模式分辨率对台风“天鸽”（2017）模拟效果的影响

THE IMPACT OF RESOLUTION ON THE SIMULATION RESULTS OF TYPHOON HATO(2017)

利用WRF模式,研究了模式水平和垂直网格分辨率对台风“天鸽”(2017)模拟的影响。结果表明:水平分辨率的改变会对台风路径造成一定的影响,这种影响与改变水平分辨率以后所引起的台风强度和结构的变化有关。使用更高的水平分辨率时模拟的台风强度往往更强。此外,改变垂直分辨率对台风的路径模拟也有一定的影响。采用双曲正切的垂直分层方法,提高垂直层数,模式大气的垂直分辨率都有增加,但是在低层和高层垂直分辨率的增加更大。低层和高层垂直分辨率增加,模拟的台风强度增强。模式的水平分辨率和垂直分辨率之间匹配才能比较好地模拟台风,双向嵌套模式在提高嵌套层数的同时也要增加模式的垂直分辨率。台风强度和结构变化密切相关,台风强度增强的重要原因是台风云墙随着分辨率的增加更加陡峭,垂直风速随着水平分辨率的提高逐渐增强。

In this article,the effect of horizontal and vertical grid resolution on typhoon Hato(2017)are studied by using WRF model.The results show that changing horizontal resolution will affect the simulation results of typhoon tracks to some extent because changing of horizontal resolution is related to the change of typhoon intensity and structure tightly,while higher horizontal resolution tends to produce stronger typhoon.In addition,changing the vertical resolution also has certain influence on the simulation of typhoon tracks.Using hyperbolic tangent to layer vertical level,increasing the number of vertical layers,vertical resolution would increase,but the increase of resolution at low level and high level is more obvious and this change tends to produce stronger typhoon.Typhoon can be simulated well only when horizontal and vertical resolution of the model match and in the two-way nesting model,the vertical resolution of the model should also be increased simultaneously with the increase of the number of nesting layers.Typhoon's intensity is closely related to its structure.One important reason for the increase of intensity of typhoon is that the inclination of typhoon cloud wall would be steeper while increasing the horizontal resolution.The intensity of the simulated vertical wind speed increases with the increase of horizontal resolution.