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WAVEWATCH-Ⅲ海浪模式中岛屿次网格效应的检验与比较 总被引：1，自引：1，他引：0
综合利用水深数据和高分辨率海岸线数据,在优化WAVEWATCH-Ⅲ模式计算网格的基础上,发展了波能通量穿透度系数自动计算方法,完善了岛屿次网格地形效应计算方案;并与直接提高网格空间分辨率来分辨多岛屿地形处理方案的计算效果进行对比研究。表明:岛屿次网格效应方案充分体现了海岸和多岛屿地形对海浪传播的影响,且主要是对低频海浪能量的抑制和阻碍作用,对模式计算结果有明显改善;在低分辨计算网格中考虑岛屿次网格效应时,模式对有效波高的计算精度与高分辨率网格的结果精度相当,且计算效率有显著提高。 相似文献
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岛屿岛礁海域海浪能谱模型研究进展 总被引：2，自引：0，他引：2
波浪能谱模型在岛屿岛礁海域的波浪预报研究和海洋工程中应用广泛,但存在模式计算格点无法充分体现岛屿岛礁的复杂地形特征和很难刻画波浪受到岛屿岛礁影响发生变形物理过程等两个关键问题。多重网格嵌套方案、岛屿次网格地形效应计算方案以及非结构网格、无网格、动态自适应四叉树网格等技术在体现岛屿岛礁复杂地形方面取得了较好的效果;将相位解析模型与波浪能谱模型优势互补是提高能谱模型对岛屿近岸波浪变形物理过程计算能力的一个有效方法。开展球坐标系下波作用密度谱方程的自适应四叉树网格求解方法研究,借鉴相位解析模型最新成果完善能谱模式的绕射、反射、底摩擦等物理过程,是提高岛屿岛礁海域海浪精细预报技术水平的前沿性、探索性研究方向。 相似文献
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旨在提高模拟海域潮流计算的分辨率,着重研究在计算垵中存在宽度小于一个网格步长的防波堤、狭长岛屿以及小于一个网格步长的港口口门、防波堤开口等特殊地形的数值处理方法。以连云港西大堤工程为例,进行了数值计算,取得了满意的结果。 相似文献
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采用WRF模型构造的再分析风场作为海浪模式的驱动场,由于嵊泗位于长江、钱塘江的交会处,附近海域地形复杂,不可避免的会产生折射、变浅、绕射、波浪破碎、非线性波相互作用等近岸物理过程,因此采用第三代海浪数值模式SWAN。本文采用矩形网格和加密的三角网格对2012年4月嵊泗列岛海域波浪场进行模拟,并将模拟的有效波高与实测数据进行验证和误差指标分析,分析结果显示,2种网格模拟的海浪场的效果都很好,其中三角网格的模拟效果更好,可以进一步提高海域有效波高模拟的准确度,可以更精确的刻画复杂的地形。 相似文献
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近岸台风浪的嵌套数值模式 总被引：2，自引：0，他引：2
本文将混合数值海浪模式与第三代海浪模式结合起来研究近岸台风浪。在西北太平洋及中国海域采用混合数值海浪模式预报海浪，而在近岸台风区域采用包括海底绕射项的ＷＡＭ模式，该小区域的浪边界条件由大区域上得到的计算结果提供。我们建立的数值近岸台风浪预报系统既利用了混合海模式节省计算机时的优点，又用细网格的ＷＡＭ模式抓住了近岸海底地形对海浪的作用，该模式的后报结果表明，模式计算的近岸台风浪台站的实测资料符 合料 相似文献
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根据福建元洪港无长期海浪和风观测资料及该水域的多岛礁地形的特征，以邻近的平潭海洋站３０ａ实测海浪资料，采用考虑底摩擦效应的浅水波浪折射数值模式进行港区设计波高计算，并与港工程规范算法相比较，得出码头，航道口门和航道中段的设计波高参数。 相似文献
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根据钓鱼岛海域海监巡航执法保障预报、重点海洋安全保障目标精细化预报等海浪业务化预报工作的新需求,基于
WRF 海面风场预报模型,利用结构网格海浪模型WaveWatch 芋和非结构网格海浪模型SWAN （Simulating Waves Nearshore）
的嵌套计算,建立一套适用于东海区和上海近海的海浪数值预报系统。通过不同数值实验,证明此系统的稳定性和时效性。
利用观测数据对连续2 个月的有效波高值的预报结果进行检验,结果表明：24小时预报平均绝对误差在0.3 m以下;48 小时
预报平均绝对误差在0.5 m以下;72 小时预报平均绝对误差在0.7 m以下,且误差极值主要是由台风过程引起,但预报趋势
仍值得参考。对2次台风过程采用不同风场源数据进行对比试验,结果显示采用实况路径的后报风场,海浪预报精度明显改
善。对于近岸区域采用嵌套计算的SWAN模型预报结果比WaveWatch III 模型预报结果精度显著提高,证明建立的海浪数值
预报系统在满足“稳定性”和“时效性”的基础上,各尺度和分辨率的预报产品“准确性”也能得到保证。 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献
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Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations. 相似文献
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《海洋学报(英文版)》2014,(8):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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Nabil Sultan Pierre Cochonat Jean Fran ois Bourillet Florence Cayocca 《Marine Georesources & Geotechnology》2001,19(2):107-133
This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed. 相似文献