Measuring snow water equivalent from common offset GPR records through migration velocity analysis
Measuring snow water equivalent from common offset GPR records through migration velocity analysis
复制标题
通过迁移速度分析从常见偏移探地雷达记录测量雪水当量
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
W. Holbrook
中科院分区：
文献类型：
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作者：
J. S. Clair;W. Holbrook
摘要。许多山区的水资源依赖季节性降雪。目前预测水资源可用性的方法依赖于孤立地点的流量和积雪监测之间的长期关系，在异常雪年，这种方法不太可靠。由于积雪密度与雷达速度之间的密切关系，探地雷达已被证明是测量雪水当量（SWE）的有效工具。然而，测量雷达速度的标准方法可能是耗时的。本文将一种最初用于从零偏移地震剖面观测到的衍射能量中提取速度信息的偏移聚焦方法应用于从共偏移GPR数据中估计季节积雪雷达速度的问题。采用平面波消去滤波对衍射进行隔离，并根据偏移图像的变模选择最佳偏移速度。然后我们使用雷达速度来估计雪密度、深度和SWE。当GPR天线耦合到雪面上时，GPR导出的SWE估计值与手动SWE测量值相差不到6% %，当天线安装在雪地摩托前部时，其距离雪面约 0.5 m，其SWE估计值与手动测量值相差3 - 21% %。
Abstract. Many mountainous regions depend on seasonal snowfall for their water resources. Current methods of predicting the availability of water resources rely on long-term relationships between stream discharge and snowpack monitoring at isolated locations, which are less reliable during abnormal snow years. Ground-penetrating radar (GPR) has been shown to be an effective tool for measuring snow water equivalent (SWE) because of the close relationship between snow density and radar velocity. However, the standard methods of measuring radar velocity can be time-consuming. Here we apply a migration focusing method originally developed for extracting velocity information from diffracted energy observed in zero-offset seismic sections to the problem of estimating radar velocities in seasonal snow from common-offset GPR data. Diffractions are isolated by plane-wave-destruction (PWD) filtering and the optimal migration velocity is chosen based on the varimax norm of the migrated image. We then use the radar velocity to estimate snow density, depth, and SWE. The GPR-derived SWE estimates are within 6 % of manual SWE measurements when the GPR antenna is coupled to the snow surface and 3–21 % of the manual measurements when the antenna is mounted on the front of a snowmobile ∼ 0.5 m above the snow surface.