Continuation of Physical Properties of the Siple Dome Deep Ice Core

0087160该奖项为继续对西南极西半球的Siple Dome深冰芯和相关浅冰芯进行古气候和冰动力学研究提供支持，以帮助了解气候和冰盖稳定性的历史。对冰芯的可见检查有助于确定所需的古气候记录的年代。由于在深层冰中很难对积雪速率进行冰流校正，因此将根据气泡大小历史和积雪致密化和颗粒生长的物理原理，开发一种新的基于物理的温度或积雪积累的古气候指标。夏季温度的古气候重建将通过观察和分析冰芯中的稀有融化层来完成。将继续研究气候变化在空间和时间上的分布，重点是大约1500年的气候振荡与淡水通量变化的“噪声”相结合的可能性，迫使气候系统的运行模式发生快速、大范围、近同步、广泛的变化。对冰芯中冰粒的目视和c轴研究将有助于检测流动扰动，例如在GISP2冰芯中看到的那些扰动，如果它们存在于Siple Dome内核中的话。这项研究的结果应该有助于更好地了解南极洲的快速气候变化，并通过比较，更好地了解世界各地的其他记录。这项研究还应有助于了解西南极冰盖的流动和稳定性。

0087160 AlleyThis award provides support to continue paleoclimate and ice dynamical studies of the Siple Dome deep ice core and associated shallow cores from West Antarctica, to help understand the history of climate and ice-sheet stability. Visible examination of the ice cores contributes to the required dating of the paleoclimatic records. Because ice-flow corrections for accumulation rates are difficult in deep ice, a new physically based paleoclimatic indicator of temperature or snow accumulation will be developed, based on bubble-size histories and on the physics of firn densification and grain growth. The paleoclimatic reconstruction of summer temperatures will be accomplished through observation and analysis of the rare melt layers in the ice core. Studies of the distribution of climate change in space and time will be continued, focusing on the possibility that a climate oscillation of ~ 1500 years has combined with "noise" from changes in freshwater fluxes to force rapid, large, nearly synchronous, widespread to global changes in the mode of operation of the climate system. Visual and c-axis studies of ice grains in the core will help detect flow disturbances, such as the ones which were seen in the GISP2 ice cores, if they are present in the Siple Dome core. The results of this study should lead to a better understanding of rapid climate change in Antarctica and, through comparison, to other records worldwide. The study should also contribute to knowledge of the flow and stability of the West Antarctic ice sheet.