Interpreting the Mass Balance of the Greenland Ice Sheet

摘要9807521范德文冰川学的主要挑战之一是为极地冰盖的未来演化发展设想。这项工作需要准确测量主要冰盖的当前质量平衡，并了解任何不平衡的原因。在这项研究中，将开发和测试二维流动模型，以帮助解释质量平衡结果。其目的是对冰盖的质量平衡结果做出解释，如果它应该共生、消退或保持不变。将对质量不平衡的每一种情况进行建模，以便能够容易地评估模型预测对参数变化的敏感性。这些模型将应用于格陵兰岛西北部的彼得曼冰川和洪堡冰川，这两个冰川有一套数据可用于测试和验证模型。800年前的冰芯记录将被用来帮助获得该地区的高分辨率气候记录。将对彼得曼冰川和洪堡冰川及其集水区的现有数据进行分析，以更好地了解冰川动力学。彼得曼冰川是格陵兰岛北部的主要出口冰川，但人们对这一快速移动的冰川的动态知之甚少。下方60公里处漂浮着，似乎可以畅通无阻地穿过峡湾。在接地线上方，覆盖着一条深冰下海沟的地表地形发生了显著变化。暗示着流量的变化。纵向速度剖面在接地线下游变得压缩，但横向速度剖面表明横向阻力在该区域并不重要。最近绘制的彼得曼冰川接地线位置图表明冰川正在退缩。

Abstract OPP-9807521 van der Veen One of the major challenges in glaciology is to develop scenarios for the future evolution of polar ice sheets. This effort requires accurately measuring the current mass balance of the major ice sheets and an understanding of the causes of any imbalances. In this study, two-dimensional flow models will be developed and tested to aid in the interpretation of the mass balance results. The objective is to make interpretations of mass-balance results for the ice sheet if it should accrete, recede, or remain the same. Each of these scenarios for mass imbalance will be modeled so that the sensitivity of model predictions to parameter variations can be readily evaluated. The models will be applied to the Petermann and Humboldt glaciers in northwest Greenland, for which a suite of data is available that can be used to test and validate the models. An eight hundred year old ice core record will be used to help obtain a high-resolution climate record for the region. Existing data over the Petermann and Humboldt glaciers and their catchment basins will be analyzed to better understand glacier dynamics. The Petermann glacier is the main outlet glacier in northern Greenland, but very little is known about the dynamics of this fast-moving glacier. The lower 60 km is floating and appears to be moving unimpeded through the fjord. Above the grounding line, there is a marked change in surface topography overlying a deep subglacial trench. suggesting a change in flow. The longitudinal velocity profile becomes compressive downstream of the grounding line, but transverse velocity profiles indicate that lateral drag is not important in that region. Recent mapping of the position of the grounding line of the Petermann glacier indicates retreat.