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《海洋通报(英文版)》2017,(1)
自2000年以来,渤海海域每年都有赤潮发生,这往往使渤海沿海水域受其影响。卫星遥感技术和海洋水色观测卫星图像,已经成功地用于识别和观测赤潮的发生、发展和消亡。然而,由于研究的水体、使用的遥感数据和建模方法都各不相同,因此需针对渤海海域的水体特点建立特定的赤潮反演模型。本文利用MODIS光谱反射率数据和渤海海域实测叶绿素a浓度进行了相关分析,选择表达式(B10-B8)/(B13-B8)作为渤海海域赤潮反演的指标,相关系数达到0.781 5,呈现显著相关结果。研究发现2014年渤海海域赤潮灾害的时空分布特征较为明显。其中渤海海域赤潮大规模爆发的主要原因归结于其半封闭型的地理形态导致的水交换不畅和沿岸径流的大量陆源物质输入,河流输入是陆源污染入海的主要来源。然后,本文利用云覆盖较少的GOCI遥感数据,建立了一个改进型赤潮指数的赤潮反演模型,并且证明了在浑浊水域中描述赤潮的有效性。2014年5月15日、26日和30日的每小时RI图像在一天中呈现出基本一致的赤潮变化,并且一天中渤海海域的赤潮面积变化非常明显,赤潮藻类优势种的垂直迁移可能是导致赤潮表面表达短期变化的主要原因。 相似文献
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近年来,海州湾赤潮暴发日益频繁,对当地经济发展和生态安全构成严重威胁.本文以海州湾2004～2006年每年5～10月赤潮实测资料和同期的水文气象资料为研究对象,首先通过因子分析的方法降低模型的维数,在17种与赤潮生消过程有密切联系的环境要素的基础上提取出营养盐、温度、耗氧量和pH值、水动力、降水等共计7个特征因子.然后对因子分析的结果结合赤潮状况利用支持向量机建立赤潮状况判别模型,采用径向基函数(RBF)作为核函数,并通过选择合适的模型参数组合,取得了90%以上的平均判别正确率,可以为沿海生产和管理部门发布赤潮预警信息提供依据. 相似文献
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非结构化网格下近岸波生流数值模拟 总被引：5，自引：2，他引：3
波浪破碎产生的近岸流是近岸海域关键的水动力因素之一。基于近岸波浪的椭圆型缓坡方程和二维近岸波生流方程,建立了非结构化网格下近岸波浪破碎形成的近岸流数值模型。数值模型中,在空间上采用有限体积法进行数值离散,在时间上采用欧拉向前格式数值离散。数值计算结果表明,该数值模型可以有效地模拟近岸波浪破碎产生的近岸流。 相似文献
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海洋浮游生态系统连续介质动力学模型的建立 总被引：3，自引：0，他引：3
运用质点、连续介质和状态变量等观点来描述海洋浮游生态系统,根据生物生命运动、生化反应、水动力学和物质守恒等基本规律,建立海洋浮游生态系统动力学的模型方程。推广地球流体力学的湍流二阶闭合理论,建立实用的雷诺平均生态系统动力学模型方程及其二阶相关项的闭合模型方程,将生态动力学状态变量的湍扩散参数化。本文还讨论了该模型与通常的N-P-Z-D模型的关系,提出了其适用范围。 相似文献
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《海洋技术学报》2017,(6)
自2000年以来,渤海海域每年都有赤潮发生,这往往使渤海沿海水域深受其害。世界首个地球同步海洋水色成像仪GOCI在监测渤海海域赤潮的分布和短期运动上具有明显的优势。利用GOCI遥感数据,建立了一个改进型赤潮指数(red tide index)的赤潮反演模型,并且证明了在浑浊水域中描述赤潮的有效性。2014年5月15日、26日和28日的每天8幅RI图像均呈现出赤潮面积先增大后减小的变化,并且使用RI阈值3.8,4和4.2,虽然赤潮面积有所改变,但1 d内相对的变化趋势仍基本保持一致。5月15日、26日和28日赤潮区域叶绿素a浓度均在11:30达到最大值,1 d内赤潮区域叶绿素a浓度的不断变化是引起赤潮的藻类垂直迁移导致的结果,从而导致赤潮1 d内发生明显的变化。因此,GOCI可以有效地进行渤海赤潮的短期和长期运动监测。 相似文献
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海洋浮游生态系统连续介质动力学的模型的建立 总被引：3，自引：0，他引：3
运用质点、连续介质和状态变量等观点来描述海洋浮游生态系统,根据生物生命运动、生化反应、水动力学和物质守恒等基本规律,建立海洋浮游生态系统动力学的模型方程,推广地球流体力学的湍流二阶闭合理论,建立实用的雷诺平均生态系统动力学模型方程及其二阶相关项的闭合模型方程,将生态动力学状态变量的湍扩散参数化,本文还讨论了该模型与通常的Ｎ－Ｐ－Ｚ－Ｄ模型的关系,提出了其适用范围。 相似文献
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渤海是我国的内海,由于其独特的地理环境特点及渤海沿岸地区经济社会的快速发展导致的污染排放和生态破坏,渤海已成为我国污染最为严重的海区之一。“十五”期间虽然各级部门为渤海环境治理做出了大量努力,但渤海环境状况仍在进一步恶化。如污染总面积虽无明显的增大趋势,但近岸海域的污染程度显著加重;从赤潮发生情况来看,虽然近年来赤潮年发生次数在逐渐减少,但赤潮面积总体上呈增大趋势,而且有毒藻类引发的赤潮次数和面积大幅增加;从渤海的主要富营养化物质变化来看,近年来渤海近岸海域其浓度呈加速增大趋势;从污染源变化来看,海上污染源的增速明显高于陆源。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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《海洋学报(英文版)》2014,(9):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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Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
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This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
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Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献