Radar Investigations of Former Shear Margins: Roosevelt Island and Ice Stream C

这项奖励是对两年的支持，以在罗斯福岛和冰流C的前剪切边缘进行雷达调查，以测量内部层和床的结构和连续性的变化。这些调查的广泛目标是了解冰流流动以及冰流关闭的时间和机制。高分辨率短脉冲雷达系统将用于详细检查积雪和冰层的最高百米，单脉冲探测雷达系统将用于对冰柱(包括内层)和冰床的其余部分进行成像。冰层形状和连续性的变化将被用来解释冰流流动的机制和模式，包括停滞锋面的可能迁移和停滞率。河床反射率的变化将被用来推断不同地层的基本水文条件。从积雪坑和浅岩心得出的累积速率将被用来估计近地表深度-年龄分布。对冰流历史的进一步了解使人们有可能将南极西部冰盖的变化与维多利亚北部陆地的地质证据以及罗斯海接地线撤退的海洋记录联系起来。

This award is for two years of support to perform radar investigations across former shear margins at Roosevelt Island and Ice Stream C in order to measure changes in the configuration and continuity of internal layers and the bed. The broad goal of these investigations is to gain an understanding of ice stream flow and the timing and mechanisms of ice stream shutdown. A high-resolution short-pulse radar system will be used for detailed examination of the uppermost hundred meters of the firn and ice, and a monopulse sounding-radar system will be used to image the rest of the ice column (including internal layers) and the bed. Changes in the shape and continuity of layers will be used to interpret mechanisms and modes of ice stream flow including the possible migration of stagnation fronts and rates of shut-down. Variations in bed reflectivity will be used to deduce basal hydrology conditions across lineations. Accumulation rates deduced from snow pits and shallow cores will be used to estimate near-surface depth-age profiles. Improved understanding of ice stream history opens the possibility of linking changes in the West Antarctic ice sheet with the geologic evidence from Northern Victoria Land and the ocean record of the retreat of the grounding line in the Ross Sea.