Study On The Response Of Ocean Mixed Laver To Diurnal Cycle Flux Based On LES

The upper ocean is a bridge that connecting the ocean and the atmosphere, which plays an important role in the exchange of the air-sea momentum, heat and mass transfer. It is of great scientific significance to study the response of the upper ocean to the various forces exerted on the surface of the ocean.Firstly, this paper summarizes the research status of the upper ocean and air sea flux, giving an overview of the main influence factors that affecting the dynamic and thermodynamic structure of the ocean mixed layer and turbulence generation mechanism. The commonly used mixed layer model is briefly introduced, and we modify the control equation combining with existing theoretical research. Large eddy simulation method is used to study the response of the upper ocean to various forcing conditions.This paper analyzes the response of thermal structure and dynamic structure to the diurnal cycle of heat flux alone, choosing the vertical velocity, turbulence dissipation rate, temperature and mixed layer depth as parameters. Result shows that convection is produced at night during cooling when surface heat flux is negative and turbulence is strengthened because of this action. However, when it comes to diurnal heating, sea surface heat flux is positive and causes stratification, making the turbulence collapse at sunrise.Results of considering both the wind force and diurnal cycle of heat flux show that the instability generated by wind stress can deepen the depth of ocean mixed layer, and the curl caused by wind stress will cause the divergence of the upper ocean, resulting in upwelling zones and downwelling zones.Wind stress can generate turbulence in the ocean, strengthening the vertical mixing processes in the mixed layer, and is the most direct impact factors that making the ocean mixed layer deepen, determining the dynamical structure of the mixed layer.