Iturbe Ion, Roux Philippe, Virieux Jean, Nicolas Barbara
GIPSA Laboratory, INPG-CNRS, 961 rue de la Houille Blanche, Domaine Universitaire, Saint Martin d'Heres, France.
J Acoust Soc Am. 2009 Aug;126(2):713-20. doi: 10.1121/1.3158922.
In recent years, the use of sensitivity kernels for tomographic purposes has been frequently discussed in the literature. Sensitivity kernels of different observables (e.g., amplitude, travel-time, and polarization for seismic waves) have been proposed, and relationships between adjoint formulation, time-reversal theory, and sensitivity kernels have been developed. In the present study, travel-time sensitivity kernels (TSKs) are derived for two source-receiver arrays in an acoustic waveguide. More precisely, the TSKs are combined with a double time-delay beam-forming algorithm performed on two source-receiver arrays to isolate and identify each eigenray of the multipath propagation between a source-receiver pair in the acoustic waveguide. A relationship is then obtained between TSKs and diffraction theory. It appears that the spatial shapes of TSKs are equivalent to the gradients of the combined direction patterns of the source and receiver arrays. In the finite-frequency regimes, the combination of TSKs and double beam-forming both simplifies the calculation of TSK and increases the domain of validity for ray theory in shallow-water ocean acoustic tomography.
近年来，文献中经常讨论用于层析成像目的的灵敏度核。已经提出了不同可观测量（例如地震波的振幅、走时和极化）的灵敏度核，并建立了伴随公式、时间反转理论和灵敏度核之间的关系。在本研究中，推导了声波导中两个源-接收器阵列的走时灵敏度核（TSK）。更确切地说，将TSK与在两个源-接收器阵列上执行的双时延波束形成算法相结合，以隔离和识别声波导中源-接收器对之间多径传播的每个本征射线。然后得到了TSK与衍射理论之间的关系。结果表明，TSK的空间形状等同于源和接收器阵列组合方向图的梯度。在有限频率范围内，TSK与双波束形成的结合既简化了TSK的计算，又扩大了射线理论在浅海海洋声学层析成像中的有效范围。
