High Resolution Radar Profiling of the Snow and Ice Stratigraphy beneath the ITASE Traverses, West Antarctic Ice Sheet

0088035 arcone该合同支持继续获取高分辨率的冰雪地层学雷达反射剖面，这些地层学分布在沿国际跨南极科学考察（U.S.- itase）美国组成部分的横贯路线规划的核心站点之间。目的是利用这些剖面来确定数百公里厚地层的结构和连续性，并定量评估地形和冰运动对雪沉积的影响。其他目标是确定单个地点所代表的气候范围，并调查光线反射的原因。该雷达还将用于识别导线车辆前方的裂缝，以保护导线上科学家和支持人员的安全。与ITASE的其他研究人员合作，将利用雷达视界作为岩心定年固定的连续等时参考来计算历史积雪率。初级雷达系统使用400-MHz（中心频率）短脉冲天线，（经过处理）穿透50-70米。这是需要超过沿穿越路线200年沉积水平的深度。如果感兴趣的深度大于70米，也将记录200 MHz的剖面。处理将通过数据压缩（堆叠）来完成，以揭示远距离地层变形，距离增益校正以适当地加权信号振幅，GPS校正以调整当前冰盖地形的记录。近地表地层学将使地形和冰运动的影响分离开来。这项工作对美国itase项目的成功至关重要。

0088035 ArconeThis award supports continued acquisition of high resolution, radar reflection profiles of the snow and ice stratigraphy between core sites planned along traverse routes of the U.S. component of the InternationalTrans-Antarctic Scientific Expedition (U.S.-ITASE). The purpose is to use the profiles to establish the structure and continuity of firn stratigraphic horizons over hundreds of kilometers and to quantitativelyassess topographic and ice movement effects upon snow deposition. Other objectives are to establish the climatic extent that a single site represents and to investigate the cause of firn reflections. The radarwill also be used to identify crevasses ahead of the traverse vehicles in order to protect the safety of the scientists and support personnel on the traverse. Collaboration with other ITASE investigators will use the radar horizons as continuous isochronic references fixed by the core dating to calculate historical snow accumulation rates. The primary radar system uses 400-MHz (center frequency) short-pulse antennas, which (with processing) gives the penetration of 50-70 meters. This is the depth which is required to exceed the 200-year deposition horizon along the traverse routes. Profiles at 200 MHz will also be recorded if depths greater than 70 meters are of interest. Processing will be accomplished by data compression (stacking) to reveal long distance stratigraphic deformation, range gain corrections to give proper weight to signal amplitudes, and GPS corrections to adjust the records for the present ice sheet topography. Near surface stratigraphy will allow topographic and ice movement effects to be separated. This work is critical to the success of the U.S.-ITASE program.