International Research Fellowship Program: Inferring Changes in Ice-Sheet Flow and Accumulation

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。国际研究奖学金项目使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Michelle R. Koutnik博士与哥本哈根大学的Dorthe Dahl-Jensen博士一起进行为期24个月的研究。丹麦的冰与气候研究中心。冰盖流动和积累的时空历史对于重建过去的冰量和海平面历史以及预测冰盖对未来气候变化的响应是必要的。这些有价值的历史的一些细节可以从冰芯中恢复，但冰芯只代表一个点的情况。由于深层冰芯的恢复是资源密集型的，仅从冰芯中重建重要的空间维度是不切实际的。一种解决办法是利用现有的破冰雷达数据来推断这一信息。穿冰雷达剖面图是了解冰川和冰盖内部的窗口。这些冰内部的图像显示了由冰流、冰厚和冰积的时空变化所形成的内层。最深可见层受冰流和冰积累时空梯度的显著影响。因此，深层数据非常有价值，但解释起来也更加复杂。PI使用逆理论方法来正确地提取这些有价值的信息。雷达成像的内层可能是唯一可获得的保存下来的档案，它包含了过去在大范围的冰盖和冰盖上冰流和冰积累的时空变化的记录，并且可以追溯到遥远的过去。在东道主科学家多特·达尔-詹森博士（Dr. Dorthe Dahl-Jensen）和哥本哈根大学（University of Copenhagen）冰与气候研究中心（Center for Ice and Climate Studies）的一组研究人员的合作下，PI正在研究格陵兰冰盖和北极冰盖部分地区气候变化与冰盖演变之间关系的重要问题。

0853407KoutnikThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Michelle R. Koutnik to work with Dr. Dorthe Dahl-Jensen at the University of Copenhagen?s Centre for Ice and Climate Studies in Denmark.The spatial and temporal histories of ice-sheet flow and accumulation are necessary to recreate past ice-volume and sea-level histories, and to predict the response of ice sheets to future climate changes. Some details of these valuable histories can be recovered from ice cores, but ice cores represent conditions at only a single point. Since it is resource intensive to recover a deep ice core, it is impractical to reconstruct the important spatial dimension from ice cores alone. A solution is to use available ice-penetrating radar data to infer this information.Ice-penetrating-radar profiles are windows to the interior of glaciers and ice sheets. These views inside the ice show internal layers that have been shaped by spatial and temporal changes in ice flow, in ice thickness, and in accumulation. The deepest visible layers have been significantly affected by spatial and temporal gradients in ice flow and accumulation. Therefore, deep layers are highly valuable, but they are also more complicated to interpret. The PI uses an inverse-theory approach to properly extract this valuable information. Radar-imaged internal layers may be the only accessible surviving archive that contains a record of past spatial and temporal variations in ice flow and accumulation over broad areas of the ice sheets and ice caps, and reaching far into the past. In collaboration with host scientist, Dr. Dorthe Dahl-Jensen, and the team of researchers at the Center for Ice and Climate Studies at the University of Copenhagen, the PI is addressing important questions about the relationship between climate changes and ice-sheet evolution for parts of the Greenland Ice Sheet and Arctic Ice Caps.