On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes
Focusing on conditions of subsidence when low clouds are present, ground-based observations in both the North Atlantic and the Southern Ocean reveal strong relationships between cloud boundary (base and top heights) and different measures of lower tropospheric instability. The difference in potentia...
Published in: | Journal of Geophysical Research: Atmospheres |
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Online Access: | http://www.osti.gov/servlets/purl/1802938 https://www.osti.gov/biblio/1802938 https://doi.org/10.1029/2020jd032465 |
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ftosti:oai:osti.gov:1802938 2023-07-30T04:05:20+02:00 On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes Naud, Catherine M. Booth, James F. Lamer, Katia Marchand, Roger Protat, Alain McFarquhar, Greg M. 2021-08-16 application/pdf http://www.osti.gov/servlets/purl/1802938 https://www.osti.gov/biblio/1802938 https://doi.org/10.1029/2020jd032465 unknown http://www.osti.gov/servlets/purl/1802938 https://www.osti.gov/biblio/1802938 https://doi.org/10.1029/2020jd032465 doi:10.1029/2020jd032465 54 ENVIRONMENTAL SCIENCES 2021 ftosti https://doi.org/10.1029/2020jd032465 2023-07-11T10:04:50Z Focusing on conditions of subsidence when low clouds are present, ground-based observations in both the North Atlantic and the Southern Ocean reveal strong relationships between cloud boundary (base and top heights) and different measures of lower tropospheric instability. The difference in potential temperature between the surface and 800 hPa (a metric called M) provides a stronger relationship than measures of inversion strength such as the lower tropospheric stability and estimated inversion strength. This is because (1) inversion strength itself does not correlate well with cloud boundaries, and (2) M contains information that appears important for cloud boundaries. These include the surface forcing through the use of sea surface rather than near-surface air temperature and an upper level close to the real cloud top. These results expand upon previous work on the importance of M as a predictor of cloud morphology. However, important differences are found in low-cloud conditions for the North Atlantic as compared to the Southern Ocean (for a given value of M): stronger inversions, deeper boundary layers, and much larger sea level pressures. Therefore, the relationship between cloud boundaries and M differs between the two regions. A general circulation model provides similar relationships as observed between M and both cloud top height and temperature but tends to place clouds higher and at colder temperatures than observed for a given M. This might cause issues with the representation of precipitation, cloud cover and radiation in the Southern Ocean. Other/Unknown Material North Atlantic Southern Ocean SciTec Connect (Office of Scientific and Technical Information - OSTI, U.S. Department of Energy) Southern Ocean Journal of Geophysical Research: Atmospheres 125 13 |
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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 Naud, Catherine M. Booth, James F. Lamer, Katia Marchand, Roger Protat, Alain McFarquhar, Greg M. On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes |
topic_facet |
54 ENVIRONMENTAL SCIENCES |
description |
Focusing on conditions of subsidence when low clouds are present, ground-based observations in both the North Atlantic and the Southern Ocean reveal strong relationships between cloud boundary (base and top heights) and different measures of lower tropospheric instability. The difference in potential temperature between the surface and 800 hPa (a metric called M) provides a stronger relationship than measures of inversion strength such as the lower tropospheric stability and estimated inversion strength. This is because (1) inversion strength itself does not correlate well with cloud boundaries, and (2) M contains information that appears important for cloud boundaries. These include the surface forcing through the use of sea surface rather than near-surface air temperature and an upper level close to the real cloud top. These results expand upon previous work on the importance of M as a predictor of cloud morphology. However, important differences are found in low-cloud conditions for the North Atlantic as compared to the Southern Ocean (for a given value of M): stronger inversions, deeper boundary layers, and much larger sea level pressures. Therefore, the relationship between cloud boundaries and M differs between the two regions. A general circulation model provides similar relationships as observed between M and both cloud top height and temperature but tends to place clouds higher and at colder temperatures than observed for a given M. This might cause issues with the representation of precipitation, cloud cover and radiation in the Southern Ocean. |
author |
Naud, Catherine M. Booth, James F. Lamer, Katia Marchand, Roger Protat, Alain McFarquhar, Greg M. |
author_facet |
Naud, Catherine M. Booth, James F. Lamer, Katia Marchand, Roger Protat, Alain McFarquhar, Greg M. |
author_sort |
Naud, Catherine M. |
title |
On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes |
title_short |
On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes |
title_full |
On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes |
title_fullStr |
On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes |
title_full_unstemmed |
On the Relationship Between the Marine Cold Air Outbreak M Parameter and Low-Level Cloud Heights in the Midlatitudes |
title_sort |
on the relationship between the marine cold air outbreak m parameter and low-level cloud heights in the midlatitudes |
publishDate |
2021 |
url |
http://www.osti.gov/servlets/purl/1802938 https://www.osti.gov/biblio/1802938 https://doi.org/10.1029/2020jd032465 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
North Atlantic Southern Ocean |
genre_facet |
North Atlantic Southern Ocean |
op_relation |
http://www.osti.gov/servlets/purl/1802938 https://www.osti.gov/biblio/1802938 https://doi.org/10.1029/2020jd032465 doi:10.1029/2020jd032465 |
op_doi |
https://doi.org/10.1029/2020jd032465 |
container_title |
Journal of Geophysical Research: Atmospheres |
container_volume |
125 |
container_issue |
13 |
_version_ |
1772817180337897472 |