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.DESCRIPTIONThe 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:ByrdLocation: 80 degrees 01'S 119 degrees 31'WElevation: 1530 m aslReference 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.: CO2measurements from polar ice cores - More data from differentsites, Tellus B, 43, 91-6, doi:10.1034/j.1600-0889.1991.t01-1-00003.x, 1991.Siple DomeLocation: 81 degrees 40'S 148 degrees 49'WElevation: 621 m aslReference 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 atmosphericCO2 during the last 40,000 years from the SipleDome, Antarctica ice core, J. Geophys. Res., 109, D13305,doi:10.1029/2003JD004415, 2004.

南极冰芯为至少过去80万年的冰期-间冰期旋回（glacial/interglacial cycles）中，南极温度变化与大气CO₂浓度之间的紧密耦合关系提供了明确证据。精确的温度与CO₂变化相对时序信息，有助于深化我们对这一耦合过程所涉及的物理机制的理解。

本研究聚焦于末次冰消期（last deglaciation）——距今19000至11000年，该时期大气CO₂浓度以体积计上升了约80百万分比（parts per million by volume, ppm），南极温度升高约10℃。本研究利用新近开发的南极区域温度代用指标（proxy）——基于5个近岸冰芯与2份定年精度极高的冰芯CO₂记录构建而成——结果显示：CO₂浓度上升大概率滞后于南极区域温度上升的时长不足400年，且无法完全排除CO₂浓度小幅超前于温度升高的可能性。这一基于两份CO₂记录均得到的结论，表明温度与CO₂之间的耦合速率快于此前的估算结果——此前的研究允许存在最长可达千年尺度的滞后。本研究为AAS 757项目的研究内容之一。

### 数据集说明
本南极区域温度代用指标数据集可通过以下路径获取：ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/antarctica2011iso.txt

以下为CO₂数据的相关信息，以及其向GICC05年代标尺（GICC05 timescale）校准的依据：
1. **Byrd冰芯**
采样位置：南纬80°01′，西经119°31′
海拔高度：1530米（海平面以上，asl）
GICC05年代标尺校准参考文献：Pedro et al., Clim. Past. 8, 2012.
CO₂数据参考文献：
(1) Neftel, A., Oeschger, H., Staffelbach, T., et al. *Nature*, 331, 609-611, 1988, doi:10.1038/331609a0.
(2) Staffelbach, T., Stauffer, B., Sigg, A., et al. CO₂ measurements from polar ice cores - More data from different sites, *Tellus B*, 43, 91-96, 1991, doi:10.1034/j.1600-0889.1991.t01-1-00003.x.
2. **Siple Dome冰芯**
采样位置：南纬81°40′，西经148°49′
海拔高度：621米（海平面以上，asl）
GICC05年代标尺校准参考文献：Pedro et al., Clim. Past. 8, 2012.
CO₂数据参考文献：Ahn, J., Wahlen, M., Deck, B. L., et al. A record of atmospheric CO₂ during the last 40,000 years from the Siple Dome, Antarctica ice core, *Journal of Geophysical Research*, 109, D13305, 2004, doi:10.1029/2003JD004415.