Effects of sediment properties on surface-generated ambient noise in a shallow ocean     

Jin-Yuan Liu  I-Chun Lin 《Ocean Engineering》2005,32(16):1887-1905

Surface-generalized ambient noise in a shallow ocean waveguide with a sediment layer possessing a specific class of density and sound speed distributions capable of describing a realistic seabed environment is considered in this analysis. This class of non-uniform sediment layer has the density and sound speed distributions varying with respect to depth as a generalized-exponential and an inverse-square function, respectively. The study invokes a formulation developed by Kuperman and Ingenito (Kuperman, W. A., Ingenito, F., 1980. Spatial correlation of surface-generated noise in a stratified ocean. J. Acoust. Soc. Am., 67, 1988-1996.) for surface noise generation, in conjunction with the analytical solutions for the Helmholtz equation corresponding to the sediment layer, to arrive at an analytical expression convenient for numerical implementation. The intensity and spatial correlation of the noise sound field are analyzed with respect to the variation of the system parameters, including frequency, sediment layer thickness, sound speed gradient, with emphasis on the effects of sediment properties on the ambient noise field. The results have demonstrated that the intensity of the noise field is relatively sensitive to the variation of the parameters, but the spatial correlation is affected to a less extent, suggesting that the energy distribution, rather than the spatial structure, of the noise field is more susceptible to the environmental variations.  相似文献   

海洋测绘中影像图与港口航道图的镶嵌技术运用     

奉定平  邢攸姿 《海洋技术学报》2007,26(3):94-96

文中介绍陆地影像图与港口航道图镶嵌的制图工艺,影像图与港口航道图镶嵌后的成图质量评价。简单阐述了作者在绘制该图种过程中的一些体会,以及影像图取代现有港口航道图上陆地地形的可行性。  相似文献   

度量泥炭腐殖化度的一种简便方法:泥炭灰度   总被引：1，自引：0，他引：1  

于学峰  周卫建  史江峰 《海洋地质与第四纪地质》2005,25(1):133-136

介绍了一种度量泥炭腐殖化程度简便易得的指标——灰度。通过将同一剖面灰度测量结果与传统的腐殖化度测量结果进行对比，发现二者的变化具有较强的相关性，说明导致二者变化的因素大致相同。泥炭赋色物质鉴定的实验表明腐殖质含量变化是引起灰度在剖面上变化的原因，从而进一步论证了用灰度值作为泥炭腐殖化程度指标的可行性。  相似文献   

耿贝尔逻辑模型在极值风速和有效波高联合概率分布中的应用   总被引：7，自引：1，他引：7  

周道成  段忠东 《海洋工程》2003,21(2):45-51

首先介绍了耿贝尔逻辑模型，采用该模型对南海海域的涠州岛海洋站的风速和有效波高实测数据进行了分析，结果表明耿贝尔逻辑模型较好地描述了年极值风速和有效波高两随机变量的联合分布；采用得到的极值风浪联合概率分布推算了不同重现期的极值风速和波高，表明考虑风速和波高相关性对设计荷载的确定有显著影响。由于耿贝尔逻辑模型具有函数结构简单，参数估计方便，因此有望成为极值风速和波高联合分布的较理想概率模型。  相似文献   

Estimating mortality rates from tag recoveries: incorporating over-dispersion, correlation, and change points     

Kitada  Shuichi; Hiramatsu  Kazuhiko; Kishino  Hirohisa 《ICES Journal of Marine Science》1994,51(3):241-251

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广西沿岸海平面变化的关联维数研究     

梁士楚 《热带海洋学报》2001,20(2):15-19

采用相空间重构和关联维数方法，研究了广西沿岸月平均海平面变化的分形特征，结果表明，相空间重构的延迟时间τ为3△t，当关联维数趋于饱和时，石头埠，北海和龙尾的相空间维数为7，而涠洲岛为9，它们的关联维数平均值平均值分别为6.6507,6.5414,6.7059.  相似文献   

Hydrocarbon Potential of Pre-cenozoic Strata in the North Yellow Sea Basin     

蔡峰戴春山  陈建文李刚 孙萍 《海洋通报(英文版)》2005,7(1):21-36

The North Yellow Sea Basin ( NYSB ), which was developed on the basement of North China (Huabei) continental block, is a typical continental Mesozoic Cenozoic sedimentary basin in the sea area. Its Mesozoic basin is a residual basin, below which there is probably a larger Paleozoic sedimentary basin. The North Yellow Sea Basin comprises four sags and three uplifts. Of them, the eastern sag is a Mesozoic Cenozoic sedimentary sag in NYSB and has the biggest sediment thickness; the current Korean drilling wells are concentrated in the eastern sag. This sag is comparatively rich in oil and gas resources and thus has a relatively good petroleum prospect in the sea. The central sag has also accommodated thick Mesozoic-Cenozoic sediments. The latest research results show that there are three series of hydrocarbon source rocks in the North Yellow Sea Basin, namely, black shales of the Paleogene, Jurassic and Cretaceous. The principal hydrocarbon source rocks in NYSB are the Mesozoic black shale. According to the drilling data of Korea, the black shales of the Paleogene, Jurassic and Cretaceous have all come up to the standards of good and mature source rocks. The NYSB owns an intact system of oil generation, reservoir and capping rocks that can help hydrocarbon to form in the basin and thus it has the great potential of oil and gas. The vertical distribution of the hydrocarbon resources is mainly considered to be in the Cretaceous and then in the Jurassic.  相似文献   

自组织竞争人工神经网络在砂岩型铀矿测井数据解释中的应用     

徐建国  ;吴显礼  ;王卫国 《国外铀金地质》2008,(2):114-118

详细介绍了自组织竞争人工神经网络模型结构、原理和钻孔岩性自动识别过程,给出了神经网络模型在钻孔岩性自动识别过程中的有效性实例。自组织竞争人工神经网络具有自组织能力、自适应能力和较高的容错能力;与BP算法相比较,计算量小,收敛速度快,且不需要已知的先验信息而自动确定分类类别。钻孔岩性识别结果与岩心地质编录的对比试验表明,在砂岩型铀矿测井数据的解释中,应用自组织竞争人工方法可较好地完成钻孔岩性自动分类。  相似文献   

一种新型遥感影像快速匹配算法(英文)     

Jin Liu  Li Yan 《地球空间信息科学学报》2008,11(3):197-200

An iterative algorithm to calculate mutual correlation using hierarchical key points and the search space mark principle is proposed. An effective algorithm is designed to improve the matching speed. By hierarchical key point algorithm and mutual correlation coefficients of the matching images, the important points can be iteratively calculated in the images hierarchically, and the correlation coefficient can be obtained with satisfactory precision. Massive spots in the parameter space which are impossible to match can be removed by the search space mark principle. Two approximate continuities in the correlation image matching process, the image gray level distribution continuity and the correlation coefficient value in the parameter space continuity, are considered in the method. The experiments show that the new algorithm can greatly enhance matching speed and achieve accurate matching results.  相似文献   

镇泾地区延长组河流相砂体分布与圈闭形成的关系研究   总被引：3，自引：1，他引：2  

张宗林  周文  苏付义 《矿物岩石》2008,28(4)

鄂尔多斯盆地镇泾地区侏罗系地层以三角洲-湖泊沉积体系为主,研究区范围内主要发育主河道和部分分流河道砂体。研究区构造平缓,主要为单斜地层、在东南部存在大型鼻状构造。通过对主要储层段(长6、8油层组)砂体分布及与构造之间关系进行研究,分析砂体走向与构造线方向的关系认为在构造单斜地区,当两者相交时(交角β≠0)是形成圈闭的关键因素之一,在大型鼻状构造地区因构造线的弯曲与河道砂体组合可以形成圈闭。根据研究区砂体分布和构造线组合出4种地层-岩性及岩性圈闭。利用构造图与砂体分布图对主要储层段存在的圈闭确定出长6、8油层组10个层圈闭。  相似文献