Numerical simulation of a diurnal cycle on the structure of ocean mixed layer

Purpose - The purpose of this paper is to study a diurnal cycle on the structure of ocean mixed layer. Also, in different set of numerical simulations, wind stress is discussed to refine the mixing process and to make closer situation to the natural phenomenon of the upper ocean dynamic processes. Design/methodology/approach - A large-eddy simulation is used to study the effect of cooling and heating, which represent a diurnal cycle on the convection and structure of the surface mixed layer. A modified subgrid scale model in which formulation corresponds to a nonlinear subgrid scale eddy viscosity formulation is used. Solar calculator is used to impose the solar radiation energy irradiated on the sea surface. Findings - 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. Originality/value - The net surface heat flux has major contribution to the sea surface temperature (SST) variation and SST is a necessary parameter to calculate sea surface heat flux, presenting the forced effect of the ocean on the atmosphere. Through air-sea interaction, ocean supplies energy for a typhoon's intensification, causing significant SST cooling, and because of this, SST has its universal affect on adjusting the global climate.