WRF-BASED SIMULATION OF WIND FIELD AND ASYMMETRY FEATURE OF RADIUS TO MAXIMUM WINDS DURING TYPHOON MARIA

Typhoons are extremely destructive, and the accurate reproduction of typhoon wind fields is the key to ensure the structural safety in typhoon-affected areas. The maximum wind speed radius is one of the key parameters in typhoon field calculation, and it is very important to study its distribution. Taking the NO.1808 super typhoon Maria as an example, the wind field was simulated by the mesoscale numerical prediction model WRF. A total of 7 parameterization scheme combinations were set for comparison to ensure the accuracy of the simulated wind field. The wind field is studied using the optimal simulation results, and the influence of topographic changes on typhoon structure is analyzed. The radius to maximum wind speeds in each direction of the typhoon is searched. The Holland pressure model and gradient component of the parametric wind field model are introduced to illustrate the effect of the asymmetry of radius to maximum wind speeds. The research results show that: adopting different microphysics schemes has little influence on Maria’s track simulation but changes the minimum sea-level pressure, and using Lin microphysics scheme, RRTM long-wave radiation scheme, and Dudhia short-wave radiation scheme can have better simulation results; the typhoon wind field was greatly affected by the change of underlying surface topography during Maria, and the wind speed gradually decreased when the topography changed from sea to land; the radius to maximum wind speeds shows a strong asymmetry and ignoring the asymmetry will affect the distribution of radial pressure and wind speed.