近60年来长江河口河势变化及其对水动力和盐水入侵的影响Ⅲ.盐水入侵

本文应用本系列论文Ⅱ中建立的长江河口水动力和盐水入侵三维数值模式,模拟长江河口20世纪50年代、70年代和2012年盐水入侵,定量分析不同年代河势下盐水入侵状况和变化程度及其原因。在北支,不同年代盐水入侵的变化是由分流比和潮差共同作用造成的。50年代北支盐水入侵较强,70年代大幅下降,中上段出现淡水,2012年盐水入侵极为严重,整个北支被高盐水占据,上段出现强烈的盐度锋面。50年代和2012年,北支盐水倒灌南支,大潮期间远大于小潮期间,2012年远强于50年代,70年代没有北支盐水倒灌南支现象。在南支,50年代、70年代南支大部分为盐度都小于0.45的淡水,在2012年大潮期间由于出现了强烈的北支盐水倒灌,南支上段出现盐度大于0.45的盐水。在南北港,在50年代盐水入侵最严重;大潮期间,北港净分流比南港大21.6%,北港盐度小于南港盐度,外海盐水主要通过南港入侵,出现南港盐水倒灌进入北港的现象。至70年代,南支主流转向南港,南港净分流比增大,比北港大10.4%,南港盐度明显小于北港盐度;南北港盐水入侵较弱。在2012年,南支主流再次转向北港,北港分流比比南港大10.4%,南港的盐水入侵再次强于北港。小潮期间,50年代由于南港分流比相比于大潮时更小,南港盐水上溯距离更远,上段盐度比更大;至70年代,北港分流比减少,盐水入侵减弱;至2012年,由于大潮时期北支倒灌的盐水在小潮期间到达北港,北港净盐通量比大潮时期大。由于潮动力减弱,小潮期间各年代垂向盐度分层更明显,盐水入侵变化与大潮期间一致。     

Impact of the eastern water diversion from the south to the north project on the saltwater intrusion in the Changjiang Estuary in China

The south to the north project(WDP) on the saltwater intrusion in the Changjiang Estuary is studied by the improved three-dimensional(3D) numerical model.The net unit width flux in the Changjiang Estuary as well as the sectional salt flux is calculated in the North Branch(NB),the South Branch(SB),the North Channel(NC),the South Channel(SC),the North Passage(NP) and the South Passage(SP),respectively.The net seaward water flux in the SB is reduced,and the net water flux spilling over from the NB to the SB is enhanced after the eastern WDP.Under the mean river discharge condition in the dry season,the net salt flux spilling over from the NB to the SB is increased by 2.09 t/s and 0.52 t/s during the spring and neap tides,respectively,due to the eastern WDP.The saltwater intrusion in the Changjiang Estuary is enhanced by the eastern WDP.Compared with that during the spring tide,the net water diversion ratio during the neap tide in the NC is smaller,and thus the enhancement of the saltwater intrusion by the eastern WDP is smaller in the NC,and larger in the NP and the SP.The tidally averaged surface salinity at the water intakes of the Dongfengxisha Reservoir,the Chenhang Reservoir and the Qingcaosha Reservoir rises both during the spring and neap tides.     

A modeling study on saltwater intrusion to western four watercourses in the Pearl River estuary

Saltwater intrusion has been serious in the Pearl River estuary in recent years. For better understanding and analysis of the saltwater movement to the estuary, the three-dimensional Finite-Volume Coastal Ocean Model (FVCOM) is made to simulate the salinity intrusion to the four western watercourses in the Pearl River estuary under three semilunar conditions. With the measured and simulated Root Mean Square Error (RMSE) and the mean absolute percentage error of water level and salinity at multiple sites, the results show that the numerical water levels, salinity and flow velocities are in agreement with the measured data. It is acceptable and feasible to apply the FVCOM to simulate the salt water intrusion in the western four watercourses of the Pearl River. With the numerical data, the time and spatial movement patterns of saltwater intrusion along the Modao watercourse are analyzed. The salinity contour reaches its peak generally during 3-5 days before the spring tide. The salinity stratification is more obvious in the period of ebb tide than that in the rising tide whether in the spring or neap tides. Salt fluxes reflect changes of salt into the estuary, and the change rules are close to the rules of salinity intrusion.     

长江河口青草沙水库盐水入侵来源

应用改进的三维数值模式ECOM-si,从模式计算的盐度和流向的变化过程、涨憩和落憩时刻盐度等值线和淡水区域的变化,分析在一般动力条件下青草沙水库取水口盐水入侵来源。计算结果表明,小潮后中潮、大潮、大潮后中潮和小潮期间北支倒灌占青草沙水库取水口表层盐水入侵比例分别为69.5%、89.3%、98.5%和99.5%,占底层盐水入侵比例分别为34.9%、88.9%、98.5%和99.5%。除了小潮后中潮期间底层盐水入侵来源主要来自下游外海(占65.1%),青草沙水库取水口表层和底层盐水入侵来源主要来自北支盐水倒灌,尤其是大潮后中潮和小潮期间几乎全部来自北支盐水倒灌。     

长江河口悬沙与盐分输运机制分析

2004年9月15~22日在长江口南支口门区域进行了水位、流速、悬沙浓度、盐度的全潮观测,基于这些现场数据,分析河口区域流速结构、悬沙浓度与盐度的时空分布特征;利用机制分解法研究河口悬沙、盐分的通量和输运机制,并探讨它们与水体垂向结构之间的关系。主要结论如下:长江河口区的悬沙浓度存在显著的时空变化特征,从口内向口外,悬沙浓度呈显著减小趋势,大潮期间的悬沙浓度较大,是小潮期间的数倍。通量机制分析结果表明,长江河口区以欧拉余流为主,向海输运,并有向海方向逐渐减小的趋势,斯托克斯余流向陆输运,在大、小潮期间有显著差异。盐分输运机制中,以欧拉余流占主导地位,潮泵效应、垂向重力环流、垂向剪切扩散作用的贡献次之。长江河口悬沙净输运率在向海方向逐渐减小,大潮期间的悬沙净输运率比小潮期间的大1~2个数量级,水动力条件是造成长江河口悬沙净输运时空差异的主要因素。悬沙输运机制小潮期间以欧拉余流占主导地位,在大潮期间则以与紊流相关的垂向剪切扩散作用取代欧拉余流占据主导地位。悬沙瞬时输运机制中的剪切扩散项在中下层水体的理查德森数(Ri)小于0.25时才有较大的量值,在南槽内,当底层水体的理查德森数(Ri)处于-0.1相似文献   

Suspended sediment transport of the Hangzhou Bay and its related hydrodynamic analyses

The 25-h measurements of current speed, flow direction, water depth, suspended sediment concentration and salinity were carried out at six anchored stations in the study area during spring and neap tides in winter of 1987 and summer of 1989. Caculations and analyses of the data obtained show that large amounts of suspended sediments are moved back and forth under the action of tidal current, and the net transport of sediment is small, with its predominance upstream in winter and downstream in summer. These calculations and analyses also suggest that the advective transport of sediment is dominant, while the vertical gravitational circulation of the suspended sediment comes next. Meantime, it is indicated that tidal currents play a major role in the suspended sediment transport, and residual flows have effect on the net transport of the suspended sediment, which is more remarkable during neap tide than during spring tide.     

Modelling salinity and circulation for the Columbia River Estuary

Simulations of the time and depth-dependent salinity and current fields of the Columbia River Estuary have been performed using a multi-channel, laterally averaged estuary model. The study simulated two periods. The first, in October 1980, with low riverflow of about 4,000m³s⁻¹, which showed marked changes in the salinity intrusion processes between neap and spring tides; and second, in spring 1981, with high riverflow varying between 7,000 and 15,000m³s⁻¹, which showed the rapid response of the salinity intrusion to changes in riverflow and that vertical mixing did not change character with increasing tidal energy because of the maintenance of stratification by freshwater flow. An extreme low flow simulation (riverflow of 2,000m³s⁻¹) showed a more partially mixed character of the estuary channels with tidal dispersion of salt across the Taylor Sands from the North Channel to the upper reaches of the Navigation Channel. Asymmetries in the non-linear tidal mean flows, in the flood and ebb circulations, and salinity intrusion characteristics between the two major channels were observed at all riverflows. The model confirms Jay and Smith's (1990) analysis of the circulation processes in that tidal advection of salt by the vertically sheared tidal currents is the dominant mechanism by which the salinity intrusion is maintained against large freshwater flows. An accurate finite-difference method, which minimized numerical dispersion, was used for the advection terms and was an important component in reasonably simulating the October neap-spring differences in the salinity intrusion. The simulations compare favorably with elevation, current and salinity time series observations taken during October 1980 and spring 1981.     

长江河口下扁担沙水域最长连续不宜取水时间

长江河口已建成陈行水库、青草沙水库和东风西沙水库，提供了约80%的上海用水。但随着社会和经济的发展，用水缺口仍然存在。下扁担沙位于南北港分汊口上游，大潮落潮期间滩涂露出。本文利用研究组长期研发和应用的长江河口盐水入侵三维数值模式，计算在1978-1979年特枯径流量条件下该水域的盐水入侵和连续最长不宜取水时间，了解下扁担沙水域能否作为备用水源地。本文采用2017年2月19日到3月1日北支8个站位的观测资料，结果表明表层和底层盐度模拟值和实测值之间相关系数、均方根误差和技术分数的平均值分别为0.85、1.82和0.82，模式计算盐度和实测值吻合良好，能较好地模拟长江河口盐水入侵。模式计算表明，下扁担沙模式输出点最长连续不宜取水时间为13.79 d，盐水入侵在大潮后期和大潮后中潮主要源自上游北支倒灌，小潮后中潮主要源自下游正面入侵，且前者影响比后者大。能取水时段就出现在小潮后中潮，淡水是南支上游南侧随落潮流平流过来的。下扁担沙水域的最长连续不宜取水时间远比青草沙水库和东风西沙水库的短，表明下扁担沙水域淡水资源远比南支上游和下游水域充足，是个极为优越的备用水源地。     

Variations of suspended sediment transport caused by changes in shoreline and bathymetry in the Zhujiang (Pearl) River Estuary in the wet season

A wave-current-sediment coupled numerical model is employed to study the responses of suspended sediment transport in the wet season to changes in shoreline and bathymetry in the Zhujiang (Pearl) River Estuary (ZRE) from 1971 to 2012. It is shown that, during the wavy period, the large wave-induced bottom stress enhances sediment resuspension, resulting in an increase in the area of suspended sediment concentration (SSC) greater than 100 mg/L by 183.4%. On one hand, in spring tide, the change in shoreline reduces the area of SSC greater than 100 mg/L by 17.8% in the west shoal (WS) but increases the SSC, owing to the closer sediment source to the offshore and the stronger residual current at the Hengmeng (HEM) and Hongqili (HQL) outlets. The eastward Eulerian transport is enhanced in the WS and west channel (WC), resulting in a higher SSC there. The reclamation of Longxue Island (LXI) increases SSC on its east side and east shoal (ES) but decreases the SSC on its west and south sides. Moreover, in the WC, the estuarine turbidity maximum (ETM) is located near the saltwater wedge and moves southward, which is caused by the southward movement of the maximum longitudinal Eulerian transport. In neap tide, the changes are similar but relatively weaker. On the other hand, in spring tide, the change in bathymetry makes the SSC in the WS increase, and the area of SSC greater than 100 mg/L increases by 11.4% and expands eastward and southward, which is caused by the increases in wave-induced bottom stress and eastward Eulerian transport. On the east side of the WC, the eastward Eulerian transport decreases significantly, resulting in a smaller SSC in the middle shoal (MS). In addition, in the WC, the maximum SSC is reduced, which is caused by the smaller wave-induced bottom stress and a significant increase of 109.88% in southward Eulerian transport. The results in neap tide are similar to those in spring tide but with smaller changes, and the sediment transports northward in the WC owing to the northward Eulerian transport and vertical shear transport. This study may provide some references for marine ecological environment security and coastal management in the ZRE and other estuaries worldwide affected by strong human interventions.     

Impacts of Different Dynamic Factors on the Saltwater Intrusion in the Northern Branch of the Yangtze Estuary

A 3-D baroclinic numerical model is established to study the temporal and spatial distribution of salinity in the Northern Branch(NB) of the Yangtze Estuary(YE) in response to river runoff, wind and currents. The idealized,process-oriented studies show that the lower river runoff in the dry season is the main driving factor for the spilling over from the NB to the Southern Branch(SB). The NB takes longer time to get in dynamic stable state compared with the SB, as the runoff transfers from the wet season to the dry season. The vertical stratification intensity of the NB has obvious periodic phenomena in the dry season, and the stratification strength is enhanced under the action of low runoff and north wind, which further weakens the vertical transport of water. Momentum balance analysis suggested that the landward net flux increases when considering the influence of the moderate north wind, and the landward flux will enhance if considering the boundary current during the spring tide. With the influence of the boundary current, increases the average salinity of the NB, as well as the intrusion degree from the NB to the SB.This indicates that the nearshore ocean current of the Yellow Sea is an important factor affecting the saltwater intrusion in the NB of the YE.     

海南岛南渡江河口的盐水入侵

南渡江是海南岛最大的河流,河口长度较短(约25 km),口外濒临琼州海峡。南渡江的盐水入侵近年来呈加剧趋势,急需对其过程与机理进行研究。本研究运用FVCOM模型,采用2009年枯季的实测数据对模型进行了验证。根据模型计算结果分析了枯季和洪季南渡江河口的流速和盐度的时空分布及盐水入侵的变化,探讨了河口不同位置驱动盐分向陆输运的机制。研究结果表明:枯季小潮时的河口环流强度大于大潮时,而洪季河口环流在大潮时更加发育,洪枯季都表现出大潮期的盐度分层(表底层盐度差)大于小潮期;口门附近,潮汐振荡输运在总的向陆盐分输运通量中占主导,而向上游方向,稳定剪切输运则表现得更重要。主河道内损失的盐分主要通过海甸溪的盐分输入进行补充。     

基于潮沟定点观测的潮间带水、沙、盐交换研究

为研究潮间带和潮下带的水、沙、盐交换,于2006年6月25~28日（夏季大潮）和2006年12月29日~2007年1月4日（冬季中-大潮和小潮）在长江口九段沙一典型潮沟的固定点利用OBS-3A和ADP-XR进行了水深、浊度、盐度、流速流向剖面和回声强度观测。结果和结论为：（1）夏季大潮、冬季中-大潮、冬季小潮的潮周期垂向平均流速分别为26.5、15.9和8.4 cm/s,夏、冬季观测到的最大流速分别为84 cm/s和35 cm/s。（2）夏季盐度变化范围为0.65~4.91,平均盐度2.14;冬季盐度变化范围为3.5~10.3,中-大潮和小潮平均盐度分别为6.26和7.98。（3）高悬沙浓度出现在涨潮初期和部分落潮末期的低水位阶段;涨潮阶段的平均悬沙浓度是落潮阶段的1.11~7.0倍。（4）涨、落潮阶段的水体和盐输运量大体上趋于平衡;（5）无论是冬夏季或大小潮,潮沟在潮周期内的净输沙方向均指向陆,即落潮输沙量小于涨潮输沙量（平均小40%）;平均每个潮周期的净输沙量为6102 kg,结合潮盆面积推算的潮周期沉积速率为0.0112 mm/tide,或8.2 mm/a。     

The principal factors contributing to the flux of salt in a narrow, partially stratified estuary

Observations of the velocity and salinity structure of the Tees estuary were made at eight stations along the estuary axis between Victoria Bridge and the sea during the summer of 1975. The measurements were made on ten separate tidal periods covering neap and spring tides.The data were collected over a period of relatively low freshwater flows and the residual current was found to have a strong dependence on the Stokes drift. At the upstream stations, the residuals were more than an order of magnitude greater than the currents anticipated from the freshwater discharge. Although the mean stratification decreased as the tidal range increased, the vertical circulation was stronger on spring tides than on neaps. Vertical variations in the amplitude and phase of the tidal current results in a current which strengthens the vertical circulation. However, this effect only made a relatively small contribution to the observed vertical circulation.The relative contribution of the individual salt flux terms to the net upstream transport of salt varies along the estuary. As the estuary narrows, the contribution by the oscillatory terms dominates that from the shear in the steady state flow. Of these oscillatory terms, the correlation of velocity and salinity fluctuations plays a key rôle in the salt transport. The depth mean values make a greater contribution than deviations from the depth mean and the flux due to phase variations over depth is smaller than either of these. Since the Stokes drift is compensated by a down-stream steady state flow, it does not contribute to the tidal mean transport of salt.At the seaward end of the estuary, the salt fluxes due to the steady state vertical shear and the convariance of the tidal fluctuations act in a complementary way to counter the seaward transport of salt by the freshwater flow. With the possible exceptions of the wide or narrow reaches of the Tees, the longitudinal fluxes of salt due to transverse variations in velocity, salinity and depth and turbulent fluctuations are of secondary importance as contributors to the estuary salt budget.On both neap and spring tides, the computed total salt transports at the Newport and Victoria bridges did not match the values required for a salt balance with the corresponding freshwater flows. These fluxes were probably the cause of the observed downstream displacement of the tidal mean salinity distribution between neap and spring tides.     

Classification of highly turbid Jiaojiang Estuary

ThisstudywassupportedbytheNationalNaturalScienceFoundationofChinaundercontractNo.49276274,theZhejiangProvinceNaturalScienceFoundationundercontractNo.490013,theChina-Australiabilateralscienceandtechnologyprogram,theAustralianInstituteofMarineScience,theModellingLaboratoryoftheMarineScienceintheSecondInstituteofOceanographyoftheStateOceanicAdministration.INTRODUCTIONTheJiaojiangEstuaryis1ocatedintheeasterncoastofChina,2OokmfromthesouthoftheChangjiangRiver(YangtzeRiver),linkedin…     

A three-dimensional hydrodynamic and salinity transport model of estuarine circulation with an application to a macrotidal estuary

A three-dimensional semi-implicit finite volume numerical model has been developed and applied to study tidal circulation and salinity stratification in the region of Oujiang River Estuary, China. The model employs horizontally unstructured grids and boundary-fitted coordinate system in the vertical direction. Governing equations consisting of continuity, momentum, and transport equations are all solved in the integral form of the equations, which provides a better representation of the conservative laws for mass, momentum, and transport in the coastal region with complex geometry and bottom bathymetry. The model performance was firstly quantified with skill assessment statistics on the choice of different parameters and validated with observed tidal elevation, current velocity, direction and salinity data over a spring–neap tidal cycle collected in 2006. Numerical results show that the model with wetting–drying capability successfully simulated the tidal currents and salinity fields with a reasonable accuracy and indicate that the Oujiang River Estuary is a macrotidal estuary with strong tidal mixing. In addition, the model results also show that the Oujiang River Estuary is a well-mixed estuary during spring tide. Then, the numerical simulations were performed to compare the hydrodynamic process and salinity distribution before and after a river training, which was conducted by blocking the south branch of the Oujiang River mouth. The results reveal that with the only north access to the sea, the influence of the blocking project on the flood discharge capacity is limited and the incremental velocity is beneficial to the navigation channel maintenance, although it will cause some scour to the embankment. Furthermore, the redistribution of tidal prism passing in or out the north branch makes a little severe salinity intrusion during high tide or low tide. However, the salinity intrusion is still within acceptable range, although it can cause some adverse effect on water intaking of production and life. The variations of salinity levels in Yueqing Bay situated at the north of the river mouth are not obvious, so the blocking project will not bring damage to local aquiculture. However, significant changes of salinity happen inside or outside of the south branch, so enough attention need to be paid to the changes of environment caused by the salinity variation after the blocking project. Overall, by weighing advantages and disadvantages of the blocking project, it is feasible and the model can be considered as a tool for managing and studying estuarine circulation.     

长江口咸潮入侵变化特征及成因分析

本文基于海洋站潮位观测数据、海平面变化影响调查信息以及长江口水文站径流量数据等，重点分析了2009?2018年长江口咸潮入侵的变化特征及其影响因素，分析结果表明:(1)长江口咸潮入侵季节变化特征明显。咸潮一般从每年的9?10月开始入侵，翌年4?5月结束。3月咸潮入侵次数最多，达12次。2009?2018年，长江口咸潮入侵次数和咸潮持续时间均呈下降趋势，2009年长江口咸潮入侵次数最多，达13次，时间均发生在10月至翌年的4月；咸潮持续时间年际变化较大，2011年咸潮入侵持续时间最长，累计为55 d。2015?2018年，咸潮入侵次数和入侵持续时间均明显减少，2018年没有监测到咸潮入侵过程。(2) 1?4月，长江口处于季节性低海平面期，且同期径流量少，但是受东亚季风影响，持续的增水过程使得增减水?径流量综合影响指数明显偏高，其中1月、2月、3月的影响指数分别为1.5、1.9和1.6，该时段长江口的咸潮入侵过程主要受增减水的影响。5?7月，长江口径流量明显增加，海平面?径流量综合影响指数均小于0，径流的作用强于海水上溯。8月，长江口径流量开始下降，虽然季节海平面较高，但是长江口呈现明显的减水过程，海平面?径流量和增减水?径流量的综合影响指数分别为0.1和?1.6，基本不会发生咸潮入侵。9月，长江口处于季节高海平面期，并且以增水为主，海平面?径流量和增减水?径流量的综合影响指数较大，分别为1.2和1.0，易发生咸潮入侵。10月、11月长江口海平面?径流量的综合影响指数分别为1.5和0.8，径流影响弱于海水上溯，易发生咸潮入侵。(3) 2009?2018年发生的48次咸潮入侵过程有2/3恰逢天文大潮。在某些年份长江口沿海基础海平面偏高，若持续增水恰逢天文大潮，则加剧咸潮入侵的影响程度。     

椒江河口层化动力特性研究

基于椒江河口大、小潮期间水位、流速、盐度和悬沙浓度观测数据,研究了椒江河口主潮汐通道的水动力、盐度和悬沙浓度的时空变化特征,解释了高浊度强潮作用下的层化物理机制。椒江河口大潮期悬沙浓度和盐度均大于小潮期,主潮汐通道区域落潮期悬沙浓度大于涨潮期;盐度随潮变化,盐水锋面出现在S2测站,锋面附近出现最大浑浊带;自陆向海,悬沙浓度递减,盐度递增;随水深增加,悬沙浓度与盐度递增。Richardson数与混合参数显示,盐度和悬沙引起的层化现象,是随着潮汐的变化而变化,涨潮时的层化均强于落潮,小潮时的层化持续时间最长,区域更广。混合参数随潮周期变化,大潮期高于临界值1.0,小潮期低于临界值1.0。小潮期水体层化强于大潮期;潮汐应变项是影响势能差异变化率的重要因素;落潮期间层化向混合状态转化,涨潮相反。     

Estimates of mixing on the South China Sea shelf

1 Introduction The outer shelf of the South China Sea is a di- verse environment characterized by sharp changes in bottom topography (Wang et al., 2002). Internal wave and diapycnal mixing may be a vital mechanism con- trolling the distribution of physical water properties, nutrient fluxes, and concentrations of particulate mat- ter. Therefore, the research on diapycnal mixing on the outer shelf in the South China Sea is of great impor- tance to explore the level and variability of the abov…     

珠江河口盐度和输运过程对未来海平面上升的响应

研究海平面上升对河口的影响情况有助于了解输运过程的变化,基于21世纪海平面上升预测研究(陈长霖,2012;张吉,2014),本文选取珠江河口这一径优型与潮优型并存的河口为研究区域,利用数值模拟的方法,研究其在未来海平面上升后可能出现的响应。结果表明,河口的平均盐度、咸潮上溯距离和层化强度都将随着海平面的上升而增加,这些因素的变化有着明显的季节性。伶仃洋平均盐度在4月和10月增加更多;伶仃洋枯水期咸潮上溯距离的增量大于丰水期,磨刀门则相反;伶仃洋丰水期层化强度及其增量都要大于枯水期。海平面上升后的输运过程响应结果显示:(1) 垂向输运时间将增加,虽然海平面上升带来的潮差潮流的增强将加强垂向混合,但是层化的加强会削弱垂向交换。垂向输运时间的增加是由于层化的加强,层化加强抑制了潮汐变化带来的影响,表层水更难交换到底层; (2) 南北向河口环流将加强,表层余流向海加强,底层余流向陆加强,南北向余流整体向海减小。造成这些现象的主要原因是海平面上升后水深增加带来的河道比降的减小和压力梯度力的改变。     

应用走航式ADCP测量分析与验证金塘水道的高悬沙浓度

在金塘水道西口门2006年冬季和2007年夏季大、小潮期间应用美国RDI公司生产的300 kHz声学多普勒流速剖面仪(ADCP)进行25 h的走航式断面观测,同步采集水样过滤获得悬沙浓度.实测断面流速、流向表明:落潮时流向为东南向,涨潮时分两股,靠近北仑为西南向,靠近金塘岛为西北向;夏季大潮最大流速为260 cm/s,大于冬季大潮;观测期间断面悬沙浓度为0.4～1.5 g/L,冬季大于夏季约0.3～0.5 g/L;ADCP后向散射强度冬季大于夏季约5 dB.应用实测CTD数据进行声吸收系数校正,通过计算,断面后向散射强度分布趋势基本不变.后向散射强度与悬沙浓度成正比,与水深成正比,垂向分布与潮时有关,冬季小潮水深增大时,后向散射强度反而减小.回归ADCP后向散射强度与水样悬沙浓度之间半经验半理论统计关系,发现冬季不成线性关系,夏季成线性关系,且相关性较好,相关系数为0.7,说明夏季较高浓度下后向散射强度可以表示悬沙浓度的大小.夏季大、小潮期间高分辨率的悬沙浓度断面数据分析表明,反演后的悬沙浓度值与流速成正比;近岸悬沙浓度大于断面中部;涨急和落急时同一水深高低含沙量值错落分布,涨憩和落憩则分层明显;大潮悬沙浓度大于小潮流约0.05 g/L.断面两端点反演后的悬沙浓度与实测值比较,呈现半日潮含沙量双峰特征,夏季大潮反演后的悬沙浓度与实测值分布一致,实测值大于0.9 g/L时,两者量值相差大,小潮则拟合很好.因此,应用走航式ADCP测量高悬沙浓度是可行的,它可大大提高测量效率,为获取现场悬沙浓度提供了一种新方法.