scholarly journals Impact of Sea Ice on the Hydrodynamics and Suspended Sediment Concentration in the Coastal Waters of Qinhuangdao, China

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 611
Author(s):  
Man Jiang ◽  
Chongguang Pang ◽  
Zhiliang Liu ◽  
Jingbo Jiang
Keyword(s):  
Sea Ice ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Resuspension ◽  
Parabolic Type ◽  
Bottom Layer ◽  
Sediment Concentration ◽  
Shielding Effect ◽  
Strong Wind ◽  
Seabed Sediment

The influence of sea ice on the hydrodynamics, sediment resuspension, and suspended sediment concentration (SSC) in the coastal area of Qinhuangdao was systematically investigated using 45-day in situ measurements at two stations (with ice at station M1 and without ice at station M2) in the Bohai Sea in the winter of 2018. It was found that the daily fluctuations of temperature and salinity at M1 are more significant than those at M2. During a typical seawater icing event on January 28, the temperature and salinity of the bottom water at M1 were decreased by 1.77 °C and increased by 0.4 psu, respectively. Moreover, due to the shielding effect of the sea ice, the residual current was much less affected by the wind at M1 than at M2. For the vertical distribution of current velocity, it changed from a traditional logarithmic type under ice-free conditions to parabolic type under ice-covered conditions due to the larger drag coefficient of the water body on the solid ice surface. For the SSC and turbidity at the bottom layer, the average values were 4.9 μL/L and 8.6 NTU at M1, respectively, approximately half of those at M2. The smaller SSC and turbidity at M1 can be attributed to the lower near-bottom turbulent kinetic energy (TKE). At M2, however, the larger SSC is closely related to the strong wind forcing, which could induce higher TKE without sea ice cover, and hence stronger turbulent resuspension. The seabed sediment analysis results showed that in the study area, fine sand is most likely to resuspend, while cohesive particles would resuspend only under strong hydrodynamic conditions.

scholarly journals Characterization of bottom sediment resuspension events observed in a micro-tidal bay

Ocean Science ◽  
2019 ◽  
Vol 15 (2) ◽  
pp. 307-319 ◽  
Author(s):  
Manel Grifoll ◽  
Pablo Cerralbo ◽  
Jorge Guillén ◽  
Manuel Espino ◽  
Lars Boye Hansen ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Optical Sensors ◽  
Suspended Sediment Concentration ◽  
Sediment Resuspension ◽  
Ecological Status ◽  
Sediment Concentration ◽  
Strong Wind ◽  
Sedimentary Process ◽  
Sea Bottom ◽  
Wind Events

Abstract. In this study we investigate the variability in near-bottom turbidity in Alfacs Bay (in the northwestern Mediterranean Sea). The bay is characterized by a micro-tidal environment and seiching activity that may lead to flow velocities of more than 50 cm s−1. A set of current meters and optical sensors were mounted near the sea bottom to acquire synchronous hydrodynamic and optical information from the water column. The time-series observations showed an evident relation between seiche activity and sediment resuspension events. The observations of turbidity peaks are consistent with the node–antinode location of the fundamental and first resonance periods of the bay. The implementation of a coupled wave–current numerical model shows strong spatial variability of the potential resuspension locations. Strong wind events are also a mechanism responsible for the resuspension of fine sediment within the bay. This is confirmed by suspended sediment concentration maps derived from Sentinel-2 satellite imagery. We suggest that the sequence of resuspension events plays an important role in the suspended sediment concentration, meaning that the occurrence of sediment resuspension events may increase the suspended sediment in subsequent events. The suspended sediment events likely affect the ecological status of the bay and the sedimentary process over a long-term period.

Characteristics of Suspended Sediment and Resuspension Process in Wendeng Coastal Area, Shandong Peninsula

2013 ◽  
Vol 807-809 ◽  
pp. 1595-1599 ◽  
Author(s):  
Xiao Liu ◽  
Xiu Li Feng ◽  
Jie Liu
Keyword(s):  
Suspended Sediment ◽  
Coastal Area ◽  
Tidal Cycle ◽  
Suspended Sediment Concentration ◽  
Sediment Resuspension ◽  
Analysis Data ◽  
Sediment Concentration ◽  
Velocity Variation ◽  
Shandong Peninsula ◽  
Maximum Value

Based on the field observations and laboratory analysis data of the suspended sediment of Wendeng coastal area, this paper studied the change process of suspended sediment concentration and characteristics of surface sediment resuspension in the study area. In results: (1) In vertical, the suspended sediment concentration of each station increased gradually from surface to bottom, and the maximum value could reach 0.11 kg/m3; (2) Suspended sediment concentration is well correlated with velocity variation in a tidal cycle, and the peak of suspended sediment concentration occurs four times in a tidal cycle, indicating that there are four resuspension processes during a tidal cycle in the study area; (3) According to the suspended sediment concentration at different times and the content of the previous time, the maximum settlement is between 0.063~0.092kg/m3, and the maximum resuspension is between 0.057~0.125kg/m3 in the study area.

scholarly journals Characterization of bottom sediment resuspension events observed in a micro-tidal bay

2018 ◽  
Author(s):  
Manel Grifoll ◽  
Pablo Cerralbo ◽  
Jorge Guillén ◽  
Manuel Espino ◽  
Lars Boye Hansen ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Optical Sensors ◽  
Sediment Resuspension ◽  
Ecological Status ◽  
Sediment Concentration ◽  
Strong Wind ◽  
Sedimentary Process ◽  
Node Location ◽  
Nw Mediterranean ◽  
Wind Events

Abstract. In this contribution we investigate the origin of the variability in near-bottom turbidity observations in the Alfacs Bay (NW Mediterranean Sea). This bay is characterized by a micro-tidal environment and a relevant seiching activity which may lead to flow velocities of more than 50 cm s−1. A set of current meters and optical sensors mounted near the sea bottom were used to acquire synchronous hydrodynamic and optical information of the water column. The time-series observations showed an evident relation between seiche activity and sediment resuspension events. The observations of turbidity peaks are consistent with the node/anti-node location for the fundamental and first resonance periods of the bay. The implementation of a coupled wave-current numerical model shows a strong spatial variability of the potential resuspension locations. Strong wind events are also a mechanism responsible of the resuspension of fine sediment within the bay. This is confirmed using retrieval of suspended sediment concentration from Sentinel-2 data. We suggest that the sequence of resuspension events plays a relevant role in SSC, in such a way that previous sediment resuspension events may influence the increase of suspended sediment in subsequents events. The suspended sediment events likely affect the ecological status of the Bay and the sedimentary process at long-term period.

Tide-induced fine sediment resuspension in the well-mixed Hangzhou Bay, East China Sea, China

2011 ◽  
Vol 102 (1) ◽  
pp. 25-34 ◽  
Author(s):  
John Z. Shi
Keyword(s):  
Suspended Sediment ◽  
East China Sea ◽  
Suspended Sediment Concentration ◽  
Sediment Resuspension ◽  
Sediment Concentration ◽  
Fine Sediment ◽  
East China ◽  
Hangzhou Bay ◽  
China Sea ◽  
Suspended Sediment Concentrations

ABSTRACTHangzhou Bay is a typical funnel-shaped high turbid estuary along a mesotidal coast of the East China Sea. In this paper, field studies are undertaken in an attempt to better understand tide-induced fine sediment transport processes in the Bay. Field observations were made mainly of current velocities (speeds and directions) and suspended sediment concentrations at six different relative depths and two stations in September 1992. Results show that (1) high near-bed suspended sediment concentrations varied from 1·81 to 4·00 kg m−3 during the spring tide and from 1·04 to 8·00 kg m−3 during the neap tide; (2) tide-induced near-bed fine sediment resuspension processes are indicated by several periodic suspended sediment concentration peaks; and (3) a hysteresis effect, or suspension-lag, occurs in suspended sediment concentration and resuspension events. Tide-induced fine sediment processes are mainly responsible for very high concentration suspensions of fine sediments in Hangzhou Bay. The occurrence of the suspension-lag phenomenon is likely to be common in other similar muddy tidal environments.

Neural networks approached for modelling river suspended sediment concentration due to tropical storms

2013 ◽  
Vol 11 (4) ◽  
pp. 457-466
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Time Series Data ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Series Data ◽  
Generalized Regression Neural Network ◽  
Event Based

Artificial neural networks are one of the advanced technologies employed in hydrology modelling. This paper investigates the potential of two algorithm networks, the feed forward backpropagation (BP) and generalized regression neural network (GRNN) in comparison with the classical regression for modelling the event-based suspended sediment concentration at Jiasian diversion weir in Southern Taiwan. For this study, the hourly time series data comprised of water discharge, turbidity and suspended sediment concentration during the storm events in the year of 2002 are taken into account in the models. The statistical performances comparison showed that both BP and GRNN are superior to the classical regression in the weir sediment modelling. Additionally, the turbidity was found to be a dominant input variable over the water discharge for suspended sediment concentration estimation. Statistically, both neural network models can be successfully applied for the event-based suspended sediment concentration modelling in the weir studied herein when few data are available.

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