Byrd and Siple Dome CO2 data on the GICC05 timescale (9--21 ka)

Antarctic ice cores provide clear evidence of a close coupling between variations in Antarctic temperature and the atmospheric concentration of CO2 during the glacial/interglacial cycles of at least the past 800-thousand years. Precise information on the relative timing of the temperature and CO2 changes can assist in refining our understanding of the physical processes involved in this coupling. Here, we focus on the last deglaciation, 19 000 to 11 000 yr before present, during which CO2 concentrations increased by ~80 parts per million by volume and Antarctic temperature increased by ~10 degrees C.

Utilising a recently developed proxy for regional Antarctic temperature, derived from five near-coastal ice cores and two ice core CO2 records with high dating precision, we show that the increase in CO2 likely lagged the increase in regional Antarctic temperature by less than 400 yr and that even a short lead of CO2 over temperature cannot be excluded. This result, consistent for both CO2 records, implies a faster coupling between temperature and CO2 than previous estimates, which had permitted up to millennial-scale lags.

This work was done as part of project AAS 757.

DESCRIPTION
The regional Antarctic temperature proxy data series is avaliable elsewhere: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/antarctica2011iso.txt The locations and original references for the CO2 data and transfers to the GICC05 timescale are as follows:

Byrd
Location: 80 degrees 01'S 119 degrees 31'W
Elevation: 1530 m asl
Reference for transfer to GICC05 timescale: Pedro et al., Clim. Past. 8, 2012.
Reference for CO2 data: (1) Neftel, A., Oeschger, H., Staffelbach, T., and
Nature, 331, 609-11, doi:10.1038/331609a0, 1988.
(2) Staffelbach, T., Stauffer, B., Sigg, A., and Oeschger, H.: CO2
measurements from polar ice cores - More data from different
sites, Tellus B, 43, 91-6, doi:10.1034/j.1600-0889.1991.t01-1-
00003.x, 1991.

Siple Dome
Location: 81 degrees 40'S 148 degrees 49'W
Elevation: 621 m asl
Reference for transfer to GICC05 timescale: Pedro et al., Clim. Past. 8, 2012.
Reference for CO2 data:
Ahn, J., Wahlen, M., Deck, B. L., Brook, E. J., Mayewski,
P. A., Taylor, K. C., and White, J. W. C.: A record of atmospheric
CO2 during the last 40,000 years from the Siple
Dome, Antarctica ice core, J. Geophys. Res., 109, D13305,
doi:10.1029/2003JD004415, 2004.