人工神经网络在台风风暴潮模拟中的解释应用

将BP人工神经网络引入到风暴潮数值预报的解释应用中,并以惠州站为例,根据台风参数与增水的关系建立3套神经网络模型,对风暴潮的数值预报结果进行订正,计算结果显示:BP人工神经网络可以改进风暴潮数值模式的预报精度,可以作为惠州站数值预报结果解释应用的一种方法,同时也为台风风暴潮数值预测的解释应用提供了新思路。     

基于BP神经网络的厦门沿海风暴潮预报应用

以BP人工神经网络可有效描述非线性问题的特性应用于短期风暴潮增水预报,利用风暴潮增水与各项影响因素的关系,建立厦门沿海的风暴潮增水预报的人工神经网络模型。该模型将以台风中心最低气压、最大风速,七级大风半径、台风中心距测站位置的距离和测站当地气压、当地风速、天文潮位及增水值、作为主要的输入因子,预测未来1 h、2 h、3 h及6 h风暴潮增水值。分别探讨厦门沿海的风暴潮増水在3种代表性热带气旋路径的影响下的模型应用情况,由预报结果的分析显示:该BP神经网络模型所预报的风暴潮增水较好的拟合了实际变化趋势,表明本模型对于厦门沿海风暴潮増水的预报具有相当不错的成效。     

神经网络在珠江口风暴潮预报中的应用

当风暴潮沿河道上溯时,处于珠江口地区的灯笼山测站和黄埔测站的水位之间存在着非线性响应关系。文章利用BP人工神经网络,建立了两测站台风暴潮和天文潮的综合增水效应预报模型,对9903、9908和9910号台风期间黄埔站的综合增水进行了预报,并针对不同预报时段对计算结果和潮位极值的准确程度进行了相应的讨论。结果表明,该方法的预报精度较高。最后通过与纯风暴增水模型的对比,说明了综合增水模型的优越性。     

改进BP算法在风暴潮极值水位预报中的应用

提出1种基于改进BP算法的风暴潮极值水位预报方法。首先针对现有人工神经网络BP算法存在的缺陷,引入Cauchy训练方法计算连接权的调整,解决BP算法的局部极小点和网络瘫痪的问题。然后结合山东海区水文观测站每年的台风风暴潮资料,应用该改进算法建立台风强度、风速和台风移速与风暴潮极值水位的非线性网络预报模型,对该站极值水位进行预报。实验结果表明,该算法具有很好的稳定性和准确性,为风暴潮预报分析提供了1种可靠的技术手段。     

莱州湾温带风暴潮预报研究

本文依据莱州湾羊角沟、夏营两站建国以来的风暴增水资料，对莱州湾建国后发生的风暴潮进行了统计分析，并探讨了温带风暴潮产生的物理机制，此外还对莱州湾温带风暴增水以及诱发增水的天气形势进行了分析分类。在此基础上建立了莱州湾温带风暴潮统计预报方法，并在作业预报中对模型进行了检验，取得较为理想的效果。     

浙江海门站风暴潮增水特征及其预报

台州湾地区是浙江省风暴潮灾害重灾区之一,海门站位于浙江台州湾口门处.本文分析1950-2004年间对浙江造成重大影响的台风风暴潮过程,了解海门站台风风暴增水特征,并结合实际预报工作初步探讨海门站风暴潮预报方法和预报着眼点.     

Delft3D在天文潮与风暴潮耦合数值模拟中的应用

本文应用Delft-3D水动力学计算软件，以长江口地区为例建立的台风风暴潮、天文潮耦合数值预报模型，对台风风暴潮、天文潮两潮耦合预报模式进行探研和分析。该模式不同于以往的单纯台风增水模型与天文潮叠加的风暴潮模式，而是在计算中直接对天文潮和台风风暴潮进行两潮耦合，有效地消除了近岸地区潮波与增水之间叠加的非线性影响。通过模拟台风8114和7708过境对长江口的影响，并与实测数据比较，预报结果和实测水位过程的对比说明，台风风暴潮耦合数值预报模式对增水和高潮的过程预报是准确的，两者在高水位时同步且相差甚微。     

福建沿海精细化台风风暴潮集合数值预报技术研究及应用

该文首先基于高级环流模型(ADCIRC)建立了一个适合台湾海峡及福建沿海区域的精细化台风风暴潮数值预报模式。利用所建立的精细化数值预报模式对影响台湾海峡及福建沿海的8次台风风暴潮个例进行了模拟,对模拟的24个站次的风暴潮增水峰值与实测值进行了对比,平均绝对误差小于15 cm;其次,为了尽可能减小由于台风路径预报误差而造成的风暴潮增减水误差,本文采用了集合数值预报技术,试报证明此方法可以在一定程度上减小风暴潮增减水误差。     

莱州湾夏营站温带风暴潮预报方案编制

本文依据莱州湾夏营站１９６０－１９８７年的风暴增水资料，对夏营站的风暴增水以及诱发增水的天气形势进行了分析分类，对夏营站的温带风暴潮预报方法进行了研究，从而建立了经验相关和统计相关两类预报方案，通过对这些方案的检验，都获得了比较满意的结果。     

江苏近海风暴潮增水数值模拟研究

为研究江苏近海海域风暴潮的特性以及为该海域风暴潮增水变化机理及后报做铺垫,本文基于FVCOM(Finite Volume Coast and Ocean Model)海洋模式和Jelesnianski圆形台风风场模型,建立了江苏近海风暴潮数值模型,并对江苏近海的天文潮以及1109号台风和1210号台风引起的风暴潮进行模拟。结合验潮站水位观测,研究了连云港站和吕泗站的天文潮和风暴潮增水过程。我们将风暴潮与天文潮非线性作用下的风暴潮增水和纯风暴潮增水过程进行对比,讨论了天文潮与1109号和1210号台风风暴潮之间的非线性作用引起的增水特征。结果均表明,在天文潮高潮时,天文潮和风暴潮之间的非线性作用可以抑制增水,在天文潮低潮时,天文潮和风暴潮之间的非线性作用有利于增水。除了气象因子以及天文潮和风暴潮之间的非线性作用外,该海区的地理环境也对台风风暴潮增水产生影响。因此对江苏近海的海岸线变化和浅滩地形变化进行敏感性试验,结果表明,本文所设计的海岸线变化对该海域的风暴潮增水影响较小,江苏沿海岸线的向外推移使得江苏海域风暴潮的增水略微上涨,而本文所设计的地形的变化对风暴潮增水影响较大。     

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.     

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.     

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,     

Net Sand Transport Direction in a Tidal Inlet, using Foraminiferal Tests as Natural Tracers

The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance.     

Sea Levels and Coastal Inundation Due to Tropical Cyclones in Indian Coastal Regions of Andhra and Orissa

Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding.     

Role of Siliceous Fossil Dissolution in Downcore Variations of Grain Size and Water Content: Western Margin of Clarion-Clipperton Fracture Zone, NE Equatorial Pacific

Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors.     

Sea Levels and Western Boundary Flow Near a Tectonic Zone in the Northern Pacific

This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake.