Technical development of operational in-situ marine monitoring and research on its key generic technologies in China

In China,operational in-situ marine monitoring is the primary means of directly obtaining hydrological,meteorological,and oceanographic environmental parameters across sea areas,and it is essential for applications such as forecast of marine environment,prevention and mitigation of disaster,exploitation of marine resources,marine environmental protection,and management of transportation safety.In this paper,we summarise the composition,development courses,and present operational status of three systems of operational in-situ marine monitoring,namely coastal marine automated network station,ocean data buoy and voluntary observing ship measuring and reporting system.Additionally,we discuss the technical development in these in-situ systems and achievements in the key generic technologies along with future development trends.

Integrating Traditional Chinese Culture into Teaching Practice and Exploration - Taking the Numerical Analysis Course as an Example

China’s excellent traditional culture has a history of thousands of years,which will have a significant influence on students’thinking and behavior if integrated into teaching.In this paper,the Numerical Analysis course is taken as the research subject,and the main problems and causes of incorporating traditional culture as well as ideological and political education into teaching are analyzed.At the same time,as a way of integrating science into education,the strategy and specific implementation plan for the integration of traditional culture as well as ideological and political elements into numerical calculation methods are proposed.This provides a new idea and experience for basic mathematical courses in colleges and universities,which plays a role in traditional cultural,ideological,and political education curricula.

Coupling of wave and current numerical model with unstructured quadtree grid for nearshore coastal waters

This paper presents 2D wave-current interaction model for evaluating nearly horizontal wave-induced currents in the surf-zone and coastal waters.The hydrodynamic model is the two-dimensional depth-averaged nonlinear shallow water equations by using an unstructured non-staggered and multiple-level quadtree rectangular mesh,this mesh information is stored in simple data structures and it is easy to obtain a locally high resolution for important region.The intercell fluxes are computed based on the HLL(Harten-Lax-van Leer) approximate Riemann solver with shock capturing capability for computing the dry-to-wet interface of coastal line.The effects of pressure and gravity are included in source term in the model,this treatment can simplify the computation and eliminate numerical imbalance between source and flux terms.The wave model readily provides the radiation stresses that represent the shortwave-averaged forces in a water column for the hydrodynamic model and the wave model takes into account the effect of wave-induced nearshore currents and water level.The coupling model is applied to verify different experimental cases and real life case of considering the wave-current interaction.The calculated results agree with analytical solution,experimental and field data.The results show that the modeling approach presented herein should be useful in simulating the nearshore processes in complicated natural coastal domains.

Offshore system safety and operational challenges in harsh Arctic operations

Offshore oil and gas drilling operations are going to remote and harsh arctic environments with demands forheightened safety and resilience of operational facilities. The remote and harsh environment is characterized byextreme waves, wind, storms, currents, ice, and fog that hinder drilling operations and cause structural failuresof critical offshore infrastructures. The risk, safety, reliability, and integrity challenges in harsh environment operations are critically high, and a comprehensive understanding of these factors will aid operations and protectthe investment. The dynamics, environmental constraints, and the associated risk of the critical offshore infrastructures for safe design, installation, and operations are reviewed to identify the current state of knowledge.This paper introduces a systematic review of harsh environment characterization by exploring the metoceanphenomena prevalent in harsh environments and their effects on the floating offshore structures performanceand supporting systems. The dynamics of the floating systems are described by their six degrees of freedom andtheir associated risk scenarios. The systematic methodology further explores the qualitative, quantitative, andconsequences modeling techniques for risk analysis of floating offshore systems in a harsh environment. Whilepresenting the current state of knowledge, the study also emphasizes a way forward for sustainable offshore operations. The study shows that the current state of knowledge is inexhaustive and will require further researchto develop a design that minimizes interruption during remote harsh offshore operations. Resilient innovation,IoT and digitalization provide opportunities to fill some of the challenges of remote Arctic offshore operations.

Analysis and application of the acoustic interfered field distortion for acoustic forward-scattering detection of underwater targets

The signal-to-direct-blast ratio SDRF in acoustic forward-scattering detection can measure the relative magnitudes of the forward scattered wave and the direct-blast,but it does not consider the interference and superimposition effects between the two waves.These two waves inevitably interfere with one another and are difficult to distinguish,so it is difficult to directly apply SDRF in target detection and analysis.Based on SDRF and considering the interference between the forward scattered wave and the direct-blast,a new parameter called the acoustic interfered field distortion ΔFTL is developed,and the corresponding calculation formula is deduced.Compared with SDRF,ΔFTL can be obtained directly from data and has the advantage of not relying on prior information to a certain extent.The following is found according to this formula in combination with data from the Qiandao Lake scaled-target detection experiment.(1) Estimating the geometric expansion loss coefficient reveals that the acoustic wave propagates spherically,which is consistent with the simulation results of the ray model based on the measured hydrological parameters.(2) The relation between ΔFTL and the target crossing position is quantitatively confirmed,confirming the effectiveness of the ΔFTL formula.(3) A performance evaluation scheme independent of prior information is established for direct-blast suppression and then applied to an adaptive direct-blast suppression method.The influences of acoustic leakage and disturbances in the attitude angle of the target on the results can be ignored.These results show that ΔFTL can effectively replace SDR_(F),providing theoretical references for conducting performance evaluations on acoustic forward-scattering detection and direct-blast suppression.