Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island
In order to complement the picture of the atmospheric water cycle in the Southern Ocean, we have continuously monitored water vapor isotopes since January 2020 on Amsterdam Island in the Indian Ocean. We present here the first 2-year long water vapor isotopic record at this site. We show that the wa...
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ftcopernicus:oai:publications.copernicus.org:acp113252 2024-06-23T07:45:23+00:00 Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island Landais, Amaelle Agosta, Cécile Vimeux, Françoise Magand, Olivier Solis, Cyrielle Cauquoin, Alexandre Dutrievoz, Niels Risi, Camille Leroy-Dos Santos, Christophe Fourré, Elise Cattani, Olivier Jossoud, Olivier Minster, Bénédicte Prié, Frédéric Casado, Mathieu Dommergue, Aurélien Bertrand, Yann Werner, Martin 2024-04-18 application/pdf https://doi.org/10.5194/acp-24-4611-2024 https://acp.copernicus.org/articles/24/4611/2024/ eng eng doi:10.5194/acp-24-4611-2024 https://acp.copernicus.org/articles/24/4611/2024/ eISSN: 1680-7324 Text 2024 ftcopernicus https://doi.org/10.5194/acp-24-4611-2024 2024-06-13T01:25:01Z In order to complement the picture of the atmospheric water cycle in the Southern Ocean, we have continuously monitored water vapor isotopes since January 2020 on Amsterdam Island in the Indian Ocean. We present here the first 2-year long water vapor isotopic record at this site. We show that the water vapor isotopic composition largely follows the water vapor mixing ratio, as expected in marine boundary layers. However, we detect 11 periods of a few days where there is a strong loss of correlation between water vapor δ 18 O and water vapor mixing ratio as well as abrupt negative excursions of water vapor δ 18 O . These excursions often occur toward the end of precipitation events. Six of these events show a decrease in gaseous elemental mercury, suggesting subsidence of air from a higher altitude. Our study aims to further explore the mechanism driving these negative excursions in water vapor δ 18 O . We used two different models to provide a data–model comparison over this 2-year period. While the European Centre Hamburg model (ECHAM6-wiso) at 0.9° was able to reproduce most of the sharp negative water vapor δ 18 O excursions, hence validating the physics process and isotopic implementation in this model, the Laboratoire de Météorologie Dynamique Zoom model (LMDZ-iso) at 2° (3°) resolution was only able to reproduce seven (one) of the negative excursions, highlighting the possible influence of the model resolution for the study of such abrupt isotopic events. Based on our detailed model–data comparison, we conclude that the most plausible explanations for such isotopic excursions are rain–vapor interactions associated with subsidence at the rear of a precipitation event. Text Amsterdam Island Southern Ocean Copernicus Publications: E-Journals Indian Southern Ocean Atmospheric Chemistry and Physics 24 8 4611 4634 |
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Open Polar |
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Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
In order to complement the picture of the atmospheric water cycle in the Southern Ocean, we have continuously monitored water vapor isotopes since January 2020 on Amsterdam Island in the Indian Ocean. We present here the first 2-year long water vapor isotopic record at this site. We show that the water vapor isotopic composition largely follows the water vapor mixing ratio, as expected in marine boundary layers. However, we detect 11 periods of a few days where there is a strong loss of correlation between water vapor δ 18 O and water vapor mixing ratio as well as abrupt negative excursions of water vapor δ 18 O . These excursions often occur toward the end of precipitation events. Six of these events show a decrease in gaseous elemental mercury, suggesting subsidence of air from a higher altitude. Our study aims to further explore the mechanism driving these negative excursions in water vapor δ 18 O . We used two different models to provide a data–model comparison over this 2-year period. While the European Centre Hamburg model (ECHAM6-wiso) at 0.9° was able to reproduce most of the sharp negative water vapor δ 18 O excursions, hence validating the physics process and isotopic implementation in this model, the Laboratoire de Météorologie Dynamique Zoom model (LMDZ-iso) at 2° (3°) resolution was only able to reproduce seven (one) of the negative excursions, highlighting the possible influence of the model resolution for the study of such abrupt isotopic events. Based on our detailed model–data comparison, we conclude that the most plausible explanations for such isotopic excursions are rain–vapor interactions associated with subsidence at the rear of a precipitation event. |
format |
Text |
author |
Landais, Amaelle Agosta, Cécile Vimeux, Françoise Magand, Olivier Solis, Cyrielle Cauquoin, Alexandre Dutrievoz, Niels Risi, Camille Leroy-Dos Santos, Christophe Fourré, Elise Cattani, Olivier Jossoud, Olivier Minster, Bénédicte Prié, Frédéric Casado, Mathieu Dommergue, Aurélien Bertrand, Yann Werner, Martin |
spellingShingle |
Landais, Amaelle Agosta, Cécile Vimeux, Françoise Magand, Olivier Solis, Cyrielle Cauquoin, Alexandre Dutrievoz, Niels Risi, Camille Leroy-Dos Santos, Christophe Fourré, Elise Cattani, Olivier Jossoud, Olivier Minster, Bénédicte Prié, Frédéric Casado, Mathieu Dommergue, Aurélien Bertrand, Yann Werner, Martin Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island |
author_facet |
Landais, Amaelle Agosta, Cécile Vimeux, Françoise Magand, Olivier Solis, Cyrielle Cauquoin, Alexandre Dutrievoz, Niels Risi, Camille Leroy-Dos Santos, Christophe Fourré, Elise Cattani, Olivier Jossoud, Olivier Minster, Bénédicte Prié, Frédéric Casado, Mathieu Dommergue, Aurélien Bertrand, Yann Werner, Martin |
author_sort |
Landais, Amaelle |
title |
Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island |
title_short |
Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island |
title_full |
Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island |
title_fullStr |
Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island |
title_full_unstemmed |
Abrupt excursions in water vapor isotopic variability at the Pointe Benedicte observatory on Amsterdam Island |
title_sort |
abrupt excursions in water vapor isotopic variability at the pointe benedicte observatory on amsterdam island |
publishDate |
2024 |
url |
https://doi.org/10.5194/acp-24-4611-2024 https://acp.copernicus.org/articles/24/4611/2024/ |
geographic |
Indian Southern Ocean |
geographic_facet |
Indian Southern Ocean |
genre |
Amsterdam Island Southern Ocean |
genre_facet |
Amsterdam Island Southern Ocean |
op_source |
eISSN: 1680-7324 |
op_relation |
doi:10.5194/acp-24-4611-2024 https://acp.copernicus.org/articles/24/4611/2024/ |
op_doi |
https://doi.org/10.5194/acp-24-4611-2024 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
24 |
container_issue |
8 |
container_start_page |
4611 |
op_container_end_page |
4634 |
_version_ |
1802639453163880448 |