Glaciological Characteristics of the Ross/Amundsen Sea Ice-flow Divide Deduced by a New Analysis of Ice-penetrating Radar Data

该奖项支持对冰温和冰下条件的空间变化进行研究，利用现有的破冰雷达数据，在南极西部冰盖罗斯和阿蒙森流分水岭附近的未来深冰取芯点进行研究。除了反射层的几何形状外，重点将放在几百米深的冰层内的雷达回波强度上，也将检查来自冰层床的回波。初步的理论研究和与日本东南极洲雷达数据的比较表明，冰内雷达回波的垂直梯度存在很大的空间变化，这主要是由冰的温度引起的，其次是由晶体取向结构引起的。将检验垂直梯度代表冰温的假设。该项目将利用南极航空地球物理研究支持办公室（SOAR）的现有数据集，并将补充德克萨斯大学正在进行的雷达数据分析工作。该项目将为本科生提供研究经验，重点是时间序列和大型数据集的计算机分析，以及基于网络的结果和方法资源的开发，并将通过讨论两国研究地点的初步结果，支持美国和日本之间的国际合作。通过这项研究制定的实际程序将在第三年从该项目的网站上下载，并将允许使用现有雷达数据集调查其他冰盖。该项目将有助于解释未来南极西部内陆冰芯，并有助于了解冰盖历史和气候变化。

This award supports an investigation of spatial variations of ice temperature and subglacial conditions using available ice-penetrating radar data around a future deep ice coring site near the Ross and Amundsen flow divide of West Antarctic Ice Sheet. Besides geometry of reflection layers the focus will be on intensities of radar echoes from within ice deeper than several hundred meters and will also examine echoes from the bed. Preliminary studies on theory and comparison with Japanese radar data from East Antarctica suggest that large spatial variations of the vertical gradient of radar echoes from within ice exist and are caused primarily by ice temperature and secondarily by crystal-orientation fabric. The hypothesis that the vertical gradient is a proxy of ice temperature will be tested. The project will utilize an existing data set from the Support Office for Aerogeophysical Research in Antarctica (SOAR) and will complement work already underway at University of Texas to analyze the radar data. The project will provide undergraduate research experience with an emphasis on computer analysis of time series and large data sets as well as development of web-based resource of results and methods and will support an international collaboration between US and Japan through discussions on the preliminary results from their study sites. Practical procedures developed through this study will be downloadable from the project's web site in the third year and will allow investigation of other ice sheets using existing radar data sets. This project will contribute to the interpretation of the future inland West Antarctic ice core and will help in the understanding of ice sheet history and climate change.