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将海洋模式与声传播模型结合在一起,设计开发了一种适用于高性能计算机的全球海洋声学预报系统FIO-GOAFS,该系统以自然资源部第一海洋研究所全球0.1°分辨率海浪-潮流-环流耦合模式(FIO-COM)为基础,利用海洋模式预报的温、盐、深参数计算声速剖面,并对声速剖面进行水声环境特征诊断,之后将海洋模式与水下声场传播模型协同连接,结合地声模型(海底地形和底质参数),实现了全球海域的水声环境特征诊断及水下声场及相关结果的预报。海洋模型提供水下声学预报所需的水体声速、海浪波高等参数,地声模型提供海底地形、底质声速、密度以及衰减等参数,通过调用海洋-声学连接模块提取声传播路径的地形及海洋环境参数剖面,实现海洋模型和声学模型的有效连接。全球海洋声学预报系统在高性能计算机上并行实现,主要包括声场计算中的频点、方位角并行以及声学预报时针对地理空间区域的并行。最后,利用该系统预报并分析了全球海域的水声环境特性及声呐作用距离的季节变化和空间分布特征,为现代声呐的设计、操作和水下应用提供参考。 相似文献
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Delft3D在天文潮与风暴潮耦合数值模拟中的应用 总被引:6,自引:0,他引:6
本文应用Delft-3D水动力学计算软件,以长江口地区为例建立的台风风暴潮、天文潮耦合数值预报模型,对台风风暴潮、天文潮两潮耦合预报模式进行探研和分析。该模式不同于以往的单纯台风增水模型与天文潮叠加的风暴潮模式,而是在计算中直接对天文潮和台风风暴潮进行两潮耦合,有效地消除了近岸地区潮波与增水之间叠加的非线性影响。通过模拟台风8114和7708过境对长江口的影响,并与实测数据比较,预报结果和实测水位过程的对比说明,台风风暴潮耦合数值预报模式对增水和高潮的过程预报是准确的,两者在高水位时同步且相差甚微。 相似文献
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为厘清海底沉积层声学特性信息的水声环境保障需求,构建浅海两层海底环境参数模型,并参考Hamilton海底底质9种分类设置沉积层声速、密度、衰减系数及厚度的参考值及计算采样区间,利用Kraken简振波模型,采用控制变量的方法,研究了浅海沉积层声学特性参数对声传播损失的影响;开展了建模理论推导及数值技术分析,研究了海底沉积层声学特性参数在模型计算过程中调用过程,并从建模计算的角度对仿真计算的结果进行解释,对海底沉积层声学特性调查装备发展及调查重点参数具有一定的参考价值。 相似文献
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基于稀疏AR模型的潮流信号建模与预报 总被引:1,自引:0,他引:1
潮流信号处理与预报在很多方面具有非常重要的意义和价值。本文引入信号稀疏表示理论,构建一种稀疏AR模型,寻找各潮流数据间的历史关联性,并进行预报分析。首先由实测潮流信号进行常规AR建模,获得一组过完备稀疏基;其次随机从该过完备稀疏基抽取部分建立欠定方程组,利用稀疏优化算法获得最稀疏的AR系数;多次重复上一步,获得稀疏AR系数的平均以增强稀疏AR模型的稳定性;最后利用这些稀疏AR系数来重构或预测潮流信号。文章针对实测潮流信号,特别是存在多峰值有回流现象的潮流信号,进行了稀疏AR建模与预测的多次实验。实验结果与传统的潮流信号调和预报方法相对比,发现基于稀疏AR模型的潮流预报对于潮流存在多变的现象时,具有明显优越性,从回报结果来看,稀疏AR模型的潮流预报均方差明显小于传统潮流调和分析预报方法。 相似文献
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地磁日变改正是海洋磁测资料处理过程中的一个重要环节。本文利用地磁场综合模型与IGRF模型联合计算了西太平洋某调查工区的地磁日变数据,对比分析了相同位置的海洋地磁日变站观测数据。使用两种不同类型的地磁日变数据,分别对该测区中15条测线进行了磁测数据处理,并对这些测线及其56个交叉点进行了误差分析。研究结果认为:①当用计算数据做海洋磁测的处理时,其交叉点内符合精度在调差前基本满足海洋地质规范的要求,在调差后完全符合海洋地质规范的要求,但使用计算数据的精度低于实测数据。②磁静时,计算日变曲线和实测日变曲线拟合程度高;磁扰时,两者幅值差异较大,磁扰越强相关系数越小。磁情指数K>4时的模型计算数据,建议谨慎使用或不使用。 相似文献
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SMOS卫星盐度数据在中国近岸海域的准确度评估 总被引:3,自引:3,他引:0
盐度是描述海洋的关键变量,对海表面盐度进行观测可以推进对全球水循环的理解。本文的主要目的是在中国近海海域对SMOS卫星盐度数据进行准确度评估。主要方法是将SMOS卫星L2海洋盐度数据产品(V317)与实测ARGO数据和走航数据进行匹配,并采用统计学的方法对SMOS卫星数据准确度进行评估。结果表明:匹配数据的线性关系不显著,SMOS卫星盐度数据(V317)在南海和东海的均方根误差分别约为1.2和0.7,应用海表面粗糙度修正模型得到的3组海表盐度数据准确度都相对较低,尤其在近岸强风场区域,海表盐度卫星数据相对于实测数据偏高,这可能是由于海表粗糙度和陆地射频干扰(RFI)作用影响的结果;SMOS卫星数据在东海的均方根误差比南海高0.5左右,这可能是由于东海海域为相对开阔海域,受陆地RFI影响相对南海较小;在中国近岸海域,应用SSS1和SSS3模型得到的盐度数据准确度相对较高,可以对模型进行地球物理参数修正,进行局地化改进,预计可以提高近岸海域盐度反演的准确度。 相似文献
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《Oceanic Engineering, IEEE Journal of》2006,31(2):299-307
A common problem in sonar system prediction is that the ocean environment is not well known. Utilizing probabilistic based results from geoacoustic inversions we characterize parameters relevant to sonar performance. This paper describes the estimation of transmission loss and its statistical properties based on posterior parameter probabilities obtained from inversion of ocean acoustic array data. This problem is solved by first finding an ensemble of relevant environmental model parameters and the associated posterior probability using a likelihood based inversion of the acoustic array data. In a second step, each realization of these model parameters is weighted with their posterior probability to map into the transmission loss domain. This approach is illustrated using vertical-array data from a recent benchmark data set and from data acquired during the Asian Seas International Acoustics Experiment (ASIAEX) 2001 in the East China Sea. The environmental parameters are first estimated using a probabilistic-based geoacoustic inversion technique. Based on the posterior probability that each of these environmental models fits the ocean acoustic array data, each model is mapped into transmission loss. This enables us to compute a full probability distribution for the transmission loss at selected frequencies, ranges, and depths, which potentially could be used for sonar performance prediction. 相似文献
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Harmful algal blooms (HABs), caused by the overgrowth of certain phytoplankton species, have negative effects on marine environments and coastal fisheries. In addition to cell-counting methods using phytoplankton nets, a hydroacoustic technique based on acoustic backscattering has been proposed for the detection of phytoplankton blooms. However, little is known of the acoustic properties of HAB species. In this study, as essential data to support this technique, we measured the acoustic properties of two HAB species, Akashiwo sanguinea and Alexandrium affine, which occur in the South Sea off the coast of Korea. Due to the small size of the target, we used ultrasound for the measurements. Experiments were conducted under laboratory and field conditions. In the laboratory experiment, the acoustic signal received from each species was directly proportional to the cell abundance. We derived a relationship between the cell abundance and acoustic signal received for each species. The measured signals were compared to predictions of a fluid sphere scattering model. When A. sanguinea blooms appeared at an abundance greater than 3 500 cells/mL, the acoustic signals varied with cell abundance, showing a good correlation. These results confirm that acoustic measurements can be used to detect HAB species. 相似文献
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There are two types of gas hydrate-bearing reservoirs in the permafrost area of Qilian Mountain. Most of the gas hydrates occur mainly in the fractured mudstone reservoirs and rarely in the pores of the sandstone reservoirs. In this study, for the acoustic velocity characterization of the fractured gas hydrate reservoirs of the Qilian Mountain permafrost area, some mudstone core samples were collected for physical rock experiments, such as the acoustic experiment and the porosity and permeability experiment. An acoustic velocity numerical simulation of gas hydrate reservoirs was performed according to the Biot theory and the differential effective medium theory, with the conditions of multiple gas hydrate occurrence models, including the suspension model, the semi-cementation model and the cementation model, and considering both infinite and penny-shaped cracks. Fracture porosity was added to the core samples that only contain matrix porosity. With fracture porosity ranging from 0.01% to 5%, the variation laws between acoustic velocity with fractured porosity and hydrate saturation are obtained: (1) In the case of an infinite crack, if the fractured porosity is 0.01%–1%, the P-wave velocity decreases rapidly in the case of the three occurrence models. If the fractured porosity is higher than 1%, the acoustic velocity decreases gradually. If the crack shape is a penny-shaped crack, the P-wave velocity decreases almost linearly with increasing fracture porosity. (2) If the hydrate occurrence model is the suspension model, the P-wave velocity increases slightly with increasing hydrate saturation. If the occurrence model is the semi-cementation model or the cementation model, when the gas hydrate saturation of the infinite crack ranges from 0 to 80%, the acoustic velocity increases approximately linearly, whereas when the gas hydrate saturation ranges from 80% to 100%, the velocity increases rapidly. If the crack is a penny-shaped crack, the velocity increases almost linearly with increasing gas hydrate saturation from 0 to 100%. (3) It is found that the fractured gas hydrate reservoirs of the Qilian Mountain permafrost area contain both penny-shaped and infinite cracks, of which the infinite crack is the main crack shape. The gas hydrate occurrence in the Qilian Mountain permafrost area mainly follows the suspension model. This has significance for the seismic exploration and log evaluation of gas hydrate-bearing fractured reservoirs in the permafrost area of the Qilian Mountain in studying the acoustic velocity characterization, the crack shapes and occurrence models of gas hydrate reservoirs in the study area. 相似文献
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为了探究厄尔尼诺的预测方法,提高其预报准确度与预报时效,本文基于均生函数的基本原理,在普通均生函数模型中分别加入气候序列的本征模函数和预报因子变量,构建了基于EEMD(Ensemble EmpiricalModeDecomposition)的均生函数模型和多变量均生函数模型;并应用三种方案对NINO3区海温指数进行了预报试验。结果表明,两种改进模型对厄尔尼诺的预报效果好于普通均生函数模型,是提高预报准确度的有效手段;同时,利用统计的预报模型,可以在一定程度上有效延长厄尔尼诺的预报时效,具有一定实践意义。 相似文献
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Quantitative application on remote sensing of suspended sediment is an important aspect of the engineering application of remote sensing study.In this paper,the Xiamen Bay is chosen as the study area.Eleven different phases of the remote sensing data are selected to establish a quantitative remote sensing model to map suspended sediment by using remote sensing images and the quasi-synchronous measured sediment data.Based on empirical statistics developed are the conversion models between instantaneous suspended sediment concentration and tidally-averaged suspended sediment concentration as well as the conversion models between surface layer suspended sediment concentration and the depth-averaged suspended sediment concentration.On this basis,the quantitative application integrated model on remote sensing of suspended sediment is developed.By using this model as well as multi-temporal remote sensing images,multi-year averaged suspended sediment concentration of the Xiamen Bay are predicted.The comparison between model prediction and observed data shows that the multi-year averaged suspended sediment concentration of studied sites as well as the concentration difference of neighboring sites can be well predicted by the remote sensing model with an error rate of 21.61% or less,which can satisfy the engineering requirements of channel deposition calculation. 相似文献
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声学方法监测悬浮物浓度的定标技术研究 总被引:2,自引:0,他引:2
海洋中特别是河口海岸中存在着大量的悬浮物,其中,包含有内陆河流夹带的大量泥沙、海洋内浮游生物及残骸,以及大陆倾倒的大量废水废渣,造成对海洋的污染。研究悬浮物随深度剖面的变化关系,即它的时空特性,将给河口和港湾的疏浚、泥沙综合治理、沿岸工程建设、环境污染防止等方面提供可靠的理论依据和直观方便的监测手段。所以,对悬浮物浓度的定标的研究有着十分重要的现实意义。 相似文献