Numerical Simulation And Research Of The Dynamic Mechanism Of Abyssal Circulation In Japan Sea Based On HYCOM Model

Located in the Northwest Pacific,Japan Sea is surrounded by Russia,the Korean Peninsula and Japan and connected to the East China Sea.It is of great significance for the forecast of its marine environment to carry out scientific research or military training in the future in this region.Japan Sea has the characteristics of a "miniature ocean" with a small horizontal extension but a quite deep and well-mixed abyss in it.With a semi-closed geographic structure but many basin-scale circulation above its complex terrain,the study of the Japan Sea can not only accumulate mesoscale The experience of the marine environment in marginal seas can also deepen the understanding of the process of marine environmental variability in the oceans.The ocean numerical simulation can effectively avoid the defects of traditional observation methods such as long observation period,inconsistent data and high cost.The Hybrid Coordinate Ocean Model(HYCOM)was developed to address known shortcomings in the vertical coordinate scheme of the Miami Isopycnic-Coordinate Ocean Model(MICOM)developed by Rainer Bleck and colleagues.HYCOM is a primitive equation,general circulation model with vertical coordinates that remain isopycnic in the open,stratified ocean.However,the isopycnal vertical coordinates smoothly transition to z-coordinates in the weakly stratified upper-ocean mixed layer,to terrain-following sigma coordinates in shallow water regions,and back to z-level coordinates in very shallow water.The latter transition prevents layers from becoming too thin where the water is very shallow.It has been proved HYCOM has a pretty good performance in simulating many ocean areas.Based on previous studies,we chose HYCOM as the basic experimental platform in the following research.In order to validate the effect of experimental simulation,we use WOA-13 data and SODA-clim reanalysis data as the control field for quantitative analysis,and set up an experimental platform based on HYCOM ocean numerical model.By nesting technology and vertical stratification optimization method,This paper optimizes and adjusts the model and obtains a simulation experiment platform of the sea environment of Japan Sea that is acceptable both in calculation and accuracy.In the following research,we have made human intervention on several major parameters that affect the Japan Sea and analysis based on experiment about the dynamic mechanism of the abyssal circulation has been concluded.HYCOM numerical model has the basic ability to simulate the physical parameters of the Japan Sea.The application of the nesting technique not only successfully restored the interaction between the Sea of Japan and the outer sea area,but also reduced the computational cost without sacrifice the simulation accuracy.The vertical stratification improvement improves the model’s ability to simulate the deep circulation by optimizing the stratification of the ocean during mode operation.It also optimizes the simulation of the mode in whole area overall.Based on the optimized experiment platform,result from the intervention experiments shows that the wind forcing has a significant effect on the circulation structure in the north of the Japan Sea.The effect of heat-flux forcing field on deep circulation is also indirectly achieved through the change of surface circulation,but not as significant as that of the wind forcing.The invasion flow field also directly affects the deep circulation.Above all,the deep circulation in the major sea basins in the Sea of Japan is not completely independent of each other.The deep circulation in the major sea basins in the Sea of Japan is not completely independent of each other,but there is an internal relationship between them.