Global prediction of abyssal hill root‐mean‐square heights from small‐scale altimetric gravity variability
Global prediction of abyssal hill root‐mean‐square heights from small‐scale altimetric gravity variability
复制标题
根据小尺度高度重力变化对深海山均方根高度进行全局预测
DOI：
10.1029/2010jb007867
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发表时间：
2010
影响因子：
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通讯作者：
J. Goff
中科院分区：
文献类型：
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作者：
J. Goff
[1]深海丘陵是地球海洋海底普遍存在的地貌，是大洋中脊扩张历史的潜在构造记录。然而，根据卫星测高重力场绘制的最详细的全球海底图不能用来确定这种小尺度（<10公里）形态的特征。然而，重力场的小尺度变化可以与使用向上延拓公式的深海丘陵形态的统计特性有关。在本文中，我构建了一个全球性的预测深海丘陵均方根（rms）高度的小尺度变化的高度重力场。重力场中与深海丘陵有关的部分是通过首先掩盖海山、洋中脊和大陆边等明显特征，然后应用新设计的自适应方向滤波算法去除断裂带/不连续结构而得出的。噪声场是通过将小尺度重力场的均方根变化与地形起伏很小的区域的测高噪声场相关联而凭经验得出的，并且噪声方差从小尺度重力方差中减去。根据水深、基底均方根高度和沉积物厚度生成综合导出的深海丘陵形成重力场套件，并用于根据校正后的小尺度重力均方根高度预测深海丘陵海底均方根高度。由此产生的全球深海丘陵均方根高度的预测进行验证，定性比较预期的变化，在深海丘陵形态和定量比较均方根高度的实际测量。虽然存在离散性，但预测似乎是无偏的。
[1] Abyssal hills, which are pervasive landforms on the seafloor of the Earth's oceans, represent a potential tectonic record of the history of mid-ocean ridge spreading. However, the most detailed global maps of the seafloor, derived from the satellite altimetry-based gravity field, cannot be used to deterministically characterize such small-scale (<10 km) morphology. Nevertheless, the small-scale variability of the gravity field can be related to the statistical properties of abyssal hill morphology using the upward continuation formulation. In this paper, I construct a global prediction of abyssal hill root-mean-square (rms) heights from the small-scale variability of the altimetric gravity field. The abyssal hill-related component of the gravity field is derived by first masking distinct features, such as seamounts, mid-ocean ridges, and continental margins, and then applying a newly designed adaptive directional filter algorithm to remove fracture zone/discontinuity fabric. A noise field is derived empirically by correlating the rms variability of the small-scale gravity field to the altimetric noise field in regions of very low relief, and the noise variance is subtracted from the small-scale gravity variance. Suites of synthetically derived, abyssal hill formed gravity fields are generated as a function of water depth, basement rms heights, and sediment thickness and used to predict abyssal hill seafloor rms heights from corrected small-scale gravity rms height. The resulting global prediction of abyssal hill rms heights is validated qualitatively by comparing against expected variations in abyssal hill morphology and quantitatively by comparing against actual measurements of rms heights. Although there is scatter, the prediction appears unbiased.