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: 1443341
• 负责人: Robert Hawley
• 金额: $ 61.91万
• 依托单位: Dartmouth College
• 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 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1443341&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.

冰核记录对于理解过去的气候变化至关重要。目前正在南极钻的南极冰芯将允许对大气气体进行详细研究，并填补重要的空白，以了解整个南极的气候变化模式。对任何冰核的解释至关重要的是：1）冰和被困气体的准确时间和2）冰核记录可靠地反映气候的演示。拟议的研究将通过对上游流域中的积雪压实进行测量，以限制冰的年龄模型，从而改善冰和气体的时间表。这些测量结果将是更好地理解和预测冰盖上部的时变条件所需的关键数据集。研究团队将在上游集水区的浅冰芯中测量现代空间梯度，以确定冰核记录中的气候历史，从而从浅层冰芯的累积速率，表面温度和水位稳定的同位素来测量现代空间梯度。新的冰流测量结果将使从上游到南极冰核钻头的冰路径可以评估降雪中的空间梯度，并推断冰盖内部层的降雪史。 该项目将由早期职业科学家领导，为研究生提供广泛的培训，并从事公共宣传。变化。拟议的研究将通过对上游流域中的FIRN压实进行原位测量来限制煤气年龄差异的模型，从而改善南极冰芯中的冰和气体。 FIRN测量结果将是形成FIRN构成关系所需的关键数据集，并将推动对瞬态FIRN进化的更好理解和预测。研究团队将在上游流域的积累速率，表面温度和水位稳定的同位素方面测量现代梯度，以将冰核记录中时间（气候）变化的空间（对流）变化分开。冰流的测量值将定义钻井位点上游的流线，评估积累中的空间梯度，并从雷达观料射击的内层中推断出积累的历史。结果将直接增强对南极冰核记录的解释，并提高对FIRN致密化并推动下一代FIRN模型的理解。