环台湾岛海域全日分潮的特征和潮汐、潮流的综合性质

用97版POC海洋模式，对环台湾岛海域的全日分潮和整个潮汐，潮流综合特征进行三维数值研究。研究海域全日分潮是由太平洋传入的，且来自台湾岛北部海区传入的潮波穿越海峡。由吕宋海峡传入的全日分潮对维持南海的潮运动起着重要作用。全日分潮最大流同时线分布表层有5个圆流点，其中4个本文首次得到。台湾海峡及其以北海区和台湾东部洋区为不规则半日潮区，台湾东南为全日分潮为主的混合潮区。台湾岛北部为气旋式余流涡旋区，环绕台浅滩为反气旋余流涡旋区，澎湖水道开始的转向流预示着海峡及其邻近海区的涨潮流或落潮流的来临。     

台湾海峡潮汐和潮流的一个数值模型

本文根据二维非线性流体动力学方程,用有限差分方法同时计算了台湾海峡的半日和全日潮波,所得结果与观测值基本符合,半日潮相当大,M₂潮汐振幅在海峡西北角最大,超过2米,M₂最强潮流出现在台湾浅滩及澎湖列岛附近,可超过1米/秒,全日潮弱且变化较小,K₁和O₁平均潮汐振幅在0.2至0.3米间,平均潮流振幅大多在0.05至0.1米/秒,文章对四分日潮及潮汐余水位的分布也作了简述,在海峡西南端的靖海角附近四分日潮有一定相对重要性。     

台湾海峡M2分潮潮波研究进展

台湾海峡内各种与潮波相关的现象,可以归因于在地形及岸线的影响下自台湾海峡南北两端进入的潮波的相互作用。近20余年来台湾海峡潮波的研究获得显著进展,然而即使作为台湾海峡主要分潮的M2分潮,其相关研究中也还存在着诸多分歧。从台湾海峡M2分潮潮波分布特征及解释研究出发,并针对以往各种研究中差别较大的M2分潮潮流的分布及变化特征,归纳总结了相关研究的主要分歧：(1)对台湾海峡M2分潮潮波的研究的争议主要集中在2点,包括对自台湾海峡南、北两端进入海峡的潮波的作用范围的研究以及台湾海峡内部潮波系统形成机制的探讨;(2)台湾海峡M2分潮潮位分布研究的主要分歧在于对台湾岛西岸潮时潮差的分布特征的解释;(3)台湾海峡M2分潮潮流研究中最大的差异在于对最大潮流同潮时线分布特征的描述,其实质仍为对潮波作用范围的描述;对应于M2分潮最大潮流同潮时线研究观点的差异,在M2分潮圆流点是否存在、圆流点存在位置及圆流点旋转方向的研究上也存在着较大的差异;对台湾海峡内部椭圆率为零的分隔线位置的讨论,主要分歧在于该椭率零线靠近台湾岛附近及澎湖列岛附近时的分布状况。此外,最强流区的位置判定及极值区潮流流速量值的大小问题上也存在差异。     

台湾海峡M_2分潮的三维数值模拟

本文利用普林斯顿海洋模式对台湾海峡 Ｍ ２ 分潮作了分辨率较高的三维数值模拟。在较准确地模拟了潮汐分布的基础上,研究了 Ｍ ２ 分潮流椭圆分析、最大流同时线分布、潮流场的水平及垂直结构,最后还给出了 Ｍ ２ 分潮余流、余水位的分布。结果表明, Ｍ ２ 分潮最大流同时线在海峡中部同时形成密集区和一个圆流点;构成海峡潮波系统的两股潮波中,南支潮波的影响似超出了以往所认为的范围;最大潮流仅在近海底处急剧减小,最大流方向随深度增加右转,到近底层又向左转;潮汐余流和余水位均较弱,仅在澎湖水道、台湾浅滩附近余流较大。     

越南中部沿岸潮汐、潮流特征

基于越南中部2007年夏季潮汐、潮流实测资料,对该区域的潮汐、潮流特征进行分析,分析结果表明：1）研究海区为以日潮为主的潮汐过渡地带,每月有20d属日潮,10d属半日潮;2）潮流以不正规半日潮流为主,其次为不正规全日潮流,潮流运动以往复流为主;3）O1、K1、M2?、S2分潮流长轴方向集中在SW-NE之间,与岸线走向基本一致;4）受西南季风的影响,表层存在一沿岸形自SW向NE运动的顺时针余流场。     

环台湾岛海域半日潮波特征的三维模拟

用1997版POM海洋模式,首次应用于环台湾岛海域的潮波数值研究.得到该海域的半日潮波主要为23°N以南西太平洋传来的胁振潮.影响台湾海峡的半日潮波分别由海峡南北口传入的两支潮波,且北支强于南支.福建沿岸湄州湾-兴化湾为最强潮区,其M₂分潮最大振幅可达240cm.最强潮流区位于澎湖水道,M₂分潮最大潮流达196cm/s.环台湾岛海域潮波潮流水平结构上除海峡北部原有一个圆流点外,还发现另外存在4个新的圆流点.潮流垂直结构上主要为右偏,接近底层处为左偏.     

台湾海峡M2分潮潮汐潮流特征分布及机制研

台湾海峡同时拥有居我国第二位的大潮区和除无潮点外的小潮区，M₂分潮作为主要分量，其潮汐结构的形成机制尚存争议。本研究基于MIKE 21水动力模型，建立了台湾海峡及其周边海域潮汐潮流的数值模型，数值模拟结果与20个验潮站以及4个ADCP（Acoustic Doppler Current Profiler）观测站数据吻合程度良好。根据数值模拟结果分别给出M₂分潮在台湾海峡的同潮图、潮流椭圆和潮能通量分布，同时分别针对地形和南边界条件进行敏感性实验。研究结果表明M₂分潮受东海传入的潮波控制，潮波受台湾岛以南陡峭地形影响发生反射，由于反射波的迟角与吕宋海峡传入潮波的相近，二者叠加后向北传入台湾海峡，在与南下潮波迟角相同处，出现最大振幅，即在台湾海峡西岸形成强潮区。研究还表明，吕宋海峡传入潮波在台湾岛南缘迟角与南下潮波的相反是出现波节带结构的主要原因，其对台湾海峡西岸振幅增益也起到促进作用。     

江苏海岸中部近岸冬季潮汐和潮流特征

南黄海西侧的江苏海岸近岸区域,素以地形复杂、潮流强劲、悬沙输运剧烈著称,但是较长期的同步潮位和潮流观测数据仍然缺乏,尤其是在近岸(20 km)浅水(20 m)区域。2014年1月在大丰港附近开展了连续潮位和潮流观测,获得的数据揭示了一系列特征。此地潮汐潮流为正规半日潮,浅水分潮显著。平均潮差为3.05 m,最显著的两个分潮为M2和S2分潮,振幅分别为1.45 m和0.52 m。潮流最显著的半日分潮M2分潮和最显著的浅水分潮M4分潮在沿岸方向上振幅分别为0.84m/s和0.12m/s,在跨岸方向上振幅分别为0.24 m/s和0.01 m/s,沿岸方向占绝对优势。潮波的沿岸传播介于前进波和驻波之间,驻波的特征稍强。M2分潮潮流椭圆最大流(长轴)方向为南偏东7.4°。存在冬季沿岸向北的余流,垂向平均值的大小为2.2 cm/s。以上潮汐潮流特征为该区域海洋物质输运研究提供了基础资料。     

台湾海峡及其邻近海域潮汐数值计算

建立二维潮波模式,模拟了台湾海峡及其邻近海域(18-30°N,110-130°E)八个主要分潮(M2、S2、K1、O1、P1、Q1、K2、N2),并利用中国大陆及环台湾岛20多个潮位站的实测资料进行验证,计算结果与实测值吻合良好.此外,给出了八个主要分潮的同潮图,并逐个讨论了潮汐特征.结果显示:⑴台湾海峡中的潮波运动是北部蜕化了的旋转潮波系统和南部的前进潮波系统共同作用的结果.⑵半日分潮南、北两支潮波在台湾海峽中部汇合,而全日分潮则在台湾海峽南部海域汇合后继续朝西南方向传播.⑶半日分潮振幅最高值发生在福建省湄洲湾—兴化湾一带,全日分潮最高值则出现在雷州半岛以东一带近岸海域.⑷N2、K2和O1、P1、Q1分潮的振幅、迟角分布分别同M2与K1分潮的整体分布趋势相似.     

基于FVCOM的厦门湾及其周边海域三维潮流数值模拟

基于非结构三角形网格、干-湿判别技术和有限体积法的FVCOM（finite volume coastal oceanmodel）海洋数值模式,建立了厦门湾及其周边海域高分辨率（30 m）的三维潮汐、潮流数值模型.模拟结果同该海域2个验潮站和4个连续海流站的观测资料符合良好,较好地反映了厦门湾及其周边海域潮汐、潮流运动的变化状况和分布特征,并给出了M2、S2、K1、O1共4个主要分潮的同潮图、表层潮流椭圆、最大可能潮流流速及表、底层潮余流分布.厦门湾及其周边海域属正规半日潮类型,4个分潮的最大潮汐振幅分别为200、65、36、29 cm,厦门湾内外迟角差分别为20°、25°、18°、10°;镇海角至围头角连线东南侧湾口区为逆时针旋转的驻波,西北侧湾内为前进潮波.湾内潮流属正规半日潮流,湾口区潮流以逆时针方向的旋转流运动为主,湾内各水道为往复潮流,椭圆长轴与水道走向一致,4个分潮流表层最大流速分别为201、51、34、25 cm/s;九龙江口区3条港道内的流速以南港最大;表层余流大于底层余流,二者水平分布形态基本一致,都为北进南出.     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

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。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

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.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

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,