分层流体中内孤立波在潜浮式竖直薄板上透射和反射

采用边缘层理论研究了两层流体系统中内孤立波在潜浮式竖直薄板上的透射和反射问题,提出了非线性演化方程的“初值”条件,分析了内孤立波与薄板非线性相互作用的效应。研究表明:流体层的密度比以及薄板伸入上下层的深度对于反射和透射波结构具有显著的影响,薄板伸入下层越深、密度差越小,则薄板阻碍孤立波透射的效率越高;透射波通常演化为单峰孤立波和迅速衰减的尾波,反射波演化为缓慢衰减的尾波列;对于具有小密度差的跃层结构,内孤立波在潜浮式竖直薄板上的透射及其演化近乎是无障碍的。     

Geographical distribution of fish catches and temperature variations in the northeast Atlantic since 1945

Warming of the northeast Atlantic is expected to affect the location and productivity of fish stocks. It is examined whether variations in catches of cod, herring, mackerel, anchovy and sardines in the ICES statistical areas are related to variations in ocean temperature. Temperatures at certain locations along the Norwegian coast are taken as proxies for temperatures in the Norwegian Sea and the North Sea. It is found that the catches of cod in the North Sea are inversely correlated with temperature and that recruitment and catches of cod in the Norwegian Sea and the Barents Sea are positively related to temperature. There is also some indication of a positive correlation between temperature and the catches of mackerel in the North Sea and the Norwegian Sea, and between temperature and the catches of sardines in the North Sea.     

Chalk shore platform erosion in the vicinity of sea defence structures and the impact of construction methods

Erosion of the intertidal chalk platform in the vicinity of groynes and seawalls is evident to the naked eye along many stretches of the engineered coastline of southeast England, leading to undermining and eventually failure of these structures. However, quantification of the magnitude and spatial extent of the erosion has been difficult to date because of a lack of data about the past elevation of the platform. The application of softcopy photogrammetry makes it possible to recreate past platform elevations from historic air photographs and to compare these with elevations from modern air photographs. Coastal sea defence structures have been installed along the chalk coast east of Brighton at various dates over the past 70 years. During this period, the construction methods have changed from predominantly manual labour to a reliance on heavy machines. The analysis of erosion patterns around structures built since the 1970s using heavy machinery show that surface lowering is 4 to 25 times greater in the vicinity of these structures than across the platform as a whole. In contrast, there is no similar pattern of increased erosion around structures built using predominantly manual labour in the 1930s. A four fold increase in average surface lowering is found also along a vehicle trackway that crosses the mid platform. Depressions developed by enhanced lowering in the front of seawalls generate their own dynamic of increased erosion by trapping pebbles and cobbles that enhance the abrasion of the chalk through bedload transport under standing waves in front of the walls.     

黄、东海环流的数值研究Ⅲ——正压环流的数值模拟

依据黄、东海环流的的动力学模型 ,运用“流速分解法”对黄、东海正压环流进行了数值模拟。计算结果表明冬季黄海正压环流主要受风应力影响 ,基本形态为黄海暖流由济州岛西南进入南黄海中部 ,其东西两侧分别为两支向南流动的沿岸流 ;夏季主要受到潮致体力的影响 ,为一逆时针涡旋。东海环流主要是边界力作用驱动的结果 ,东海黑潮、台湾暖流和对马暖流较稳定。冬季风应力对东海环流表层流场有消弱作用 ,在夏季则有一定增强作用。     

Formation of Equilibrium Beach Profile of the Abandoned Yellow River Delta Coast in North Jiangsu

The abandoned Yellow River Delta coast is a typical erodible silty and muddy coast in China. The paper analyses the marine dynamic characteristics and the mechanism of beach erosion of this area. Analysis and calculation show that in this sea area wave and tidal current action should be considered. Based on the above analysis, an equilibrium beach profile calculation model is developed, in which the wave-current interaction is considered while sediment supply and sediment re-deposition are neglected. The model consists of four parts: (1) calculation of wave parameters, (2) calculation of velocity due to wave-current interaction at different water depth, (3) calculation of friction velocity and shear stress at different water depths, and (4) calculation of the amount of sediment erosion, erosion intensity and variation of beach profile. Calculated results are in good agreement with observed data. Finally, the evolution tendency is discussed and the equilibrium beach profile of this coast is calculated. B     

Fractal Dimension and Fractals in Ocean Engineering

- This paper discusses the application of fractal dimension and fractals in ocean engineering. To handle some ocean environment problems, the existing fractal method, in which the fractal dimension is a constant, can be used. For some complicated problems in ocean engineering, this paper presents the concept of the variable dimension fractals (D = f(r)), i. e., the fractal dimension D is the function of characteristic scale r instead of a constant. By using variable dimension fractals, several deformation and stress states of offshore structures are described.     

Subunit composition and chromophore content of R-phycocyanin and allophycocyanin from Porphyra haitanensis

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南海輓近海平面变化与构造升降初步研究

揭示南海輓近海平面变动和古岸线诸多遗迹,探讨晚更新世以来海平面变化一般规律,初步分析南海周缘中全新世和现代地壳构造升降速率,得出本区海平面上升率适中参考值为0.10—2.0mm/a,初步估算未来50年内海平面变化趋势在1.26—4.0mm/a之间;而构造升降受块断差异运动控制,一般规律是南海北部沿岸自东向西递减,由福建南部1.15mm/a至海南岛南部0.54mm/a。近代地壳形变资料亦证实这种变化规律。     

地质环境特征及工程适应性与选择性分析——青岛市城市地质环境研究

根据地形地貌、地质构造、水文地质条件将青岛市划分为６个工程地质亚区，论述了各亚区地质环境特征，结合不同城市建筑工程特点，进行了工程场地适应性和选择性分析评价，为充分合理利用城市地质环境提供良好依据     

Distribution of As, Cr and V species in the Po-Adriatic mixing area, (Italy)

The distribution of dissolved and participate concentrations of As, Cr and V was investigated in the mixing area of the Po river in five surveys over the period March 1992-March 1995. The data obtained indicate noticeable contamination of coastal waters of the northern Adriatic with Cr but not As or V. Total dissolved concentrations for As and V were comparable with oceanic levels but were higher by a factor of 4 for Cr. These results suggest either low anthropogenic inputs of As and V, from terrigenous and atmospheric sources, or efficient removal mechanisms. The investigated metals had low reactivity during freshwater-seawater mixing and the distribution of concentrations in the dissolved and solid phases suggests that the dilution process is the main factor controlling the transport of these metals to the sea in low-to-medium solid transport conditions. Further investigations are required to elucidate the behavior of these metals during high solid transport conditions. Significant changes in the speciation of As occurred during the transition between the two end-member matrices. In the coastal waters of the northern Adriatic, the arsenite fraction in winter, and the arsenite and dimethylarsinate fractions in summer increased with respect to riverine waters. Changes in the speciation of chromium were minor, but also showed a small increase in reduced species in marine waters.