Search

Your search keyword '"Camille Bréant"' showing total 6 results
Start Over Author "Camille Bréant"
6 results on '"Camille Bréant"'

1. Coastal water vapor isotopic composition driven by katabatic wind variability in summer at Dumont d'Urville, coastal East Antarctica

Author

Vincent Favier, Frédéric Prié, Mathieu Casado, Amaelle Landais, Christophe Leroy-Dos Santos, Camille Bréant, Sentia Goursaud, Anais Orsi, Benjamin Golly, Olivier Cattani, Elise Fourré, Valérie Masson-Delmotte, Cécile Agosta, and Patricia Martinerie

Subjects
Katabatic wind, 010504 meteorology & atmospheric sciences, Global wind patterns, Antarctic ice sheet, Humidity, 010502 geochemistry & geophysics, Snow, 01 natural sciences, Geophysics, Oceanography, Ice core, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Diel vertical migration, Water vapor, Geology, 0105 earth and related environmental sciences
Abstract

Dumont d'Urville station, located on the East coast of Antarctica in Adelie Land, is in one of the windiest coastal region on Earth, due to katabatic winds downslope from the East Antarctic ice sheet. In summer, the season of interest in this study, coastal weather is characterized by well-marked diel cycles in temperature and wind patterns. Our study aims at exploring the added value of water vapor stable isotopes in coastal Adelie Land to provide new information on the local atmospheric water cycle and climate. An important application is the interpretation of water isotopic profiles in snow and ice cores recently drilled in Adelie Land. We present the first continuous measurements of δ 18 O and d-excess in water vapor over Adelie Land. During our measurements period (26/12/2016 to 03/02/2017), we observed clear diel cycles in terms of temperature, humidity and isotopic composition. The cycles in isotopic composition are particularly large given the muted variations in temperature when compared to other Antarctic sites where similar monitoring have been performed. Based on data analyses and simulations obtained with the regional MAR model on the coastal Adelie Land, we suggest that the driver for δ 18 O and d-excess diel variability in summer at Dumont d'Urville is the variation of the strength of the wind coming from the continent: the periods with strong wind are associated with the arrival of relatively dry air with water vapor associated with low δ 18 O and high d-excess from the Antarctic plateau. Finally, in addition to the interpretation of snow and ice core isotopic profiles in the coastal regions, our study has implications for the evaluation of atmospheric models equipped with water isotopes.

Published
2019

2. Unveiling the anatomy of Termination 3 using water and air isotopes in the Dome C ice core, East Antarctica

Author

Barbara Stenni, Markus Leuenberger, Anais Orsi, Frédéric Prié, Thomas Extier, Jean Jouzel, Amaelle Landais, Camille Bréant, Patricia Martinerie, Valérie Masson-Delmotte, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Scienze Geologiche [Trieste], Università degli studi di Trieste, Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern]-Universität Bern [Bern], Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut des Géosciences de l’Environnement (IGE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Università degli studi di Trieste = University of Trieste, and Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE)

Subjects
010506 paleontology, Archeology, 010504 meteorology & atmospheric sciences, δ18O, Ice core, Context (language use), 01 natural sciences, Latitude, Antarctic temperature, Deglaciation, Bipolar seesaw, Deglaciations, Water and air isotopes, Glacial period, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, Termination 3, Heinrich like events, Northern Hemisphere, Geology, Settore GEO/08 - Geochimica e Vulcanologia, 13. Climate action, [SDU]Sciences of the Universe [physics], Climatology, Interglacial, Firn densification model
Abstract

Each glacial – interglacial transition of the Quaternary occurs in a different orbital context leading to various timing for the deglaciation and sequence of high vs low latitudes events. Termination 3, 250 kyears before present (ka), is an unusual deglaciation in the context of the last 9 deglaciations recorded in the old EPICA Dome C (EDC) Antarctic ice core: it exhibits a three-phase sequence, two warming phases separated by a small cooling, the last phase suggesting a particularly rapid temperature increase. We present here new high resolution δ15N and deuterium excess (d-excess) data from the EDC ice core to provide a detailed temperature change estimate during this termination. Then, we combined the δD and δ18O to discuss the relationship between high and low latitude changes through the d-excess. We also provide the high vs low latitude sequence of events over this deglaciation without chronological uncertainty using low latitude ice core proxies. In agreement with previous studies based on speleothem analyses, we show that the first phase of Termination 3 (256–249 ka) is associated with small Heinrich like events linked to changes in ITCZ position, monsoon activity and teleconnections with Antarctica. In a context of minimum Northern Hemisphere insolation, this leads to a rather strong Antarctic warming, as observed in the δ15N record in contrast to the relatively small δD increase. The second warming phase occurs during the rise of the Northern hemisphere insolation, with a large Heinrich like event leading to the characteristic Antarctic warming observed in the δ15N and δD increase as for the more recent terminations.

Published
2019

3. On the use of δ18Oatm for ice core dating

Author

Frédéric Prié, Amaelle Landais, Lucie Bazin, Didier M. Roche, Markus Leuenberger, Gabrielle Dreyfus, Camille Bréant, Thomas Extier, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] ( LSCE ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Groupe Sup de Co La Rochelle ( La Rochelle Business School ), Physics Institute, University of Bern, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation du climat (CLIM), Earth and Climate, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, Archeology, 010504 meteorology & atmospheric sciences, Dome, Ice core, 010502 geochemistry & geophysics, 01 natural sciences, Isotopes of oxygen, Ice age, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, Glacial period, SDG 14 - Life Below Water, Water cycle, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Chronology, Glacial terminations, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, δO, Intertropical Convergence Zone, Geology, 13. Climate action, Oxygen isotopes, Physical geography
Abstract

Deep ice core chronologies have been improved over the past years through the addition of new age constraints. However, dating methods are still associated with large uncertainties for ice cores from the East Antarctic plateau where layer counting is not possible. Indeed, an uncertainty up to 6 ka is associated with AICC2012 chronology of EPICA Dome C (EDC) ice core, which mostly arises from uncertainty on the delay between changes recorded in δ18Oatm and in June 21st insolation variations at 65°N used for ice core orbital dating. Consequently, we need to enhance the knowledge of this delay to improve ice core chronologies. We present new high-resolution EDC δ18Oatm record (153–374 ka) and δO2/N2 measurements (163–332 ka) performed on well-stored ice to provide continuous records of δ18Oatm and δO2/N2 between 100 and 800 ka. The comparison of δ18Oatm with the δ18Ocalcite from East Asian speleothems shows that both signals present similar orbital and millennial variabilities, which may represent shifts in the InterTropical Convergence Zone position, themselves associated with Heinrich events. We thus propose to use the δ18Ocalcite as target for δ18Oatm orbital dating. Such a tuning method improves the ice core chronology of the last glacial inception compared to AICC2012 by reconciling NGRIP and mid-latitude climatic records. It is especially marked during Dansgaard-Oeschger 25 where the proposed chronology is 2.2 ka older than AICC2012. This δ18Oatm – δ18Ocalcite alignment method applied between 100 and 640 ka improves the EDC ice core chronology, especially over MIS 11, and leads to lower ice age uncertainties compared to AICC2012.

Published
2018

5. Modelling the firn thickness evolution during the last deglaciation: constrains on sensitivity to temperature and impurities

Author

Camille Bréant, Patricia Martinerie, Anaïs Orsi, Laurent Arnaud, and Amaëlle Landais

Abstract

The transformation of snow into ice is a complex phenomenon difficult to model. Depending on surface temperature and accumulation rate, it may take several decades to millennia for air to be entrapped in ice. The air is thus always younger that the surrounding ice. The resulting gas-ice age difference is essential to document the phasing between CO2 and temperature changes especially during deglaciations. The air trapping depth can be inferred in the past using a firn densification model, or using δ15N of air measured in ice cores. All firn densification models applied to deglaciations show a large disagreement with δ15N measurements in several sites of East Antarctica, predicting larger firn thickness during the Last Glacial Maximum, whereas δ15N suggests a reduced firn thickness compared to the Holocene. We present here modifications of the LGGE firn densification model, which significantly reduce the model-data mismatch for the gas trapping depth evolution over the last deglaciation, while preserving the good agreement between measured and modelled modern firn density profiles. In particular, we introduce a dependency of the activation energy to temperature and impurities in the firn densification rate calculation. The temperature influence reflects the existence of different mechanisms for firn compaction at different temperatures. We show that both the new temperature parameterization and the influence of impurities contribute to the increased agreement between modelled and measured δ15N evolution during the last deglaciation at sites with low temperature and low accumulation rate, such as Dome C or Vostok. However, the inclusion of impurities effects deteriorates the agreement between modelled and measured δ15N evolution in Greenland and Antarctic sites with high accumulation.

Published
2016

Catalog

Books, media, physical & digital resources
See catalog results