Adaptability evaluation of boundary layer schemes for simulation of sea and land breeze circulation in the west coast of the Yellow Sea

Abstract

In the study, a three dimensional Doppler Wind Lidar placed at a coastal city Rizhao in west coast of Yellow sea was used to evaluate the wind field simulated by ten different planetary boundary layer parameterization schemes (PBLS) in the Weather Research and Forecasting model. It is found that the characteristics of the simulated wind field are very sensitive to the boundary layer parameterization schemes used in the model, especially for the sea-land breeze (SLB). Analysis shows that Grenier-Bretherton-McCaa (GBM), Mellor-Yamada Nakanishi and Niino Level 2.5 (MYNN2), and Yonsei University (YSU) produced more realistic results of the three dimensional wind field, as well as the occurrence time, duration and heights of SLB. This is because the entrainment effect is adopted in the GBM scheme, which improves the radiation process between the ground and the atmosphere and ensures the accuracy of turbulent diffusion calculation caused by the differences of temperature and humidity in coastal area. The YSU scheme introduces a local gradient correction term, so that the non-local thermals brings the surface hot air to the middle and upper part of the boundary layer. This process increases the turbulent mixing induced by thermal forcing in the simulation of SLB. The MYNN2 scheme specifies the relationship between the length scale and buoyancy, turbulence scale and surface layer in turbulent kinetic energy equation, and introduces a set of closure parameters representing buoyancy and shear. However, the disadvantages of this scheme are that the influence of the underlying surface is not considered in detail, and the entrainment heat flux at the top of the convective boundary layer is underestimated.