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Raisbeck, G. M.; Yiou, F.; Jouzel, J.; Stocker, T. F. (2007)
Publisher: European Geosciences Union (EGU)
Languages: English
Types: Article
Subjects: DOAJ:Earth and Environmental Sciences, [SDU.STU.GL] Sciences of the Universe [physics]/Earth Sciences/Glaciology, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, [SDE.MCG.CPE] Environmental Sciences/Global Changes/domain_sde.mcg.cpe, G, Geography. Anthropology. Recreation, Environmental protection, TD169-171.8, [ SDU.STU.GL ] Sciences of the Universe [physics]/Earth Sciences/Glaciology, [ SDU.STU.GC ] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, GE1-350, DOAJ:Environmental Sciences, Environmental pollution, TD172-193.5, Environmental sciences, [SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [ SDE.MCG.CPE ] Environmental Sciences/Global Changes/domain_sde.mcg.cpe
Gas is trapped in polar ice sheets at 50–120m below the surface and is therefore younger than the surrounding ice. Firn densification models are used to evaluate this ice age-gas age difference (1age) in the past. However, such models need to be validated by data, in particular for periods colder than present day on the East Antarctic plateau. Here we bring new constraints to test a firn densification model applied to the EPICA Dome C (EDC) site for the last 50 kyr, by linking the EDC ice core to the EPICA Dronning Maud Land (EDML) ice core, both in the ice phase (using volcanic horizons) and in the gas phase (using rapid methane variations). We also use the structured 10Be peak, occurring 41 kyr before present (BP) and due to the low geomagnetic field associated with the Laschamp event, to experimentally estimate the 1age during this event. Our results seem to reveal an overestimate of the 1age by the firn densification model during the last glacial period at EDC. Tests with different accumulation rates and temperature scenarios do not entirely resolve this discrepancy. Although the exact reasons for the 1age overestimate at the two EPICA sites remain unknown at this stage, we conclude that current densification model simulations have deficits under glacial climatic conditions. Whatever the cause of the 1age overestimate, our finding suggests that the phase relationship between CO2 and EDC temperature previously inferred for the start of the last deglaciation (lag of CO2 by 800±600 yr) seems to be overestimated.
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    • Beer, J., Johnsen, S. J., Bonani, G., Finkel, R. C., Langway, C. C., Oeschger, H., Stauffer, B., Suter M., and Wo¨lfli, W.: 10Be peaks as time markers in polar ice core records, in: The Last Deglaciation: Absolute and Radiocarbon Chronologies, edited by: Bard, E. and Broecker, W. S., Springer, New York, 141-143, 1992.
    • Bender, M., Sowers, T., Dickson, M.-L., Orchardo, J., Grootes, P., Mayewski, P. A., and Meese, D. A.: Climate correlations between Greenland and Antarctica during the past 100 000 years, Nature, 372, 663-666, 1994.
    • Bender, M., Malaize´, B., Orchardo, J., Sowers, T., and Jouzel, J.: High precision correlations of Greenland and Antarctic ice core records over the last 100 kyr, in: Mechanisms of Global Climate Change at Millennial Time Scales, edited by: Clark, P. U., Webb, D. J., Keigwin, L. D., American Geophysical Union, Washington, vol. 112, pp. 149-164, 1999.
    • Blunier, T. and Brook, E. J.: Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period, Science, 291, 109-112, 2001.
    • Blunier, T., Chappellaz, J., Schwander, J., Dallenbach, A., Stauffer, B., Stocker, T. F., Raynaud, D., Jouzel, J., Clausen, H. B., Hammer, C. U., and Johnsen, S. J., Asynchrony of Antarctic and Greenland climate change during the last glacial period, Nature, 394(6695), 739-743, 1998.
    • Blunier, T., Spahni, R., Barnola, J. M., Loulergue, L., and Schwander, J.: Synchronization of ice core records via atmospheric gases, Clim. Past, 3, 325-330, 2007, http://www.clim-past.net/3/325/2007/.
    • Broecker, W. S.: Paleocean circulation during the last deglaciation: a bipolar seesaw?, Paleoceanography, 13, 119-121, 1998.
    • Caillon, N., Jouzel, J., Severinghaus, J. P., Chappellaz, J., and Blunier, T.: A novel method to study the phase relationship between Antarctic and Greenland climate, Geophys. Res. Lett., 30(17), 1899-2002, 2003.
    • Castagnoli, G. C., Albrecht, A., Beer, J., Bonino, G., Shen, C., Callegari, E., Taricco, C., Dittrich-Hannen, B., Kubik, P., Suter, M., and Zhu, G. M.: Evidence for enhanced Be-10 deposition in Mediterranean sediments 35-Kyr BP, Geophys. Res. Lett., 22(6), 707-710, 1995.
    • Crowley, T. J.: North Atlantic deep water cools the southern hemisphere, Paleoceanography, 7, 489-497, 1992.
    • Dansgaard, W., Johnsen, S. J., Clausen, H. B., Dahl-Jensen, D., Gundestrup, N. S., Hammer, C. U., Hvidberg, C. S., Steffensen, J. P., Sveinbjo¨rnsdottir, A. E., Jouzel, J., and Bond, G.: Evidence for general instability of past climate from a 250-kyr ice-core record, Nature, 364, 218-220, 1993.
    • EPICA Community Members: Eight glacial cycles from an Antarctic ice core, Nature, 429, 623-628, 2004.
    • EPICA Community Members: Interhemispheric coupling of millenial scale variability during the last glacial, Nature, 444, 195- 198, 2006.
    • Grootes, P. M., Stuiver, M., White, J. W. C., Johnsen, S., and Jouzel, J.: Comparison of oxygen isotope records from the GISP2 and GRIP Greenland ice cores, Nature, 366, 552-554, 1993.
    • Huber, C., Leuenberger, M., Spahni, R., Flu¨ckiger, J., Schwander, J., Stocker, T. F., Johnsen, S., Landais, A., and Jouzel, J.: Isotope calibrated Greenland temperature record over Marine Isotope Stage 3 and its relation to CH4, Earth Planet. Sci. Lett., 243, 504-519, 2006.
    • Johnsen, S. J., Dansgaard, W., and White, J. W. C.: The origin of Arctic precipitation under present and glacial conditions, Tellus, 41B, 452-468, 1989.
    • Johnsen, S. J., Clausen, H. B., Dansgaard, W., Fuhrer, K., Gundestrup, N., Hammer, C. U., Iversen, P., Jouzel, J., Stauffer, B., and Steffensen, J. P.: Irregular glacial interstadials recorded in a new Greenland ice core, Nature, 359, 311-313, 1992.
    • Johnsen, S. J., DahlJensen, D., Gundestrup, N., Steffensen, J. P., Clausen, H. B., Miller, H., Masson-Delmotte, V., Sveinbjornsdottir, A. E., and White, J.: Oxygen isotope and palaeotemperature records from six Greenland ice-core stations: Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIP, J. Quat. Sci., 16(4), 299-307, 2001.
    • Jouzel, J., Lorius, C., Johnsen, S., and Grootes, P.: Climate instabilities - Greenland and Antarctic records, Comptes Rendus de l'Acade´mie des Sciences Se´rie II, 319(1), 65-77, 1994.
    • Jouzel, J., Masson-Delmotte, V., Cattani, O., Dreyfus, G., Falourd, S.,Hoffmann, G., Minster, B., Nouet, J., Barnola, J. M., Chappellaz, J., Fischer, H., Gallet, J. C., Johnsen, S., Leuenberger, M., Loulergue, L., Luethi, D., Oerter, H., Parrenin, F., Raisbeck, G., Raynaud, D., Schilt, A., Schwander, J., Selmo, E., Souchez, R., Spahni, R., Stauffer, B., Steffensen, J. P., Stenni, B., Stocker, T. F., Tison, J. L., Werner, M., and Wolff, E. W.: Orbital and millenial Antarctic climate variability over the last 800 000 years, Science, 317, 793-796, doi:10.1126/science.1141038, 2007.
    • Knutti, R., Flu¨ckiger, J., Stocker, T. F., and Timmermann, A.: Strong hemispheric coupling of glacial climate through freshwater discharge and ocean circulation, Nature, 430, 851-856, 2004.
    • Landais, A., Masson-Delmotte, V., Jouzel, J., Raynaud, D., Johnsen, S., Huber, C., Leuenberger, M., Schwander, J., and Minster, B.: The glacial inception as recorded in the NorthGRIP Greenland ice core: timing, structure and associated abrupt temperature changes, Clim. Dynam., 26(2-3), 273-284, 2006.
    • Loulergue, L., Parrenin, F., Blunier, T., Barnola, J.-M., Spahni, R., Scilt, A., Raisbeck, G., and Chappellaz, J.: New constraints on the gas age-ice age difference along the EPICA ice cores, 0- 50 kyr, Clim. Past, 3, 527-540, 2007, http://www.clim-past.net/3/527/2007/.
    • McHargue, L. R., Damon, P. E., and Donahue, D. J.: Enhanced cosmic-ray production of Be-10 coincident with the Mono Lake and Laschamp geomagnetic excursions, Geophys. Res. Lett., 22(5), 659-662, 1995.
    • Muscheler, R., Beer, J., Wagner, G., Laj, C., Kissel, C., Raisbeck, G. M., Yiou, F., and Kubik, P. W.: Changes in the carbon cycle during the last deglaciation as indicated by the comparison of Be10 and C-14 records, Earth Planet. Sci. Lett., 219(3-4), 325-340, 2004.
    • North GRIP Members: High-resolution climate record of the northern hemisphere back into the last interglacial period, Nature, 431, 147-151, 2004.
    • Paillard, D., Labeyrie, L. D., and Yiou, P.: Macintosh program performs time-series analysis, EOS, Transactions of the American Geophysical Union, 77, 379, 1996.
    • Parrenin, F., Barnola, J.-M., Beer, J., Blunier, T., Castellano, E., Chappellaz, J., Dreyfus, G., Fischer, H., Fujita, S., Jouzel, J., Kawamura, K., Lemieux, B., Loulergue, L., Masson-Delmotte, V., Narcisi, B., Petit, J.-R., Raisbeck, G. M., Raynaud, D., Ruth, U., Schwander, J., Severi, M., Spahni, R., Steffensen, J. P., Svensson, A., Udisti, R., Waelbroeck, C., and Wolff, E. The EDC3 agescale for the EPICA Dome C ice core, Clim. Past, 3, 485-497, 2007, http://www.clim-past.net/3/485/2007/.
    • Raisbeck, G. M., Yiou, F., Bourle`s, D., Lorius, C., Jouzel, J., and Barkov, N. I., Evidence for two intervals of enhanced Be-10 deposition in Antarctic ice during the last glacial period, Nature, 326(6110), 273-277, 1987.
    • Raisbeck, G. M., Yiou, F., Jouzel, J., Petit, J. R., Bard, E., and Barkov, N. I.: 10Be deposition at Vostok, Antarctica, during the last 50000 years and its relationship to possible cosmogenic production variations during this period, in: The Last Deglaciation: Absolute and Radiocarbon Chronologies, edited by: Bard, E. and Broecker, W. S., Springer, New York, 127-139, 1992.
    • Raisbeck, G. M., Yiou, F., Bard, E., Dollfus, D., Jouzel, J., and Petit, J. R.: Absolute dating of the last 7000 years of the Vostok ice core using 10Be, Mineralogical Magazine, 62A, 1228, 1998.
    • Raisbeck, G. M., Yiou, F., and Jouzel, J.: Cosmogenic 10Be as a high resolution correlation tool for climate records, Geochim. Cosmochim. Acta, 66, A623, 2002.
    • Robinson, C., Raisbeck, G. M., Yiou, F., Lehman, B., and Laj, C.: The relationship between Be-10 and geomagnetic field strength records in central North Atlantic sediments during the last 80 ka, Earth Planet. Sci. Lett., 136(3-4), 551-557, 1995.
    • Ruth, U., Barnola, J.-M., Beer, J., Bigler, M., Blunier, T., Castellano, E., Fischer, H., Fundel, F., Huybrechts, P., Kaufmann, P., Kipfstuhl, J., Lambrecht, A., Morganti, A., Oerter, H., Parrenin, F., Rybak, O., Severi, M., Udisti, R., Wilhelms, F., and Wolff, E.: EDML1: A chronology for the EDML ice core, Antarctica, over the last 150 000 years, Clim. Past, 3, 474-484, 2007, http://www.clim-past.net/3/474/2007/.
    • Schmittner, A., Saenko, O. A., and Weaver, A. J.: Coupling of the hemispheres in observations and simulations of glacial climate change, Quat. Sci. Rev., 22, 659-671, 2003.
    • Steig, E. J. and Alley, R. B.: Phase relationships between Antarctic and Greenland climate records, Ann. Glaciol., 35, 451-456, 2002.
    • Stenni, B., Jouzel, J., Masson-Delmotte, V., Roethlisberger, R., Castellano, E., Cattani, O., Falourd, S., Johnsen, S. J., Longinelli, A., Sachs, J. P., Selmo, E., Souchez, R., Steffensen, J. P., and Udisti, R.: A late-glacial high-resolution site and source temperature record derived from the EPICA Dome C isotope records (East Antarctica), Earth Planet. Sci. Lett., 217(1-2), 183-195, 2004.
    • Stocker, T. F.: The seesaw effect, Science, 282, 61-62, 1998.
    • Stocker, T. F. and Johnsen, S. J.: A minimum thermodynamic model for the bipolar seesaw, Paleoceanography, 18, 1087, doi:10.1029/2003PA000920, 2003.
    • Waelbroeck, C., Labeyrie, L., Michel, E., Duplessy, J. C., McManus, J. F., Lambeck, K., Balbon, E., and Labracherie, M.: Sea-level and deep water temperature changes derived from benthic foraminifera isotopic records, Quat. Sci. Rev., 21(1-3), 295- 305, 2002.
    • Wagner, G., Beer, J., Masarik, J., Muscheler, R., Kubik, P. W., Mende, W., Laj, C., Raisbeck, G. M., and Yiou, F.: Presence of the solar de Vries cycle (∼ 205 years) during the last ice age, Geophys. Res. Lett., 28(2), 303-306, 2001.
    • Yiou, F., Raisbeck, G. M., Baumgartner, S., Beer, J., Hammer, C., Johnsen, S., Jouzel, J., Kubik, P. W., Lestringuez, J., Stievenard, M., Suter, M., and Yiou, P., Beryllium 10 in the Greenland Ice Core Project ice core at Summit, Greenland, J. Geophys. Res., 102, 26 783-26 794, 1997.
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