Evaluation of Shipboard and Satellite‐Derived Bathymetry and Gravity Data Over Seamounts in the Northwest Pacific Ocean
Evaluation of Shipboard and Satellite‐Derived Bathymetry and Gravity Data Over Seamounts in the Northwest Pacific Ocean
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DOI：
10.1029/2020jb020396
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发表时间：
2020-10
期刊：
影响因子：
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通讯作者：
A. Watts;B. Tozer;H. Harper;B. Boston;D. Shillington;R. Dunn
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文献类型：
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作者：
A. Watts;B. Tozer;H. Harper;B. Boston;D. Shillington;R. Dunn
地球表面地形/水深和重力场对地壳结构和作用于地壳的构造过程提供了重要的制约，例如，由于板块挠曲和地幔对流。然而，这种研究需要在广泛的空间尺度上进行高精度的测量。在过去几十年中，在利用船上和卫星高度计方法获取测深和重力数据方面取得了很大进展。令人惊讶的是，这些数据的比较很少。在2019年4月至6月期间，我们有机会登上R/V Marcus G。Langseth在西北太平洋巡航，将EM 122孔斯贝格条带测深系统和翻新的Bell Aerospace BGM-3重力仪获得的数据与最新的全球测深和重力场进行比较。我们发现，虽然在船载数据稀少的地区，从卫星雷达高度计数据中恢复测深和重力的效果令人印象深刻，但船载数据和卫星数据之间存在175.5-303.4 m和2.6-6.3 mGal的均方根差异。虽然这些差异很小，但它们高度相关，因此对深海海底的密度结构、岩石类型和地质过程产生影响。应继续获取船上数据，特别是与短波长（波长<25公里）测深和重力特征有关的海山、沙洲和洋脊等特征的数据，而这些特征是卫星数据无法恢复的。
Earth's surface topography/bathymetry and gravity fields provide important constraints on crustal structure and the tectonic processes that act on it due, for example, to plate flexure and mantle convection. Such studies require, however, high accuracy measurements at a wide range of spatial scales. During the past few decades much progress has been made in the acquisition of bathymetry and gravity data using both shipboard and satellite altimeter methods. Surprisingly, there have been few comparisons of these data. During April–June, 2019 we had the opportunity onboard a R/V Marcus G. Langseth cruise in the northwest Pacific Ocean to compare data acquired with an EM122 Kongsberg swath bathymetry system and a refurbished Bell Aerospace BGM‐3 gravimeter with the most recent global bathymetry and gravity fields. We find that while the recovery of bathymetry and gravity from satellite radar altimeter data in areas of sparse shipboard data has been impressive, root mean square discrepancies in the range 175.5–303.4 m and 2.6–6.3 mGal exist between shipboard and satellite‐derived data. While these discrepancies are small, they are highly correlated and therefore have implications for the density structure, rock type and geological processes occurring on the deep seafloor. Shipboard data should continue to be acquired, especially over features such as seamounts, banks, and ridges that are associated with short wavelength (<25 km wavelength) bathymetric and gravimetric features beyond that is recoverable in satellite‐derived data.