Dynamics of a Temperate Tidewater Glacier: LeConte Glacier Alaska

摘要OPP-9806275 Motyka Echelmeyer勒孔特冰川是阿拉斯加东南部快速退缩的温带冰川。它已经稳定了33年，但在1994年12月开始迅速崩解和消退。在9个月的时间里，它已经后退了1公里，正在融化到270米深的水中。这项提案解决了最近由国家科学基金会(NSF)赞助的潮水冰川研讨会的许多关键问题和建议。以前对类似冰川的研究主要集中在冰川末端及其附近的冰川过程。在这项研究中，首席调查人员将沿着整个冰川长度测量和描述一些参数，而不仅仅是口鼻或末端。其目的是：1)了解控制冰川崩解稳定性的因素；2)冰川崩解的特征，特别是海底事件；以及3)测量和描述冰川沉积，以评估其对崩解冰川动态和稳定性的影响。由于勒孔特冰川正在迅速崩解，这是一项“时间紧迫”的研究，在冰川处于崩解退缩的初始阶段时开始收集数据是很重要的。重复的航空高程剖面图并没有被精确地用于冰川，它将被用来测量冰川全长表面几何形状的季节和年度变化。

Abstract OPP-9806275 Motyka Echelmeyer The Le Conte Glacier is a rapidly retreating temperate glacier in southeastern Alaska. It has been stable for 33 years, but rapidly began to calve and retreat in December 1994. It has receded one kilometer over nine-months and is calving into 270-meter deep water. This proposal addresses many of the key issues and recommendations from the recent National Science Foundation (NSF)-sponsored tidewater glacier workshop. Previous studies on similar glaciers have focused on processes at and near the terminus. In this study, the Principal Investigators will measure and characterize a number of parameters along the entire length of the glacier and not just the snout or terminus. The objectives are to: 1) understand what controls the stability of calving glaciers; 2) characterize glacier calving, especially submarine events; and 3) measure and characterize proglacial sedimentation to assess its effects on the dynamics and stability of calving glaciers. Because the Le Conte Glacier is rapidly calving, this is a "time-critical" study and it is important to begin collecting data while the glacier is in the initial stages of the calving retreat. Repeated airborne elevation profiling, which has not been preciously used on glaciers, will be used to measure changes in surface geometry along the full length of the glacier on a seasonal and annual basis.