Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations
International audience The isotopic composition of water vapour in the North Atlantic free troposphere is investigated with Infrared Atmospheric Sounding Interferometer (IASI) measurements of the D / H ratio (δD) above the ocean. We show that in the vicinity of West Africa, the seasonality of δD is...
Published in: | Atmospheric Chemistry and Physics |
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Main Authors: | , , , , |
Other Authors: | , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2017
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Online Access: | https://insu.hal.science/insu-01573892 https://insu.hal.science/insu-01573892/document https://insu.hal.science/insu-01573892/file/acp-17-9645-2017.pdf https://doi.org/10.5194/acp-17-9645-2017 |
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ftuniversailles:oai:HAL:insu-01573892v1 |
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openpolar |
institution |
Open Polar |
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Université de Versailles Saint-Quentin-en-Yvelines: HAL-UVSQ |
op_collection_id |
ftuniversailles |
language |
English |
topic |
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] |
spellingShingle |
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] Lacour, Jean-Lionel Flamant, Cyrille Risi, Camille Clerbaux, Cathy Coheur, Pierre-François Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations |
topic_facet |
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] |
description |
International audience The isotopic composition of water vapour in the North Atlantic free troposphere is investigated with Infrared Atmospheric Sounding Interferometer (IASI) measurements of the D / H ratio (δD) above the ocean. We show that in the vicinity of West Africa, the seasonality of δD is particularly strong (130 ‰), which is related with the influence of the Saharan heat low (SHL) during summertime. The SHL indeed largely influences the dynamic in that region by producing deep turbulent mixing layers, yielding a specific water vapour isotopic footprint. The influence of the SHL on the isotopic budget is analysed on various time and space scales and is shown to be large, highlighting the importance of the SHL dynamics on the moistening and the HDO enrichment of the free troposphere over the North Atlantic. The potential influence of the SHL is also investigated on the inter-annual scale as we also report important variations in δD above the Canary archipelago region. We interpret the variability in the enrichment, using backward trajectory analyses, in terms of the ratio of air masses coming from the North Atlantic and air masses coming from the African continent. Finally, the interest of IASI high sampling capabilities is further illustrated by presenting spatial distributions of δD and humidity above the North Atlantic from which we show that the different sources and dehydration pathways controlling the humidity can be disentangled thanks to the added value of δD observations. More generally, our results demonstrate the utility of δD observations obtained from the IASI sounder to gain insight into the hydrological cycle processes in the West African region. |
author2 |
TROPO - LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Institute of Earth Sciences Reykjavik University of Iceland Reykjavik Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-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) Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique Université libre de Bruxelles (ULB) |
format |
Article in Journal/Newspaper |
author |
Lacour, Jean-Lionel Flamant, Cyrille Risi, Camille Clerbaux, Cathy Coheur, Pierre-François |
author_facet |
Lacour, Jean-Lionel Flamant, Cyrille Risi, Camille Clerbaux, Cathy Coheur, Pierre-François |
author_sort |
Lacour, Jean-Lionel |
title |
Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations |
title_short |
Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations |
title_full |
Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations |
title_fullStr |
Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations |
title_full_unstemmed |
Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations |
title_sort |
importance of the saharan heat low in controlling the north atlantic free tropospheric humidity budget deduced from iasi δd observations |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://insu.hal.science/insu-01573892 https://insu.hal.science/insu-01573892/document https://insu.hal.science/insu-01573892/file/acp-17-9645-2017.pdf https://doi.org/10.5194/acp-17-9645-2017 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 1680-7316 EISSN: 1680-7324 Atmospheric Chemistry and Physics https://insu.hal.science/insu-01573892 Atmospheric Chemistry and Physics, 2017, 17, pp.9645 - 9663. ⟨10.5194/acp-17-9645-2017⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/acp-17-9645-2017 insu-01573892 https://insu.hal.science/insu-01573892 https://insu.hal.science/insu-01573892/document https://insu.hal.science/insu-01573892/file/acp-17-9645-2017.pdf doi:10.5194/acp-17-9645-2017 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.5194/acp-17-9645-2017 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
17 |
container_issue |
15 |
container_start_page |
9645 |
op_container_end_page |
9663 |
_version_ |
1799484447747211264 |
spelling |
ftuniversailles:oai:HAL:insu-01573892v1 2024-05-19T07:44:37+00:00 Importance of the Saharan heat low in controlling the North Atlantic free tropospheric humidity budget deduced from IASI δD observations Lacour, Jean-Lionel Flamant, Cyrille Risi, Camille Clerbaux, Cathy Coheur, Pierre-François TROPO - LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Institute of Earth Sciences Reykjavik University of Iceland Reykjavik Laboratoire de Météorologie Dynamique (UMR 8539) (LMD) Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-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) Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique Université libre de Bruxelles (ULB) 2017 https://insu.hal.science/insu-01573892 https://insu.hal.science/insu-01573892/document https://insu.hal.science/insu-01573892/file/acp-17-9645-2017.pdf https://doi.org/10.5194/acp-17-9645-2017 en eng HAL CCSD European Geosciences Union info:eu-repo/semantics/altIdentifier/doi/10.5194/acp-17-9645-2017 insu-01573892 https://insu.hal.science/insu-01573892 https://insu.hal.science/insu-01573892/document https://insu.hal.science/insu-01573892/file/acp-17-9645-2017.pdf doi:10.5194/acp-17-9645-2017 info:eu-repo/semantics/OpenAccess ISSN: 1680-7316 EISSN: 1680-7324 Atmospheric Chemistry and Physics https://insu.hal.science/insu-01573892 Atmospheric Chemistry and Physics, 2017, 17, pp.9645 - 9663. ⟨10.5194/acp-17-9645-2017⟩ [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] info:eu-repo/semantics/article Journal articles 2017 ftuniversailles https://doi.org/10.5194/acp-17-9645-2017 2024-04-25T00:33:36Z International audience The isotopic composition of water vapour in the North Atlantic free troposphere is investigated with Infrared Atmospheric Sounding Interferometer (IASI) measurements of the D / H ratio (δD) above the ocean. We show that in the vicinity of West Africa, the seasonality of δD is particularly strong (130 ‰), which is related with the influence of the Saharan heat low (SHL) during summertime. The SHL indeed largely influences the dynamic in that region by producing deep turbulent mixing layers, yielding a specific water vapour isotopic footprint. The influence of the SHL on the isotopic budget is analysed on various time and space scales and is shown to be large, highlighting the importance of the SHL dynamics on the moistening and the HDO enrichment of the free troposphere over the North Atlantic. The potential influence of the SHL is also investigated on the inter-annual scale as we also report important variations in δD above the Canary archipelago region. We interpret the variability in the enrichment, using backward trajectory analyses, in terms of the ratio of air masses coming from the North Atlantic and air masses coming from the African continent. Finally, the interest of IASI high sampling capabilities is further illustrated by presenting spatial distributions of δD and humidity above the North Atlantic from which we show that the different sources and dehydration pathways controlling the humidity can be disentangled thanks to the added value of δD observations. More generally, our results demonstrate the utility of δD observations obtained from the IASI sounder to gain insight into the hydrological cycle processes in the West African region. Article in Journal/Newspaper North Atlantic Université de Versailles Saint-Quentin-en-Yvelines: HAL-UVSQ Atmospheric Chemistry and Physics 17 15 9645 9663 |