Reconciling theoretical versus empirical target strengths of krill: effects of phase variability on the distorted-wave Born approximation
Reconciling theoretical versus empirical target strengths of krill: effects of phase variability on the distorted-wave Born approximation
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DOI：
10.1016/s1054-3139(03)00002-x
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发表时间：
2003-04-01
影响因子：
3.3
通讯作者：
Conti, SG
中科院分区：
文献类型：
--
作者：
Demer, DA;Conti, SG
最近提出了一个模型来预测南极磷虾（Euphausia superba）的目标强度（TS）与入射角（θ）的关系（Deep Sea Res.1145（7）（1998）1273）。基于扭曲波玻恩近似（DWBA），该模型依赖于从一个离散的弯曲圆柱的元素的散射的相干求和。它在120 kHz近宽边入射（θ近似为90度）下得到了经验验证，但在远离主瓣的其他角度下观察到了较大的差异。由于旁瓣测量值都高于模型预测值，也高于本底噪声，因此作者指出，这些差异并不完全是由于噪声造成的。在这项研究中，DWBA模型的准确性进一步探讨。结果表明，在离散弯曲圆柱体（磷虾模型）的元素的散射的相位变化导致TS（θ）的旁瓣区域中的戏剧性的平坦化，而可以忽略不计的影响的主散射瓣。这些结果是一致的磷虾TS测量报告的麦基希等人。因此，通过占DWBA模型的解决方案中的相位变化，一个更准确的，从而实用的工具，开发用于预测磷虾TS。(C)2003年国际海洋考察理事会。由爱思唯尔科技有限公司出版。保留所有权利。
A model was recently proposed to predict the target strengths (TS) of Antarctic krill, Euphausia superba, versus incidence angle (theta) (Deep Sea Res. 1145(7) (1998) 1273). Based on the distorted-wave Born approximation (DWBA), the model depends on the coherent summation of scattering from elements of a discretized-bent cylinder. It was empirically validated at 120 kHz near-broadside incidence (theta approximate to 90degrees), but large discrepancies were observed at other angles away from the main lobe. As the side-lobe measurements were both higher than the model predictions and above the noise floor, the authors noted that the differences were not entirely due to noise. In this study, the accuracy of the DWBA model is further explored. Results indicate that phase variability in the scatter from elements of a discretized-bent cylinder (krill model) causes a dramatic flattening in the side-lobe regions of TS(theta), while negligibly affecting the main scattering lobe. These results are consistent with the krill TS measurements reported by McGehee et al. Thus, by accounting for phase variability in the solution of the DWBA model, a more accurate and thus practical tool is developed for predicting krill TS. (C) 2003 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.