Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments
Global climate models (GCMs) are challenged by difficulties in simulating cloud phase and cloud radiative effect over the Southern Ocean (SO). Some of the new-generation GCMs predict too much liquid and too little ice in mixed-phase clouds. This misrepresentation of cloud phase in GCMs results in we...
Published in: | Journal of Geophysical Research: Atmospheres |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Wiley-Blackwell
2023
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Online Access: | https://lup.lub.lu.se/record/5c93a4a9-4cf8-45d3-8185-3e9c841f24ce https://doi.org/10.1029/2022JD037513 |
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ftulundlup:oai:lup.lub.lu.se:5c93a4a9-4cf8-45d3-8185-3e9c841f24ce 2023-05-15T18:24:55+02:00 Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments Zhao, Xi Liu, Xiaohong Burrows, Susannah DeMott, Paul J. Diao, Minghui McFarquhar, Greg M. Patade, Sachin Phillips, Vaughan Roberts, Greg C. Sanchez, Kevin J. Shi, Yang Zhang, Meng 2023-02-27 https://lup.lub.lu.se/record/5c93a4a9-4cf8-45d3-8185-3e9c841f24ce https://doi.org/10.1029/2022JD037513 eng eng Wiley-Blackwell https://lup.lub.lu.se/record/5c93a4a9-4cf8-45d3-8185-3e9c841f24ce http://dx.doi.org/10.1029/2022JD037513 scopus:85148650834 Journal of Geophysical Research: Atmospheres; 128(4), no e2022JD037513 (2023) ISSN: 2169-897X Meteorology and Atmospheric Sciences cloud microphysics ice formation ice nucleating particle secondary ice production contributiontojournal/article info:eu-repo/semantics/article text 2023 ftulundlup https://doi.org/10.1029/2022JD037513 2023-03-15T23:27:19Z Global climate models (GCMs) are challenged by difficulties in simulating cloud phase and cloud radiative effect over the Southern Ocean (SO). Some of the new-generation GCMs predict too much liquid and too little ice in mixed-phase clouds. This misrepresentation of cloud phase in GCMs results in weaker negative cloud feedback over the SO and a higher climate sensitivity. Based on a model comparison with observational data obtained during the Southern Ocean Cloud Radiation and Aerosol Transport Experimental Study, this study addresses a key uncertainty in the Community Earth System Model version 2 (CESM2) related to cloud phase, namely ice formation in pristine remote SO clouds. It is found that sea spray organic aerosols (SSOAs) are the most important type of ice nucleating particles (INPs) over the SO with concentrations 1 order of magnitude higher than those of dust INPs based on measurements and CESM2 simulations. Secondary ice production (SIP) which includes riming splintering, rain droplet shattering, and ice-ice collisional fragmentation as implemented in CESM2 is the dominant ice production process in moderately cold clouds with cloud temperatures greater than −20°C. SIP enhances the in-cloud ice number concentrations (Ni) by 1–3 orders of magnitude and predicts more mixed-phase (with percentage occurrence increased from 15% to 21%), in better agreement with the observations. This study highlights the importance of accurately representing the cloud phase over the pristine remote SO by considering the ice nucleation of SSOA and SIP processes, which are currently missing in most GCM cloud microphysics parameterizations. Article in Journal/Newspaper Southern Ocean Lund University Publications (LUP) Southern Ocean Journal of Geophysical Research: Atmospheres 128 4 |
institution |
Open Polar |
collection |
Lund University Publications (LUP) |
op_collection_id |
ftulundlup |
language |
English |
topic |
Meteorology and Atmospheric Sciences cloud microphysics ice formation ice nucleating particle secondary ice production |
spellingShingle |
Meteorology and Atmospheric Sciences cloud microphysics ice formation ice nucleating particle secondary ice production Zhao, Xi Liu, Xiaohong Burrows, Susannah DeMott, Paul J. Diao, Minghui McFarquhar, Greg M. Patade, Sachin Phillips, Vaughan Roberts, Greg C. Sanchez, Kevin J. Shi, Yang Zhang, Meng Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments |
topic_facet |
Meteorology and Atmospheric Sciences cloud microphysics ice formation ice nucleating particle secondary ice production |
description |
Global climate models (GCMs) are challenged by difficulties in simulating cloud phase and cloud radiative effect over the Southern Ocean (SO). Some of the new-generation GCMs predict too much liquid and too little ice in mixed-phase clouds. This misrepresentation of cloud phase in GCMs results in weaker negative cloud feedback over the SO and a higher climate sensitivity. Based on a model comparison with observational data obtained during the Southern Ocean Cloud Radiation and Aerosol Transport Experimental Study, this study addresses a key uncertainty in the Community Earth System Model version 2 (CESM2) related to cloud phase, namely ice formation in pristine remote SO clouds. It is found that sea spray organic aerosols (SSOAs) are the most important type of ice nucleating particles (INPs) over the SO with concentrations 1 order of magnitude higher than those of dust INPs based on measurements and CESM2 simulations. Secondary ice production (SIP) which includes riming splintering, rain droplet shattering, and ice-ice collisional fragmentation as implemented in CESM2 is the dominant ice production process in moderately cold clouds with cloud temperatures greater than −20°C. SIP enhances the in-cloud ice number concentrations (Ni) by 1–3 orders of magnitude and predicts more mixed-phase (with percentage occurrence increased from 15% to 21%), in better agreement with the observations. This study highlights the importance of accurately representing the cloud phase over the pristine remote SO by considering the ice nucleation of SSOA and SIP processes, which are currently missing in most GCM cloud microphysics parameterizations. |
format |
Article in Journal/Newspaper |
author |
Zhao, Xi Liu, Xiaohong Burrows, Susannah DeMott, Paul J. Diao, Minghui McFarquhar, Greg M. Patade, Sachin Phillips, Vaughan Roberts, Greg C. Sanchez, Kevin J. Shi, Yang Zhang, Meng |
author_facet |
Zhao, Xi Liu, Xiaohong Burrows, Susannah DeMott, Paul J. Diao, Minghui McFarquhar, Greg M. Patade, Sachin Phillips, Vaughan Roberts, Greg C. Sanchez, Kevin J. Shi, Yang Zhang, Meng |
author_sort |
Zhao, Xi |
title |
Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments |
title_short |
Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments |
title_full |
Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments |
title_fullStr |
Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments |
title_full_unstemmed |
Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments |
title_sort |
important ice processes are missed by the community earth system model in southern ocean mixed-phase clouds : bridging socrates observations to model developments |
publisher |
Wiley-Blackwell |
publishDate |
2023 |
url |
https://lup.lub.lu.se/record/5c93a4a9-4cf8-45d3-8185-3e9c841f24ce https://doi.org/10.1029/2022JD037513 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Journal of Geophysical Research: Atmospheres; 128(4), no e2022JD037513 (2023) ISSN: 2169-897X |
op_relation |
https://lup.lub.lu.se/record/5c93a4a9-4cf8-45d3-8185-3e9c841f24ce http://dx.doi.org/10.1029/2022JD037513 scopus:85148650834 |
op_doi |
https://doi.org/10.1029/2022JD037513 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
128 |
container_issue |
4 |
_version_ |
1766205958648758272 |