Wei Zhang

Hohai University · State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering

The long-term changes of ocean surface waves associated with tropical cyclones (TCs) are poorly observed and understood. Here, we present the global trend analysis of TC waves for 1979–2022 based on the ERA5 wave reanalysis. The maximum height and the area of the TC wave footprint in the six h reanalysis have increased globally by about 3%/decade a...

Salt intrusion presents a significant environmental challenge in numerous estuaries around the world, including the Modaomen Estuary in China. This phenomenon typically occurs during the winter season due to reduced freshwater flow. However, an unusual salt intrusion event was observed during the autumn of 2022, coinciding with a typhoon. In this s...

BDDE substituted HA hydrogels remain the most commonly used HA product in the biomedical field. The physical and biochemical properties of the hydrogels are dependent on the degree of modification and substitution patterns/positions, thus, characterizing their fine structure is of great importance for quality assurance. In this study, we developed...

The characteristics of dynamic and delayed channel geomorphic responses to changing hydrological processes are still insufficiently understood, especially in large dammed rivers and segments farther downstream from the dam. Geomorphic effects farther downstream from the dam could be easily underestimated. This study investigated the hydrological ch...

Delayed response behaviour commonly occurs in conjunction with changes in riverbed scouring and sediment deposition and is a key component in understanding the intrinsic behaviour of reservoir siltation. Due to the complexity of the riverbed siltation process, the variability in the factors that influence siltation and the limitations of available...

Storm surges are among the deadliest natural hazards, but understanding and prediction of year-to-year variability of storm surges is challenging. Here, we demonstrate that the interannual variability of observed storm surge levels can be explained and further predicted, through a process-based study in Hong Kong. We find that El Niño-Southern Osci...

In an estuary, stratification processes play a major role in inhibiting estuarine circulation, sediment transport, and the estuarine ecosystem. A detailed examination of the salinity stratification through the gradient Richardson number and the potential energy anomaly equation has been undertaken along the West Channel of the Pearl River Estuary,...

A simple and convenient method for the electrosynthesis of fused 1,2,4-triazoles with two components of N-tosylhydrazones and quinolone derivatives has been established. The electrochemical method could be smoothly carried out at room temperature with the addition of KI and base to afford the desired products in good yields, which has potential for...

A double-layer transverse oscillating grid for a flume was designed and manufactured, in order to generate approximately isotropic homogeneous turbulence, and allowing the effect of suspended sediment stratification on turbulence characteristics to be studied experimentally. In the experiment, the diachronic variations in turbulence and suspended s...

An approach for the synthesis of pyrazolo[4,3-c]quinoline derivatives has been developed by the combination of pyrazole-arylamines and β-keto esters via cleavage of C–C bonds. The strategy shows good tolerance and compatibility with a wide range of functional groups. Moreover, this method features simple conditions, generates a series of alkyl subs...

Tidal current asymmetry, an important factor for waterborne substance transport, is strongly affected by the changing shoreline. Lingding Bay (LDB), located in the center of the Guangdong-Hong Kong-Macao Greater Bay Area, has suffered great shoreline changes since the 1970s. A well-validated numerical model is built to investigate how the changing...

Differential scanning calorimetry (DSC) technology has been proven to be able to detect the purity of chemical reference substances, but there are few studies on its applicability to volatile organic compounds. In this study, the purity of a volatile deuterated compound (benzene-d6) was successfully assessed by the DSC combined with quantitative nu...

The Pearl River Delta represents a tide‐influenced lowland delta where sand mining has deepened the distributary channels. This study sets out to investigate the impacts of channel deepening on peak water levels across the delta. Based on collected hydrological data before and after sediment mining and hydrodynamic modeling, three regions are ident...

A metrological technical specification for the purity assessment of organic pure substance certified reference materials (CRMs) in China was formulated based on the practical experience from CRM developers, comments from experts, the “IUPAC Organic Purity Technical Report—Methods for the SI Value Assignment of the Purity of Organic Compounds”, and...

Deep-water navigation channels in the tidal reaches of the lower Yangtze River are affected by water and sediment fluxes that produce complex shoals and unstable channel conditions. The Fujiangsha reach is particularly difficult to manage, as it has many braided channels within the tidal fluctuation zone. In this study, hydrologic and topographic d...

This paper proposes a modified approximation method for failure probability estimation of high-dimension structural systems with numerous correlated failure modes. Compared with the existing approximation methods, more critical factors such as component correlation, reliability index, reliability index ratio and the correlation between the current...

Large dams on rivers have substantial impacts on the flow process, sediment transport, and river morphology. The flow-sediment regimes and river morphology in the Yangtze River downstream of the Three Gorges Dam (TGD) have undergone significant adjustments owing to the impoundment of the TGD. Different methods have been adopted to assess the spatio...

17 Understanding water level (WL) fluctuations in river deltas is of importance for managing 18 water resources and minimizing the impacts of floods and droughts. Here, we demonstrate 19 the competing effects of atmospheric and oceanic forcing on multi-timescale variability and of in-situ observations at 13 hydrological stations. PRD WL presents si...

SLR induced by global climate would by changing tidal dynamics in the deltaic and coastal regimes aggravate inundation risks. In order to have a thorough understanding of the tidal responses to SLR in the RSR of SYS, a comprehensive analysis on the tidal and tidal components’ responses to SLR are conducted. Spatial variations of tides and tidal com...

Sea levels in the Western North Pacific (WNP) are presented with anomalous intraseasonal variations. This study examines the response of sea level in the WNP to the atmospheric Intraseasonal Oscillation modes, namely the Madden–Julian Oscillation (MJO) and the Boreal Summer Intraseasonal Oscillation (BSISO), using the 25 years (1993–2017) of satell...

This paper aims to study the hydrodynamic characteristics and power generation capacity of raft-type WEC (Wave Energy Converter), and to investigate the feasibility of adaptive damping control for this kind of WEC. The numerical model of Pelamis WEC is built in software ANSYS-AQWA. By calling external force and power routines at each time step to c...

Accurate synchronous measurement of salinity and sediment concentration has always been a concern for estuarine researchers. Considering salinity measurement based on electrical conductivity and sediment concentration measurement based on optical backscatter are still the most widely used measurement methods, a set of salinity measuring instrument...

A varied class method is applied to calculate the effective discharges and their variations after the Three Gorges Dam (TGD) construction based on the mean daily flow discharge and suspended sediment concentration field data from 1981 to 2016. For comparison, the bankfull discharges are also determined according to the cross-section profiles and fl...

The certified reference materials (CRMs) are necessary for accurate quantification and insurance of comparability and traceability of results. Patulin is a typical mycotoxin in a variety of food commodities. Here, patulin CRM GBW(E)100673 was characterised and its purity was assessed by two independent orthogonal approaches including mass balance (...

This paper deals with one-dimensional beam-type flexural wave behaviours of the orthogonally stiffened plate. A truncated model with one stringer and multiple stiffeners is experimentally investigated for free vibration behaviours of natural frequencies and beam-type mode shapes. Numerical simulations of the truncated model of the orthogonally stif...

Sediment deposition carried by flood flow is the main cause of reservoir sedimentation. This can be reduced by an appropriate operational strategy of flood flow and sediment in the reservoir. High-precision and large-scale hydrodynamic models to predict flood propagation and sediment transport in reservoirs are extremely important for an efficient...

Owing to the high mortality and the spread rate, the infectious disease caused by SARS-CoV-2 has become a major threat to public health and social economy, leading to over 70 million infections and 1. 6 million deaths to date. Since there are currently no effective therapeutic or widely available vaccines, it is of urgent need to look for new strat...

Variations in river hydraulic geometry (HG) are of fundamental importance to fluvial geomorphological research and catchment management. In tide-influenced river deltas, channel geometry displays a mixed scaling behavior since the channel forming discharge is of both tidal and river origins. This study aims to map the tidal signature on delta morph...

Hawser single point moored (SPM) shuttle tankers are widely used in various offshore oil development system. In this paper, the experiment of 1:40 shuttle tanker model with hawser SPM system in irregular waves is carried out. The effects of loading status, wave parameters, hawser line length and stiffness on the motion response of the shuttle tanke...

It is expected that a resilient condition monitoring (CM) system can identify the faults of sensors and key components, assess the system risk level based upon multichannel monitoring data, and recover missing real data when complete sensor failure occurs. As for CM of an offshore system, sensors are usually less reliable than the components being...

Ji, X.-M.; Yang, Y.; Fang, Y.-J., and Zhang, W., 2020. Tidal-fluvial processes at the outlets of delta distributaries: A multi-cruise observational study. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1449-1453. Coconut Creek (Florida), ISSN 0749-0208. The hydrodynamics...

Peak sediment transport during flood events is very important to the sustainability of the Three Gorges Reservoir (TGR), and thus, in-depth research on peak sediment transport must be performed for the refined regulation of this reservoir. The variation in peak sediment transport and its corresponding causes following the completion of the cascade...

The Yangtze River Estuary (YRE) is one of the world’s largest river-tidal systems with rapidly changing hydrology and morphology following the construction of multiple dams. The effects of dam construction may extend to the region close to the coast, where channel stability depends on the asymmetry of the tide. Here, we focus on the possible effect...

The spectrum of tidal and subtidal water level variations in river deltas responds to river discharge variation, ocean tides, and human activities of many kinds. It remains a contemporary challenge to identify the main sources of changes in tidal dynamics in deltas, because of nonlinear interactions between tides and the river discharge in a changi...

Variations in the water level of tide-influenced deltas are strongly related to the evolution of tides as the tidal waves propagate upriver. However, the impacts of tidal species on these water level variations are not well understood, particularly in delta channel networks. Therefore, a one-dimensional hydrodynamics model of the Pearl River Delta...

The lowest low waters usually occur during spring tides in tide-dominated coastal environments. However, they could also occur during neaps, rather than springs, at more landward stations, and this phenomenon is known as the reversal of the lowest low waters (RLLW). The RLLW greatly depends on subtidal and daily oscillations in the water level, the...

In branching delta channel networks, tides intrude into parallel river outlets causing complex tidal behavior. The tidal motion can impact the division of river discharge over distributary channels. Under some circumstances, the discharge averaged over a tidal cycle may even reverse, drawing ocean water into the delta, such as observed in the Yangt...

Quantifying how tides evolve with coupling between future sea level rise (SLR) and different coastline configurations is imperative for proposing appropriate coastal defense strategies. By using numerical models, we investigated tidal changes and determined a realistic trend of SLR on the Jiangsu coastal area and adjacent sea on the Yellow Sea shel...

Knowledge of the processes governing salt intrusion in estuaries is important, since it influences the eco-environment of estuaries as well as its water resource potential in many ways. Analytical models of salinity variation offer a simple and efficient method for studying salt intrusion in estuaries. In this paper, an unsteady analytical solution...

Upstream damming has profoundly impacted downstream channel morphology by altering inflowing water and sediment conditions, which can mostly be ascribed to variations in the flow hydrograph and sediment supply regime. In this paper, channel erosion and deposition during different flow-sediment processes are quantified using a 2D hydro-morphodynamic...

In this paper, the bifurcation characteristics and perturbation response in vortex induced vibration of cylinder with two degrees of freedom is investigated, aiming to study the law and mechanism of the influence of perturbation on the bifurcation of vortex-induced vibration, and to give some engineering suggestions. The main content of this paper...

The discharge distribution is influenced by the tidal behaviour at tidally affected junctions. The Pearl River Delta (PRD) is one of the most complicated deltas and highly affected by human interventions. The tides are reinforced by the riverbed downcutting caused by intensive sand dredging in the PRD. While some efforts have been made to interpret...

Knowledge of the processes governing salt intrusion in estuaries is important since it influences the eco-environment of estuaries as well as its water resource potential in many ways. Analytical models of salinity variation offer a simple and efficient method to study salt intrusion in estuaries. In this paper, an unsteady analytical solution is p...

Dam operation modifies downstream flow and river sediment regimes, resulting in convex point bar erosion and concave pool deposition along sand-bed meandering rivers, with different erosion patterns and consequent chute cutoff processes. The underlying mechanisms are not thoroughly understood. In this study, based on Chibakou Bend in the Jingjiang...

Wave-induced seabed instability caused by the residual liquefaction of seabed may threaten the safety of an offshore foundation. Most previous studies have focused on the structure that sits on the seabed surface (e.g., breakwater and pipeline), a few studies investigate the structure embedded into the seabed (e.g. a mono-pile). In this study, by c...

Under the influence of a climate of extreme drought and the Three Gorges Dam (TGD) operation, the water levels in the middle and lower reaches of the Yangtze River in 2006 and 2011 changed significantly compared with those in the extreme drought years of 1978 and 1986. To quantitatively analyze the characteristics of water level variations in 2006...

Tidal asymmetry in deltas is caused by both the intrinsic asymmetry, resulting from the combination of astronomical tides, and by nonlinear tidal interactions that occur in shallow water. The relative importance of these sources of tidal asymmetry in delta channel networks have remained poorly studied, partly due to the limitations of classical har...

Dam operation profoundly modifies downstream flow-sediment regimes, resulting in a variety of geomorphologic responses, without uniform laws. The Jingjiang reach of the middle Yangtze River has undergone significant adjustment mode alterations, with intensive channel erosion and major adjustment area changing from the bankfull channel to the medium...

At tidal junctions, flow, sediment, and, indirectly, flooding risk are distributed over the downstream river branches. To characterize the hydrodynamic pattern related to the transport and distribution of suspended sediment, an intra-tidal field measurement was conducted at the first order tidal junction in the Pearl River Network, Makou-Sanshui (M...

Elucidating the influence of dams on fluvial processes can benefit river protection and basin management. Based on hydrological and topographical data, we analyzed channel evolution in anabranching reaches under changing hydrological regimes influenced by the Three Gorges Dam. The main conclusions are as follows: 1) the channels of specific anabran...

Salt intrusion has some negative impact on the estuarine eco-environment as well as the water resource potential. The paper proposes an analytical model to describe salt intrusion in the estuaries with multiple freshwater sources. The impact of river discharge on the salinity distribution changes along the multiple-fresh-source estuaries, which is...

Elucidating the influence of dams on fluvial processes can inform river protection and basin management. However, relatively few studies have focused on how multiple factors interact to affect the morphological evolution of meandering reaches. Using hydrological and topographical data, we analyzed the factors that influence and regulate the meander...

Flow division at bifurcations in the Yangtze Estuary has received ample attention, since it may control the pathways of terrestrial sediments over downstream river branches, which in turn has directly impact on the 12.5 m Deepwater Navigation Engineering. While some efforts have been made to interpret flow division at the bifurcations of the Yangtz...

Particle size distributions (PSDs) of bottom sediments in a coastal zone are generally multimodal due to the complexity of the dynamic environment. In this paper, bottom sediments along the deep channel of the Pearl River Estuary (PRE) are used to understand the multimodal PSDs′ characteristics and the corresponding depositional environment. The re...

River basin reservoir construction affects water and sediment transport processes in downstream reaches. The downstream impact of the Three Gorges Projects (TGP) has started to become apparent: (1) reduction in flood duration and discharge, and significant reduction in sediment load. Although there was some restoration in downstream sediment load,...

Channel morphology in an alluvial river usually varies due to the altered flow and sediment regime from upstream damming. This paper reports an evaluation of the dynamical changes of sedimentation and erosion in the middle and lower reaches of the Yangtze River after operation of the Three Gorges Dam (TGD). Here, we present the results from a case...

Trends and variability of hydrological variables can reflect the redistribution of seasonal patterns that can be caused by both climatic and anthropic factors. In this paper, China’s East River, the most regulated tributary in the Pearl River Delta (PRD), is selected to be a typical study case. Annual and seasonal-scale analyses of the river regime...

A massive green tide (i.e., Ulva prolifera bloom) event in summer 2015 in the Yellow Sea was investigated using satellite imagery and a trajectory model. First, the occurrence and evolution of the macroalgal bloom were studied based on time series of cloud-free Moderate Resolution Imaging Spectroradiometer imagery during May to August using the Flo...

In this study, the net bottom sediment transport pattern is measured and compared with flow pattern in the Pearl River Estuary (PRE). Based on 106 bottom sediment samples taken from the PRE, the spatial distribution of bottom sediment of mean grain size μ (mm), sorting coefficient σ, and skewness SK is calculated. Then the grain size trend analysis...

The general features of oscillations within a rectangular harbor of exponential bottom are investigated analytically. Based on the linear shallow water approximation, analytical solutions for longitudinal oscillations induced by the incident perpendicular wave are obtained by the method of matched asymptotics. The analytic results show that the res...

Biography: YANG Yun-ping (1985-), Male, Ph. D., Senior Engineer

Tide is one of the most important hydrodynamic driving forces and has unique features in the Yangtze Estuary (YE) due to the complex geometry of third-order bifurcations and four outlets. This paper characterizes the tidal oscillations, tidal dampening, tidal asymmetry and tidal wave propagation, which provides insights into the response of the est...

This study examines seasonal circulation, hydrography, and associated spatial variability over the inner shelf of the northern South China Sea (NSCS) using a nested-grid coastal ocean circulation model. The model external forcing consists of tides, atmospheric forcing, and open boundary conditions based on the global ocean circulation and hydrograp...

In this study, a new three-dimensional model was developed to provide a better understanding of the mechanism for wave-induced seabed response around the mono-pile. Based on the poro-elastic theory, the fully dynamic formulations were adopted in the present model to simulate the pore pressure, soil stresses and the displacements of both soil and mo...

Xu, Y.; Zhang, W.; Chen, X.; Zheng, J.; Chen, X., and Wu, H., 2015. Comparison of analytical solutions for salt intrusion applied to the Modaomen Estuary. Salt intrusion in estuaries is an urgent environmental challenge across the world, because salinity influences water quality. The Modaomen Estuary is the main source of freshwater supply in the e...

Morphological changes in the Pearl River Delta (PRD) have been investigated using bathymetric charts, underwater Digital Elevation Models, remote sensing data and Geographic Information Systems. Water depths were extracted from digitized charts to explore the accretion-erosion characteristics of three estuarine environments, and to provide quantita...

Long-term variations of the stage-discharge relationships can reflect the channel morphology changes that can be caused by both natural factors and human activities. The rating curves are usually employed to predict discharges at monitoring hydrometric sections of interest. In this paper, the variation of rating curves is investigated with the purp...

River networks and estuaries are very common in coastal areas. Runoff from the upper stream interacts with tidal current from open sea in these two systems, leading to a complex hydrodynamics process. Therefore, it is necessary to consider the two systems as a whole to study the flow and suspended sediment transport. Firstly, a 1D model is establis...

With the aim to link tidal and subtidal water level changes to human interventions, 70 years of water level data for the Rhine–Meuse tidal river network is analysed using a variety of statistical methods. Using a novel parameterization of probability density functions, mean high and low water levels are examined, and extreme water levels are invest...

Evapotranspiration is one of the most important hydrological variables in the context of water resources management. An attempt was made to understand and predict the dynamics of reference evapotranspiration from a nonlinear dynamical perspective in this study. The reference evapotranspiration data was calculated using the FAO Penman-Monteith equat...

Principal component analyses (PCA) were used to identify the space-time patterns of long-term tidal fluctuation in the Pearl River delta (PRD) region. The tidal levels of the 35 stations over the entire PRD were divided into four regions by the PCA. The results show that different regions display different trends, indicating spatial variability of...

Flow and suspended sediment transport in distributary channel networks play an important role in the evolution of deltas and estuaries, as well as the coastal environment. In this study, a 1D flow and suspended sediment transport model is presented to simulate the hydrodynamics and suspended sediment transport in the distributary channel networks....

Bifurcations in tidal networks strongly control the distribution of flow and sediment flux over a river network system. These distributions are important in determining the fluvial sediment dispersal and transport from river networks to shorelines, thereby greatly affecting river channel, estuary, and coastal environments. Long-term observations of...

Spatial variations in grain-size parameters contain information on sediment transport patterns. Therefore, in this study, 106 surficial sediment samples taken from the Pearl River Estuary (PRE), South China, were analyzed, to better understand the net sediment transport pattern in this region. The PRE is an area of fine-grained sediment and shows m...

In recent years, large-scale saltwater intrusion has been threatening the freshwater supply in the metropolitan cities surrounding the Pearl River delta (PRD). Therefore, a better understanding of the saltwater intrusion process in this region is necessary for local water resource management. In this paper, a one-dimensional flow and salinity model...

Flow discharge from the river basin into the sea has severe impacts on the immediate vicinity of river channels, estuaries, and coastal areas. This paper analyzes the features and temporal trends of flow discharge at Pearl River's three main gauge stations: the Wuzhou, Shijiao, and Boluo gauge stations on the West River, North River, and East River...

In this study, sediment rating curves are employed to study the variations in relationships between water discharge and suspended sediment concentration based on the recent 50 years of monthly data set in the three major rivers of the Pearl River Delta. Results show that sediment rating parameters vary with time. The lowest rating coefficient, ln(a...

Data on sediment flux at three hydrologic stations from the 1950s to 2006 are utilized to study the decadal, annual, and monthly variations in suspended sediment load delivered from the Pearl River to the ocean. Results show that variations in sediment flux from three main tributaries, including the West River, the North River and the East River, a...

Among existing remote sensing applications, land-based X-band radar is an effective technique to monitor the wave fields, and spatial wave information could be obtained from the radar images. Two-dimensional Fourier Transform (2-D FT) is the common algorithm to derive the spectra of radar images. However, the wave field in the nearshore area is hig...

This paper focuses on identifying changes in the tidal range and the duration of the flood tide in the Pearl River Delta region, China. Mann–Kendall test and regression methods are employed to verify the existence of trends in the annual tidal range and duration series (from the 1950s to 2005) at 17 stations in the 3 major tributaries of the delta....

This paper is concerned with identifying the spatial and temporal patterns in the annual maximum and minimum water level in the Pearl River Delta (PRD) region. The Mann–Kendall test and Pettitt test are used to detect trends and abrupt change points, and the Trend Free Pre-Whitening (TFPW) approach then eliminates the effect of serial correlation i...

The Dongjiang River Delta lies in the eastern part of the whole Pear River Delta, Guangdong Province, China. In this paper, based on the 1-D numerical model and measured data, a study on the characteristics of tide, the suspended sediment transport during the flood and drought of the Dongjiang River Delta is made. Based on the “Three Steps Methods”...

The Lingding Estuary is one of the main parts of the whole Pearl River Delta, which lies in the South Sea, China. It is about 60 km wide from Hong Kong in the east to Macao in the west and the water areas are approximately 2110 km2 . The process of suspended sediment movement is influenced by many factors, such as the estuarine geometry, tidal rang...

Measurements of the flow velocity profiles through one tidal cycle were taken in the Yangtze Estuary. The flow velocity profile during the experiment was characteristic of a tidal boundary layer growing through the tide, and with increasing velocity, especially on the accelerating flood tide. Due to the bed friction, the near bottom flow, which for...

Ling Ding Yang (LDY) estuary is one of the main parts of the whole Zhujiang estuary, which lies in the south sea, China. It is about 60km wide from Hong Kong in the east to Macao in the west and the water areas are approximately 2110 km2 . The mixing process of salt water and fresh water in the estuary is influenced by many factors, such as the est...

The Pearl River Delta (PRD) lies in the south of GuangDong province in China. It is the river networks area of the lower reaches of MaKou of West River, Sanshui of North River and ShiLong of Dongjiang River. Over the last 20 years, in order to keep sustainable development of economy, many regulations engineering to improve grade of channel from riv...