厦门港湖汐水流及浑水悬沙整体模型设计

厦门港湖汐水流及浑水悬沙整体物理模型于1989年建成后，已进行了不少有意义的试验研究工作，取得较好效果。本文主要介绍模型的设计思想、相似准则、浑水悬沙相似理论的探讨、模型设计方法以及模型沙的选择等。     

波-流作用下悬沙体积比垂向分布研究

在悬沙体积比垂向分布的研究中往往只研究悬沙体积比时均浓度分布，忽略悬沙体积比随时间的变化。而Wikramanayake悬沙模型采用时不变的紊动黏滞系数，利用奇异摄动理论中的多重尺度法分离波流作用下悬沙运动的对流扩散方程，将悬沙体积比按照时均值和周期分量进行了分析。作者在Wikramanayake悬沙模型中的周期浓度的基础上考虑了对流项的影响，从而使描述瞬时悬沙体积比的数学模型更加合理。     

青岛近海悬沙输运的三维数值模拟

研究近海海域水流、悬沙运动规律，运用基于COHERENS发展的水动力悬沙模型COHERENS-SED,结合当地一般波浪条件，模拟了青岛近海悬浮泥沙输运情况，并验证及分析了水动力环境及悬沙输运的模拟结果。结果表明：在波流合作用下，近岸掀沙明显，大潮期间该海域近岸悬沙浓度值最高可达50mg／L。     

半日潮流作用下悬移质泥沙的运动特征及其影响因素研究

本文通过建立一维水深平均悬沙模型，对典型潮流控制的水道内悬沙运动特征进行研究。模型以泥沙再悬浮、沉降和平流为主要物理过程，动力因素包含M₂、S₂分潮及余流，采用湄洲湾2007年8月潮位、潮流、悬沙、底质同步观测资料进行分析和验证。通过三角傅里叶分析，将悬沙的时间序列分解为12个主要的谐波分量，其中主要分量包括:M₂分潮作用下产生的具有M₂倍潮角速度的1/4日分潮项，M₂与S₂分潮共同作用下且角速度为两分潮角速度之和的1/4日分潮项，及水平悬沙梯度、余流与M₂分潮共同作用下具有M₂分潮角速度的半日潮项。悬沙在时间上的平均值受到余流、悬沙水平梯度、M₂分潮流及悬沙起动条件等因素控制。余流导致了悬沙序列中相邻周期之间的不对称性。反映泥沙特性的参量对悬沙的曲线特征具有重要影响，泥沙沉降速度影响悬沙的相位，并影响其振幅；再悬浮有关的参量仅影响各谐波分量的振幅，但不影响相位。     

悬浮泥沙浓度遥感反演模式研究

利用野外采集的悬沙样品配置不同粒径和浓度等级的悬沙水样,进行实验室光谱测量,分析悬沙水样的光谱特征及其反射率与粒径之间的关系。根据实验结果选取泥沙浓度和粒径的敏感波段,建立了敏感波段模型和主成分模型。结果表明,主成分分析法能大量获取多通道悬沙水体光谱反射率信息,模型的反演能力优于敏感波段模型。     

悬对沙Mellor-Yamada海洋边界层模型计算结果的影响

为了分析海洋水体垂向水流紊动及紊动交换情况而采用了一维的海洋边界层模型(Mellor-Yamada)并利用数值实验的方法对悬沙、盐度、温度等数据进行分析。原模型未将悬沙考虑在内，本文试将它引入进去探讨由于它的存在对紊动混合特性的影响。2000年4月，Mellor将最初的模型引入了依赖于Richardson数的紊动动能耗散率。本文通过比较具有悬沙和不具有悬沙两种情况下的速度、温度和盐度垂向分布随时间的变化，分析讨论由于悬沙的存在所引发的密度层化对紊动混合作用的影响，并发现悬浮泥沙抑制了部分模拟时间的紊动混合作用。     

悬沙的ADCP估测方法

ADCP估测悬沙含量是基于声波的背散射强度正比于悬沙浓度的理论。在实际测验中，由于多种因素干扰，ADCP所得到的背散射强度与悬沙浓度之间存在着不定的非线性关系。同传统的回归方法比较，BP网络模型方法可以使含沙估测精度有较大的提高。     

悬沙水体光谱反射率与质量浓度、粒径的相关关系

根据实验室测得的和野外现场实测的悬沙质量浓度、粒度与光谱数据,分析了不同质量浓度的悬沙水体和同一质量浓度不同粒径大小的悬沙水体的光谱特征,选取了质量浓度的敏感波段,建立光谱反射率与质量浓度、粒径之间的关系模型.分析结果表明:不同质量浓度的悬沙水体光谱反射率具有双峰特征;同一质量浓度的悬沙水体,随着粒径的减小,光谱反射率逐渐增大,粒径大小与反射率呈反比关系;光谱反射率、质量浓度和粒径的指数关系模型能较好地反映三者的关系.     

瓯江杨府山边滩围垦工程试验研究

瓯江杨府山河段边滩发育丰富，底沙运动频繁，悬沙含量高，对边滩围垦促淤极为有利。本文依据大量的水文、泥沙、地形等实测资料，在模型验证试验相似的基础上进行围垦工程试验，分别论证其工程的可行性、工程布置形式的促淤效果。对类似的边滩围涂工程具有借鉴作用。     

辽东半岛东岸近海泥区悬沙浓度的时空分布及控制因素分析

鸭绿江作为典型的中小型河流，细颗粒沉积物从鸭绿江流域到辽东半岛东岸近海泥区的源汇过程有着独特的机制，而遥感解译是了解入海沉积物在河口-陆架输运过程和机制的有效手段之一。因此，本文通过在辽东半岛东岸海域进行了现场悬沙浓度测量，并与GOCI影像建立关系，反演了该地区2011年4月至2017年3月间的表层悬沙浓度，从而揭示了该海域表层悬沙浓度的时空特征，分析了潮流、大风天气和洪水对悬沙浓度变化的影响，在此基础上探讨了研究区的悬沙浓度输运格局。结果显示，研究区表层悬沙浓度空间差异大，河口附近是悬沙浓度高值区，可达500 g/m3以上，其他区域则悬沙浓度多小于20 g/m3。另外，研究区表层悬沙浓度枯季高，洪季低，有着显著的季节性变化。进一步分析表明，枯季大风天气引起的风浪作用增强，是导致表层悬沙浓度增高的主要原因；洪季虽然悬沙浓度较低，但流域洪水期间的悬沙浓度显著增加。此外，作为典型的中小型源-汇传输体系，沉积物从鸭绿江到辽东半岛东岸近海泥区总体上仍遵循"夏储冬输"的输运机制。     

海岸悬沙运移数学模型

根据适合大范围缓变地形情况下,不恒定、非均匀流场中随机波折绕射联合数值模式及波浪作用下的二维浅水环流方程和悬沙扩散方程,建立了波浪、潮流共同作用下二维悬沙数学模型,并将该模型应用于渤海湾北部海域,进行了波、流共同作用下航道疏浚弃土的悬沙扩散、运移及海床演变的数值模拟,为工程单位决策提供科学依据     

Development of acoustic suspended sediment monitor

INTRODUCTIONA~q~tityofmudsandSandsbIDughtbyinfluentriverssUSpendin~talseawater.ThemudsandSands,affectedbythetidesandc~ts,areconstantlymoving,tranSportinganddealting,andcancauseseriousinfluencesonharhars,channelsandwaterconservancies,coaStalandOffshae...     

波浪-海流-微地形耦合的沉积动力模式建立及应用

沙纹微地形普遍存在于海底,沙纹的消长能改变底部应力进而影响泥沙的运移。以往研究较多侧重于波致沙纹,并已应用于波浪模式的底摩擦计算,而较少考虑波流联合效应产生的沙纹,也未将其应用于综合的水动力模式和沉积物输运模式。本文在POM水动力模式中嵌入新南威尔士大学泥沙模式,通过耦合波流共同作用的微地形模型与波流相互作用底边界层模型,发展了波浪-海流-微地形（沙纹）耦合的沉积动力模式。本文将该模式应用于澳大利亚Jervis湾,针对波主导和波流联合主导沙纹两种类型,分别进行了沙纹发展状态、几何形态的分布及悬浮泥沙的模拟。结果表明:波致沙纹比波流联合作用的沙波具有更大的波高和波长,因此当波主导时沙纹对悬浮泥沙起着关键作用。通过考虑随沙纹变化的粗糙度,相比于以往模式设置均一的粗糙度,该模型能对悬浮物浓度的骤升过程进行更精细的预测。     

Quantitative application study on remote sensing of suspended sediment

Quantitative application on remote sensing of suspended sediment is an important aspect of the engineering application of remote sensing study.In this paper,the Xiamen Bay is chosen as the study area.Eleven different phases of the remote sensing data are selected to establish a quantitative remote sensing model to map suspended sediment by using remote sensing images and the quasi-synchronous measured sediment data.Based on empirical statistics developed are the conversion models between instantaneous suspended sediment concentration and tidally-averaged suspended sediment concentration as well as the conversion models between surface layer suspended sediment concentration and the depth-averaged suspended sediment concentration.On this basis,the quantitative application integrated model on remote sensing of suspended sediment is developed.By using this model as well as multi-temporal remote sensing images,multi-year averaged suspended sediment concentration of the Xiamen Bay are predicted.The comparison between model prediction and observed data shows that the multi-year averaged suspended sediment concentration of studied sites as well as the concentration difference of neighboring sites can be well predicted by the remote sensing model with an error rate of 21.61% or less,which can satisfy the engineering requirements of channel deposition calculation.     

A wave-resolving model for nearshore suspended sediment transport

This paper presents a wave-resolving sediment transport model, which is capable of simulating sediment suspension in the field-scale surf zone. The surf zone hydrodynamics is modeled by the non-hydrostatic model NHWAVE (Ma et al., 2012). The turbulent flow and suspended sediment are simulated in a coupled manner. Three effects of suspended sediment on turbulent flow field are considered: (1) baroclinic forcing effect; (2) turbulence damping effect and (3) bottom boundary layer effect. Through the validation with the laboratory measurements of suspended sediment under nonbreaking skewed waves and surfzone breaking waves, we demonstrate that the model can reasonably predict wave-averaged sediment profiles. The model is then utilized to simulate a rip current field experiment (RCEX) and nearshore suspended sediment transport. The offshore sediment transport by rip currents is captured by the model. The effects of suspended sediment on self-suspension are also investigated. The turbulence damping and bottom boundary layer effects are significant on sediment suspension. The suspended sediment creates a stably stratified water column, damping fluid turbulence and reducing turbulent diffusivity. The suspension of sediment also produces a stably stratified bottom boundary layer. Thus, the drag coefficient and bottom shear stress are reduced, causing less sediment pickup from the bottom. The cross-shore suspended sediment flux is analyzed as well. The mean Eulerian suspended sediment flux is shoreward outside the surf zone, while it is seaward in the surf zone.     

长江河口悬浮泥沙向浙闽沿岸输运近期变化的遥感分析

利用2000~2015年Terra-MODIS(terra-moderate resolution imaging spectroradiometer,中等分辨率成像光谱仪)数据和2014年洪枯季现场数据建立泥沙反演模型,分析入长江河口泥沙大幅减少后河口表层悬沙向浙闽沿岸输运的时空变化和扩散形态。结果表明:(1)利用MODIS数据的二次型模型能够揭示长江口及邻近海域悬沙分布及输运特征,入海输运的长江口悬浮泥沙是浙闽沿岸连续悬浮泥沙带存在的物源;(2)受季风和沿岸流动力驱动,长江口悬沙向浙闽沿岸输运具有明显的季节性:春季,悬浮泥沙从长江口向浙闽沿岸呈条带状输运,春夏之交,南下的悬沙至温岭近岸海域出现中断现象;夏季,长江口大量悬沙滞留在长江口杭州湾近岸,仅有少量悬沙向南输运,泥沙带中断;秋季,10月下旬—11月中旬逐渐形成连续的近岸泥沙带;历冬至春,循环复始;(3)受近年来长江流域进入河口的泥沙减少影响,浙闽沿岸秋冬季连续的输沙带在春季提前断开,在秋季有推迟恢复的现象。本研究对于探究浙闽沿岸泥沙减少新格局,分析近海生态环境新变化具有重要意义。     

Measurements and modelling of the advection of suspended sediment in the swash zone by solitary waves

Novel laboratory experiments and numerical modelling have been performed to study the advection scales of suspended sediment in the swash zone. An experiment was designed specifically to measure only the sediment picked up seaward of the swash zone and during bore collapse. The advection scales and settling of this sediment were measured during the uprush along a rigid sediment-free beach face by a sediment trap located at varying cross-shore positions. Measurements were made using a number of repeated solitary broken waves or bores. Approximately 25% of the pre-suspended sediment picked up by the bores reaches the mid-swash zone (50% of the horizontal run-up distance), indicating the importance of the sediment advection in the lower swash zone. The pre-suspended sediment is sourced from a region seaward of the shoreline (still water line) which has a width of about 20% of the run-up distance. An Eulerian–Lagrangian numerical model is used to model the advection scales of the suspended sediment. The model resolves the hydrodynamics by solving the non-linear shallow water equations in an Eulerian framework and then solves the advection–diffusion equation for turbulence and suspended sediment in a Lagrangian framework. The model provides good estimates of the measured mass and distribution of sediment advected up the beach face. The results suggest that the correct modelling of turbulence generation prior to and during bore collapse and the advection of the turbulent kinetic energy into the lower swash is important in resolving the contribution of pre-suspended sediment to the net sediment transport in the swash zone.     

江苏如东西太阳沙及烂沙洋海域潮流泥沙数值模拟

基于不规则三角形网格有限差分法并考虑波浪及其破碎作用,建立了平面二维潮流场和泥沙场数学模型.该模型对有望建设成深水码头和深水航道的江苏如东西太阳沙和烂沙洋海域的潮流场和泥沙场进行了细化数值模拟.数值模拟结果表明：（1）本海区潮流基本上是顺深槽流动的往复流,潮流流速大,烂沙洋北水道和西太阳沙附近大潮涨落潮最大流速分别在2 m/s和1 m/s以上;（2）本海区的潮平均水体含沙量在0.5 kg/m^3以下,落潮含沙量大于涨潮含沙量;（3）小浪对水体含沙量影响很小,大浪作用下水体含沙量明显增加.     

大沽河口悬浮泥沙遥感模式实验研究

河口悬浮泥沙反射率渡谱特性研究是悬浮泥沙遥感定量分析的基础工作。不同水域悬浮泥沙物质成份、粒径分布和浓度的不同,其相应的反射率波谱特性也有所差异。对此,国内外尚未建立起具有普适型的算法模式,用以处理不同水域的悬浮泥沙遥感问题。鉴于此,我们于1991年9月6～11日对胶州湾大沽河口区进行了现场悬浮泥沙波谱特性实验。由此建立了大沽河口悬浮泥沙落度SSC与陆地卫星TM_3和TM_4渡段相应的光谱反射率之间的数学模式。经过相关分析和误差分析的检验证明,由模式计算所得结果是令人满意的。