Rutford Ice Stream Cooperative Research Program with British Antarctic Survey

Anandakrishnan/1643961该奖项支持一个研究拉特福德冰流下条件的项目，拉特福德冰流是一种大型冰川，从西南极冰盖内部流向菲尔奇内尔·罗恩冰架，然后进入海洋。这个冰川和类似的冰川向海洋输送冰的速度和体积是未来几十年海平面变化问题的核心：如果拉特福德携带的冰进入海洋的体积增加，那么它将有助于海平面的上升。用于预测未来条件的冰川流动数值模型必须包括一个解释冰层滑过其河床的组件。由于缺乏关于冰川底部的详细信息，滑动过程的模拟很差，导致冰流模型的不确定性增加。这个项目的数据将提供这样的信息。在该项目期间，将与英国南极调查局的研究人员合作，对拉特福德冰流床的性质进行详细调查。这些调查包括使用地震仪器(对冰川内自然发生的地震--称为冰川地震--敏感)来监测冰川床上这些冰川的分布。冰川的位置、大小和时间由床层的性质控制，如孔隙度、水压力和应力。作为该项目的一部分，将在冰川底部钻一个洞，以监测水压并提取基材样本。通过将压力变化与冰川生产进行比较，可以更好地确定大面积基材的性能。这些结果将有助于数值模型的应用，因为它们描述了滑动过程。这一奖项需要在南极洲进行实地考察。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Anandakrishnan/1643961This award supports a project to study conditions under the Rutford Ice Stream, a large glacier that flows from the interior of the West Antarctic Ice Sheet to the Filchner Ronne Ice Shelf and then on to the ocean. The speed and volume of ice delivered to the ocean by this and similar glaciers is central to the question of sea-level change in the coming decades: if the volume of ice carried by Rutford to the ocean increases, then it will contribute to a rise in sea level. Numerical models of glacier flow that are used to forecast future conditions must include a component that accounts for the sliding of the ice over its bed. The sliding process is poorly modeled because of lack of detailed information about the bottom of glaciers, leading to increased uncertainty in the ice-flow models. Data from this project will provide such information. During this project, in collaboration with researchers at the British Antarctic Survey, a detailed survey of the properties of the bed of Rutford Ice Stream will be carried out. These surveys include using seismic instruments (which are sensitive to naturally occurring earthquakes within glaciers--called icequakes) to monitor the distribution of those icequakes at the bed. The locations, size, and timing of icequakes are controlled by the properties of the bed such as porosity, water pressure, and stress. As part of this project, a hole will be drilled to the bed of the glacier to monitor water pressures and to extract a sample of the basal material. By comparing the pressure variations with icequake production, the properties of the basal material over a large area can be better determined. Those results will aid in the application of numerical models by informing their description of the sliding process. This award requires field work in Antarctica.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.