Validating contrasting terrestrial climate-sensitive Pliocene deposits through high resolution modeling of paleo-environments in the Transantarctic Mountains

Intellectual Merit: Neogene sediment records recovered by ANDRILL suggest multiple events of open water conditions and elevated sea surface temperatures at times when terrestrial data from the McMurdo Dry Valleys indicate hyper arid, cold, desert conditions. Interpretation of the ANDRILL data suggests the West Antarctic Ice Sheet is highly sensitive to changes in Pliocene sea surface temperatures and this conclusion has been supported by recent Global Circulation Model results for the early to mid Pliocene. The PIs propose to model paleo-ice configurations and warm orbits associated with a WAIS collapse to assess potential climate change in East Antarctica. During such episodes of polar warmth they propose to answer: What is the limit of ablation along the East Antarctic Ice Sheet?; Are relict landforms in the Dry Valleys susceptible to modification from increase in maximum summertime temperatures?; and Is there sufficient increase in minimum wintertime temperatures to sustain a tundra environment in the Dry Valleys? Integration of depositional records and model outputs have the potential to test the performance of numerical models currently under development as part of ANDRILL; reconcile inconsistencies between marine and terrestrial paleoclimate records in high Southern Latitudes; and improve understanding of Antarctic climate and ice volume sensitivity to forcing for both the East Antarctic and West Antarctic Ice Sheets. Broader impacts: Results from this study have the potential to be used widely by the research community. Outreach to local elementary schools from other funded efforts will continue and be extended to homeschooled students. A Post Doc will be supported as part of this award.学术价值：ANDRILL项目获取的新近纪沉积记录显示，当麦克默多干谷（McMurdo Dry Valleys）的陆地数据指示当地处于极端干旱寒冷的荒漠环境时，南极海域曾发生多次开阔水域事件且海表温度升高。对ANDRILL数据的解读表明，西南极冰盖（West Antarctic Ice Sheet）对上新世海表温度变化极为敏感，这一结论也得到了新近发布的上新世早中期全球环流模型（Global Circulation Model）结果的佐证。本项目负责人（Principal Investigators，PIs）拟通过建模还原古冰盖构型及与西南极冰盖（WAIS）崩塌相关的暖期轨道参数，以评估东南极地区的潜在气候变化。在这类极地变暖事件期间，他们拟解答以下科学问题：东南极冰盖（East Antarctic Ice Sheet）的消融极限为何？干谷内的残余地貌是否会因夏季最高气温升高而发生改造？干谷内冬季最低气温的增幅是否足以维持苔原（tundra）环境？整合沉积记录与模型输出结果，将有望验证当前作为ANDRILL项目组成部分的数值模型的性能，调和南纬高纬度地区海洋与陆地古气候记录间的不一致性，并加深对南极气候及冰体体积对强迫因子响应敏感性的理解，覆盖东南极冰盖与西南极冰盖。Broader影响：本研究成果有望为全球科研群体广泛使用。本项目将延续此前受资助项目针对当地小学开展的科普推广工作，并将服务对象拓展至在家接受教育的学生。本项目将资助1名博士后研究员开展相关研究工作。