基于小波分析的海洋锋形态特征提取

遥感影像中海洋锋具有弱边缘(Weak Edge)信息特性,其空间尺度在不同的空间位置存在较大的差异。针对传统边缘算子只能提取某一尺度的海洋锋信息,而损失其他尺度信息不足,本文利用小波多尺度分析特性,探讨了海洋锋信息在各尺度间的分布的继承性,提出最佳尺度确定的算法框架,设计出最佳尺度确定算法的流程,进一步进行海洋锋各尺度信息的提取。最后以海面温度锋-墨西哥湾流为实例进行形态特征提取,并与典型的边缘提取算子效果在信息量、抗干扰性、定位精度、连续性和对比度上进行对比分析。试验结果表明了该算法在提取多尺度的海洋锋信息上的可行性和实用性。     

我国周边海域典型海洋锋特征建模研究

基于海洋锋空间位置、水平分布结构和垂直扩展特征等时空特征参数,结合海洋锋空间结构几何模型,建立了区域海洋锋温盐三维结构快速重构特征模型,对黄海西部沿岸锋和东海黑潮中段锋锋区温度场进行了仿真计算,并与实测数据进行了比较分析,实验结果表明：仿真结果与实测数据符合较好,实验结果验证了特征模型的有效性和可推广性。海洋锋区声速具有明显的水平梯度变化,对声纳的水下探测和反探测产生显著影响,因此,需要建立实时估计获取锋区水下温、盐结构的方法。海洋锋特征模型能够快速有效地重构海洋锋区温度场,为实时获取海洋锋水下结构特征提供了方法。     

1987年南半球夏季南设得兰群岛邻近海域CWB的特征及其成因

本文利用1987年1-2月中国第三次南极考察期间在南设得兰群岛邻近海域获得的STD资料,详细阐述了群岛以北海域中的一条海洋峰——大陆水边界(CWB)在表层、次表层和深层的表观特征,并给出了测区表面的地转流分布,计算了斜压变形半径R_bc.作者认为这里沿锋向海流处于地转平衡状态,且锋主要由边界流的作用所致.CWB的沿锋尺度约360km,平均宽度约30km.     

融合scSE模块的改进Mask R-CNN海洋锋检测方法

海洋锋是重要的中尺度海洋现象,具有数据量小、目标小、弱边缘等特性。针对实际检测任务中弱边缘、小目标海洋锋的检测精度低、错检及漏检率高等问题,融合scSE (spatial and channel Squeeze&Excitation)空间注意力模块构建了一种改进的Mask R-CNN海洋锋检测模型。该方法首先对Mask R-CNN骨干网络结构进行改进,采用scSE模块引导的ResNet-50网络作为特征提取网络,通过加权策略对图像通道和空间位置进行特征突出,提升网络对重要特征的提取能力;其次,针对海洋锋目标边缘定位不准确的问题,引入IoU boundary loss构建新的Mask损失函数,提高边界检测精度。最后,为验证方法的有效性,从训练数据和实验模型上,分别设计多组对比实验。实验结果表明,相比传统Mask R-CNN、YOLOv3神经网络及现有Mask R-CNN改进网络,本文方法对SST梯度影像数据集上的强、弱海洋锋检测效果最好,定位准确率（IoU,Intersection-over-union））及检测精度（mAP,Mean Average Precision）均达0....     

黄海西部春季海洋锋及其与渔业的关系

海洋锋是一种海洋学特征。作者根据1960—1981年的资料,用温、盐指标依聚类方法分析研究了该海区的环流结构和水团的混合带,最后定出了海洋锋的位置。本文还描述了春季黄海中的海洋锋的分布及特征,及其与鹰爪虾、鲅鱼、鲐鱼洄游规律和渔场的关系。     

合成孔径雷达图像中海洋内波的特征检测

海洋内波在合成孔径雷达(SAR)图像中具有特定纹理分布,因此可以根据海洋内波SAR图像的纹理分布特性,进行内波海面特征检测。利用功率谱对具有不同纹理特征的SAR图像进行分析,并对特征进行分类统计得出内波的功率谱特征。在海洋内波区域,利用多孔小波变换及多尺度融合提取海洋内波特征,在此基础上对波-流散射系数进行提取。提出了"内波特征的功率谱特征-多孔小波综合检测算法",为海洋内波参数反演奠定了基础。     

东海海洋锋的波动及演变特征

本文利用近十年来获得的ＮＯＡＡ卫星红外影像，较为系统地分析了东海海洋锋（黑潮锋、对马暖流锋和浙江沿岸锋）的波动谱特征以及形态的演变。同时还利用浮标测流结果分析了锋面波动中的流态。分析结果表明：东海黑潮锋通常存在４～５个折叠波形，其波长平均约２００ｋｍ，波动随黑潮流向东北方向传播，速度约１６ｃｍ／ｓ。浙江沿岸锋的波动多呈锯齿形，其波长较短，波数多。在浙江沿岸锋波动发展过程中，其波长从开始的２０～４０ｋｍ发展成３０～６０ｋｍ，它们约以１８ｃｍ／ｓ的速度向东北方向传播。东海海洋锋波动演变形态复杂，其中黑潮锋的波动可能演变成锋面涡旋、暖丝和暖环。     

东北亚海温度盐度主要特征研究

基于WOA东北亚海1/10°温盐统计数据产品、海洋水文图集和历史海洋调查相关研究成果,系统研究了东北亚海温度盐度结构主要特征;春季和夏季,黄海东西沿岸存在温度低值中心;描述和定义了黑潮右侧次表层伸向西南方向的"黑潮逆流冷舌";研究了东北亚海主要流系和部分海洋中尺度现象(海洋涡旋、海洋锋、上升流、长江冲淡水等)引起的温度盐度结构特征。日本海40°N附近海洋温度锋一年四季都比较强,中国东海海面温度锋在冬季和春季比较强。台湾东北冷涡和日本以南超级暖涡附近是温度极值中心。该研究成果为东北亚海海洋水文环境保障提供技术支撑。     

海洋平台结构形状与拓扑优化设计

以实际环境荷载作用下的实际海洋导管架平台结构为对象，研究了海洋平台结构在风，流，海冰等多荷载模式和多荷载工况下的优化设计的理论方法和应用技术，建立了结构尺寸优化，形状优化和拓扑优化问题的统一模型。计算结果反映出形状优化比尺寸优化所得设计更优，而拓扑优化的设计效果最好。不同的荷载工况对应的最优拓扑形式不同，因此在实际设计中应考虑实际的荷载工况，选取不同的拓扑形式。     

山东半岛东北部海洋牧场海域冬季海水流动的时空分布特征

为丰富山东半岛近岸海洋牧场海域水动力环境研究,本文利用2019年12月3日至2020年1月1日在山东半岛东北部4个海洋牧场获取的海流资料,应用功率谱分析、调和分析、余流主轴分析和相关分析,探讨冬季各海洋牧场的潮流、余流特征及其影响机制。结果表明:(1)各海洋牧场潮流由M2分潮潮流主导,受地形边界限制,各主要分潮潮流均为往复流,且潮流椭圆主轴平行岸线。(2)不同海洋牧场呈现不同的余流特征和影响机制。烟台安源海洋牧场余流大致垂直于岸线流向近岸,平均流速约为0.9～1.7cm/s;日平均流以经向流为主,与经向风呈显著正相关,海水受北风强迫在近岸堆积。威海瑜泰海洋牧场余流大致垂直于岸线流向外海,平均流速约为1.4～1.7 cm/s;日平均流亦以经向流为主,与经向风呈显著负相关,表层海水受北风强迫向近岸堆积,在近岸产生下降流,海面以下存在北向的离岸流。威海西港海洋牧场余流为东南向,平均流速约为2.5～3.0 cm/s,日平均流具有较为显著的正压性。荣成楮岛海洋牧场余流为东北向,平均流流速约为5.6～9.9 cm/s,日平均流表明海水沿桑沟湾南岸流出海湾,推测桑沟湾海水在湾内逆时针流动。研究成果利于进一步研究山东半岛邻近海域动力环境的多尺度时空变化特征及其影响机制。     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

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.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

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。     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

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.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

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.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

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.     

INFORMATION FOR AUTHORS

<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,     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.