Ballard Megan S, Becker Kyle M
Applied Research Laboratories, University of Texas at Austin, Texas 78758, USA.
J Acoust Soc Am. 2010 Jun;127(6):3411-21. doi: 10.1121/1.3397451.
The environment of the New Jersey shelf is characterized by high spatial and temporal variability of water column properties caused by intrusions of warm, salty water from the continental slope. These intrusions cause fluctuations in the water column sound speed profile which can have significant effects on acoustic propagation in shallow water. In this work, a linearized perturbative inverse technique is applied to estimate range-dependent water column sound speed profiles. This method utilizes estimates of horizontal wave numbers to determine sound speed as a function of depth. This technique is appropriate for the range-dependent shallow-water environment as horizontal wave numbers can be measured semilocally (1-2 km aperture) and their values are a direct measurement of the local environmental parameters. Difficulty is encountered in application of the perturbative inverse technique because the wave number data are insensitive to some portions of the waveguide and, as a result, the solution can deviate wildly from true values. This issue is addressed by application of approximate equality constraints which force the solution to be close to likely values at prescribed locations.
新泽西海岸架的环境特点是，大陆坡暖盐水的侵入导致水柱特性在空间和时间上具有高度变异性。这些侵入导致水柱声速剖面出现波动，这可能会对浅水中的声学传播产生重大影响。在这项工作中，应用了一种线性化微扰反演技术来估计与距离有关的水柱声速剖面。该方法利用水平波数估计值来确定声速随深度的函数关系。这种技术适用于与距离有关的浅水环境，因为水平波数可以在半局部（1-2公里孔径）进行测量，其值是当地环境参数的直接测量结果。在应用微扰反演技术时遇到了困难，因为波数数据对波导的某些部分不敏感，因此，解可能会与真实值有很大偏差。通过应用近似等式约束来解决这个问题，该约束迫使解在规定位置接近可能的值。
