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

该奖项是两年的支持，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配置和连续性的变化。 这些调查的主要目标是了解冰流流动和冰流关闭的时间和机制。 一个高分辨率的短脉冲雷达系统将被用于对最上面几百米的积雪和冰进行详细的检查，一个单脉冲探测雷达系统将被用于对冰柱的其余部分（包括内部层）和冰床进行成像。 层的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，包括停滞锋的可能迁移和关闭率。 河床反射率的变化将用于推断各线理的基本水文条件。 从雪坑和浅层岩心中推断出的积累率将用于估算近地表深度-年龄剖面。 对冰流历史的更好理解打开了将南极西部冰盖的变化与北方维多利亚地的地质证据和罗斯海接地线后退的海洋记录联系起来的可能性。

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.