Stress Transmission at Ice-Stream Shear Margins

该奖项是支持一个为期三年的计划，研究应力传输在三个冰流剪切边缘。 其目的是确定冰流的运动有多少是由流间脊控制的，将这种横向阻力的大小与冰流上的驱动应力和冰流宽度进行比较，并确定横向阻力支持是否与边缘的横向迁移有关。 根据应变率的测量结果，可以推导出冰脊和冰流冰之间单位冰流长度的净力。 实地工作将需要Twin Otter安装偏远营地，第一季每个营地将占用约12天，第二季约6天。 南极航空地球物理研究支助办事处设施将进行航空勘测，以确定冰流间冰脊的冰厚以及冰流的冰厚和表面坡度。 现场测量将通过现场附近冰流E的重复SPOT图像来补充，以确定边缘冰流侧的速度。 将这些速度与从应变网格测量中获得的速度进行比较，将提供对边缘冰软化量的估计。

This award is for support for a three year program to study stress transmission at three ice stream shear margins. The objectives are to determine how much of the motion of the ice streams is controlled from the inter-stream ridges, to compare the magnitude of this lateral drag with the driving stress on the ice stream, and with ice stream width and to determine whether lateral drag support is associated with lateral migration of the margin. The net force per unit ice-stream length transmitted between ridge ice and ice-stream ice will be deduced from measurements of strain rate. Field work will entail Twin Otter installation of remote camps that will each be occupied for about 12 days during the first season and about 6 days during the second. The Support Office for Aerogeophysical Research in Antarctica (SOAR) facility will conduct aerial surveys to determine ice thickness on the inter-stream ridges, as well as the ice thickness and surface slope on the ice streams. The field measurements will be complemented by repeat SPOT imagery of Ice Stream E adjacent to the field site, to allow velocities in the ice-stream side of the margin to be determined. Comparing these velocities to those obtained from the strain-grid surveys will provide an estimate of the amount of softening of the ice in the margins.