Collaborative Research: Characterization of Upstream Ice and Firn Dynamics affecting the South Pole Ice Core

合作研究：影响南极冰芯的上游冰和冷杉动力学特征

• 批准号: 1443471
• 负责人: Michelle Koutnik
• 金额: $ 76.02万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443471&HistoricalAwards=false
• 关键词: Collaborative; Research; Characterization; Upstream; Ice

Ice-core records are critical to understanding past climate variations. An Antarctic ice core currently being drilled at the South Pole will allow detailed investigation of atmospheric gases and fill an important gap in understanding the pattern of climate variability across Antarctica. Critical to the interpretation of any ice core are: 1) accurate chronologies for both the ice and the trapped gas and 2) demonstration that records from the ice core reliably reflect climate. The proposed research will improve the ice and gas chronologies by making measurements of snow compaction in the upstream catchment in order to constrain age models of the ice. These measurements will be a key data set needed for better understanding and predicting time-varying conditions in the upper part of the ice sheet. The research team will measure the modern spatial gradients in accumulation rate, surface temperature, and water stable isotopes from shallow ice cores in the upstream catchment in order to determine the climate history from the ice-core record. The new ice-flow measurements will make it possible to define the path of ice from upstream to the South Pole ice-core drill site to assess spatial gradients in snowfall and to infer histories of snowfall from internal layers within the ice sheet. The project will be led by an early-career scientist, provide broad training to graduate students, and engage in public outreach on polar science.Ice-core records of stable isotopes, aerosol-born particles, and atmospheric gases are critical to understanding past climate variations. The proposed research will improve the ice and gas chronologies in the South Pole ice core by making in situ measurements of firn compaction in the upstream catchment to constrain models of the gas-age ice-age difference. The firn measurements will be a key data set needed to form a constitutive relationship for firn, and will drive better understanding and prediction of transient firn evolution. The research team will measure the modern gradients in accumulation rate, surface temperature, and water stable isotopes in the upstream catchment to separate spatial (advection) variations from temporal (climate) variations in the ice-core records. The ice-flow measurements will define the flowline upstream of the drill site, assess spatial gradients in accumulation, and infer histories of accumulation from radar-observed internal layers. Results will directly enhance interpretation of South Pole ice-core records, and also advance understanding of firn densification and drive next-generation firn models.

冰芯记录对了解过去的气候变化至关重要。目前正在南极钻取的南极冰芯将有助于对大气气体进行详细调查，并填补了解南极洲气候变化模式方面的一个重要空白。解释任何冰芯的关键是：1)冰和被困气体的准确年表；2)证明冰芯的记录可靠地反映了气候。拟议的研究将通过测量上游集水区的雪压实来改进冰和气的年表，从而限制冰的年龄模型。这些测量结果将成为更好地理解和预测冰盖上部随时间变化的条件所需的关键数据集。研究小组将测量上游集水区浅层冰芯中积累速率、地表温度和水稳定同位素的现代空间梯度，以便根据冰芯记录确定气候历史。新的冰流测量将有可能定义冰从上游到南极冰芯钻孔点的路径，以评估降雪的空间梯度，并从冰盖的内层推断降雪的历史。该项目将由一位早期职业科学家领导，为研究生提供广泛的培训，并参与极地科学的公共宣传。稳定同位素的冰芯记录、气溶胶产生的颗粒和大气气体对了解过去的气候变化至关重要。拟议的研究将通过对上游集水区的铁石压实度进行现场测量来限制气体年龄冰期差异的模型，从而改善南极冰芯的冰和气年代学。植被测量将是形成植被本构关系所需的关键数据集，并将推动更好地理解和预测瞬态植被演化。研究小组将测量上游集水区积累速率、地表温度和水稳定同位素的现代梯度，以区分冰芯记录中的空间（平流）变化和时间（气候）变化。冰流测量将定义钻井地点上游的流线，评估堆积的空间梯度，并从雷达观测到的内层推断堆积的历史。研究结果将直接增强南极冰芯记录的解释，也将促进对冰层致密化的理解，并推动下一代冰层模型的发展。