Collaborative Research: A New Reconstruction of the Last West Antarctic Ice Sheet Deglaciation in the Ross Sea

该奖项支持一个项目，以更好地了解WAIS对气候变化的反应。利用原位地球宇宙成因核素（3He, 10Be, 14C, 26Al, 36Cl）对罗斯海西部沿海关键地区和海拔的冰川不稳定进行定年，可以改善罗斯海西部最后一次消冰期的时间。一个最先进的冰原-冰架模型将被用来确定北极地区罗斯海部分的冰川消融机制。模式结果和强迫将与观测结果进行比较，包括这里提出的新的宇宙成因数据，目的是更好地确定和理解罗斯海WAIS冰川消融的历史和原因。然而，在接地线从末次冰期最大位置撤退的历史中，存在着相当大的不确定性，而且在大约1万年前之前，对冰面下降的时间几乎一无所知。考虑到这些不确定性，我们目前无法评估关于全球冰盖最后一次消融的一个最重要的问题，即wis的罗斯海部分是否对融水脉冲1A （MWP-1A）做出了重大贡献，这是一个发生在约14500年前的海平面上升约20米的异常快速（持续约500年）事件。该项目的知识价值在于，最近对格陵兰岛和南极冰盖边缘惊人变化的观测表明，对变暖的动态响应可能在未来冰盖的质量平衡中发挥比目前海平面上升的数值预测所考虑的更大的作用。这项工作的更广泛的影响是，它与提高对南极西部冰盖对当前和未来可能的环境变化的响应的理解具有直接的社会相关性，包括全球变暖导致的冰川和冰盖融化对海平面的响应。PI将通过发表同行评议的论文和向公众发表演讲，将该项目的成果传达给各种受众。最后，该项目将支持研究生和本科生在所有阶段的实地工作，实验室工作和数据解释。

1043517/ClarkThis award supports a project to develop a better understanding of the response of the WAIS to climate change. The timing of the last deglaciation of the western Ross Sea will be improved using in situ terrestrial cosmogenic nuclides (3He, 10Be, 14C, 26Al, 36Cl) to date glacial erratics at key areas and elevations along the western Ross Sea coast. A state-of-the art ice sheet-shelf model will be used to identify mechanisms of deglaciation of the Ross Sea sector of WAIS. The model results and forcing will be compared with observations including the new cosmogenic data proposed here, with the aim of better determining and understanding the history and causes of WAIS deglaciation in the Ross Sea. There is considerable uncertainty, however, in the history of grounding line retreat from its last glacial maximum position, and virtually nothing is known about the timing of ice- surface lowering prior to ~10,000 years ago. Given these uncertainties, we are currently unable to assess one of the most important questions regarding the last deglaciation of the global ice sheets, namely as to whether the Ross Sea sector of WAIS contributed significantly to meltwater pulse 1A (MWP-1A), an extraordinarily rapid (~500-year duration) episode of ~20 m sea-level rise that occurred ~14,500 years ago. The intellectual merit of this project is that recent observations of startling changes at the margins of the Greenland and Antarctic ice sheets indicate that dynamic responses to warming may play a much greater role in the future mass balance of ice sheets than considered in current numerical projections of sea level rise. The broader impacts of this work are that it has direct societal relevance to developing an improved understanding of the response of the West Antarctic ice sheet to current and possible future environmental changes including the sea-level response to glacier and ice sheet melting due to global warming. The PI will communicate results from this project to a variety of audiences through the publication of peer-reviewed papers and by giving talks to public audiences. Finally the project will support a graduate student and undergraduate students in all phases of field-work, laboratory work and data interpretation.