Tools for quantifying the role of basal processes in glacier dynamics

要求资金购买工具，以帮助量化基础过程在确定冰川流动、稳定性和气候响应特征方面所起的作用。这些工具将提供(1)快速进入冰川床，允许在那里安装各种仪器；(2)全年控制冰下仪器，对冰川床的机械和水文条件进行现场测量；(3)全天候高精度测量能力，使地表流量与基础运动的仪器记录相关联；(4)全年测量当地环境条件，这将有助于量化冰下排水系统的融水输入。该设备将有助于建立一个新的研究项目，旨在观察和量化弱层状山谷冰川下机械过程和水文条件之间的强烈相互作用。从该计划的现场部分获得的数据将用于约束基础过程的数值模型，其长期目标是改善冰动力学模型的基础边界条件的处理。这将使我们能够更准确地确定（过去和现在）冰盖对气候变化的反应，并将阐明现代冰流、汹涌的冰川和潮汐冰川的行为。下面是柔软的、可变形的沉积物的冰川通过冰变形、沉积物变形和基底滑动的某种组合而移动。流的后两个组成部分对冰块的运动有很大的帮助。此外，冰床接触处的侵蚀过程决定了冰川和冰盖对基岩地形的物理影响。由于高冰下水压促进冰川滑动和沉积物变形，基底运动受到冰川床水文条件的强烈影响。因此，对床上的机械过程和水文条件之间关系的进一步了解是理解冰块动力学及其对景观影响的关键。

Funds are requested to purchase tools to aid in quantifying the role basal processes play in determining glacier flow, stability, and climate response characteristics.  These tools will provide (1) rapid access to the glacier bed, allowing a variety of instruments to be installed there; (2) year-round control of subglacial instruments, allowing in situ measurement of mechanical and hydrological conditions at the glacier bed; (3) all-weather high precision survey capability, allowing surface flow rates to be related to instrument records of basal motion; and (4) year-round measurement of local environmental conditions, which will aid in quantifying meltwater input to the subglacial drainage system.  This equipment will help establish a new research program that aims to observe and quantify the strong interaction between mechanical processes and hydrological conditions present beneath weak-bedded valley glaciers.   Data obtained from the field component of the program will be used to constrain numerical models of basal processes, with the long-term goal of improving the treatment of the basal boundary condition for ice-dynamics models.  This will allow more accurate determination of the response of ice sheets (both past and present) to climate change, and will elucidate the behaviours of modern-day ice streams, surging glaciers, and tidewater glaciers.      Glaciers that are underlain by soft, deformable sediments move by some combination of ice deformation, sediment deformation and basal sliding.  These last two components of flow can contribute greatly to the motion of ice masses.  In addition, erosional processes at the ice-bed contact determine the physical effect that glaciers and ice sheets have on the bedrock topography.  Because high subglacial water pressures facilitate both glacier sliding and sediment deformation, basal motion is strongly influenced by hydrological conditions at the glacier bed.  An improved knowledge of the relationship between mechanical processes and hydrological conditions at the bed is thus key to understanding both the dynamics of ice masses and their effect on the landscape.