Collaborative Research: Greenland Ice Sheet Basal Hydrology and Sliding Dynamics - The Proof of the Drill

该奖项是根据2009年《美国复苏和再投资法案》(Public Law 111-5)资助的。最近格陵兰冰盖流动动态和整体几何形状的变化与表面融化的增加同步：一些出口冰川的速度增加，冰盖边缘变薄，冰盖总质量的下降超过了单靠融化所能解释的程度。表面融化和冰盖变化之间的直接联系通常是有争议的，但尚未得到证实。在拟议的工作中，将沿着格陵兰冰盖的流线横断面量化表面融化、基础水文系统和冰运动之间的直接联系。研究区域表面融化程度较高，但远离海洋潮汐水动力的影响。将在床上钻六个钻孔，在三个地点各钻两个孔，直接测量基本条件。冰面融化和冰速的空间梯度将被量化，以实现融化水强迫、基本水文条件和冰流动力学之间的详细比较。地面、冰内和床上的仪器将以高时间分辨率收集数据，最长可达2年。将使用两个模型来解释测量的机械和热环境。反过来，密集的测量活动将唯一地约束建模并启用模型评估。这项综合的测量和建模活动将全面研究水在冰盖运动中的作用。这项工作将支持两篇博士论文，并为至少五名学生提供实地研究经验。几项非正式教育和外展活动将得到支持，包括高比例的美洲原住民参与者。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Recent changes in the flow dynamics and overall geometry of the Greenland Ice Sheet have been concurrent with increased surface melting: the velocity of some outlet glaciers has increased, the ice sheet margins have thinned, and the overall mass of the ice sheet has declined by more than melt alone can account for. A direct linkage between surface melt and ice sheet change is commonly argued but has not been proven. In the proposed work, direct connections between surface melt, the basal hydrological system, and ice motion will be quantified along a flow-line transect of the Greenland Ice Sheet. The region to be studied receives high surface melt, but is located far from the influence of ocean tidewater dynamics. Basal conditions will be directly measured in six boreholes drilled to the bed, with two holes at each of three sites. Surface melt and spatial gradients in ice velocity will be quantified to enable detailed comparison between melt water forcing, basal hydrologic conditions, and ice flow dynamics. Instrumentation at the surface, within the ice, and at the bed will collect data at high time resolution for up to 2 years. Two models will be used to interpret the mechanical and thermal context of the measurements. In turn, the intensive measurement campaign will uniquely constrain the modeling and enable model assessment. This integrated measurement and modeling campaign will be a comprehensive investigation of the role of water in ice sheet motion. This work will support two Ph.D. dissertations and provide field research experiences to at least five students. Several informal education and outreach activities will be supported, including a high proportion of Native American participants.