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Multi-frequency acoustic measurement of zooplankton

浮游动物的多频声学测量

基本信息

批准号：
04660196
负责人：
AOKI Ichiro
金额：
$ 1.22万
依托单位：
Ocean Research Institute, University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04660196/
关键词：
Scattering Model Zooplankton Acoustic Measurement Biomass Size Distribution

项目摘要

1.A method for size estimation of small organisms composing sound scattering layrs in the sea was developed using 4 frequencies and the Kristensen model. In this study, it was assumed that scattering layrs consist of a dominant size class. Then, equivalent spherical radius of the dominant size was estimated by the procedure based on least squares and rank conformity.2.The size estimate was compared to size composition of organisms taken by net sampling. While zooplankton taken by net tended to be smaller than acoustic size estimate, both were consistent with one another in a relative sense, i.e.large, small, and medium sizes. The current system has a limitation in resolution of size composition because of having only 4 frequencies, but it is useful for rapid and continuous measurement with wide coverage where zooplankton composition is simple. Since, at present, research vessels are generally equipped with acoustic instruments similar to our system, the method developed in this study can be applied widely.3.The volume scattering strength was corrected by size estimated above. The relationship between the corrected volume scattering strength and logarithmic total volume of zooplankton taken by net was expressed by first-order equation which was common for 4 frequencies. The constant term, which is theoretically to be zero, remaining in this equation is due to an error in measurement and/or difference from real biomass by net-avoidance. Main causes for the error are probably biovolume estimation of organisms sampled by net and parameter values given in the scattering model, which are needed to be examined further.

1.提出了一种利用四个频率和Kristensen模型估算海洋中组成声散射层的小生物体尺寸的方法。在这项研究中，它被假定为散射层由一个占主导地位的大小类。然后，利用最小二乘法和秩一致性估计优势个体的等效球半径。2.将优势个体的大小估计值与网样大小组成进行比较。虽然网采取的浮游动物往往小于声学尺寸估计，两者是一致的，在相对意义上，即大，小，和中等大小。目前的系统由于只有4个频率而在尺寸组成的分辨率上有限制，但它对于在浮游动物组成简单的情况下进行快速和连续的测量是有用的。由于目前研究船普遍配备了与我们系统类似的声学仪器，因此本研究中开发的方法可以广泛应用。3.通过上述估算的尺寸对体积散射强度进行了校正。经校正的体积散射强度与网获浮游动物总体积对数的关系可用一阶方程表示，该方程在4个频率下通用。在该方程中保留的常数项（理论上为零）是由于测量误差和/或通过净回避与真实的生物量的差异。造成误差的主要原因可能是网采生物量的估算和散射模型中的参数值，需要进一步检验。