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

冰芯记录对于了解过去的气候变化至关重要。目前正在南极钻探的南极冰芯将允许对大气气体进行详细调查，并填补在了解整个南极洲气候变化模式方面的一个重要空白。对任何冰芯的解释至关重要的是：1)冰和被困气体的准确年表，以及2)从冰芯记录可靠地反映气候。这项拟议的研究将通过测量上游集水区的积雪压实来改进冰和气体的年代学，以约束冰的年龄模型。这些测量将是更好地理解和预测冰盖上部时间变化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的积累率、表面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确定从上游到南极冰芯钻探地点的冰路径，以评估降雪的空间梯度，并从冰盖内的内层推断降雪史。该项目将由一位职业生涯早期的科学家领导，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、气溶胶生成的颗粒和大气气体的冰芯记录对于了解过去的气候变化至关重要。这项拟议的研究将改进南极冰芯的冰和气体年代学，方法是对上游集水区的降雪压实进行现场测量，以约束气体年龄冰龄差异的模型。积雪测量将是形成积雪本构关系所需的关键数据集，并将推动对瞬时积雪演化的更好理解和预测。研究小组将测量上游集水区的积累率、表面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。冰流测量将确定钻探地点上游的流线，评估堆积的空间梯度，并从雷达观测到的内部层推断堆积的历史。结果将直接加强对南极冰芯记录的解释，还将促进对积雪致密化的理解，并推动下一代积雪模型。

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.