Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake
The Southern Ocean has absorbed most of the excess heat associated with anthropogenic greenhouse gas emissions. Since Southern Ocean observations are sparse in certain regions and seasons, much of our knowledge of ocean heat uptake is based on climate model simulations. However, climate models still...
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Online Access: | http://www.osti.gov/servlets/purl/1856247 https://www.osti.gov/biblio/1856247 https://doi.org/10.1029/2021jd035487 |
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ftosti:oai:osti.gov:1856247 2023-07-30T04:06:59+02:00 Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake Morrison, Ariel L. Singh, Hansi A. Rasch, Philip J. 2022-06-06 application/pdf http://www.osti.gov/servlets/purl/1856247 https://www.osti.gov/biblio/1856247 https://doi.org/10.1029/2021jd035487 unknown http://www.osti.gov/servlets/purl/1856247 https://www.osti.gov/biblio/1856247 https://doi.org/10.1029/2021jd035487 doi:10.1029/2021jd035487 54 ENVIRONMENTAL SCIENCES 2022 ftosti https://doi.org/10.1029/2021jd035487 2023-07-11T10:11:17Z The Southern Ocean has absorbed most of the excess heat associated with anthropogenic greenhouse gas emissions. Since Southern Ocean observations are sparse in certain regions and seasons, much of our knowledge of ocean heat uptake is based on climate model simulations. However, climate models still inadequately represent some properties of Southern Ocean clouds, and they have not identified the mechanisms by which clouds may affect SOHU. Here we use the ERA5 and JRA-55 reanalyses to assess the influence of clouds and other atmospheric processes on SOHU over the past 42 years. We find that years with the highest SOHU between 45-65°S are dominated by ocean heat uptake anomalies during winter and spring, but not during summer or fall. Winter and spring cloud cover are up to 7% higher when SOHU is up to 5.5 W/m 2 higher than the seasonal mean, with the largest increases in the South Pacific Ocean. Clouds are also optically thicker. These changes in cloud properties increases downwelling longwave radiation, amplifying ocean heat uptake. Cloud changes also increase heat uptake by maintaining a stable lower atmosphere, which suppresses turbulent heat fluxes out of the surface. Overall, we find that SOHU is likely not mediated by enhanced surface shortwave absorption over the observational time period. A better understanding of how atmospheric processes impact ocean heat uptake may help improve our understanding of ocean heat uptake mechanisms in the current generation of climate models. Other/Unknown Material Southern Ocean SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Southern Ocean Pacific Journal of Geophysical Research: Atmospheres 127 4 |
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SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) |
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ftosti |
language |
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topic |
54 ENVIRONMENTAL SCIENCES |
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54 ENVIRONMENTAL SCIENCES Morrison, Ariel L. Singh, Hansi A. Rasch, Philip J. Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
The Southern Ocean has absorbed most of the excess heat associated with anthropogenic greenhouse gas emissions. Since Southern Ocean observations are sparse in certain regions and seasons, much of our knowledge of ocean heat uptake is based on climate model simulations. However, climate models still inadequately represent some properties of Southern Ocean clouds, and they have not identified the mechanisms by which clouds may affect SOHU. Here we use the ERA5 and JRA-55 reanalyses to assess the influence of clouds and other atmospheric processes on SOHU over the past 42 years. We find that years with the highest SOHU between 45-65°S are dominated by ocean heat uptake anomalies during winter and spring, but not during summer or fall. Winter and spring cloud cover are up to 7% higher when SOHU is up to 5.5 W/m 2 higher than the seasonal mean, with the largest increases in the South Pacific Ocean. Clouds are also optically thicker. These changes in cloud properties increases downwelling longwave radiation, amplifying ocean heat uptake. Cloud changes also increase heat uptake by maintaining a stable lower atmosphere, which suppresses turbulent heat fluxes out of the surface. Overall, we find that SOHU is likely not mediated by enhanced surface shortwave absorption over the observational time period. A better understanding of how atmospheric processes impact ocean heat uptake may help improve our understanding of ocean heat uptake mechanisms in the current generation of climate models. |
author |
Morrison, Ariel L. Singh, Hansi A. Rasch, Philip J. |
author_facet |
Morrison, Ariel L. Singh, Hansi A. Rasch, Philip J. |
author_sort |
Morrison, Ariel L. |
title |
Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake |
title_short |
Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake |
title_full |
Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake |
title_fullStr |
Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake |
title_full_unstemmed |
Observations Indicate That Clouds Amplify Mechanisms of Southern Ocean Heat Uptake |
title_sort |
observations indicate that clouds amplify mechanisms of southern ocean heat uptake |
publishDate |
2022 |
url |
http://www.osti.gov/servlets/purl/1856247 https://www.osti.gov/biblio/1856247 https://doi.org/10.1029/2021jd035487 |
geographic |
Southern Ocean Pacific |
geographic_facet |
Southern Ocean Pacific |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
http://www.osti.gov/servlets/purl/1856247 https://www.osti.gov/biblio/1856247 https://doi.org/10.1029/2021jd035487 doi:10.1029/2021jd035487 |
op_doi |
https://doi.org/10.1029/2021jd035487 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
127 |
container_issue |
4 |
_version_ |
1772820041032531968 |