Sound scattering by several zooplankton groups. II. Scattering models.
Sound scattering by several zooplankton groups. II. Scattering models.
复制标题
几个浮游动物群的声音散射。
DOI：
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复制
发表时间：
1998
影响因子：
2.4
通讯作者：
P. Wiebe
中科院分区：
文献类型：
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作者：
T. Stanton;D. Chu;P. Wiebe
数学散射模型的推导和比较数据从浮游动物从几个总的解剖组-流体状，弹性壳，和气体轴承。这些模型是基于声学推断的边界条件，这些边界条件是根据本系列第一部分中提供的实验室后向散射数据确定的[Stanton等人，J. Acoust.美国社会103，225-235（1998）]。该模型结合了射线理论、模态级数解和扭曲波玻恩近似（DWBA）。的配方，这是固有的近似，被设计为只包括从实验中确定的主要散射机制。流体状动物（在这种情况下为磷虾）的模型范围从涉及两条射线的最简单的情况，可以定性地描述目标强度与单次ping频率的结构，到最复杂的情况，涉及一个粗糙的不均匀的非对称锥形弯曲圆柱体，使用DWBA为基础的公式，可以预测所有入射角（包括端入射的困难区域）的回波水平。弹性带壳体（在这种情况下为腹足类）的模型涉及分析模型的开发，该模型考虑到壳的不规则性和不连续性。含气动物（管水母）的模型是一个混合模型，它是由气体球的精确解和近似的DWBA为基础的配方为任意形状的流体状体的总和。还有一个简化的基于射线的模型的管水母。该模型适用于涉及单ping，ping到ping的变化，并在许多ping平均回波的数据。在预测与单脉冲数据之间存在合理的定性一致性，并且在预测与回波数据的变异性和平均值之间存在合理的定量一致性。
Mathematical scattering models are derived and compared with data from zooplankton from several gross anatomical groups--fluidlike, elastic shelled, and gas bearing. The models are based upon the acoustically inferred boundary conditions determined from laboratory backscattering data presented in part I of this series [Stanton et al., J. Acoust. Soc. Am. 103, 225-235 (1998)]. The models use a combination of ray theory, modal-series solution, and distorted wave Born approximation (DWBA). The formulations, which are inherently approximate, are designed to include only the dominant scattering mechanisms as determined from the experiments. The models for the fluidlike animals (euphausiids in this case) ranged from the simplest case involving two rays, which could qualitatively describe the structure of target strength versus frequency for single pings, to the most complex case involving a rough inhomogeneous asymmetrically tapered bent cylinder using the DWBA-based formulation which could predict echo levels over all angles of incidence (including the difficult region of end-on incidence). The model for the elastic shelled body (gastropods in this case) involved development of an analytical model which takes into account irregularities and discontinuities of the shell. The model for gas-bearing animals (siphonophores) is a hybrid model which is composed of the summation of the exact solution to the gas sphere and the approximate DWBA-based formulation for arbitrarily shaped fluidlike bodies. There is also a simplified ray-based model for the siphonophore. The models are applied to data involving single pings, ping-to-ping variability, and echoes averaged over many pings. There is reasonable qualitative agreement between the predictions and single ping data, and reasonable quantitative agreement between the predictions and variability and averages of echo data.