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Damutu Bay in eastern Zhejiang, China has abundant tidal flat resources for years of silt deposition in the wide open seas, making it an ideal place for mudflat reclamation. In this study we set up a two-dimensional hydrodynamic and sediment transport model based on Mike 21 FM to investigate changes in suspended sediment concentration (SSC) after reclaiming to 1 m and 3 m depth contours in the seas...
The acoustic properties including sound speed and the attenuation coefficient are important factors which determine the efficacy of acoustic equipments and targets detection of seafloor sediments. This paper presents a multi-mode acoustic in situ measurement system to be used in the deep sea. We analyzed the major system framework and relevant hardware and software. The proposed system provides two...
Temperature has a notable effect on sound speed and attenuation of sediment both in theoretical analysis and in laboratorial measurement. The speed of sediment is positively correlated with temperature universally, but the relationship between attenuation and temperature may be more complicated. In the paper, based on the analysis of influence of permeability, frequency, and other physical parameters...
Study of the concentration and the distribution of underwater suspended particles is vital for understanding the mechanism of material transport in oceanographic. However, existing in situ monitoring instruments and methods (based on optical and acoustic method) have certain limitations. The holography technique provides a high-resolution, three-dimensional and non-intrusive measurement method to...
A model is developed for bistatic bottom reverberation in the deep ocean, which includes the propagation and scattering processes. The two-way propagations from the source to scatterer and the scatterer to receiver are described by ray theory. The sound speed profile in the deep ocean is taken into account for the accuracy. The scattering intensity is assumed to be a sum of the roughness-scattering...
Sediment transport at the Yellow river delta is affected by many different factors, including tide, waves and river flows. With the change of river exit in 1996, a new delta is rapidly growing which leads to a new sediment transport regime. Most existing computer modelling work at the site is yet to take such changes into account. In addition, the wave action at the river mouth is often ignored in...
In order to study the geoacoustic relations for shallow water sediments, a project has started in 2014, bringing together French academic and industrial partners. One of this project objectives is to build a large database of acoustical and sedimentological parameters collected in-situ with specific devices. Therefore, an important task is to manage the data acquisition, storage, and exploitation...
Islands and coastal cities which have larger amounts of population and abundant marine resources, often bear the important responsibility of economic development. And environmental problems that coexist with it are occupied an important position of urban construction. What's more, high turbidity water caused by high sediment concentration has a great influence on coastal landscape and production....
The requirement of oil has increased the potential hazard of the accidents of the marine oil more evident, which urgently needs human to pay attention to monitoring oil production in order to reduce the economic loss and environmental damage. Although many efforts has been made to develop devices or instruments for marine oil spill monitoring, the droplet processing in micro environment is still not...
Capping contaminated sediments is an in situ remediation technique by placing capping material on top of the sediments to prevent continued contamination of surface water and biota from contaminated sediments. Capping is considered as much cheaper than dredging and is expected to be very effective to block the diffusion of contaminants in short-term. The research on capping material for controlling...
Model-based passive source localization is known to be quite sensitive to model mismatch. In this paper, we present a new implementation based on matched-mode processing. Specifically we formulate mode filtering as a convex optimization problem, and ℓ1-regularized least squares is applied, which is robust in terms of the numerical implementation. Simulations with respective full-depth and partially-spanned...
Inversion of modal dispersion curves is an effective method for obtaining underwater acoustic parameters. In this paper, an inversion scheme for synchronously obtaining the sound speed profile and bottom parameters using two wideband explosive sound sources is proposed based on modal dispersion characteristics. First, the first three orders of empirical orthogonal functions were determined and used...
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