Numerical Simulation Of Typhoon Lekima With Two Microphysical Parameterization Schemes

This work compares the performance of Thompson and CLR microphysical parameterization schemes on simulations of typhoon Lekima with Weather Research and Forecast(WRF)model.The typhoon track,intensity,and precipitation simulated with the two schemes were analyzed.Firstly,steering flow was calculated,along with vertical velocity and latent heating to infer that the differences in typhoon tracks were associated with the typhoon kinematic structures simulated with the two schemes.The primary rainbands behind the eyewall in the Thompson simulation likely explain the slow-motion speed and right-shifted track of typhoons after landing.Secondly,variation and horizontal distribution of hydrometeors are compared.It is found that graupel content has a good corresponding relationship with typhoon intensity.Considering the cloud-radiation effect,the Thompson scheme produced more cloud ice and less outgoing long-wave radiation than the CLR scheme at the initial simulation stage(0-6hr),which was found to have a positive effect on the typhoon intensity.Thirdly,the vertical distribution of five hydrometeors and the fall speeds of the dominant species was examined.It reveals that when the ice hydrometeors at mid-and-high levels are precipitating,they could be carried away by outflow to different horizontal distances with respect to the particle size and fall speed presumed differently in the two microphysical schemes.The divergence flows outwards,forming different intensities and precipitation at different distances to the center of the typhoon,which explains why the Thompson and CLR schemes form different outer spiral rainbands at about 100km and 150km from the center of the typhoon,respectively.