Global and local isostatic coherence from the wavelet transform
Global and local isostatic coherence from the wavelet transform
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DOI：
10.1029/2004gl021569
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发表时间：
2004-12
影响因子：
5.2
通讯作者：
J. Kirby;C. Swain
中科院分区：
文献类型：
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作者：
J. Kirby;C. Swain
本文提出了一种利用小波变换计算岩石圈弹性厚度变化的方法。该技术使用二维Morlet小波在称为“扇形”小波的几何结构中的叠加，旨在为重力和地形数据的共谱和互谱产生各向同性但复杂的小波系数。然后，这些用于计算空间变化的均衡相干性，由此可以获得全局和局部估计。我们将该方法应用于均匀厚度为20 km的薄弹性板的合成重力和地形，产生24.5 ± 3.5 km的视空间可变Te。该模型的估计全局相干性似乎符合理论预测以及基于傅立叶变换的估计，并且比这些更平滑。我们还计算了非均匀厚度板的小波相干性，从而计算了空间变化的Te，与模型的差异为−2.0 ± 1.7 km。
A method to compute the variations in lithospheric elastic thickness (Te) has been developed, using the wavelet transform. The technique, which uses a superposition of two‐dimensional Morlet wavelets in a geometry named a ‘fan’ wavelet, is designed to yield isotropic yet complex wavelet coefficients for the co‐ and cross‐spectra of gravity and topography data. These are then used to compute a spatially‐varying, isostatic coherence, from which both global and local estimates may be obtained. We applied the method to synthetic gravity and topography generated for a thin elastic plate of uniform thickness 20 km, yielding an apparent, spatially variable Te of 24.5 ± 3.5 km. The estimated global coherence for this model appears to fit the theoretical prediction as well as Fourier transform‐based estimates, and is smoother than these. We also computed the wavelet coherence, and hence spatially‐varying Te, for a plate of non‐uniform thickness, yielding a difference with the model of −2.0 ± 1.7 km.