Collaborative Research: Deciphering the Deep Ice and the Ice-water Interface over Lake Vostok Using Existing Radar Data

该合同支持一个项目，该项目将评估覆盖沃斯托克湖的网格以及从Ridge B到湖泊的四条区域轨道上可用的SOAR穿冰雷达数据中的无线电回波强度。该项目有两个目标；首先，它将检查湖泊的上表面和反射物，这些反射物被假设为大气冰和积冰之间的边界。它们将提供关于湖泊动态演变的关键知识。其次，该项目将研究南极洲中部东部深冰内一个鲜为人知的无回声区。该带可能由扭曲的滞冰组成，而其上边界可能是剪切带。SOAR雷达数据为研究时空水循环模式提供了独特的资源，为了选择最佳的湖泊直接采样策略，应该了解这些模式。沃斯托克冰芯为开展这项工作提供了一个独特的机会。首先，路径效应，即传播损耗和双折射，将利用冰的温度、化学和织物数据在冰芯处得到。其次，通过跟踪与雷达探测到的等时层相关的化学物质，以及通过可以复制这些层的冰流模型推断温度，可以估计传播损失的横向变化。将从大约100个雷达轨迹交叉点的反射率的各向异性推断冰结构模式。就更广泛的影响而言，将培训一名研究生根据雷达理论和沃斯托克湖的冰川学背景解释雷达数据，并将在西雅图和纽约为K-12教师提供夏季讲习班。该项目将有助于研究沃斯托克湖的持续努力，并将补充俄罗斯和法国作为国际极地年计划提出的北沃斯托克冰芯的选址。

0538674/0537752Matsuoka/StudingerThis award supports a project to evaluate radio-echo intensities in the available SOAR ice-penetrating radar data along grids covering Lake Vostok, and along four regional tracks from Ridge B toward the lake. The project has two objectives; first, it will examine the upper surface of the lake and reflectors hypothesized to be a boundary between the meteoric and accreted ice. They will provide crucial knowledge on the dynamic evolution of the lake. Second, this project will examine a poorly understood echo-free zone within the deep ice in central East Antarctica. This zone may consist of distorted stagnant ice, while its upper boundary may be a shear zone. The SOAR radar data provide a unique resource to examine spatiotemporal water circulation patterns that should be understood in order to select the best direct-sampling strategy to the lake. The Vostok ice core provides a unique opportunity to do this work. First, the path effects, i.e. propagation loss and birefringence, will be derived at the ice-core site using ice temperature, chemistry, and fabric data. Second, lateral variations of the propagation loss will be estimated by tracking chemistry associated with radar-detected isochronous layers, and by inferring temperatures from an ice-flow model that can replicate those layers. Ice-fabric patterns will be inferred from anisotropy in the reflectivity at about 100 radar-track cross-over sites. In terms of broader impacts, a graduate student will be trained to interpret the radar data in the light of radar theory and glaciological context of Lake Vostok and summer workshops for K-12 teachers will be provided in Seattle and New York. This project will contribute to ongoing efforts to study Lake Vostok and will complement the site selection for a North Vostok ice core, which has been proposed by Russia and France as an IPY program.