Dynamics of a Temperate Tidewater Glacier: LeConte Glacier, Alaska

勒孔特冰川是阿拉斯加东南部一个迅速退缩的温带冰川。它已经稳定了33年，但在1994年12月迅速开始产犊和撤退。它在9个月的时间里后退了1公里，并在270米深的水中崩解。该提案解决了最近由美国国家科学基金会（NSF）赞助的潮汐冰川研讨会上提出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过程。在这项研究中，首席调查员将沿着冰川的整个长度测量和描述一些参数，而不仅仅是鼻子或末端。目标是：1)了解是什么控制着冰川崩解的稳定性；2)描述冰川崩解，特别是海底事件；3)测量和表征前冰沉积，以评估其对冰解冰川动力学和稳定性的影响。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非常重要。重复的空中高程剖面尚未在冰川上得到宝贵的应用，将用于在季节和年的基础上测量冰川全长表面几何形状的变化。

The LeConte 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 LeConte 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.