Radio-echo sounding (RES) can be used to understand ice-sheet processes, englacial flow structures and bed properties, making it one of the most popular tools in glaciological exploration. However, RES data are often subject to ‘strip noise’, caused by internal instrument noise and interference, and/or external environmental interference, which can hamper measurement and interpretation. For example, strip noise can result in reduced power from the bed, affecting the quality of ice thickness measurements and the characterization of subglacial conditions. Here, we present a method for removing strip noise based on combined wavelet and two-dimensional (2-D) Fourier filtering. First, we implement discrete wavelet decomposition on RES data to obtain multi-scale wavelet components. Then, 2-D discrete Fourier transform (DFT) spectral analysis is performed on components containing the noise. In the Fourier domain, the 2-D DFT spectrum of strip noise keeps its linear features and can be removed with a ‘targeted masking’ operation. Finally, inverse wavelet transforms are performed on all wavelet components, including strip-removed components, to restore the data with enhanced fidelity. Model tests and field-data processing demonstrate the method removes strip noise well and, incidentally, can remove the strong first reflector from the ice surface, thus improving the general quality of radar data.

中文翻译：

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使用组合小波和二维 DFT 滤波去除无线电回波探测数据中的“条带噪声”

无线电回波探测 (RES) 可用于了解冰盖过程、冰川流动结构和床层特性，使其成为冰川学探索中最受欢迎的工具之一。然而，RES 数据经常受到“条带噪声”的影响，这是由内部仪器噪声和干扰和/或外部环境干扰引起的，这可能会妨碍测量和解释。例如，条带噪声会导致来自床的功率降低，影响冰厚度测量的质量和冰下条件的表征。在这里，我们提出了一种基于组合小波和二维（2-D）傅里叶滤波的去除条带噪声的方法。首先，我们对 RES 数据进行离散小波分解，以获得多尺度小波分量。然后，对包含噪声的分量执行二维离散傅里叶变换 (DFT) 频谱分析。在傅里叶域中，带状噪声的二维 DFT 频谱保持其线性特征，并且可以通过“目标掩蔽”操作去除。最后，对所有小波分量（包括去除条带的分量）执行小波逆变换，以增强保真度来恢复数据。模型试验和现场数据处理表明，该方法可以很好地去除条带噪声，并且可以去除冰面上的强第一反射层，从而提高雷达数据的总体质量。对所有小波分量（包括去除条带的分量）执行小波逆变换，以增强保真度来恢复数据。模型试验和现场数据处理表明，该方法可以很好地去除条带噪声，并且可以去除冰面上的强第一反射层，从而提高雷达数据的总体质量。对所有小波分量（包括去除条带的分量）执行小波逆变换，以增强保真度来恢复数据。模型试验和现场数据处理表明，该方法可以很好地去除条带噪声，并且可以去除冰面上的强第一反射层，从而提高雷达数据的总体质量。