl.ch/record/287043 |
geographic |
Southern Ocean East Antarctica |
geographic_facet |
Southern Ocean East Antarctica |
genre |
Antarc* Antarctica East Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctica East Antarctica Southern Ocean |
op_source |
http://infoscience.epfl.ch/record/287043 |
op_relation |
doi:10.1029/2020JD033626 isi:000664863900003 http://infoscience.epfl.ch/record/287043 |
op_doi |
https://doi.org/10.1029/2020JD033626 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
126 |
container_issue |
8 |
_version_ |
1766202862280376320 |