江苏中南部潮滩有孔虫特征及其与环境的关系

江苏中南部沿岸潮滩现代表层沉积物样品的定量分析结果表明其有孔虫为混合埋葬群,由原地生活分子和外海的异地分子混合而成,其特点是分异度偏高、丰度变化大、壳径偏小、壳体机械破坏较明显,富含壳径细小的浮游有孔虫。这些特点反映出埋葬群在形成过程中辐射沙洲区强大潮流的搬运作用。在搬运、沉积和埋葬过程中有孔虫壳体经受机械分选和破坏作用。埋葬群与生态环境因素和埋葬环境因素均有密切关系。     

Eustatic and hydrodynamic controls on the architecture of a deep shelf sand bank (Celtic Sea)

The architecture of a tidal sand bank in the south-eastern Celtic Sea was examined using very high-resolution seismic surveys. The bank comprises four depositional units. The lowest unit 1 is characterized by gently dipping (1–8°) strata that strike parallel to the length of the bank. Unit 1 is erosionally overlain by unit 2, which forms the bulk of the bank. This unit consists of stacked sets of downcurrent-dipping (7–12°) master bedding formed by climbing, sinuous-crested tidal dunes that are up to 20 m high. These deposits are locally incised by an anastomosed channel network (unit 3) that may represent a buried swatchway system. The upper part of the bank comprises wave-related deposits that are mainly preserved on the bank flanks (unit 4). The outer bank surface is erosional. The bank is believed to have formed during the last post-glacial sea-level rise. The facies evolution from unit 1 to unit 3 indicates an upward increase in tidal energy, mainly characterized by the thickening of dune cross-bed sets in unit 2. The majority of bank growth is inferred to have occurred in water depths of the order of 60 m. This evolution was controlled by relative sea-level rise, which is likely to have caused an episode of tidal resonance with associated strong tidal currents that were responsible for the incision of the deep, cross-cutting channels of unit 3. The transition to wave-dominated sedimentation in unit 4 is related to the decay of resonance with continued sea-level rise.     

Tidal propagation in the Gulf of Khambhat, Bombay High, and surrounding areas

The continental shelf on the west coast of India is widest off Bombay and leads into a strongly converging channel, the Gulf of Khambhat. Tides in the Gulf are among the largest on the coast. We use data on amplitude and phase of major semi-diurnal and diurnal constituents at forty-two ports in the Gulf and surrounding areas to define characteristics of the tides. We then use a barotropic numerical model based on shallow water wave equations to simulate the sea level and circulation in the region. The model is forced by prescribing the tide along the open boundaries of the model domain. Observed sea level at Bombay and currents from the Bombay High region at the centre of the model domain and from a shallow station off the port of Dahanu compare favourably with the fields simulated by the model. The simulated amplitudes and phases of the four most prominent tidal constituents also compare favourably with those observed along the coast, except at a few locations where the model spatial resolution (6.37 km × 6.37 km) appears to be inadequate to resolve the local geometry. Though this encourages us to conclude that the circulation in the region is dominated by barotropic tides, a concern is that the observational database on hydrography and directly measured currents in the region is weak.     

对虾养殖排海废水对莱州湾环境影响的动力学计算

本文采用ＡＤＩ法对莱州湾的潮流进行了数值模拟,在此基础上,计算了莱州湾沿岸养殖区排海废水在主要半日分潮作用下的空间分布状况,推算出对虾养殖废水对近海环境的影响周期。     

旋转球体上二维水体长波的一个典型驻波问题

通过分析等深矩形海湾里的潮波运动,研究了旋转球体（地球）上二维水体长波的一个典型驻波问题。分析对比该二维驻波和一维驻波,可以看出前者的图形比后者要复杂得多,但其规律性却是十分明显的;其中最主要的特征是空间上相间配置的无潮点和圆流点。由矩形海湾里潮波能量传播的分析可知,判断该二维驻波的运动学特征,主要应从波动的宏观结构着眼,而不是像一维的那样判断有无能量的传播。文章着重从理论上进行分析,但是在实际海洋中不乏这种潮波运动的广泛例证。     

用活有孔虫分布指示三亚汊道外港潮流格局

由因子分析得知,海南岛三亚湾汊道外港海底分布有四个主因子活有孔虫群,它们分别代表海湾内水体、湖冲出半盐水水体、湾外内陆架水体及内陆架与海湾水相混的过渡水体.这些水体在潮汐作用下的运动、相互混合,可由各水体的有孔虫指示.由每个主因子因子得分最高的三个属种百分含量之和等值线图所指示的外港潮流循环格局,与海洋学研究所得的结果相当一致.利用有孔虫指示潮汐汊道潮流格局尚属首次尝试,这方法对海岸开发分析泥沙运动、污染物排放等有实践意义.     

渤海、黄海、东海M2潮汐潮流的三维数值模拟

利用建立的一种新的半隐半显三维数值格式,将渤海、黄海、东海作为一个整体,采用球面坐标系下的三维潮波方程组,考虑了引潮力的作用,数值模拟了渤海、黄海、东海的M₂分潮的潮汐与潮流,结果较好地体现了渤海、黄海、东海M₂分潮的特征.通过比较65个验潮站的实测值与计算值,所得计算结果的振幅差平均为6.4cm,相角差为6.1°,计算与实测符合良好.本文给出的问潮图与Fang于1986年给出的实测占数值综合结果基本一致.对选取的47个测流站,比较了各层潮流调和常数Ucosζ、Usinζ、Vcosη、Vsinη的计算值与实测值的偏差,偏差绝对值的平均在2.6～4.9cm/s之间.并比较分析了潮流的垂直结构,所得结果与实测符合较好.首次揭示出回流点的水平位置不随深度变化这一特性.最后给出了M₂分潮的潮能消耗.     

防潮闸启闭影响下的河口水流泥沙运动状态研究

为研究防潮闸启闭与跨水工程建设对河口地区水流泥沙运动状态的影响,以河口近闸跨水工程为背景,建立了以Godunov格式有限体积法为基础的二维浅水流动数学模型和基于固液二相流理论的二维水流泥沙数学模型,并以实测资料进行必要验证,结果较为吻合。在此基础上,建立了永定新河河口区域二维水沙数值模型,将该模型应用于滨海新区Z4线一期跨河工程段的水沙分析,并对工程建设后永定新河河口水流泥沙运动的变化趋势进行预报。结果表明永定新河河口二维全沙模型较为可靠,可为河口近闸跨水工程的相关分析提供研究思路和方法。     

太湖全新世微古化石环境的辨析

为确认太湖本身和其周围地区是否有全新世海相沉积物, 对其沉积物中的微古生物化石的性质与特征, 以及它与沉积物所含的盐度、层间水、岩相等的关系进行了研究, 并通过古遗址分布情况、古地理环境等因素的调查, 确认本区的全新世生物坪葬群是长江涨潮流带来异地埋葬的产物, 不能作为海相地层的唯一依据。     

感潮河段船闸下引航道水沙运动及泥沙淤积

通过建立一维非恒定水流泥沙数学模型,对规则断面引航道中的水流泥沙运动规律及淤积特性进行了数值模拟计算,并对影响感潮河段船闸下泥沙淤积的各种因素(如干支流水位差、开通闸水头差、主流潮差等)进行了深入分析和研究。研究结果可为有关工程设计及运行管理提供参考。