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条件的项目，拉特福德冰流是一个从南极西部冰盖内部流向菲尔希纳伦讷冰架，然后流向海洋的大型冰川。 这个冰川和类似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：如果拉特福德冰川向海洋输送的冰的体积增加，那么它将导致海平面上升。用于预测未来情况的冰川流动数值模型必须包括一个解释冰在河床上滑动的组成部分。 由于缺乏关于冰川底部的详细信息，滑动过程的模型很差，导致冰流模型的不确定性增加。本项目的数据将提供此类信息。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特性进行详细调查。 这些调查包括使用地震仪器（对冰川内自然发生的地震-称为冰震-敏感）来监测冰震在河床上的分布。 冰震的位置、大小和发生的时间是由河床的性质如孔隙度、水压和应力所控制的。 作为该项目的一部分，将在冰川床上钻一个洞，以监测水压并提取基底物质的样本。 通过比较压力变化与冰震产生，可以更好地确定大面积基底材料的性质。 这些结果将有助于数值模型的应用，告知他们的滑动过程的描述。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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.