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231.
Schooling behaviour and environmental forcing in relation to anchoveta distribution: An analysis across multiple spatial scales 总被引:7,自引:4,他引:3
Arnaud Bertrand Franois Gerlotto Sophie Bertrand Mariano Gutirrez Luis Alza Andres Chipollini Erich Díaz Pepe Espinoza Jesús Ledesma Roberto Quesqun Salvador Peraltilla Francisco Chavez 《Progress in Oceanography》2008,79(2-4):264
The Peruvian anchovy or anchoveta (Engraulis ringens) supports the highest worldwide fishery landings and varies in space and time over many scales. Here we present the first comprehensive sub-mesocale study of anchoveta distribution in relation to the environment. During November 2004, we conducted a behavioural ecology survey off central Peru and used a series of observational and sampling tools including SST and CO2 sensors, Niskin bottles, CTD probes, zooplankton sampling, stomach content analysis, echo-sounder, multibeam sonar, and bird observations. The sub-mesoscale survey areas were chosen from mesoscale acoustic surveys. A routine coast-wide (2000 km) acoustic survey performed just after the sub-mesoscale surveys, provided information at an even larger population scale. The availability of nearly concurrent sub-mesoscale, mesoscale and coast-wide information on anchoveta distribution allowed for a unique multi-scale synthesis. At the sub-mesoscale (100s m to km) physical processes (internal waves and frontogenesis) concentrated plankton into patches and determined anchoveta spatial distribution. At the mesoscale (10s km) location relative to the zone of active upwelling (and age of the upwelled water) and the depth of the oxycline had strong impacts on the anchoveta. Finally, over 100s km the size of the productive area, as defined by the upwelled cold coastal waters, was the determining factor. We propose a conceptual view of the relative importance of social behaviour and environmental (biotic and abiotic) processes on the spatial distribution of anchoveta. Our ecological space has two y-axis; one based on self-organization (social behaviour), and the other based on the environmental processes. At scales from the individual (10s cm), to the nucleus (m), social behaviour (e.g. the need to school) drives spatial organization. At scales larger than the school, environmental forces are the main driver of fish distribution. The conceptual ecosystem models presented in this paper may provide the final links needed to develop accurate forecasts of the spatial distribution of anchoveta over multiple scales. 相似文献
232.
����Delaunay�������Ĵ��ģCORS��վ���������о� 总被引:1,自引:0,他引:1
???????вο???(CORS)????????????GPS???????????λ(RTK)??????????GPS??????λ?????????????? ??λ???????????????????????????????????????????е?Delaunay?????????????????????CORS????????????????????????????????????????????????ο??????????????????????????????????????????Ч??????????? 相似文献
233.
研究了各向异性扩散方程在心室超声图像去噪中的应用.首先对P-M各向异性扩散模型进行了分析,为了更好去除噪声并保留图像的边缘等重要信息,提出对扩散系数的改进方法,并通过实验证明可达到更好的去噪效果. 相似文献
234.
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236.
将偏最小二乘回归(PLS)与神经网络(NN)耦合,建立了储层参数预报模型。利用偏最小二乘对影响储层参数的诸多因素进行分析,提取对因变量影响强的成分,从而克服了变量间的多重相关性问题,降低了神经网络的输入维数;同时,利用神经网络建模可以较好地解决非线性的储层参数预测问题。计算实例表明,本耦合模型的拟合和预报精度优于独立使用神经网络模型的精度。 相似文献
237.
238.
SANG Zunan XIA Bin ZHOU Yongsheng & JIN Zhenmin . Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China . Wuhan University Wuhan China . Institute of Geology China Seismological Bureau Beijing China . Faculty of Earth Sciences China University of Geosciences Wuhan China 《中国科学D辑(英文版)》2005,48(4):496-505
The magma immiscibility is that an originallyuniform magma split into two liquids with differentcompositions and properties because of the changes oftemperature, pressure and composition in the mag-matic processes. The phenomenon is ubiquitous in thenature and industrial production. For example, magmaimmiscibility has been widely regarded as the mainmechanism of formation of the Cu-Ni sulphide depositAs early as the 1920s, some geologists[1] noted that anon-silicate magma, which is mainly com… 相似文献
239.
野外快速偏提取技术找金的理论基础及应用 总被引:1,自引:0,他引:1
金矿体周围是上方常形成离子态、胶体分散和微细粒的Au晕。快速偏提取技术经在不同地区,不同矿种类型,不同地质景观条件,不同比例尺,已知和未知区面积性找矿实施应用表明,与常规土壤测量法相比,能排除“粒金效应”引起的次生晕运移现象,找矿定位准,对厚覆盖层矿体能强化异常,易于发现隐伏矿。 相似文献
240.
Astrid Holstad 《Computational Geosciences》2000,4(2):103-139
We formulate mathematical and numerical models for multispecies, multi-phase and non-isothermal reactive fluid flow in porous
media focusing on the chemical reactions and the transport of solutes. Mass conservation and stability in the time integration
are emphasized. We use cell-centered finite volume differencing in space and an implicit Runge-Kutta method in time. Assuming
two space dimensions, we introduce flux approximation for arbitrarily shaped convex quadrilaterals. On equidistant and variable
sized rectangular grids we choose limited κ=
related schemes to approximate the advective flux and the central difference scheme for the diffusive flux. On non-rectangular
grids we recommend the VF9 scheme for the estimation of the diffusive flux. Our model exists as a code.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献