Satellite observations from 2002 to 2017 were used investigate the spatial distribution and temporal variability of chlorophyll-a (Chl-a) in South China Sea (SCS). High levels Chl-a mostly found near coasts Vietnam, with a significantly long-term increasing trend. Large seasonal was northern SCS southeast Vietnam. The reached maximum winter minimum summer for majority SCS, while Vietnam out phase. monsoon winds sea surface temperatures most important determinants impacting along other...

Abstract Seven years of satellite observations (2003–2009) are used to describe variability in sea surface temperature (SST) fronts and the alongshore component ocean winds, investigate their relations four Eastern Boundary Current Systems (EBCS). The general patterns SST frontal activity remarkably similar all EBCS, with high probabilities along coast decreasing distance from coastline. Results empirical orthogonal function decompositions reveal that seasonal evolution wind stress...

The mesoscale eddies off the coast of Chile significantly impact distribution local chlorophyll and development marine ecosystem. Multiple processes, including eddy trapping, pumping, advection, Ekman-pumping, submesoscale dynamics, exert their impacts simultaneously on transport water masses at different distances with respect to center. cyclonic (anticyclonic) are generally characterized by upwelling (downwelling) within eddy, which elevates (depresses) inside eddy. Outside periphery,...

Abstract Fifteen years of satellite observations sea surface temperature (SST) are used to identify frontal activities in the eastern Pacific Ocean. The frontogenesis and variability mainly determined by wind forces. Strong distributed near coast decrease with increasing offshore distance. seasonal cycle dominates SST probability (FP) coastal regions, large interannual is identified tropics. Coastal driven local such that equatorward stress forces upwelling, which brings subsurface cold...

Abstract The relationship between lateral spreading and mixing in stratified gravity currents is investigated by comparing laterally confined unconfined a series of laboratory experiments. vertical turbulent buoyancy flux determined using control volume approach with velocity density fields derived from combined particle image velocimetry (PIV) planar-laser-induced fluorescence (PLIF). Lateral the experiments based on plan-view imaging optical thickness method (OTM). authors find that...

Abstract Systematical downslope‐turbidity‐current experiments were performed to clarify the relationship between sediment‐transport modes and current propagation patterns caused by rigid vegetation, as well adjustments in turbulence characteristics of current. The equations for predicting front velocities downslope turbidity currents with emergent vegetation proposed validated via experimental data. Experimental results reveal that sediment deposition causes lower turbulent kinetic energy...

Abstract Modulated by a host of complex processes, suspended sediment fronts (SSFs) on the inner shelf East China Sea persist strongly and vary notably. Using hourly concentration data collected Geostationary Ocean Color Imager over period 2011–2021, gradient‐based edge detection algorithm was implemented to extract SSFs; frontal probability (FP) seasonal interannual variability were identified interpreted. Pronounced activity is principally confined nearshore waters within 60‐m isobaths...

Considering the bending-torsional-axial-coupled vibration of helical gear transmission system, a 10 degrees freedom high-speed train system model, including motor and load, is established based on lumped parameter method. In addition, potential energy method slicing principle used to accurately calculate time-varying meshing stiffness gears. Furthermore, influence geometric parameters gears studied, impact further investigated. Meanwhile, by analyzing dynamic phenomena under different...

A series of constant-flux saline and turbidity current experiments were carried out, focusing on the coupling impact bed roughness permeability propagation, mixing, turbulence characteristics. The distinct propagation phases RI (rough impermeable) RP permeable) beds are identified, respectively. Experimental results revealed that intermittently undulating surface breaks strict no-slip boundary, thus, increasing local velocity near bed, while its reduces peak profile velocity. Interbed pores...

In nature, plumes usually enter the coastal ocean after they leave estuary, and most of them interact with continental shelf slope. To understand plume dynamics, laboratory experiments were carried out on a rotating table to simulate evolution over sloping bottom. We modified reduced gravity g’ , Coriolis parameter f slope α study their impacts characteristics freshwater fate, used optical thickness method obtain depth field. found that increasing or decreasing maximum h max decreases width...

Seasonal cycle and interannual variability in coastal circulations the northern South China Sea (NSCS) are investigated using satellite altimeter data from March 1993 to September 2016. Altimeter-derived velocity anomalies good agreement with acoustic Doppler current profilers (ADCP) observations at an adjacent location. Along-shelf volume transport NSCS indicate northeastward transports mid-spring summer southwestward mid-autumn winter, which consistent previous studies this region....

Abstract Bacterial communities in sediments of the Caiwei Seamount, a typical guyot located northwest Pacific Ocean, were investigated. A total 727,879 16S ribosomal RNA gene sequences retrieved from eight sediment samples top (mean depth = 1,407 m) and base 5,525 through pyrosequencing V6 hypervariable region clustered into 32,844 operational taxonomic units. Abundant‐weighted UniFrac metric partitioned bacterial assemblies two categories (the community community) by principal coordinates...

This study experimentally investigated the impacts of rough and porous (RP) bed sedimentation processes on coherent structures, turbulence intermittency, anisotropy saline turbidity currents. The results reveal that local current concentration responds immediately (saline current) or languidly (turbidity to bursting events. Inside dense current, turbulent momentum fluxes in streamwise (u′u′¯) vertical (w′w′¯) directions transfer downstream downward, which favor sweep ambient water, u′u′¯...

A series of laboratory experiments are presented to compare the dynamics constant-source buoyant gravity currents propagating into laterally confined (channelized) and unconfined (spreading) environments. The plan-form structure spreading current vertical density velocity structures on interface quantified using optical thickness method a combined particle image velocimetry planar laser-induced fluorescence method, respectively. With lateral boundaries, is approximately constant...

Accurate and reliable estimates of sediment yields from a watershed identification unstable stream reaches due to sediment-related disaster are crucial for management, prevention, hazard mitigation purposes. In this study, we added hydrodynamic transport modules in recently developed model estimate identify the large-scale (> 100km2). The calibrated verified models can well reproduce flow discharge at study site, Shihmen Reservoir Watershed Taiwan, during several typhoon events. For...

Abstract Many processes are known to influence the distribution of sea surface temperature (SST) fronts in Eastern Boundary Current Systems (EBCS), including wind forcing, mesoscale activity, flow instabilities, and flow‐topography interactions. Here we used satellite observations quantify relative importance one these processes, eddy on SST gradients EBCS. Eddies characterized by large gradient anomalies all At end upwelling season, eddy‐induced dominant components full offshore 300 km from...

A three-dimensional numerical model was established with OpenFOAM-5.x to investigate plume characteristics under windless and rainless weather conditions. The large eddy simulation applied, combined a modified solver for solving governing equations the Boussinesq approximation in single rotating frame. relationship between (e.g., gradient Richardson number maximum width) quantified parameters rotation period, shelf slope, reduced gravity) analyzed progressively. results show can reproduce...

Abstract When internal solitary waves (ISW) propagate to the continental shelf, they typically runup and break on forereef. This process might lead periodic temperature drops at reef slope, which has potential protect coral reefs from bleaching threats. A series of laboratory experiments were conducted investigate turbulence characteristics energy dissipation during ISW breaking events shelf slope with different bottom roughness mimic forereef environment. Particle image velocimetry (PIV)...