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Ice Core Gateway |
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Law Dome Ice Core |
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Law Dome, Antarctica 66°44' S, 112°50' E, 1390m above mean annual sea level (M.A.S.L.) The CO2 and CH4 records presented here are derived from three ice cores obtained at Law Dome, East Antarctica from 1987 to 1993. The Law Dome site satisfies many of the desirable characteristics of an ideal ice core site for atmospheric CO2 reconstructions including negligible melting of the ice sheet surface, low concentrations of impurities, regular stratigraphic layering undisturbed at the surface by wind or at depth by ice flow, and high snow accumulation rate. Further details on the site, drilling, and cores are provided in Etheridge et al. (1996), Etheridge and Wookey (1989), and Morgan et al (1997). Air bubbles were extracted using the "cheese grater" technique. Ice core samples weighing 500-1500 g were prepared by selecting crack-free ice and trimming away the outer 5-20 mm. Each sample was sealed in a polyethylene bag and cooled to -80°C before being placed in the extraction flask where it was evacuated and then ground to fine chips. The released air was dried cryogenically at -100°C and collected cryogenically in electropolished stainless steel "traps", cooled to about -255°C. Further details on the extraction technique can be found in Etheridge et al. (1988 and 1992) and additional information on the ice and air sample handling are provided in Etheridge et al. (1996). References:
Etheridge, D.M., G.I. Pearman, and F. de Silva. 1988.
Etheridge, D.M., and C.W. Wookey. 1989.
Etheridge, D.M., G.I. Pearman, and P.J. Fraser. 1992.
Etheridge, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M. Barnola,
and V.I. Morgan. 1996.
Etheridge, D. M., Steele, L. P., Francey, R. J., and Langenfelds, R. L. 1998
Hamley, T.C., V.I. Morgan, R.J. Thwaites, and X.Q. Gao. 1986. Langenfelds, R.L., P.J. Fraser, R.J. Francey, L.P. Steele, L.W. Porter, and C.E. Allison, The Cape Grim Air Archive: The first seventeen years, 1978-1995, in Baseline Atmospheric Program Australia, 1994-95, edited by R.J. Francey, et al., pp. 53-70, Bur. of Meteorol. and CSIRO Div. of Atmos. Res., Melbourne, Victoria, 1996. Levchenko, V. A., Francey, R. J., Etheridge, D. M., Tuniz, C., Head, J., Morgan, V. I., and Jacobsen, G. 1996. The 14C "bomb spike" determines the age spread and age of CO2 in Law Dome firm and ice. Geophysical Research Letters, 23 (23): 3345-3348.
Morgan, V.I., C.W. Wookey, J. Li, T.D. van Ommen, W. Skinner, and M.F.
Fitzpatrick. 1997. Trudinger, C. M., Enting, I. G., Francey, R. J., Etheridge, D. M., and Rayner, P. J. 1999. Long-term variability in the global carbon cycle inferred from a high precision CO2 and d13C ice core record . Tellus, 51 (2): 233-248. Trudinger, C. M., Enting, I. G., Etheridge, D. M., Francey, R. J., Levchenko, V. A., Steele, L. P., Raynaud, D., and Arnaud, L. 1997. Modeling air movement and bubble trapping in firn. Journal of Geophysical Research, 102 (D6): 6747-6763.
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http://www.ncdc.noaa.gov/paleo/icecore/antarctica/law/law.html Downloaded Friday, 02-Aug-2013 05:15:41 EDT Last Updated Wednesday, 20-Aug-2008 11:24:22 EDT by paleo@noaa.gov Please see the Paleoclimatology Contact Page or the NCDC Contact Page if you have questions or comments. |