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3. Polar climatic sequence over the first Dansgaard-Oeschger event (DO 25) of the last glacial period

Author

Capron, E., Chappellaz, J., Landais, A., Schilt, A., Buiron, D., Dahl-Jensen, D., Fischer, H., Johnsen, S. J., Leuenberger, M., Masson-Delmotte, V., Oerter, H., Stocker, T. F., Laboratoire des Sciences du Climat et de l'Environnement (LSCE), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
[SDU]Sciences of the Universe [physics], 0473 BIOGEOSCIENCES / Paleoclimatology and paleoceanography
Abstract

International audience; The Dansgaard-Oeschger (DO) event 25 initiates the millennial-scale climatic variability of the Northern Hemisphere during the last glacial period. This first rapid event is identified in the NorthGRIP ice core (Greenland - 75.10 °N, 42.32 °W, elevation 2917 m. a. s.l., modern accumulation rate 17.5 cm w.e.yr-1) δ18Oice record as a sharp 2.3‰ increase (half of a “classical” DO interstadial magnitude) occurring at ~112 ka (EDC3 age scale). While DO event 25 remained so far poorly studied, the other DO events of the glacial period have revealed (1) large amplitudes of temperature change over Greenland (8-16°C) (2) synchronous rapid increases of methane (CH4) and Greenland temperature (3) seesaw behaviour with Antarctic temperatures increasing slowly 300-3400 yrs before the rapid Greenland abrupt temperature changes. Thus, investigating in detail the first DO event is of primary importance to understand the onset of the climatic variability of the glacial period. To provide a complete description of DO event 25, we present new results from the EPICA Dronning Maud Land (EDML, Antarctica - 75.00 °S, 0.07 °E, 2882 m a.s.l., 6.4 cm w.e.yr1) and the NorthGRIP ice cores. We use high-resolution measurements of the isotopic composition of air nitrogen (δ15N) as a temperature proxy in the gas phase to infer the amplitude of temperature changes over Greenland. These data moreover allow determining precisely the phasing between temperature and CH4 concentration in the air trapped in the ice. Finally, the combination of new high-resolution CH4 measurements on the NorthGRIP ice core and δ18Oatm records over this first rapid event permits to propose the first accurate common timescale between EDML and NorthGRIP over DO event 25 and to discuss the bipolar seesaw pattern at the onset of the last glacial period.

Published
2023

4. Deep circulation changes during the last glacial inception: Rapid Southern Ocean response to insolation, preceding North Atlantic deep water changes

Author

Govin, A., Michel, E., Labeyrie, L., Landais, A., Capron, E., Waelbroeck, C., Janssen, E., Laboratoire des Sciences du Climat et de l'Environnement (LSCE), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
[SDU]Sciences of the Universe [physics]
Abstract

International audience; Deep water circulation changes during the initiation of the last glacial period, and its role in the global cooling are still poorly known. We compare high-resolution oxygen and carbon isotope composition records of planktic and benthic foraminifera from Southern Ocean and North Atlantic cores for the 130-100 ka period in order to establish the deep circulation changes in both area, in relationship to surface hydrology and global climatology. A common chronostratigraphic framework has been defined between marine cores from the northern and southern latitudes over that period, assuming that temperature changes occurred simultaneaously in the surface ocean and over the nearby ice cap. Thus North Atlantic and Southern Ocean sea surface temperature records have been correlated to isotopic ice core records of NGRIP and EPICA Dome C respectively. Sea surface temperatures decrease at about the same time (122ka) in both the northern Atlantic and the Southern Ocean. About 3ka after, an expansion of a poorly ventilated Antarctic Bottom water is observed in the Southern Ocean while no change occurs in the North Atlantic deep circulation. Height thousand years more are needed to observed a shoaling of the North Atlantic deep waters (NADW). We propose that the Southern Ocean respond rapidly to orbital variations: a spatial and/or temporal increase in sea-ice extent might follow the decrease in obliquity. This positive retroaction through albedo drive a decrease in sea surface temperature and a northward movement of the water fronts. A greater seasonal extent of sea-ice will lead to a less ventilated Antarctic Bottom Water (AABW). On the opposite a decrease of sea surface temperatures in the North Atlantic is not enough to produce a change in the North Atlantic deep water formation. Only when Ice sheet have build up sufficiently, can they induce a shoaling of NADW through a change in atmospheric circulation pattern and a decrease in sea surface salinity. The influence of AABW reach the North Atlantic simultaneously to the shoaling of NADW.

Published
2023

5. Sequence of events from the onset to the demise of the Last Interglacial: Evaluating strengths and limitations of chronologies used in climatic archives

Author

Govin, A., Capron, E., Tzedakis, P.C., Verheyden, S., Ghaleb, B., Hillaire-Marcel, C., St-Onge, G., Stoner, J.S., Bassinot, F., Bazin, L., Blunier, T., Combourieu-Nebout, N., El Ouahabi, A., Genty, D., Gersonde, R., Jimenez-Amat, P., Landais, A., Martrat, B., Masson-Delmotte, V., Parrenin, F., Seidenkrantz, M.-S., Veres, D., Waelbroeck, C., and Zahn, R.

Published
2015
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6. Climate sequences over the last 9 glacial Terminations from air and water isotopes on the EPICA Dome C ice core

Author

Landais, A., Grisart, A., Bouchet, M., Parrenin, F., Prié, F., Harris-Stuart, R., Capron, E., Jacob, R., Minster, B., Stenni, B., and Fourré, E.

Abstract

The drill of the EPICA Dome C ice core has been completed almost 20 years ago. This ice core already provided many reference records for climate and atmospheric greenhouse gase concentrations over the last 800,000 years, hence covering 9 glacial interglacial transitions or glacial terminations. These records combined to records from other archives have already shown the diversity in term of amplitudes and durations of the last 9 glacial terminations occurring in different orbital contexts. Still, the relatively low resolution of the current records hampered a good chronology of the oldest deglaciations as well as the study of the rapid climatic variability at centennial to multi-millennial scale superimposed to the longer term orbital climatic variability.Here, we will present high resolution measurements of water and air isotopes on the EPICA Dome C ice core over the last 800,000 years with a particular focus on glacial terminations. These new data enable to improve the chronology of the EPICA Dome C ice core hence improving the link between orbital forcing and climatic variability, especially for the period between 800,000 years and 200,000 years before present. In addition, our relatively high resolution records (50-300 years) of water and air isotopes enable us to describe on the same chronology the occurrence of millennial scale variability in the low to mid latitudes over the terminations 2, 3, 4 and 5 (occurring between 440,000 and 120,000 years before present) while local climate at the drilling site of EPICA Dome C has a much smoother evolution. &nbsp, The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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7. Biogeochemical Cycles and Aerosols Over the Last Million Years

Author

Ramstein, G, Landais, A, Bouttes, N, Sepulchre, P, Govin, A, Bopp, L, Albani, S, Vadsaria, T, Capron, E, Bouttes N., Bopp L., Albani S., Ramstein G., Vadsaria T., Capron E., Ramstein, G, Landais, A, Bouttes, N, Sepulchre, P, Govin, A, Bopp, L, Albani, S, Vadsaria, T, Capron, E, Bouttes N., Bopp L., Albani S., Ramstein G., Vadsaria T., and Capron E.

Abstract

The biogeochemical cycles encompass the exchange of chemical elements between reservoirs such as the atmosphere, ocean, land and lithosphere. Those exchanges involve biological, geological and chemical processes, hence the term “biogeochemical cycles”.

Published
2021

9. towards a better understanding of the latest warm climate: the PmiP last interglacial Working group

Author

Otto-Bliesner, B.L., Scussolini, P., Capron, E., Kageyama, Masa, Zhao, A., Otto-Bliesner, Bette, 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), Modélisation du climat (CLIM), 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), 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, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment
Abstract

International audience; The Last Interglacial is one of the five priorities within the CMIP6-PMIP4 initiative. Its 127 kyr BP model experiment allows for an assessment of climate model fidelity during a period of Northern Hemisphere warmth, sea-level high stand, and regional hydroclimate changes.

Published
2021
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13. Eemian interglacial reconstructed from a Greenland folded ice core

Author

Dahl-Jensen, D., Albert, M. R., Aldahan, A., Azuma, N., Balslev-Clausen, D., Baumgartner, M., Berggren, A.-M., Bigler, M., Binder, T., Blunier, T., Bourgeois, J. C., Brook, E. J., Buchardt, S. L., Buizert, C., Capron, E., Chappellaz, J., Chung, J., Clausen, H. B., Cvijanovic, I., Davies, S. M., Ditlevsen, P., Eicher, O., Fischer, H., Fisher, D. A., Fleet, L. G., Gfeller, G., Gkinis, V., Gogineni, S., Goto-Azuma, K., Grinsted, A., Gudlaugsdottir, H., Guillevic, M., Hansen, S. B., Hansson, M., Hirabayashi, M., Hong, S., Hur, S. D., Huybrechts, P., Hvidberg, C. S., Iizuka, Y., Jenk, T., Johnsen, S. J., Jones, T. R., Jouzel, J., Karlsson, N. B., Kawamura, K., Keegan, K., Kettner, E., Kipfstuhl, S., Kjær, H. A., Koutnik, M., Kuramoto, T., Köhler, P., Laepple, T., Landais, A., Langen, P. L., Larsen, L. B., Leuenberger, D., Leuenberger, M., Leuschen, C., Li, J., Lipenkov, V., Martinerie, P., Maselli, O. J., Masson-Delmotte, V., McConnell, J. R., Miller, H., Mini, O., Miyamoto, A., Montagnat-Rentier, M., Mulvaney, R., Muscheler, R., Orsi, A. J., Paden, J., Panton, C., Pattyn, F., Petit, J.-R., Pol, K., Popp, T., Possnert, G., Prié, F., Prokopiou, M., Quiquet, A., Rasmussen, S. O., Raynaud, D., Ren, J., Reutenauer, C., Ritz, C., Röckmann, T., Rosen, J. L., Rubino, M., Rybak, O., Samyn, D., Sapart, C. J., Schilt, A., Schmidt, A. M. Z., Schwander, J., Schüpbach, S., Seierstad, I., Severinghaus, J. P., Sheldon, S., Simonsen, S. B., Sjolte, J., Solgaard, A. M., Sowers, T., Sperlich, P., Steen-Larsen, H. C., Steffen, K., Steffensen, J. P., Steinhage, D., Stocker, T. F., Stowasser, C., Sturevik, A. S., Sturges, W. T., Sveinbjörnsdottir, A., Svensson, A., Tison, J.-L., Uetake, J., Vallelonga, P., van de Wal, R. S. W., van der Wel, G., Vaughn, B. H., Vinther, B., Waddington, E., Wegner, A., Weikusat, I., White, J. W. C., Wilhelms, F., Winstrup, M., Witrant, E., Wolff, E. W., Xiao, C., and Zheng, J.

Published
2013
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14. PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data

Author

Khider, D, Emile-Geay, J, McKay, NP, Gil, Y, Garijo, D, Ratnakar, V, Alonso-Garcia, M, Bertrand, S, Bothe, O, Brewer, P, Bunn, A, Chevalier, M, Comas-Bru, L, Csank, A, Dassié, E, DeLong, K, Felis, T, Francus, P, Frappier, A, Gray, W, Goring, S, Jonkers, L, Kahle, M, Kaufman, D, Kehrwald, NM, Martrat, B, McGregor, H, Richey, J, Schmittner, A, Scroxton, N, Sutherland, E, Thirumalai, K, Allen, K, Arnaud, F, Axford, Y, Barrows, T, Bazin, L, Pilaar Birch, SE, Bradley, E, Bregy, J, Capron, E, Cartapanis, O, Chiang, HW, Cobb, KM, Debret, M, Dommain, R, Du, J, Dyez, K, Emerick, S, Erb, MP, Falster, G, Finsinger, W, Fortier, D, Gauthier, N, George, S, Grimm, E, Hertzberg, J, Hibbert, F, Hillman, A, Hobbs, W, Huber, M, Hughes, ALC, Jaccard, S, Ruan, J, Kienast, M, Konecky, B, Le Roux, G, Lyubchich, V, Novello, VF, Olaka, L, Partin, JW, Pearce, C, Phipps, SJ, Pignol, C, Piotrowska, N, Poli, MS, Prokopenko, A, Schwanck, F, Stepanek, C, Swann, GEA, Telford, R, Thomas, E, Thomas, Z, Truebe, S, von Gunten, L, Waite, A, Weitzel, N, Wilhelm, B, Williams, J, Williams, JJ, Winstrup, M, Zhao, N, Zhou, Y, Khider, D, Emile-Geay, J, McKay, NP, Gil, Y, Garijo, D, Ratnakar, V, Alonso-Garcia, M, Bertrand, S, Bothe, O, Brewer, P, Bunn, A, Chevalier, M, Comas-Bru, L, Csank, A, Dassié, E, DeLong, K, Felis, T, Francus, P, Frappier, A, Gray, W, Goring, S, Jonkers, L, Kahle, M, Kaufman, D, Kehrwald, NM, Martrat, B, McGregor, H, Richey, J, Schmittner, A, Scroxton, N, Sutherland, E, Thirumalai, K, Allen, K, Arnaud, F, Axford, Y, Barrows, T, Bazin, L, Pilaar Birch, SE, Bradley, E, Bregy, J, Capron, E, Cartapanis, O, Chiang, HW, Cobb, KM, Debret, M, Dommain, R, Du, J, Dyez, K, Emerick, S, Erb, MP, Falster, G, Finsinger, W, Fortier, D, Gauthier, N, George, S, Grimm, E, Hertzberg, J, Hibbert, F, Hillman, A, Hobbs, W, Huber, M, Hughes, ALC, Jaccard, S, Ruan, J, Kienast, M, Konecky, B, Le Roux, G, Lyubchich, V, Novello, VF, Olaka, L, Partin, JW, Pearce, C, Phipps, SJ, Pignol, C, Piotrowska, N, Poli, MS, Prokopenko, A, Schwanck, F, Stepanek, C, Swann, GEA, Telford, R, Thomas, E, Thomas, Z, Truebe, S, von Gunten, L, Waite, A, Weitzel, N, Wilhelm, B, Williams, J, Williams, JJ, Winstrup, M, Zhao, N, and Zhou, Y

Abstract

The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches.

Published
2019

15. PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data

Author

Khider, D., Emile-Geay, J., McKay, N. P., Gil, Y., Garijo, D., Ratnakar, V, Alonso-Garcia, M., Bertrand, S., Bothe, O., Brewer, P., Bunn, A., Chevalier, M., Comas-Bru, L., Csank, A., Dassie, E., DeLong, K., Felis, T., Francus, P., Frappier, A., Gray, W., Goring, S., Jonkers, L., Kahle, M., Kaufman, D., Kehrwald, N. M., Martrat, B., McGregor, H., Richey, J., Schmittner, A., Scroxton, N., Sutherland, E., Thirumalai, K., Allen, K., Arnaud, F., Axford, Y., Barrows, T., Bazin, L., Birch, S. E. Pilaar, Bradley, E., Bregy, J., Capron, E., Cartapanis, O., Chiang, H-W, Cobb, K. M., Debret, M., Dommain, R., Du, J., Dyez, K., Emerick, S., Erb, M. P., Falster, G., Finsinger, W., Fortier, D., Gauthier, Nicolas, George, S., Grimm, E., Hertzberg, J., Hibbert, F., Hillman, A., Hobbs, W., Huber, M., Hughes, A. L. C., Jaccard, S., Ruan, J., Kienast, M., Konecky, B., Le Roux, G., Lyubchich, V, Novello, V. F., Olaka, L., Partin, J. W., Pearce, C., Phipps, S. J., Pignol, C., Piotrowska, N., Poli, M-S, Prokopenko, A., Schwanck, F., Stepanek, C., Swann, G. E. A., Telford, R., Thomas, E., Thomas, Z., Truebe, S., von Gunten, L., Waite, A., Weitzel, N., Wilhelm, B., Williams, J., Winstrup, M., Zhao, N., Zhou, Y., Khider, D., Emile-Geay, J., McKay, N. P., Gil, Y., Garijo, D., Ratnakar, V, Alonso-Garcia, M., Bertrand, S., Bothe, O., Brewer, P., Bunn, A., Chevalier, M., Comas-Bru, L., Csank, A., Dassie, E., DeLong, K., Felis, T., Francus, P., Frappier, A., Gray, W., Goring, S., Jonkers, L., Kahle, M., Kaufman, D., Kehrwald, N. M., Martrat, B., McGregor, H., Richey, J., Schmittner, A., Scroxton, N., Sutherland, E., Thirumalai, K., Allen, K., Arnaud, F., Axford, Y., Barrows, T., Bazin, L., Birch, S. E. Pilaar, Bradley, E., Bregy, J., Capron, E., Cartapanis, O., Chiang, H-W, Cobb, K. M., Debret, M., Dommain, R., Du, J., Dyez, K., Emerick, S., Erb, M. P., Falster, G., Finsinger, W., Fortier, D., Gauthier, Nicolas, George, S., Grimm, E., Hertzberg, J., Hibbert, F., Hillman, A., Hobbs, W., Huber, M., Hughes, A. L. C., Jaccard, S., Ruan, J., Kienast, M., Konecky, B., Le Roux, G., Lyubchich, V, Novello, V. F., Olaka, L., Partin, J. W., Pearce, C., Phipps, S. J., Pignol, C., Piotrowska, N., Poli, M-S, Prokopenko, A., Schwanck, F., Stepanek, C., Swann, G. E. A., Telford, R., Thomas, E., Thomas, Z., Truebe, S., von Gunten, L., Waite, A., Weitzel, N., Wilhelm, B., Williams, J., Winstrup, M., Zhao, N., and Zhou, Y.

Abstract

The progress of science is tied to the standardization of measurements, instruments, and data. This is especially true in the Big Data age, where analyzing large data volumes critically hinges on the data being standardized. Accordingly, the lack of community-sanctioned data standards in paleoclimatology has largely precluded the benefits of Big Data advances in the field. Building upon recent efforts to standardize the format and terminology of paleoclimate data, this article describes the Paleoclimate Community reporTing Standard (PaCTS), a crowdsourced reporting standard for such data. PaCTS captures which information should be included when reporting paleoclimate data, with the goal of maximizing the reuse value of paleoclimate data sets, particularly for synthesis work and comparison to climate model simulations. Initiated by the LinkedEarth project, the process to elicit a reporting standard involved an international workshop in 2016, various forms of digital community engagement over the next few years, and grassroots working groups. Participants in this process identified important properties across paleoclimate archives, in addition to the reporting of uncertainties and chronologies; they also identified archive-specific properties and distinguished reporting standards for new versus legacy data sets. This work shows that at least 135 respondents overwhelmingly support a drastic increase in the amount of metadata accompanying paleoclimate data sets. Since such goals are at odds with present practices, we discuss a transparent path toward implementing or revising these recommendations in the near future, using both bottom-up and top-down approaches.

Published
2019

16. Simulating the Last Interglacial Greenland stable water isotope peak: The role of Arctic sea ice changes

Author

Malmierca-Vallet, I, Sime, LC, Tindall, JC, Capron, E, Valdes, PJ, Vinther, BM, and Holloway, MD

Abstract

Last Interglacial (LIG), stable water isotope values (δ¹⁸O) measured in Greenland deep ice cores are at least 2.5‰ higher compared to the present day. Previous isotopic climate simulations of the LIG do not capture the observed Greenland δ¹⁸O increases. Here, we use the isotope-enabled HadCM3 (UK Met Office coupled atmosphere-ocean general circulation model) to investigate whether a retreat of Northern Hemisphere sea ice was responsible for this model-data disagreement. Our results highlight the potential significance of sea ice changes on the LIG Greenland isotopic maximum. Sea ice loss in combination with increased sea surface temperatures, over the Arctic, affect δ¹⁸O: water vapour enriched in heavy isotopes and a shorter distillation path may both increase δ¹⁸O values over Greenland. We show, for the first time, that simulations of the response to Arctic sea ice reduction are capable of producing the likely magnitude of LIG δ¹⁸O increases at NEEM, NGRIP, GIPS2 and Camp Century ice core sites. However, we may underestimate δ¹⁸O changes at the Renland, DYE3 and GRIP ice core locations. Accounting for possible ice sheet changes is likely to be required to produce a better fit to the LIG ice core δ¹⁸O values.

Published
2018

17. Ice core evidence for decoupling between midlatitude atmospheric water cycle and Greenland temperature during the last deglaciation

Author

Landais, A, Capron, E, Toucanne, S, Rhodes, R, Popp, T, Vinther, B, Minster, B, Prié, F, Rhodes, Rachael [0000-0001-7511-1969], and Apollo - University of Cambridge Repository

Subjects
13 Climate Action, 37 Earth Sciences, 3705 Geology, 3709 Physical Geography and Environmental Geoscience
Abstract

The last deglaciation represents the most recent example of natural global warming associated with large-scale climate changes. In addition to the long-term global temperature increase, the last deglaciation onset is punctuated by a sequence of abrupt changes in the Northern Hemisphere. Such interplay between orbital- and millennial-scale variability is widely documented in paleoclimatic records but the underlying mechanisms are not fully understood. Limitations arise from the difficulty in constraining the sequence of events between external forcing, high- and low- latitude climate, and environmental changes. Greenland ice cores provide sub-decadal-scale records across the last deglaciation and contain fingerprints of climate variations occurring in different regions of the Northern Hemisphere. Here, we combine new ice d-excess and 17O-excess records, tracing changes in the midlatitudes, with ice δ18O records of polar climate. Within Heinrich Stadial 1, we demonstrate a decoupling between climatic conditions in Greenland and those of the lower latitudes. While Greenland temperature remains mostly stable from 17.5 to 14.7 ka, significant change in the midlatitudes of the northern Atlantic takes place at ∼16.2 ka, associated with warmer and wetter conditions of Greenland moisture sources. We show that this climate modification is coincident with abrupt changes in atmospheric CO2 and CH4 concentrations recorded in an Antarctic ice core. Our coherent ice core chronological framework and comparison with other paleoclimate records suggests a mechanism involving two-step freshwater fluxes in the North Atlantic associated with a southward shift of the Intertropical Convergence Zone.

Published
2018

18. PaCTS 1.0: A Crowdsourced Reporting Standard for Paleoclimate Data

Author

Khider, D., primary, Emile‐Geay, J., additional, McKay, N. P., additional, Gil, Y., additional, Garijo, D., additional, Ratnakar, V., additional, Alonso‐Garcia, M., additional, Bertrand, S., additional, Bothe, O., additional, Brewer, P., additional, Bunn, A., additional, Chevalier, M., additional, Comas‐Bru, L., additional, Csank, A., additional, Dassié, E., additional, DeLong, K., additional, Felis, T., additional, Francus, P., additional, Frappier, A., additional, Gray, W., additional, Goring, S., additional, Jonkers, L., additional, Kahle, M., additional, Kaufman, D., additional, Kehrwald, N. M., additional, Martrat, B., additional, McGregor, H., additional, Richey, J., additional, Schmittner, A., additional, Scroxton, N., additional, Sutherland, E., additional, Thirumalai, K., additional, Allen, K., additional, Arnaud, F., additional, Axford, Y., additional, Barrows, T., additional, Bazin, L., additional, Pilaar Birch, S. E., additional, Bradley, E., additional, Bregy, J., additional, Capron, E., additional, Cartapanis, O., additional, Chiang, H.‐W., additional, Cobb, K. M., additional, Debret, M., additional, Dommain, R., additional, Du, J., additional, Dyez, K., additional, Emerick, S., additional, Erb, M. P., additional, Falster, G., additional, Finsinger, W., additional, Fortier, D., additional, Gauthier, Nicolas, additional, George, S., additional, Grimm, E., additional, Hertzberg, J., additional, Hibbert, F., additional, Hillman, A., additional, Hobbs, W., additional, Huber, M., additional, Hughes, A. L. C., additional, Jaccard, S., additional, Ruan, J., additional, Kienast, M., additional, Konecky, B., additional, Le Roux, G., additional, Lyubchich, V., additional, Novello, V. F., additional, Olaka, L., additional, Partin, J. W., additional, Pearce, C., additional, Phipps, S. J., additional, Pignol, C., additional, Piotrowska, N., additional, Poli, M.‐S., additional, Prokopenko, A., additional, Schwanck, F., additional, Stepanek, C., additional, Swann, G. E. A., additional, Telford, R., additional, Thomas, E., additional, Thomas, Z., additional, Truebe, S., additional, Gunten, L., additional, Waite, A., additional, Weitzel, N., additional, Wilhelm, B., additional, Williams, J., additional, Williams, J. J., additional, Winstrup, M., additional, Zhao, N., additional, and Zhou, Y., additional

Published
2019
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19. Evidence of Isotopic Fractionation During Vapor Exchange Between the Atmosphere and the Snow Surface in Greenland

Author

Madsen, M. V., primary, Steen‐Larsen, H. C., additional, Hörhold, M., additional, Box, J., additional, Berben, S. M. P., additional, Capron, E., additional, Faber, A.‐K., additional, Hubbard, A., additional, Jensen, M. F., additional, Jones, T. R., additional, Kipfstuhl, S., additional, Koldtoft, I., additional, Pillar, H. R., additional, Vaughn, B. H., additional, Vladimirova, D., additional, and Dahl‐Jensen, D., additional

Published
2019
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20. Palaeoclimate constraints on the impact of 2 °c anthropogenic warming and beyond

Author

Fischer, H, Meissner, KJ, Mix, AC, Abram, NJ, Austermann, J, Brovkin, V, Capron, E, Colombaroli, D, Daniau, AL, Dyez, KA, Felis, T, Finkelstein, SA, Jaccard, SL, McClymont, EL, Rovere, A, Sutter, J, Wolff, EW, Affolter, S, Bakker, P, Ballesteros-Cánovas, JA, Barbante, C, Caley, T, Carlson, AE, Churakova, O, Cortese, G, Cumming, BF, Davis, BAS, De Vernal, A, Emile-Geay, J, Fritz, SC, Gierz, P, Gottschalk, J, Holloway, MD, Joos, F, Kucera, M, Loutre, MF, Lunt, DJ, Marcisz, K, Marlon, JR, Martinez, P, Masson-Delmotte, V, Nehrbass-Ahles, C, Otto-Bliesner, BL, Raible, CC, Risebrobakken, B, Sánchez Goñi, MF, Arrigo, JS, Sarnthein, M, Sjolte, J, Stocker, TF, Velasquez Alvárez, PA, Tinner, W, Valdes, PJ, Vogel, H, Wanner, H, Yan, Q, Yu, Z, Ziegler, M, Zhou, L, Fischer, H, Meissner, KJ, Mix, AC, Abram, NJ, Austermann, J, Brovkin, V, Capron, E, Colombaroli, D, Daniau, AL, Dyez, KA, Felis, T, Finkelstein, SA, Jaccard, SL, McClymont, EL, Rovere, A, Sutter, J, Wolff, EW, Affolter, S, Bakker, P, Ballesteros-Cánovas, JA, Barbante, C, Caley, T, Carlson, AE, Churakova, O, Cortese, G, Cumming, BF, Davis, BAS, De Vernal, A, Emile-Geay, J, Fritz, SC, Gierz, P, Gottschalk, J, Holloway, MD, Joos, F, Kucera, M, Loutre, MF, Lunt, DJ, Marcisz, K, Marlon, JR, Martinez, P, Masson-Delmotte, V, Nehrbass-Ahles, C, Otto-Bliesner, BL, Raible, CC, Risebrobakken, B, Sánchez Goñi, MF, Arrigo, JS, Sarnthein, M, Sjolte, J, Stocker, TF, Velasquez Alvárez, PA, Tinner, W, Valdes, PJ, Vogel, H, Wanner, H, Yan, Q, Yu, Z, Ziegler, M, and Zhou, L

Abstract

Over the past 3.5 million years, there have been several intervals when climate conditions were warmer than during the pre-industrial Holocene. Although past intervals of warming were forced differently than future anthropogenic change, such periods can provide insights into potential future climate impacts and ecosystem feedbacks, especially over centennial-to-millennial timescales that are often not covered by climate model simulations. Our observation-based synthesis of the understanding of past intervals with temperatures within the range of projected future warming suggests that there is a low risk of runaway greenhouse gas feedbacks for global warming of no more than 2 °C. However, substantial regional environmental impacts can occur. A global average warming of 1-2 °C with strong polar amplification has, in the past, been accompanied by significant shifts in climate zones and the spatial distribution of land and ocean ecosystems. Sustained warming at this level has also led to substantial reductions of the Greenland and Antarctic ice sheets, with sea-level increases of at least several metres on millennial timescales. Comparison of palaeo observations with climate model results suggests that, due to the lack of certain feedback processes, model-based climate projections may underestimate long-term warming in response to future radiative forcing by as much as a factor of two, and thus may also underestimate centennial-to-millennial-scale sea-level rise.

Published
2018

22. Spatial gradients of temperature, accumulation and δ18O-ice in Greenland over a series of Dansgaard–Oeschger events

Author

Guillevic, M., Bazin, L., Landais, A., Kindler, Philippe, Orsi, A., Masson-Delmotte, V., Blunier, T., Buchardt, S. L., Capron, E., Leuenberger, Markus, Martinerie, P., Prié, F., and Vinther, B. M.

Subjects
lcsh:GE1-350, lcsh:Environmental pollution, 530 Physics, lcsh:Environmental protection, lcsh:TD172-193.5, lcsh:TD169-171.8, 550 Earth sciences & geology, lcsh:Environmental sciences
Abstract

Air and water stable isotope measurements from four Greenland deep ice cores (GRIP, GISP2, NGRIP and NEEM) are investigated over a series of Dansgaard–Oeschger events (DO 8, 9 and 10), which are representative of glacial millennial scale variability. Combined with firn modeling, air isotope data allow us to quantify abrupt temperature increases for each drill site (1σ = 0.6 °C for NEEM, GRIP and GISP2, 1.5 °C for NGRIP). Our data show that the magnitude of stadial–interstadial temperature increase is up to 2 °C larger in central and North Greenland than in northwest Greenland: i.e., for DO 8, a magnitude of +8.8 °C is inferred, which is significantly smaller than the +11.1 °C inferred at GISP2. The same spatial pattern is seen for accumulation increases. This pattern is coherent with climate simulations in response to reduced sea-ice extent in the Nordic seas. The temporal water isotope (δ18O)–temperature relationship varies between 0.3 and 0.6 (±0.08) ‰ °C−1 and is systematically larger at NEEM, possibly due to limited changes in precipitation seasonality compared to GISP2, GRIP or NGRIP. The gas age−ice age difference of warming events represented in water and air isotopes can only be modeled when assuming a 26% (NGRIP) to 40% (GRIP) lower accumulation than that derived from a Dansgaard–Johnsen ice flow model.

Published
2013
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23. Glacial–interglacial dynamics of Antarctic firn columns: comparison between simulations and ice core air-δ15N measurements

Author

Capron E., Landais A., Buiron D., Cauquoin A., Chappellaz J., Debret M., Jouzel J., Leuenberger M., Martinerie P., Masson-Delmotte V., Mulvaney R., Parrenin F., and Pri{é} F.

Subjects
lcsh:GE1-350, lcsh:Environmental pollution, lcsh:Environmental protection, lcsh:TD172-193.5, lcsh:TD169-171.8, lcsh:Environmental sciences
Abstract

Correct estimation of the firn lock-in depth is essential for correctly linking gas and ice chronologies in ice core studies. Here, two approaches to constrain the firn depth evolution in Antarctica are presented over the last deglaciation: outputs of a firn densification model, and measurements of δ15N of N2 in air trapped in ice core, assuming that δ15N is only affected by gravitational fractionation in the firn column. Since the firn densification process is largely governed by surface temperature and accumulation rate, we have investigated four ice cores drilled in coastal (Berkner Island, BI, and James Ross Island, JRI) and semi-coastal (TALDICE and EPICA Dronning Maud Land, EDML) Antarctic regions. Combined with available ice core air-δ15N measurements from the EPICA Dome C (EDC) site, the studied regions encompass a large range of surface accumulation rates and temperature conditions. Our δ15N profiles reveal a heterogeneous response of the firn structure to glacial–interglacial climatic changes. While firn densification simulations correctly predict TALDICE δ15N variations, they systematically fail to capture the large millennial-scale δ15N variations measured at BI and the δ15N glacial levels measured at JRI and EDML – a mismatch previously reported for central East Antarctic ice cores. New constraints of the EDML gas–ice depth offset during the Laschamp event (~41 ka) and the last deglaciation do not favour the hypothesis of a large convective zone within the firn as the explanation of the glacial firn model–δ15N data mismatch for this site. While we could not conduct an in-depth study of the influence of impurities in snow for firnification from the existing datasets, our detailed comparison between the δ15N profiles and firn model simulations under different temperature and accumulation rate scenarios suggests that the role of accumulation rate may have been underestimated in the current description of firnification models.

Published
2013

24. The PMIP4 contribution to CMIP6 - Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

Author

Otto-Bliesner, B, Braconnot, P, Harrison, S, Lunt, D, Abe-Ouchi, A, Albani, S, Bartlein, P, Capron, E, Carlson, A, Dutton, A, Fischer, H, Goelzer, H, Govin, A, Haywood, A, Joos, F, Legrande, A, Lipscomb, W, Lohmann, G, Mahowald, N, Nehrbass-Ahles, C, Pausata, F, Peterschmitt, J, Phipps, S, Renssen, H, Zhang, Q, Otto-Bliesner, Bette L., Braconnot, Pascale, Harrison, Sandy P., Lunt, Daniel J., Abe-Ouchi, Ayako, Albani, Samuel, Bartlein, Patrick J., Capron, Emilie, Carlson, Anders E., Dutton, Andrea, Fischer, Hubertus, Goelzer, Heiko, Govin, Aline, Haywood, Alan, Joos, Fortunat, Legrande, Allegra N., Lipscomb, William H., Lohmann, Gerrit, Mahowald, Natalie, Nehrbass-Ahles, Christoph, Pausata, Francesco S. R., Peterschmitt, Jean-Yves, Phipps, Steven J., Renssen, Hans, Zhang, Qiong, Otto-Bliesner, B, Braconnot, P, Harrison, S, Lunt, D, Abe-Ouchi, A, Albani, S, Bartlein, P, Capron, E, Carlson, A, Dutton, A, Fischer, H, Goelzer, H, Govin, A, Haywood, A, Joos, F, Legrande, A, Lipscomb, W, Lohmann, G, Mahowald, N, Nehrbass-Ahles, C, Pausata, F, Peterschmitt, J, Phipps, S, Renssen, H, Zhang, Q, Otto-Bliesner, Bette L., Braconnot, Pascale, Harrison, Sandy P., Lunt, Daniel J., Abe-Ouchi, Ayako, Albani, Samuel, Bartlein, Patrick J., Capron, Emilie, Carlson, Anders E., Dutton, Andrea, Fischer, Hubertus, Goelzer, Heiko, Govin, Aline, Haywood, Alan, Joos, Fortunat, Legrande, Allegra N., Lipscomb, William H., Lohmann, Gerrit, Mahowald, Natalie, Nehrbass-Ahles, Christoph, Pausata, Francesco S. R., Peterschmitt, Jean-Yves, Phipps, Steven J., Renssen, Hans, and Zhang, Qiong

Abstract

Two interglacial epochs are included in the suite of Paleoclimate Modeling Intercomparison Project (PMIP4) simulations in the Coupled Model Intercomparison Project (CMIP6). The experimental protocols for simulations of the mid-Holocene (midHolocene, 6000 years before present) and the Last Interglacial (lig127k, 127 000 years before present) are described here. These equilibrium simulations are designed to examine the impact of changes in orbital forcing at times when atmospheric greenhouse gas levels were similar to those of the preindustrial period and the continental configurations were almost identical to modern ones. These simulations test our understanding of the interplay between radiative forcing and atmospheric circulation, and the connections among large-scale and regional climate changes giving rise to phenomena such as land-sea contrast and high-latitude amplification in temperature changes, and responses of the monsoons, as compared to today. They also provide an opportunity, through carefully designed additional sensitivity experiments, to quantify the strength of atmosphere, ocean, cryosphere, and land-surface feedbacks. Sensitivity experiments are proposed to investigate the role of freshwater forcing in triggering abrupt climate changes within interglacial epochs. These feedback experiments naturally lead to a focus on climate evolution during interglacial periods, which will be examined through transient experiments. Analyses of the sensitivity simulations will also focus on interactions between extratropical and tropical circulation, and the relationship between changes in mean climate state and climate variability on annual to multi-decadal timescales. The comparative abundance of paleoenvironmental data and of quantitative climate reconstructions for the Holocene and Last Interglacial make these two epochs ideal candidates for systematic evaluation of model performance, and such comparisons will shed new light on the importance of external feedba

Published
2017

25. The PMIP4 contribution to CMIP6 – Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations

Author

Otto-Bliesner, B. L., Braconnot, P., Harrison, S. P., Lunt, D. J., Abe-Ouchi, A., Albani, S., Bartlein, P. J., Capron, E., Carlson, A. E., Dutton, A., Fischer, H., Goelzer, H., Govin, A., Haywood, A., Joos, F., LeGrande, A. N., Lipscomb, W. H., Lohmann, Gerrit, Mahowald, N., Nehrbass-Ahles, C., Pausata, F. S.-R., Peterschmitt, J.-Y., Phipps, S. J., Renssen, H., Otto-Bliesner, B. L., Braconnot, P., Harrison, S. P., Lunt, D. J., Abe-Ouchi, A., Albani, S., Bartlein, P. J., Capron, E., Carlson, A. E., Dutton, A., Fischer, H., Goelzer, H., Govin, A., Haywood, A., Joos, F., LeGrande, A. N., Lipscomb, W. H., Lohmann, Gerrit, Mahowald, N., Nehrbass-Ahles, C., Pausata, F. S.-R., Peterschmitt, J.-Y., Phipps, S. J., and Renssen, H.

Abstract

Two interglacial epochs are included in the suite of Paleoclimate Modeling Intercomparison Project (PMIP4) simulations in the Coupled Model Intercomparison Project (CMIP6). The experimental protocols for simulations of the mid-Holocene (midHolocene, 6000 years before present) and the Last Interglacial (lig127k, 127 000 years before present) are described here. These equilibrium simulations are designed to examine the impact of changes in orbital forcing at times when atmospheric greenhouse gas levels were similar to those of the preindustrial period and the continental configurations were almost identical to modern ones. These simulations test our understanding of the interplay between radiative forcing and atmospheric circulation, and the connections among large-scale and regional climate changes giving rise to phenomena such as land–sea contrast and highlatitude amplification in temperature changes, and responses of the monsoons, as compared to today. They also provide an opportunity, through carefully designed additional sensitivity experiments, to quantify the strength of atmosphere, ocean, cryosphere, and land-surface feedbacks. Sensitivity experiments are proposed to investigate the role of freshwater forcing in triggering abrupt climate changes within interglacial epochs. These feedback experiments naturally lead to a focus on climate evolution during interglacial periods, which will be examined through transient experiments. Analyses of the sensitivity simulations will also focus on interactions between extratropical and tropical circulation, and the relationship between changes in mean climate state and climate variability on annual to multi-decadal timescales. The comparative abundance of paleoenvironmental data and of quantitative climate reconstructions for the Holocene and Last Interglacial make these two epochs ideal candidates for systematic evaluation of model performance, and such comparisons will shed new light on the importance of external feedbac

Published
2017

26. Towards orbital dating of the EPICA Dome C ice core using δO2/N2

Author

Landais, A., Dreyfus, G., Capron, E., Pol, K., Loutre, M. F., Raynaud, D., Lipenkov, V. Y., Arnaud, L., Masson-Delmotte, V., Paillard, D., Jouzel, J., and Leuenberger, M.

Subjects
lcsh:GE1-350, lcsh:Environmental pollution, lcsh:Environmental protection, lcsh:TD172-193.5, lcsh:TD169-171.8, lcsh:Environmental sciences
Abstract

Based on a composite of several measurement series performed on ice samples stored at −25 °C or −50 °C, we present and discuss the first δO2/N2 record of trapped air from the EPICA Dome C (EDC) ice core covering the period between 300 and 800 ka (thousands of years before present). The samples stored at −25 °C show clear gas loss affecting the precision and mean level of the δO2/N2 record. Two different gas loss corrections are proposed to account for this effect, without altering the spectral properties of the original datasets. Although processes at play remain to be fully understood, previous studies have proposed a link between surface insolation, ice grain properties at close-off, and δO2/N2 in air bubbles, from which orbitally tuned chronologies of the Vostok and Dome Fuji ice core records have been derived over the last four climatic cycles. Here, we show that limitations caused by data quality and resolution, data filtering, and uncertainties in the orbital tuning target limit the precision of this tuning method for EDC. Moreover, our extended record includes two periods of low eccentricity. During these intervals (around 400 ka and 750 ka), the matching between δO2/N2 and the different insolation curves is ambiguous because some local insolation maxima cannot be identified in the δO2/N2 record (and vice versa). Recognizing these limitations, we restrict the use of our δO2/N2 record to show that the EDC3 age scale is generally correct within its published uncertainty (6 kyr) over the 300–800 ka period.

Published
2012

28. Interglacials of the last 800,000 years

Author

Berger, A., Crucifix, M., Hodell, D. A., Mangili, C., Mcmanus, J. F., Otto-bliesner, B., Pol, K., Raynaud, D., Skinner, L. C., Tzedakis, P. C., Wolff, E. W., Yin, Q. Z., Abe-ouchi, A., Barbante, C., Brovkin, V., Cacho, I., Capron, E., Ferretti, P., Ganopolski, A., Grimalt, J. O., Hoenisch, B., Kawamura, K., Landais, A., Margari, V., Martrat, B., Masson-delmotte, V., Mokeddem, Zohra, Parrenin, F., Prokopenko, A. A., Rashid, H., Schulz, M., Riveiros, N. Vazquez, Berger, A., Crucifix, M., Hodell, D. A., Mangili, C., Mcmanus, J. F., Otto-bliesner, B., Pol, K., Raynaud, D., Skinner, L. C., Tzedakis, P. C., Wolff, E. W., Yin, Q. Z., Abe-ouchi, A., Barbante, C., Brovkin, V., Cacho, I., Capron, E., Ferretti, P., Ganopolski, A., Grimalt, J. O., Hoenisch, B., Kawamura, K., Landais, A., Margari, V., Martrat, B., Masson-delmotte, V., Mokeddem, Zohra, Parrenin, F., Prokopenko, A. A., Rashid, H., Schulz, M., and Riveiros, N. Vazquez

Abstract

Interglacials, including the present (Holocene) period, are warm, low land ice extent (high sea level), end-members of glacial cycles. Based on a sea level definition, we identify eleven interglacials in the last 800,000years, a result that is robust to alternative definitions. Data compilations suggest that despite spatial heterogeneity, Marine Isotope Stages (MIS) 5e (last interglacial) and 11c (similar to 400ka ago) were globally strong (warm), while MIS 13a (similar to 500ka ago) was cool at many locations. A step change in strength of interglacials at 450ka is apparent only in atmospheric CO2 and in Antarctic and deep ocean temperature. The onset of an interglacial (glacial termination) seems to require a reducing precession parameter (increasing Northern Hemisphere summer insolation), but this condition alone is insufficient. Terminations involve rapid, nonlinear, reactions of ice volume, CO2, and temperature to external astronomical forcing. The precise timing of events may be modulated by millennial-scale climate change that can lead to a contrasting timing of maximum interglacial intensity in each hemisphere. A variety of temporal trends is observed, such that maxima in the main records are observed either early or late in different interglacials. The end of an interglacial (glacial inception) is a slower process involving a global sequence of changes. Interglacials have been typically 10-30ka long. The combination of minimal reduction in northern summer insolation over the next few orbital cycles, owing to low eccentricity, and high atmospheric greenhouse gas concentrations implies that the next glacial inception is many tens of millennia in the future.

Published
2016
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29. Bipolar and chronological consequences of methane measurements in the Talos Dome ice core

Author

Buiron D., Chappellaz J., Schilt A., Parrenin F., Lemieux B., Capron E., Masson Delmotte V., Landais A., Frezzotti M., STENNI, BARBARA, European Geosciences Union, Buiron, D., Chappellaz, J., Schilt, A., Parrenin, F., Lemieux, B., Capron, E., Masson Delmotte, V., Landais, A., Stenni, Barbara, and Frezzotti, M.

Subjects
bipolar seesaw, Ice cores, methane synchronization, Antarctica, Greenland, TALDICE, dating, Ice core
Published
2009

30. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

Author

Allin, S. J., Laube, J. C., Witrant, E., Kaiser, J., McKenna, E., Dennis, P., Mulvaney, R., Capron, E., Martinerie, P., Roeckmann, Thomas, Blunier, T., Schwander, J., Fraser, P. J., Langenfelds, R. L., Sturges, W. T., Sub Atmospheric physics and chemistry, Marine and Atmospheric Research, School of Environmental Sciences [Norwich], University of East Anglia [Norwich] (UEA), SLR (GIPSA-SLR), Département Automatique (GIPSA-DA), Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Stendhal - Grenoble 3-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), 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), Institute for Marine and Atmospheric Research [Utrecht] (IMAU), Utrecht University [Utrecht], Centre for Ice and Climate [Copenhagen], Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), University of Bern, Centre for Australian Weather and Climate Research (CAWCR), GIPSA - Systèmes linéaires et robustesse (GIPSA-SLR), Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Stendhal - Grenoble 3-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-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 Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Sub Atmospheric physics and chemistry, and Marine and Atmospheric Research

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, 530 Physics, ICE-CORE, OZONE-DEPLETING SUBSTANCES, Atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, lcsh:Chemistry, Troposphere, Isotope fractionation, Ice core, SOUTH-POLE, CHEMISTRY, [INFO.INFO-AU]Computer Science [cs]/Automatic Control Engineering, Ozone layer, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Isotope, Chemistry, POLAR FIRN, Firn, Isotopes of chlorine, NITROUS-OXIDE, GREENLAND, lcsh:QC1-999, TRANSPORT, Trace gas, SEASONAL CYCLES, lcsh:QD1-999, 13. Climate action, lcsh:Physics, ATMOSPHERIC N2O
Abstract

The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2, Laube et al., 2010a), similar to effects seen in nitrous oxide (N2O). Using air archives to obtain a long-term record of chlorine isotope ratios in CFCs could help to identify and quantify their sources and sinks. We analyse the three most abundant CFCs and show that CFC-11 (CCl3F) and CFC-113 (CClF2CCl2F) exhibit significant stratospheric chlorine isotope fractionation, in common with CFC-12. The apparent isotope fractionation (ϵapp) for mid- and high-latitude stratospheric samples are respectively −2.4 (0.5) and −2.3 (0.4) ‰ for CFC-11, −12.2 (1.6) and −6.8 (0.8) ‰ for CFC-12 and −3.5 (1.5) and −3.3 (1.2) ‰ for CFC-113, where the number in parentheses is the numerical value of the standard uncertainty expressed in per mil. Assuming a constant isotope composition of emissions, we calculate the expected trends in the tropospheric isotope signature of these gases based on their stratospheric 37Cl enrichment and stratosphere–troposphere exchange. We compare these projections to the long-term δ (37Cl) trends of all three CFCs, measured on background tropospheric samples from the Cape Grim air archive (Tasmania, 1978–2010) and tropospheric firn air samples from Greenland (North Greenland Eemian Ice Drilling (NEEM) site) and Antarctica (Fletcher Promontory site). From 1970 to the present day, projected trends agree with tropospheric measurements, suggesting that within analytical uncertainties, a constant average emission isotope delta (δ) is a compatible scenario. The measurement uncertainty is too high to determine whether the average emission isotope δ has been affected by changes in CFC manufacturing processes or not. Our study increases the suite of trace gases amenable to direct isotope ratio measurements in small air volumes (approximately 200 mL), using a single-detector gas chromatography–mass spectrometry (GC–MS) system.

Published
2014
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31. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

Author

Allin, S. J., Laube, J. C., Witrant, E., Kaiser, J., McKenna, E., Dennis, P., Mulvaney, R., Capron, E., Martinerie, P., Roeckmann, Thomas, Blunier, T., Schwander, J., Fraser, P. J., Langenfelds, R. L., Sturges, W. T., Allin, S. J., Laube, J. C., Witrant, E., Kaiser, J., McKenna, E., Dennis, P., Mulvaney, R., Capron, E., Martinerie, P., Roeckmann, Thomas, Blunier, T., Schwander, J., Fraser, P. J., Langenfelds, R. L., and Sturges, W. T.

Abstract

The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O-3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2, Laube et al., 2010a), similar to effects seen in nitrous oxide (N2O). Using air archives to obtain a long-term record of chlorine isotope ratios in CFCs could help to identify and quantify their sources and sinks. We analyse the three most abundant CFCs and show that CFC-11 (CCl3F) and CFC-113 (CClF2CCl2F) exhibit significant stratospheric chlorine isotope fractionation, in common with CFC-12. The apparent isotope fractionation (epsilon(app)) for mid- and high-latitude stratospheric samples are respectively -2.4 (0.5) and -2.3 (0.4) parts per thousand for CFC-11, -12.2 (1.6) and -6.8 (0.8) parts per thousand for CFC-12 and -3.5 (1.5) and -3.3 (1.2) parts per thousand for CFC-113, where the number in parentheses is the numerical value of the standard uncertainty expressed in per mil. Assuming a constant isotope composition of emissions, we calculate the expected trends in the tropospheric isotope signature of these gases based on their stratospheric Cl-37 enrichment and stratosphere-troposphere exchange. We compare these projections to the long-term delta (Cl-37) trends of all three CFCs, measured on background tropospheric samples from the Cape Grim air archive (Tasmania, 1978-2010) and tropospheric firn air samples from Greenland (North Greenland Eemian Ice Drilling (NEEM) site) and Antarctica (Fletcher Promontory site). From 1970 to the present day, projected trends agree with tropospheric measurements, suggesting that within analytical uncertainties, a constant average emission isotope delta (delta) is a compatible scenario. The measurement uncertainty is too high to determine whether the average emission isotope delta has been affected by changes in CFC manufacturing processes or no

Published
2015

32. IceChrono1: a probabilistic model to compute a common and optimal chronology for several ice cores

Author

Parrenin, F., Bazin, L., Capron, E., Landais, A., Lemieux-Dudon, B., Masson-Delmotte, V., Parrenin, F., Bazin, L., Capron, E., Landais, A., Lemieux-Dudon, B., and Masson-Delmotte, V.

Abstract

Polar ice cores provide exceptional archives of past environmental conditions. The dating of ice cores and the estimation of the age-scale uncertainty are essential to interpret the climate and environmental records that they contain. It is, however, a complex problem which involves different methods. Here, we present IceChrono1, a new probabilistic model integrating various sources of chronological information to produce a common and optimized chronology for several ice cores, as well as its uncertainty. IceChrono1 is based on the inversion of three quantities: the surface accumulation rate, the lock-in depth (LID) of air bubbles and the thinning function. The chronological information integrated into the model are models of the sedimentation process (accumulation of snow, densification of snow into ice and air trapping, ice flow), ice- and air-dated horizons, ice and air depth intervals with known durations, Δdepth observations (depth shift between synchronous events recorded in the ice and in the air) and finally air and ice stratigraphic links in between ice cores. The optimization is formulated as a least squares problem, implying that all densities of probabilities are assumed to be Gaussian. It is numerically solved using the Levenberg–Marquardt algorithm and a numerical evaluation of the model's Jacobian. IceChrono follows an approach similar to that of the Datice model which was recently used to produce the AICC2012 (Antarctic ice core chronology) for four Antarctic ice cores and one Greenland ice core. IceChrono1 provides improvements and simplifications with respect to Datice from the mathematical, numerical and programming point of views. The capabilities of IceChrono1 are demonstrated on a case study similar to the AICC2012 dating experiment. We find results similar to those of Datice, within a few centuries, which is a confirmation of both IceChrono1 and Datice codes. We also test new functionalities with respect to the original version of Datice: obse

Published
2015

33. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

Author

Sub Atmospheric physics and chemistry, Marine and Atmospheric Research, Allin, S. J., Laube, J. C., Witrant, E., Kaiser, J., McKenna, E., Dennis, P., Mulvaney, R., Capron, E., Martinerie, P., Roeckmann, Thomas, Blunier, T., Schwander, J., Fraser, P. J., Langenfelds, R. L., Sturges, W. T., Sub Atmospheric physics and chemistry, Marine and Atmospheric Research, Allin, S. J., Laube, J. C., Witrant, E., Kaiser, J., McKenna, E., Dennis, P., Mulvaney, R., Capron, E., Martinerie, P., Roeckmann, Thomas, Blunier, T., Schwander, J., Fraser, P. J., Langenfelds, R. L., and Sturges, W. T.

Published
2015

34. Past4Future: European interdisciplinary research on past warm climate periods.

Author

Dahl-Jensen, D., Capron, E., Vallelonga, P., Roche, D.M., Dahl-Jensen, D., Capron, E., Vallelonga, P., and Roche, D.M.

Abstract

Past4Future was a Collaborative Project in the European Union’s Framework Programme 7; it aimed to generate knowledge about climate changes during the last two interglacials. The approach was to combine proxy data with climate model simulations to investigate the existence and the cause of past abrupt climate changes during warm climate periods in order to evaluate the risk of abrupt changes in the future. Featuring contributions from a number of Past4Future participants, this Science Highlights section of PAGES Magazine showcases the cross-disciplinary nature of this very successful project that ended in December 2014.

Published
2015

36. Eemian interglacial reconstructed from a Greenland folded ice-core

Author

NEEM community members. Dahl-Jensen, D, Albert, M R, Aldahan, A, Azuma, N, Balslev-Clausen, D, Baumgartner, M, Berggren, A-M, Bigler, M, Binder, T, Blunier, T, Bourgeois, J C, Brook, E J, Buchardt, S L, Buizert, C, Capron, E, Chappellaz, J, Chung, J, Clausen, H B, Cvijanovic, I, Davies, S M, Ditlevsen, P, Eicher, O, Fischer, H, Fisher, D A, Fleet, L G, Gfeller, G, Gkinis, V, Gogineni, S, Goto-Azuma, K, Grinsted, A, Gudlaugsdottir, H, Guillevic, M, Hansen, S B, Hansson, M, Hirabayashi, M, Hong, S, Hur, S, NEEM community members. Dahl-Jensen, D, Albert, M R, Aldahan, A, Azuma, N, Balslev-Clausen, Baumgartner, M, Berggren, A-M, Bigler, Binder, T, Blunier, Bourgeois, J C, Brook, E J, Buchardt, S L, Buizert, C, Capron, E, Chappellaz, J, Chung, Clausen, H B, Cvijanovic, I, Davies, S M, Ditlevsen, P, Eicher, O, Fischer, H, Fisher, D A, Fleet, L G, Gfeller, G, Gkinis, V, Gogineni, S, Goto-Azuma, K, Grinsted, Gudlaugsdottir, Guillevic, Hansen, S B, Hansson, Hirabayashi, Hong, and Hur

Published
2013

37. Glacial-interglacial dynamics of Antarctic firn columns: comparison between simulations and ice core air- δ 15N measurements

Author

Capron, E., Landais, A., Buiron, D., Cauquoin, A., Chappellaz, J., Debret, M., Jouzel, J., Leuenberger, M., Martinerie, P., Masson-Delmotte, V., Mulvaney, R., Parrenin, F., Prié, F., 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 ), British Antarctic Survey ( BAS ), Natural Environment Research Council ( NERC ), Laboratoire de glaciologie et géophysique de l'environnement ( LGGE ), Observatoire des Sciences de l'Univers de Grenoble ( OSUG ), 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 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 ), Morphodynamique Continentale et Côtière ( M2C ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Rouen Normandie ( UNIROUEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), Climate and Environmental Physics [Bern], University of Bern, Laboratoire Chrono-environnement ( LCE ), Université Bourgogne Franche-Comté ( UBFC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), 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), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), Laboratoire Chrono-environnement (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), 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), 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), Centre National de la Recherche Scientifique (CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Universität Bern [Bern]-Universität Bern [Bern], Laboratoire Chrono-environnement - UFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), 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 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), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-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 Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC)

Subjects
530 Physics, glacial-interglacial cycle, [SDE.MCG]Environmental Sciences/Global Changes, firn, Queen Maud Land, East Antarctica, surface temperature, snow accumulation, West Antarctica, [ SDE.MCG ] Environmental Sciences/Global Changes, nitrogen isotope, [SDU]Sciences of the Universe [physics], Dome Concordia, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, Antarctica, James Ross Island, last deglaciation, numerical model, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ice core, [ SDU ] Sciences of the Universe [physics]
Abstract

International audience; Correct estimation of the firn lock-in depth is essential for correctly linking gas and ice chronologies in ice core studies. Here, two approaches to constrain the firn depth evolution in Antarctica are presented over the last deglaciation : outputs of a firn densification model, and measurements of 15N of N2 in air trapped in ice core, assuming that 15N is only affected by gravitational fractionation in the firn column. Since the firn densification process is largely governed by surface temperature and accumulation rate, we have investigated four ice cores drilled in coastal (Berkner Island, BI, and James Ross Island, JRI) and semi-coastal (TALDICE and EPICA Dronning Maud Land, EDML) Antarctic regions. Combined with available ice core air- 15N measurements from the EPICA Dome C (EDC) site, the studied regions encompass a large range of surface accumulation rates and temperature conditions. Our 15N profiles reveal a heterogeneous response of the firn structure to glacial-interglacial climatic changes. While firn densification simulations correctly predict TALDICE 15N variations, they systematically fail to capture the large millennial-scale 15N variations measured at BI and the 15N glacial levels measured at JRI and EDML - a mismatch previously reported for central East Antarctic ice cores. New constraints of the EDML gas-ice depth offset during the Laschamp event ( 41 ka) and the last deglaciation do not favour the hypothesis of a large convective zone within the firn as the explanation of the glacial firn model- 15N data mismatch for this site. While we could not conduct an indepth study of the influence of impurities in snow for firnification from the existing datasets, our detailed comparison between the 15N profiles and firn model simulations under different temperature and accumulation rate scenarios suggests that the role of accumulation rate may have been underestimated in the current description of firnification models.

Published
2013
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38. A global picture of the first abrupt climatic event occurring during the last glacial inception

Author

Capron, E., Landais, A., Chappellaz, J., Buiron, D., Fischer, H., Johnsen, S. J., Jouzel, J., Leuenberger, M., Masson-Delmotte, V., Stocker, T. F., 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), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Oeschger Centre for Climate Change Research (OCCR), University of Bern, IT University of Copenhagen, 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), and IT University of Copenhagen (ITU)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Northern Hemispheres, Glacial climate, Last glacial, Climatic variability, 530 Physics, Climatic events, glacial-interglacial cycle, Greenland, Last interglacial, interglacial, environmental change, Glacial geology, climate variation, Earth sciences, Last glacial inception, Geophysics, glacial environment, interstadial, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Climate variability, amplitude
Abstract

The orbital-scale transition from the last interglacial to glacial climate corresponds to the progressive organization of global millennial-scale climate variability. Here, we investigate the structure and the global fingerprint of the first warming event occurring during the last glacial inception, the Greenland InterStadial 25 (GIS 25). Using centennial to decadal-resolution measurements of d18O and dD in the ice together with d15N, d18O2 and CH4 in the trapped air, we show that GIS 25 does not coincide with large environmental changes at lower latitudes. Such an equivocal fingerprint questions whether GIS 25 is simply a smaller amplitude version of later rapid events or whether it reflects a more regional northern hemisphere origin for the initiation of the millennialscale climatic variability. After this ambiguous first rapid event, the onset of the global millennial-scale variability - characteristic of the last glacial period- occurs as a short (300 years) event ending GIS 25. Citation: Capron, E., A. Landais, J. Chappellaz, D. Buiron, H. Fischer, S. J. Johnsen, J. Jouzel, M. Leuenberger, V. Masson-Delmotte, and T. F. Stocker (2012), A global picture of the first abrupt climatic event occurring during the last glacial inception.

Published
2012
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39. Towards orbital dating of the EPICA Dome C ice core using deltaO2/N2

Author

Landais, A., Dreyfus, G., Capron, E., Pol, K., Loutre, M.F., Raynaud, D., Lipenkov, V.Y., Arnaud, L., Masson-Delmotte, V., Paillard, D., Jouzel, J., and Leuenberger, M.

Abstract

Based on a composite of several measurement series performed on ice samples stored at −25 °C or −50 °C, we present and discuss the first δO2/N2 record of trapped air from the EPICA Dome C (EDC) ice core covering the period between 300 and 800 ka (thousands of years before present). The samples stored at −25 °C show clear gas loss affecting the precision and mean level of the δO2/N2 record. Two different gas loss corrections are proposed to account for this effect, without altering the spectral properties of the original datasets. Although processes at play remain to be fully understood, previous studies have proposed a link between surface insolation, ice grain properties at close-off, and δO2/N2 in air bubbles, from which orbitally tuned chronologies of the Vostok and Dome Fuji ice core records have been derived over the last four climatic cycles. Here, we show that limitations caused by data quality and resolution, data filtering, and uncertainties in the orbital tuning target limit the precision of this tuning method for EDC. Moreover, our extended record includes two periods of low eccentricity. During these intervals (around 400 ka and 750 ka), the matching between δO2/N2 and the different insolation curves is ambiguous because some local insolation maxima cannot be identified in the δO2/N2 record (and vice versa). Recognizing these limitations, we restrict the use of our δO2/N2 record to show that the EDC3 age scale is generally correct within its published uncertainty (6 kyr) over the 300–800 ka period.

Published
2012
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41. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

Author

Allin, S. J., primary, Laube, J. C., additional, Witrant, E., additional, Kaiser, J., additional, McKenna, E., additional, Dennis, P., additional, Mulvaney, R., additional, Capron, E., additional, Martinerie, P., additional, Röckmann, T., additional, Blunier, T., additional, Schwander, J., additional, Fraser, P. J., additional, Langenfelds, R. L., additional, and Sturges, W. T., additional

Published
2015
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45. NGRIP CH4 concentration from 120 to 10 kyr before present and its relation to a δ15N temperature reconstruction from the same ice core

Author

Baumgartner, M., Kindler, P., Eicher, O., Floch, G., Schilt, A., Schwander, J., Spahni, R., Capron, E., Chappellaz, J., Leuenberger, M., Fischer, H., Stocker, T. F., Baumgartner, M., Kindler, P., Eicher, O., Floch, G., Schilt, A., Schwander, J., Spahni, R., Capron, E., Chappellaz, J., Leuenberger, M., Fischer, H., and Stocker, T. F.

Abstract

During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so called Dansgaard-Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from Termination 1 back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core. We find the sensitivity to oscillate between 5 parts per billion by volume (ppbv) per °C and 18 ppbv °C−1 with the approximate frequency of the precessional cycle. A remarkably high sensitivity of 25.5 ppbv °C−1 is reached during Termination 1. Analysis of the timing of the fast methane and temperature increases reveals significant lags of the methane increases relative to NGRIP temperature for the DO events 5, 9, 10, 11, 13, 15, 19, and 20. We further show that the relative interpolar concentration difference of methane is 4.6 ± 0.7% between the DO events 18 and 19 and 4.4 ± 0.8% between the DO events 19 to 20, which is in the same order as in the stadials before and after DO event 2 around the Last Glacial Maximum.

Published
2014

46. Factors controlling the last interglacial climate as simulated by LOVECLIM1.3

Author

Loutre, M. F., Fichefet, T., Goosse, H., Huybrechts, P., Goelzer, H., Capron, E., Loutre, M. F., Fichefet, T., Goosse, H., Huybrechts, P., Goelzer, H., and Capron, E.

Abstract

The last interglacial (LIG), also identified to the Eemian in Europe, began at approximately 130 kyr BP and ended at about 115 kyr BP (before present). More and more proxy-based reconstructions of the LIG climate are becoming more available even though they remain sparse. The major climate forcings during the LIG are rather well known and therefore models can be tested against paleoclimatic data sets and then used to better understand the climate of the LIG. However, models are displaying a large range of responses, being sometimes contradictory between them or with the reconstructed data. Here we would like to investigate causes of these differences. We focus on a single climate model, LOVECLIM, and we perform transient simulations over the LIG, starting at 135 kyr BP and run until 115 kyr BP. With these simulations, we test the role of the surface boundary conditions (the time-evolution of the Northern Hemisphere (NH) ice sheets) on the simulated LIG climate and the importance of the parameter sets (internal to the model, such as the albedos of the ocean and sea ice), which affect the sensitivity of the model. The magnitude of the simulated climate variations through the LIG remains too low compared to reconstructions for climate variables such as surface air temperature. Moreover, in the North Atlantic, the large increase in summer sea surface temperature towards the peak of the interglacial occurs too early (at similar to 128 kyr BP) compared to the reconstructions. This feature as well as the climate simulated during the optimum of the LIG, between 131 and 121 kyr BP, does not depend on changes in surface boundary conditions and parameter sets. The additional freshwater flux (FWF) from the melting NH ice sheets is responsible for a temporary abrupt weakening of the North Atlantic meridional overturning circulation, which causes a strong global cooling in annual mean. However, the changes in the configuration (extent and albedo) of the NH ice sheets during the L

Published
2014
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47. Factors controlling the last interglacial climate as simulated by LOVECLIM1.3

Author

UCL - SST/ELI/ELIC - Earth & Climate, Loutre, Marie-France, Fichefet, Thierry, Goosse, Hugues, Huybrechts, P., Goelzer, H., Capron, E., UCL - SST/ELI/ELIC - Earth & Climate, Loutre, Marie-France, Fichefet, Thierry, Goosse, Hugues, Huybrechts, P., Goelzer, H., and Capron, E.

Abstract

The last interglacial (LIG), also identified to the Eemian in Europe, began at approximately 130 kyr BP and ended at about 115 kyr BP (before present). More and more proxy-based reconstructions of the LIG climate are becoming more available even though they remain sparse. The major climate forcings during the LIG are rather well known and therefore models can be tested against paleoclimatic data sets and then used to better understand the climate of the LIG. However, models are displaying a large range of responses,being sometimes contradictory between them or with the reconstructed data. Here we would like to investigate causes of these differences. We focus on a single climate model, LOVECLIM, and we perform transient simulations over the LIG, starting at 135 kyr BP and run until 115 kyr BP. With these simulations, we test the role of the surface boundary conditions (the time-evolution of the Northern Hemisphere (NH) ice sheets) on the simulated LIG climate and the importance of the parameter sets (internal to the model, such as the albedos of the ocean and sea ice), which affect the sensitivity of the model. The magnitude of the simulated climate variations through the LIG remains too low compared to reconstructions for climate variables such as surface air temperature. Moreover, in the North Atlantic, the large increase in summer sea surface temperature towards the peak of the interglacial occurs too early (at 128 kyr BP) compared to the reconstructions. This feature as well as the climate simulated during the optimum of the LIG, between 131 and 121 kyr BP, does not depend on changes in surface boundary conditions and parameter sets. The additional freshwater flux (FWF) from the melting NH ice sheets is responsible for a temporary abrupt weakening of the North Atlantic meridional overturning circulation,which causes a strong global cooling in annual mean. However, the changes in the configuration (extent and albedo)of the NH ice sheets during the LIG only slight

Published
2014

48. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

Author

Allin, S. J., primary, Laube, J. C., additional, Witrant, E., additional, Kaiser, J., additional, McKenna, E., additional, Dennis, P., additional, Mulvaney, R., additional, Capron, E., additional, Martinerie, P., additional, Röckmann, T., additional, Blunier, T., additional, Schwander, J., additional, Fraser, P. J., additional, Langenfelds, R. L., additional, and Sturges, W. T., additional

Published
2014
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49. Supplementary material to "Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air"

Author

Allin, S. J., primary, Laube, J. C., additional, Witrant, E., additional, Kaiser, J., additional, McKenna, E., additional, Dennis, P., additional, Mulvaney, R., additional, Capron, E., additional, Martinerie, P., additional, Röckmann, T., additional, Blunier, T., additional, Schwander, J., additional, Fraser, P. J., additional, Langenfelds, R. L., additional, and Sturges, W. T., additional

Published
2014
Full Text
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