Ocean Acoustic Tomography in the North Atlantic
Ocean Acoustic Tomography in the North Atlantic
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DOI：
10.1175/jtech-d-18-0082.1
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发表时间：
2019-01
影响因子：
2.2
通讯作者：
B. Dushaw
中科院分区：
文献类型：
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作者：
B. Dushaw
利用模拟北大西洋温度观测的客观测绘工作，评估海洋声学层析成像结合阿尔戈浮标的分辨能力。一组基函数的流域范围内的区域得到的奇异值分解的协方差来自海洋状态估计。正如客观地图的正式不确定性估计所表明的那样，Argo和层析成像是互补的测量。在几个例子中，每个单独获得的不确定性，以确定大规模的月平均温度约50%的前（解决75%的方差），而当两个数据被采用，不确定性降低到约25%的前（解决94%的方差）。可能的层析成像配置范围从跨越特定区域的阵列到补充现有观测的线阵列，再到跨越大西洋盆地的阵列。由两个声源和七个接收器组成的流域范围的阵列可以用来显着减少估计的大尺度温度的不确定性。最佳观测系统研究将包括模拟测量，并结合数据同化技术和数值海洋建模。然而，这项客观的地图研究表明，在现有的观测系统中增加层析成像可以大大减少估计大尺度温度的不确定性。在某种程度上，层析成像提供了一个50%的不确定性减少的成本的一小部分的阿尔戈计划，这是一个具有成本效益的贡献，海洋观测系统。
An objective mapping exercise simulating observations of temperature in the North Atlantic Ocean was used to assess the resolution capabilities of ocean acoustic tomography in combination with Argo floats. A set of basis functions for a basinwide area was obtained from a singular value decomposition of a covariance derived from an ocean state estimate. As demonstrated by the formal uncertainty estimates from the objective maps, Argo and tomography are complementary measurements. In several examples, each separately obtained uncertainty for determining large-scale monthly average temperature of about 50% of prior (resolved 75% of variance), while when both data were employed, uncertainties were reduced to about 25% of prior (resolved 94% of variance). Possible tomography configurations range from arrays that span specific regions to line arrays that supplement existing observations to arrays that span the Atlantic basin. A basinwide array consisting of two acoustic sources and seven receivers can be used to significantly reduce the uncertainties of estimated broad-scale temperature. An optimal observing system study would comprise simulated measurements in combination with data assimilation techniques and numerical ocean modeling. This objective map study, however, showed that the addition of tomography to the existing observing system could substantially reduce the uncertainties for estimated large-scale temperature. To the extent that tomography offers a 50% reduction in uncertainty at a fraction of the cost of the Argo program, it is a cost-effective contribution to the ocean observing system.