Impact of Antarctic mixed-phase clouds on climate
Precious little is known about the composition of low-level clouds over the Antarctic Plateau and their effect on climate. In situ measurements at the South Pole using a unique tethered balloon system and ground-based lidar reveal a much higher than anticipated incidence of low-level, mixed-phase cl...
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Online Access: | http://www.osti.gov/servlets/purl/1348403 https://www.osti.gov/biblio/1348403 https://doi.org/10.1073/pnas.1418197111 |
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ftosti:oai:osti.gov:1348403 2023-07-30T03:59:02+02:00 Impact of Antarctic mixed-phase clouds on climate Lawson, R. Paul Gettelman, Andrew 2023-06-26 application/pdf http://www.osti.gov/servlets/purl/1348403 https://www.osti.gov/biblio/1348403 https://doi.org/10.1073/pnas.1418197111 unknown http://www.osti.gov/servlets/purl/1348403 https://www.osti.gov/biblio/1348403 https://doi.org/10.1073/pnas.1418197111 doi:10.1073/pnas.1418197111 54 ENVIRONMENTAL SCIENCES 2023 ftosti https://doi.org/10.1073/pnas.1418197111 2023-07-11T09:17:48Z Precious little is known about the composition of low-level clouds over the Antarctic Plateau and their effect on climate. In situ measurements at the South Pole using a unique tethered balloon system and ground-based lidar reveal a much higher than anticipated incidence of low-level, mixed-phase clouds (i.e., consisting of supercooled liquid water drops and ice crystals). The high incidence of mixed-phase clouds is currently poorly represented in global climate models (GCMs). As a result, the effects that mixed-phase clouds have on climate predictions are highly uncertain. In this paper, we modify the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM) GCM to align with the new observations and evaluate the radiative effects on a continental scale. The net cloud radiative effects (CREs) over Antarctica are increased by +7.4 Wm –2 , and although this is a significant change, a much larger effect occurs when the modified model physics are extended beyond the Antarctic continent. The simulations show significant net CRE over the Southern Ocean storm tracks, where recent measurements also indicate substantial regions of supercooled liquid. Finally, these sensitivity tests confirm that Southern Ocean CREs are strongly sensitive to mixed-phase clouds colder than –20 °C. Other/Unknown Material Antarc* Antarctic Antarctica South pole South pole Southern Ocean SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Antarctic Southern Ocean The Antarctic South Pole Proceedings of the National Academy of Sciences 111 51 18156 18161 |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Lawson, R. Paul Gettelman, Andrew Impact of Antarctic mixed-phase clouds on climate |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Precious little is known about the composition of low-level clouds over the Antarctic Plateau and their effect on climate. In situ measurements at the South Pole using a unique tethered balloon system and ground-based lidar reveal a much higher than anticipated incidence of low-level, mixed-phase clouds (i.e., consisting of supercooled liquid water drops and ice crystals). The high incidence of mixed-phase clouds is currently poorly represented in global climate models (GCMs). As a result, the effects that mixed-phase clouds have on climate predictions are highly uncertain. In this paper, we modify the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM) GCM to align with the new observations and evaluate the radiative effects on a continental scale. The net cloud radiative effects (CREs) over Antarctica are increased by +7.4 Wm –2 , and although this is a significant change, a much larger effect occurs when the modified model physics are extended beyond the Antarctic continent. The simulations show significant net CRE over the Southern Ocean storm tracks, where recent measurements also indicate substantial regions of supercooled liquid. Finally, these sensitivity tests confirm that Southern Ocean CREs are strongly sensitive to mixed-phase clouds colder than –20 °C. |
author |
Lawson, R. Paul Gettelman, Andrew |
author_facet |
Lawson, R. Paul Gettelman, Andrew |
author_sort |
Lawson, R. Paul |
title |
Impact of Antarctic mixed-phase clouds on climate |
title_short |
Impact of Antarctic mixed-phase clouds on climate |
title_full |
Impact of Antarctic mixed-phase clouds on climate |
title_fullStr |
Impact of Antarctic mixed-phase clouds on climate |
title_full_unstemmed |
Impact of Antarctic mixed-phase clouds on climate |
title_sort |
impact of antarctic mixed-phase clouds on climate |
publishDate |
2023 |
url |
http://www.osti.gov/servlets/purl/1348403 https://www.osti.gov/biblio/1348403 https://doi.org/10.1073/pnas.1418197111 |
geographic |
Antarctic Southern Ocean The Antarctic South Pole |
geographic_facet |
Antarctic Southern Ocean The Antarctic South Pole |
genre |
Antarc* Antarctic Antarctica South pole South pole Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica South pole South pole Southern Ocean |
op_relation |
http://www.osti.gov/servlets/purl/1348403 https://www.osti.gov/biblio/1348403 https://doi.org/10.1073/pnas.1418197111 doi:10.1073/pnas.1418197111 |
op_doi |
https://doi.org/10.1073/pnas.1418197111 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
111 |
container_issue |
51 |
container_start_page |
18156 |
op_container_end_page |
18161 |
_version_ |
1772809740170035200 |