How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region
International audience Abstract. The interaction between low-level tropical clouds and the large-scale circulation is a key feedback element in our climate system, but our understanding of it is still fragmentary. In this paper, the role of upper-level extratropical dynamics for the development of c...
Published in: | Weather and Climate Dynamics |
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Online Access: | https://hal.sorbonne-universite.fr/hal-03448547 https://hal.sorbonne-universite.fr/hal-03448547/document https://hal.sorbonne-universite.fr/hal-03448547/file/Aemisegger_etal_wcd21_isoTrades.pdf https://doi.org/10.5194/wcd-2-281-2021 |
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ftsorbonneuniv:oai:HAL:hal-03448547v1 2024-06-09T07:48:07+00:00 How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region Aemisegger, Franziska Vogel, Raphaela Graf, Pascal Dahinden, Fabienne Villiger, Leonie Jansen, Friedhelm Bony, Sandrine Stevens, Bjorn Wernli, Heini Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) 2021-03-29 https://hal.sorbonne-universite.fr/hal-03448547 https://hal.sorbonne-universite.fr/hal-03448547/document https://hal.sorbonne-universite.fr/hal-03448547/file/Aemisegger_etal_wcd21_isoTrades.pdf https://doi.org/10.5194/wcd-2-281-2021 en eng HAL CCSD Copernicus info:eu-repo/semantics/altIdentifier/doi/10.5194/wcd-2-281-2021 hal-03448547 https://hal.sorbonne-universite.fr/hal-03448547 https://hal.sorbonne-universite.fr/hal-03448547/document https://hal.sorbonne-universite.fr/hal-03448547/file/Aemisegger_etal_wcd21_isoTrades.pdf doi:10.5194/wcd-2-281-2021 info:eu-repo/semantics/OpenAccess ISSN: 2698-4016 Weather and Climate Dynamics https://hal.sorbonne-universite.fr/hal-03448547 Weather and Climate Dynamics, 2021, 2 (1), pp.281 - 309. ⟨10.5194/wcd-2-281-2021⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2021 ftsorbonneuniv https://doi.org/10.5194/wcd-2-281-2021 2024-05-16T23:55:21Z International audience Abstract. The interaction between low-level tropical clouds and the large-scale circulation is a key feedback element in our climate system, but our understanding of it is still fragmentary. In this paper, the role of upper-level extratropical dynamics for the development of contrasting shallow cumulus cloud patterns in the western North Atlantic trade wind region is investigated. Stable water isotopes are used as tracers for the origin of air parcels arriving in the sub-cloud layer above Barbados, measured continuously in water vapour at the Barbados Cloud Observatory during a 24 d measurement campaign (isoTrades, 25 January to 17 February 2018). These data are combined with a detailed air parcel back-trajectory analysis using hourly ERA5 reanalyses of the European Centre for Medium-Range Weather Forecasts. A climatological investigation of the 10 d air parcel history for January and February in the recent decade shows that 55 % of the air parcels arriving in the sub-cloud layer have spent at least 1 d in the extratropics (north of 35∘ N) before arriving in the eastern Caribbean at about 13∘ N. In 2018, this share of air parcels with extratropical origin was anomalously large, with 88 %. In two detailed case studies during the campaign, two flow regimes with distinct isotope signatures transporting extratropical air into the Caribbean are investigated. In both regimes, the air parcels descend from the lower part of the midlatitude jet stream towards the Equator, at the eastern edge of subtropical anticyclones, in the context of Rossby wave breaking events. The zonal location of the wave breaking and the surface anticyclone determine the dominant transport regime. The first regime represents the “typical” trade wind situation, with easterly winds bringing moist air from the eastern North Atlantic into the Caribbean, in a deep layer from the surface up to ∼600 hPa. The moisture source of the sub-cloud layer water vapour is located on average 2000 km upstream of Barbados. In this regime, ... Article in Journal/Newspaper North Atlantic HAL Sorbonne Université Weather and Climate Dynamics 2 1 281 309 |
institution |
Open Polar |
collection |
HAL Sorbonne Université |
op_collection_id |
ftsorbonneuniv |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Aemisegger, Franziska Vogel, Raphaela Graf, Pascal Dahinden, Fabienne Villiger, Leonie Jansen, Friedhelm Bony, Sandrine Stevens, Bjorn Wernli, Heini How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience Abstract. The interaction between low-level tropical clouds and the large-scale circulation is a key feedback element in our climate system, but our understanding of it is still fragmentary. In this paper, the role of upper-level extratropical dynamics for the development of contrasting shallow cumulus cloud patterns in the western North Atlantic trade wind region is investigated. Stable water isotopes are used as tracers for the origin of air parcels arriving in the sub-cloud layer above Barbados, measured continuously in water vapour at the Barbados Cloud Observatory during a 24 d measurement campaign (isoTrades, 25 January to 17 February 2018). These data are combined with a detailed air parcel back-trajectory analysis using hourly ERA5 reanalyses of the European Centre for Medium-Range Weather Forecasts. A climatological investigation of the 10 d air parcel history for January and February in the recent decade shows that 55 % of the air parcels arriving in the sub-cloud layer have spent at least 1 d in the extratropics (north of 35∘ N) before arriving in the eastern Caribbean at about 13∘ N. In 2018, this share of air parcels with extratropical origin was anomalously large, with 88 %. In two detailed case studies during the campaign, two flow regimes with distinct isotope signatures transporting extratropical air into the Caribbean are investigated. In both regimes, the air parcels descend from the lower part of the midlatitude jet stream towards the Equator, at the eastern edge of subtropical anticyclones, in the context of Rossby wave breaking events. The zonal location of the wave breaking and the surface anticyclone determine the dominant transport regime. The first regime represents the “typical” trade wind situation, with easterly winds bringing moist air from the eastern North Atlantic into the Caribbean, in a deep layer from the surface up to ∼600 hPa. The moisture source of the sub-cloud layer water vapour is located on average 2000 km upstream of Barbados. In this regime, ... |
author2 |
Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL) |
format |
Article in Journal/Newspaper |
author |
Aemisegger, Franziska Vogel, Raphaela Graf, Pascal Dahinden, Fabienne Villiger, Leonie Jansen, Friedhelm Bony, Sandrine Stevens, Bjorn Wernli, Heini |
author_facet |
Aemisegger, Franziska Vogel, Raphaela Graf, Pascal Dahinden, Fabienne Villiger, Leonie Jansen, Friedhelm Bony, Sandrine Stevens, Bjorn Wernli, Heini |
author_sort |
Aemisegger, Franziska |
title |
How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region |
title_short |
How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region |
title_full |
How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region |
title_fullStr |
How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region |
title_full_unstemmed |
How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region |
title_sort |
how rossby wave breaking modulates the water cycle in the north atlantic trade wind region |
publisher |
HAL CCSD |
publishDate |
2021 |
url |
https://hal.sorbonne-universite.fr/hal-03448547 https://hal.sorbonne-universite.fr/hal-03448547/document https://hal.sorbonne-universite.fr/hal-03448547/file/Aemisegger_etal_wcd21_isoTrades.pdf https://doi.org/10.5194/wcd-2-281-2021 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 2698-4016 Weather and Climate Dynamics https://hal.sorbonne-universite.fr/hal-03448547 Weather and Climate Dynamics, 2021, 2 (1), pp.281 - 309. ⟨10.5194/wcd-2-281-2021⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/wcd-2-281-2021 hal-03448547 https://hal.sorbonne-universite.fr/hal-03448547 https://hal.sorbonne-universite.fr/hal-03448547/document https://hal.sorbonne-universite.fr/hal-03448547/file/Aemisegger_etal_wcd21_isoTrades.pdf doi:10.5194/wcd-2-281-2021 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/wcd-2-281-2021 |
container_title |
Weather and Climate Dynamics |
container_volume |
2 |
container_issue |
1 |
container_start_page |
281 |
op_container_end_page |
309 |
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1801379690577920000 |