热带气旋海棠(2005)强度数值模拟试验

Numerical simulation study of the intensity for tropical cyclone Haitang(2005)

通过设计台风追随自移动嵌套网格、考虑海洋飞沫作用改进MRF边界层参数化方案、设计垂直-倾斜对流参数化方案等对MM5 V3.7中尺度模式进行改进,以NCEP逐日再分析资料为初始场,对2005年第5号热带气旋"海棠"进行了数值模拟试验。结果表明:通过设计自移动嵌套网格解决了热带气旋业务数值预报模式中细网格区域大小和位置难于确定问题,通过提高模式分辨率能大幅增强数值模式对热带气旋强度的预报能力;考虑海洋飞沫作用后,热带气旋范围内低层热通量明显增强,从而使模式大气低层增温和增湿明显,有利热带气旋内对流发生发展;考虑倾斜对流不稳定作用后,使倾斜对流有效位能得到释放,进一步提高了模式对热带气旋内部物理过程的描述能力。通过改进MM5模式,有效提高了热带气旋强度的数值模拟能力。

Based on NCEP daily reanalysis data as the initial field,the tropical cyclone Haitang（2005） is simulated using the modified MM5V3.7 model,which included automatic-vortex moving nest,sea spray flux parameterization and the vertical-slantwise convective integrated parameterization.The results show that automatic-vortex moving nest scheme can effectivly solve the difficulty of determining the size and location in tropical cyclone operational numerical prediction.The increasing of the model resolution can improve the capability in numerical model of tropical cyclone intensity forecasting.When sea spray＇s impact is taken account in the model,turbulent heat and vapor fluxes between air and sea are enhanced significantly.Deep and strong convections transport the fluxes to high troposphere,which makes tropical cyclone＇s warm core structure more obvious and leads to its intensification.The vertical-slantwise convective integrated parameterization can release the vertical and slanwise convective effective potential energy,which can further improve the model＇s capability to describe the physical processes in tropical cyclone.Through these measures the numerical model can be improved.