Global distribution of seamounts from Seasat profiles
Global distribution of seamounts from Seasat profiles
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DOI：
10.1029/jb093ib09p10408
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发表时间：
1988-09
影响因子：
--
通讯作者：
C. Craig;D. Sandwell
中科院分区：
文献类型：
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作者：
C. Craig;D. Sandwell
测深剖面图和等高线图已被用于研究深海盆地的海山分布，但船舶只对一小部分海底进行了取样。按照目前的勘探速度，绘制海底地形的重要部分将需要几个世纪。卫星测高绘制了等势海面的地形图，是研究海山重力场的一个很有前途的工具，因为可以在几年内对所有海盆进行取样。利用加载薄弹性岩石圈的高斯型海山模型，我们发展了一种从单卫星高度计剖面测量海山基本特征的新技术。该模型预测，海山直径等于垂直偏转剖面图上沿着的峰谷距离，特征的总直径显示了海山形成时岩石圈的年龄。此外，该模型表明，这两个测量值对海山的跨航迹位置相对不敏感。我们确认这些模型的预测使用Seasat高度计剖面跨越14个以及调查海山在太平洋。然后，我们将测量技术应用于26 × 1.06亿公里的Seasat剖面，从而产生一组新的全球海山位置。在海洋卫星剖面图中确定的海山中，约有四分之一以前未在地图上标出。建模表明，海山的大小与其在大地水准面上的特征之间没有直接关系;因此，这组位置并不是对海山总数的直接抽样，而是对补偿不足的海山进行加权。初步分析表明，各大洋的种群密度和类型有相当大的差异;其中最显著的是大西洋没有海山，太平洋年龄偏移的大型断裂带的种群密度各不相同，印度洋的小特征普遍存在，西太平洋的大型海山存在线性趋势。
Bathymetrie profiles and contour charts have been used to study the distribution of seamounts in the deep ocean basins, but only a small fraction of the seafloor has been sampled by ships. At the present exploration rate it will take several centuries to map significant portions of the seafloor topography. Satellite altimetry, which maps the topography of the equipotential sea surface, is a promising tool for studying the gravity fields of seamounts because all ocean basins can be sampled in a couple of years. Using a model of a Gaussian-shaped seamount loading a thin elastic lithosphere, we develop a new technique for measuring basic characteristics of a seamount from a single satellite altimeter profile. The model predicts that the seamount diameter is equal to the peak-to-trough distance along the vertical deflection profile and that the overall diameter of the signature reveals the age of the lithosphere when the seamount formed. Moreover, the model suggests that these two measurements are relatively insensitive to the cross-track location of the seamount. We confirm these model predictions using Seasat altimeter profiles crossing 14 well surveyed seamounts in the Pacific. We then apply the measurement technique to 26 × 106 million kilometers of Seasat profiles resulting in a new global set of seamount locations. Approximately one quarter of the seamounts identified in Seasat profiles were previously uncharted. Modeling suggests that there is no direct relationship between the size of a seamount and its signature in the geoid; therefore the set of locations is not a straightforward sampling of the total seamount population, but is weighted toward seamounts which are poorly compensated. A preliminary analysis indicates considerable variations in population density and type across the oceans; most notable among them are the absence of seamounts in the Atlantic, variations in population density across large age-offset fracture zones in the Pacific, the prevalence of small signatures in the Indian Ocean, and the existence of linear trends in the large seamounts of the west Pacific.