Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A
Shallow clouds in the trade-wind region over the North Atlantic contribute substantially to the global radiative budget. In the vicinity of the Caribbean island of Barbados, they appear in different mesoscale organization patterns with distinct net cloud radiative effects (CREs). Cloud formation pro...
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ftdoajarticles:oai:doaj.org/article:dca44f0d874040979cfbc88cfc9cee91 2023-05-15T17:36:12+02:00 Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A L. Villiger H. Wernli M. Boettcher M. Hagen F. Aemisegger 2022-01-01T00:00:00Z https://doi.org/10.5194/wcd-3-59-2022 https://doaj.org/article/dca44f0d874040979cfbc88cfc9cee91 EN eng Copernicus Publications https://wcd.copernicus.org/articles/3/59/2022/wcd-3-59-2022.pdf https://doaj.org/toc/2698-4016 doi:10.5194/wcd-3-59-2022 2698-4016 https://doaj.org/article/dca44f0d874040979cfbc88cfc9cee91 Weather and Climate Dynamics, Vol 3, Pp 59-88 (2022) Meteorology. Climatology QC851-999 article 2022 ftdoajarticles https://doi.org/10.5194/wcd-3-59-2022 2022-12-30T20:21:50Z Shallow clouds in the trade-wind region over the North Atlantic contribute substantially to the global radiative budget. In the vicinity of the Caribbean island of Barbados, they appear in different mesoscale organization patterns with distinct net cloud radiative effects (CREs). Cloud formation processes in this region are typically controlled by the prevailing large-scale subsidence. However, occasionally weather systems from remote origin cause significant disturbances. This study investigates the complex cloud–circulation interactions during the field campaign EUREC 4 A (Elucidate the Couplings Between Clouds, Convection and Circulation) from 16 January to 20 February 2020, using a combination of Eulerian and Lagrangian diagnostics. Based on observations and ERA5 reanalyses, we identify the relevant processes and characterize the formation pathways of two moist anomalies above the Barbados Cloud Observatory (BCO), one in the lower troposphere ( ∼ 1000–650 hPa ) and one in the middle troposphere ( ∼ 650–300 hPa ). These moist anomalies are associated with strongly negative CRE values and with contrasting long-range transport processes from the extratropics and the tropics, respectively. The first case study about the low-level moist anomaly is characterized by an unusually thick cloud layer, high precipitation totals, and a strongly negative CRE. The formation of the low-level moist anomaly is connected to an extratropical dry intrusion (EDI) that interacts with a trailing cold front. A quasi-climatological (2010-2020) analysis reveals that EDIs lead to different conditions at the BCO depending on how they interact with the associated trailing cold front. Based on this climatology, we discuss the relevance of the strong large-scale forcing by EDIs for the low-cloud patterns near the BCO and the related CRE. The second case study about the mid-tropospheric moist anomaly is associated with an extended and persistent mixed-phase shelf cloud and the lowest daily CRE value observed during the campaign. The ... Article in Journal/Newspaper North Atlantic Directory of Open Access Journals: DOAJ Articles Weather and Climate Dynamics 3 1 59 88 |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
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language |
English |
topic |
Meteorology. Climatology QC851-999 |
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Meteorology. Climatology QC851-999 L. Villiger H. Wernli M. Boettcher M. Hagen F. Aemisegger Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A |
topic_facet |
Meteorology. Climatology QC851-999 |
description |
Shallow clouds in the trade-wind region over the North Atlantic contribute substantially to the global radiative budget. In the vicinity of the Caribbean island of Barbados, they appear in different mesoscale organization patterns with distinct net cloud radiative effects (CREs). Cloud formation processes in this region are typically controlled by the prevailing large-scale subsidence. However, occasionally weather systems from remote origin cause significant disturbances. This study investigates the complex cloud–circulation interactions during the field campaign EUREC 4 A (Elucidate the Couplings Between Clouds, Convection and Circulation) from 16 January to 20 February 2020, using a combination of Eulerian and Lagrangian diagnostics. Based on observations and ERA5 reanalyses, we identify the relevant processes and characterize the formation pathways of two moist anomalies above the Barbados Cloud Observatory (BCO), one in the lower troposphere ( ∼ 1000–650 hPa ) and one in the middle troposphere ( ∼ 650–300 hPa ). These moist anomalies are associated with strongly negative CRE values and with contrasting long-range transport processes from the extratropics and the tropics, respectively. The first case study about the low-level moist anomaly is characterized by an unusually thick cloud layer, high precipitation totals, and a strongly negative CRE. The formation of the low-level moist anomaly is connected to an extratropical dry intrusion (EDI) that interacts with a trailing cold front. A quasi-climatological (2010-2020) analysis reveals that EDIs lead to different conditions at the BCO depending on how they interact with the associated trailing cold front. Based on this climatology, we discuss the relevance of the strong large-scale forcing by EDIs for the low-cloud patterns near the BCO and the related CRE. The second case study about the mid-tropospheric moist anomaly is associated with an extended and persistent mixed-phase shelf cloud and the lowest daily CRE value observed during the campaign. The ... |
format |
Article in Journal/Newspaper |
author |
L. Villiger H. Wernli M. Boettcher M. Hagen F. Aemisegger |
author_facet |
L. Villiger H. Wernli M. Boettcher M. Hagen F. Aemisegger |
author_sort |
L. Villiger |
title |
Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A |
title_short |
Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A |
title_full |
Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A |
title_fullStr |
Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A |
title_full_unstemmed |
Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC 4 A |
title_sort |
lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from eurec 4 a |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/wcd-3-59-2022 https://doaj.org/article/dca44f0d874040979cfbc88cfc9cee91 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Weather and Climate Dynamics, Vol 3, Pp 59-88 (2022) |
op_relation |
https://wcd.copernicus.org/articles/3/59/2022/wcd-3-59-2022.pdf https://doaj.org/toc/2698-4016 doi:10.5194/wcd-3-59-2022 2698-4016 https://doaj.org/article/dca44f0d874040979cfbc88cfc9cee91 |
op_doi |
https://doi.org/10.5194/wcd-3-59-2022 |
container_title |
Weather and Climate Dynamics |
container_volume |
3 |
container_issue |
1 |
container_start_page |
59 |
op_container_end_page |
88 |
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1766135614787289088 |