Integrated monitoring of the hydro-morphodynamics of a beach protected by low crested detached breakwaters

The aim of this paper is to propose an integrated low cost system for monitoring the performance of beach defence works during storms. For this purpose, the site of Igea Marina, Northern Adriatic Sea, Italy, which is protected by low crested detached breakwaters, is selected. The monitoring system is composed by a video installation, for the identification of the shoreline position and of the intertidal bathymetry at high space and time resolution, and a 2DH numerical model, to reconstruct the hydrodynamics induced by coastal defenses. The accuracy of the monitoring system is verified against available measurements of waves and currents performed during a field campaign with acoustic Doppler profilers. Assimilation of data on the shoreline position in 2DH model operatively working is challenging in the improvement of the production of risk maps. These show the current intensities and flooded areas during forecasted storms. First promising results suggest the possibility of setting up an early warning tool.     

海洋水色遥感资料的经验正交函数分析

海洋中浮游植物进行光合作用,固定有机碳,是海洋生物链的基础,因此,研究浮游植物生物量的指标——光合色素(主要是叶绿素a)的时空变化具有十分重要的意义。我国自50年代以来,对海洋浮游植物色素分布进行了大量的现场调查和研究,取得了一些初步结果[1-3]。     

Temporal and spatial variability of chlorophyll concentrations in the Bering Sea using empirical orthogonal function (EOF) analysis of remote sensing data

Seasonal and interannual variability of surface chlorophyll concentration in the Bering Sea was examined using Empirical Orthogonal Function (EOF) analysis of data obtained by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) from 1998 to 2002. The analysis of normalized monthly fields (removing temporal and spatial monthly means) shows that different temporal and spatial patterns are evident in the eastern and western Bering Sea during the spring bloom period. The first EOF mode explains 30% of the variability and shows how the eastern shelf break region and the western Bering Sea are out of phase during the spring bloom. The second EOF mode (17.6%) indicates a pattern involving the eastern shelf break region and the Kamchatka Basin. This strong east–west signal is linked by both surface winds and light. EOF modes of wind-speed anomalies, derived from Special Sensor Microwave Imager (SSM/I), and photosynthetically active radiance (PAR) from SeaWiFS, show a similar dipole feature where the east–west pattern is related to the position and strength of the Aleutian Low pressure system. In years when the Aleutian Low shifts from west to east, weaker wind stress facilitates the development of stratification resulting in a strong spring bloom in the western Bering Sea. The variability of spring chlorophyll has a strong connection with variability in atmospheric forcing in the Bering Sea.     

Empirical orthogonal function analysis of short time series of sectional data in the tropical western Pacific

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Experimental study on wave transmission coefficient, mooring lines and module connector forces with different designs of floating breakwaters

This paper presents the results and conclusions obtained from the physical model tests carried out with four different designs of floating breakwaters. Changes from a basic design have been introduced in order to evaluate the improvement in the efficiency as a coastal protection structure. Incident and transmitted waves have been measured, as well as the efforts in the mooring lines and module connectors. It has been found that the width of the pontoons is one of the key design parameters, while small modifications in the floating breakwater's cross section shape are less determinant in its hydrodynamic behaviour and in mechanical loads in the discussed ranges. 2D and 3D tests were conducted, observing the great influence that the wave obliquity has in the module connector forces.     

Shoreline variability via empirical orthogonal function analysis: Part II relationship to nearshore conditions

The method of empirical orthogonal function (EOF) or principal component analysis (PCA) was used to investigate the spatial and temporal variability of shoreline data sets from Duck, North Carolina, the Gold Coast, Australia, and the United States Pacific Northwest. In the present work, an attempt is made to relate the individual modes of shoreline variability identified by the EOF analyses to select parameterizations of the nearshore environment. The parameters considered include the wave energy (E), the cross-shore and longshore wave energy fluxes (F_x and F_y), the wave steepness (H_o/L_o), the non-dimensional fall velocity parameter (Ω), the profile parameter (P), the surf-similarity parameter (ζ), and a surfzone Froude number (F_r). Correlation analyses were used to evaluate the linear relationship between each of these parameters and the temporal eigenfunctions, c_k(t), associated with individual modes of shoreline change. Typically, strong correlations were observed between longshore uniform modes and the monthly means of several of the nearshore parameters.     

1973 年以来射阳河口附近海岸蚀淤变化遥感分析

以射阳河口北部扁担港口和射阳河口南部斗龙港口之间的海岸作为研究区,基于1973,1987,2000和2013年四期Landsat影像提取了该岸段岸线,并进行了时空变化分析。结果表明,射阳河口以北的扁担港口—射阳河口岸段仍处于侵蚀状态,呈现侵蚀—淤积—缓慢侵蚀的变化格局,40 a间侵蚀面积为12.6 km2,淤积面积为1.0 km2;射阳河口以南的射阳河口—斗龙港口岸段处于淤积的态势,呈现淤积—快速淤积—缓慢淤积的格局,40 a间淤积的面积为223.1 km2,仅在2000~2013年间该岸段北部出现了侵蚀。结论是虽然射阳河口以南岸段仍总体处于淤积的过程中,但是近年来江苏海岸的侵蚀范围已经扩展到了射阳河口以南,这证明了江苏海岸侵蚀岸段有进一步扩大的趋势。     

基于EOF分析中西太平洋金枪鱼围网渔场的海洋环境

根据近10 a ECMWF的数值预报资料,主要分析了中西太平洋金枪鱼围网渔场四季和全年的海表温度、海面风场、有效波高的空间分布,利用经验正交方法(Empirical Orthogonal Function, EOF)和经验模态分解(Empirical Mode Decomposition, EMD)分析了空间和时间变化特性。研究表明:海表温度、海面风场、有效波高的四季及全年时空分布有着显著的变化;海表温度的第一、第二、第三模态方差贡献率分别为62.59%、10.98%和6.7%,具有0.5 a、1 a和3 a的周期变化;海面风场的第一、第二、第三模态方差贡献率分别为40.29%、18.39%和9.36%,具有0.2~0.25 a、0.5 a和1 a的周期变化;有效波高的第一、第二、第三模态方差贡献率分别为44.17%、17.35%和10.96%,具有0.2~0.3 a、0.5~1 a和1 a的周期变化。     

赤道太平洋温度、流场距平EOF分析及与厄尔尼诺的关系

利用EOF分析方法,讨论了最近20a赤道太平洋次表层温度、纬向流距平与厄尔尼诺的关系.结果表明:赤道太平洋海温距平EOF分析第一、二主分量占总量的近80%,其中第一主分量类似于厄尔尼诺模态,第二主分量类似于暖池模态;后一模态存在着突变和渐变两种过程,其中由冷位相变暖位相过程为渐变过程,而暖位相变冷位相过程为突变过程.厄尔尼诺事件是赤道西太平洋暖池突变过程的结果.赤道太平洋纬向流距平EOF的第二主分量代表赤道西太平洋潜流和东太平洋南赤道流的变化,这个模态存在着半年左右的振荡和与厄尔尼诺同位相的年际振荡两种频率.另外,它还存在明显的年代际变化.赤道西太平洋潜流和东太平洋南赤道流减弱是产生厄尔尼诺的必要条件.统计回归分析表明,赤道太平洋海温距平和纬向流距平EOF的第二特征向量的时间系数对厄尔尼诺和拉尼娜均有一定的预报意义.     

海平面变化的小波和自回归模型集成预测试验

针对海面变化预测时间序列模型中趋势组份和周期(准周期)组份的提取和预测问题,基于吴淞站1955～2001年月平均潮位序列,采用小波分析(WA)与自回归(AR)模型相结合的方案,对小波分解的不同尺度分量序列,借助于时间序列模型进行分量预测,再对它们进行叠加建立预测模型,进行了月平均潮位预测试验.以1955～1996年数据为基础建立模型,1997～2001年数据作为验证,结果表明两种方法的结合使用显示了较好的效果,具有较高的精度.     

海滩体积时空变化和波浪场的奇异谱分析

海滩响应波浪动力作用的变化是海岸带陆海相互作用研究的重要内容.利用奇异谱分解方法对南湾海滩连续实测剖面的体积变化值与南湾逐日波高变化值的相关关系进行了探讨,以诊断分析波浪在海滩变化过程中的内在作用机制,结果表明:(1)海滩体积的时空变化与波浪作用力有明显的相关关系;(2)海滩响应波浪动力作用变化最明显的地方是在中间岸段,在直线岸段次之,在遮蔽岸段最弱;(3)对海滩变化有较强作用的波浪场分别位于近岸及其与上下岬角连线的邻近区域.     

梭鱼人工养殖群体与自然群体的随机扩增多态DNA(RAPD)分析

利用随机扩增多态DNA(RAPD)技术,对黄河口海域棱鱼人工养殖群体与自然群体的遗传多样性进行了分析比较,以期由分子水平了解梭鱼的种群遗传多样性背景及人为干涉因素对梭鱼种群遗传多样性造成的影响.选用OPC组20个10碱基对(bp)的随机引物,对采自河北省黄骅市的24尾野生梭鱼和15尾人工养殖梭鱼进行了分析.选出11个扩增效果稳定的引物用于群体分析,扩增结果具有较好的可重复性.11个引物共检出112个位点,其中养殖群体中有94个表现多态,多态比例为83.93%;自然群体在96个位点上表现多态,多态比例为85.71%.经计算,养殖群体的遗传多样性指数为0.2124,自然群体的遗传多样性指数为0.2271;梭鱼两群体间的相似系数为92.82%,遗传距离为0.0718.研究结果表明,目前黄河口海域梭鱼群体的遗传多样性比较丰富,人工养殖过程对其未造成明显的影响,估计这与人工养殖过程中人为干涉因素少(如育苗历史短、亲鱼来源于自然群体、无定向选择和近亲繁殖等)有关.这一结果表明,梭鱼的人工养殖业在黄河口海域有很好的发展前景.     

东海、黄海底层鱼类数量分布季节变化的因子分析

根据2000年春(4月)、夏(6月)、秋(9月)、冬(12月)四季东海、黄海底拖网鱼类资源调查资料,使用因子分析的方法分析了该海域鱼类数量分布的季节变化特征。R型分析发现,春季关系最密切的鱼种有4种:斑鳐、凤鲚、海鳗和黑鳃梅童鱼;夏季有5种:鳀、小黄鱼、黄鮟鱇、绿鳍鱼和长蛇鲻;秋季也有5种:带鱼、灰鲳、虻鲉、日本鲭和小黄鱼;冬季有3种:带鱼、鳄齿鱼和发光鲷。历史资源调查证实,夏季的这5个鱼种之间以摄食与被摄食关系为主。进一步分析发现,各季节关系密切的鱼种所聚集分布的水域,正是这些鱼种各季对应的生理周期洄游分布的主要水域。根据Q型分析可以得到各季的综合优势鱼种及其优势分布水域,发现带鱼和小黄鱼是东海、黄海渔业资源的绝对优势鱼种,除了带鱼、小黄鱼以外,其他的综合优势鱼种都是一些价值较低的、生长速度较快的小型鱼类。     

Variance estimate and taxonomic resolution: An analysis of macrobenthic spatial patterns at different scales in a Western Mediterranean coastal lagoon

The effects of taxonomic resolution on the variance estimates of macrobenthic assemblages were studied at four spatial scales in a Mediterranean coastal lagoon. The assemblages exhibited significant differences at all the investigated scales; however, spatial variability was mainly associated with the smallest and the largest scales. The decrease of taxonomic resolution (from species to family) was not related to a decrease of the overall variability and similar estimates of variance components were obtained using species and family resolution levels. The ordination models derived from species and family abundances were very similar both in terms of location and dispersion effect, while further aggregation to the class level began to alter the observed spatial patterns. In future studies aimed at assessing changes in the lagoon, resources derived from the cost reductions achieved using family level could be employed to plan more frequent surveys and/or to adopt complex spatial sampling designs with a high number of replicates.     

花鲈Claudins基因家族的鉴定、进化分析及对环境盐度的表达响应

Claudin (cldn)是细胞间紧密连接蛋白的重要功能和结构组件,通过控制细胞旁通路通透性参与渗透压平衡的调节。本研究对花鲈(Lateolabrax maculatus)cldns基因家族进行了系统的鉴定分析,结果表明:花鲈cldns基因家族共包含55个成员,分布于16条染色体上,其中34个cldns基因在哺乳动物体内有对应直系同源基因,其余21个cldns是硬骨鱼所特有。选择压力分析显示预测的花鲈cldns蛋白的跨膜区域存在14个受正选择作用的氨基酸位点,这些正选择位点可能与家族内基因的多样性和功能分化有关。此外,基于花鲈鳃转录组的基因表达结果表明,至少有24个cldns基因在鳃中表达,其中cldn8c、cldn10b、cldn10c、cldn10d、cldn27a和cldn30b在不同环境盐度处理后表达差异显著,表明其可能是花鲈鳃组织中调节渗透压平衡的候选功能基因。本研究成果为研究花鲈及其他广盐性鱼类cldns基因家族成员的渗透调节机制奠定了理论基础。