改进的基于地质信息的海底地形预测_SYNBATH
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至今，约有20%的海底被船只以400米或更高的空间分辨率测量，而剩余的80%深度则通过卫星高度计的重力测量以相对较低的分辨率预测。在本世纪十年内，南半球的许多偏远海域将无法以400米的分辨率完成测绘。本研究聚焦于开发合成海底地形来填补这些空白。卫星重力测量通常无法分辨的两类海底特征是深海丘和小海山（高度小于2.5公里）。我们通过结合已测量的深海丘统计特性和区域地质信息（包括化石扩展速率/方向、卫星重力测量的均方根高度和沉积物厚度）生成深海丘的合成实现。近年来，随着精度和分辨率的提升，卫星重力测量可以检测到高度超过800米的所有海山，并且它们的位置确定精度可优于1公里。然而，重力异常的宽度远大于海山的实际宽度，因此通过重力预测的海山高度会低估，而基底尺寸则会高估。在本研究中，我们使用垂直重力梯度（VGG）的幅度来估算海山的质量，然后基于良好测绘的海山形状替换平滑预测的海山，以生成更真实的海山形状。
To date, approximately 20% of the global seafloor has been surveyed by surface vessels at a spatial resolution of 400 meters or higher, while the remaining 80% of seafloor depth has been predicted via gravity measurements from satellite altimeters at relatively low resolution. Within the current decade, many remote marine regions of the Southern Hemisphere will not be surveyed at 400-meter resolution. This study focuses on developing synthetic seafloor topography to fill these survey gaps. Two types of seafloor features that satellite gravity measurements typically cannot resolve are abyssal hills and small seamounts (with heights less than 2.5 km). We generate synthetic realizations of abyssal hills by combining measured statistical properties of abyssal hills with regional geological information, including paleospreading rate and direction, root-mean-square (RMS) height of satellite gravity measurements, and sediment thickness. In recent years, with improvements in measurement accuracy and spatial resolution, satellite gravity surveys can detect all seamounts taller than 800 meters, and achieve position determination accuracy better than 1 kilometer. However, the width of gravity anomalies is much larger than the actual width of seamounts, so seamount heights predicted from gravity data will be underestimated, while their basal dimensions will be overestimated. In this study, we use the magnitude of the vertical gravity gradient (VGG) to estimate the mass of seamounts, then replace the smoothly predicted seamounts with well-surveyed seamount morphologies to generate more realistic seamount shapes.
