国内台风数值预报模式及其关键技术研究进展

Research Progress on China typhoon numerical prediction models and associated major techniques

我国是世界上受台风灾害影响最严重的国家之一.减轻台风灾害首先依赖于台风预报能力,这主要取决于台风数值预报模式及其关键技术的发展水平.本文简要回顾了国内台风数值预报模式的发展历程;介绍了目前国内模式在台风初始化和物理过程等方面的关键技术特点;分析了模式技术中存在的主要问题,并就今后的技术发展提出了建议.文中指出,一方面,尽管基于经验假设的涡旋构造技术在典型台风的分析和预报中仍发挥着重要作用,但为提高对异常台风路径和强度变化的预报,需要加强卫星等观测资料在模式分析中的应用.另一方面,通过加强模式细网格条件下的物理过程参数化研究,可以更加合理地刻画台风中小尺度物理过程,进一步提高台风强度、风雨预报性能.

China is one of the countries affected by the most serious typhoon disasters.The promotion of the capability of typhoon disaster prevention mainly depends on the accuracy of typhoon prediction, which relies on the performance of numerical prediction models.In this paper,history of the development of typhoon numerical models and associated techniques in China is briefly reviewed.Subsequently,major features of numerical prediction techniques on typhoon initialization and physics parameterization are addressed,in which the techniques developed by the China Typhoon 973 project during 2009-2013 are emphasized.Vortex Initialization scheme based on Retrieved Variables（VIRV）was developed to enhance the analysis of typhoon intensity.The VIRV scheme was verified effective in enhancing the dynamical balance of typhoon,which is the basis of realistic typhoon numerical prediction.To better describe the air-sea interaction process,a regional air-sea coupled model is constructed by using Global and Regional Assimilation and Prediction System-Tropical Cyclone Model（GRAPES-TCM）and Estuarine,Coastal and Ocean Model（ECOM）.Verifications show that TC intensity produced by the coupled model is more accurate than that by single atmospheric model which ignores ocean effect.Convection and radiation schemes are modified to reproduce the genesis,growth of convection and its subsequent interaction with atmospheric radiation. Moreover, the transfer of momentum between the atmosphere and the ocean is described in terms of a drag coefficient levels off as the wind speeds increase above typhoon force.Finally,major problems for the current typhoon numerical models are presented.It is stressed that,although bogus vortex has been found to be effective in prediction of typical typhoon tracks,more satellite data should be employed in typhoon initialization to enhance the prediction of unusual phenomenon of typhoons.The paper also suggests that more effors should be put into physical parameterization for high-resolution model to better describe mesoscale which leads to the difficulty of prediction on small scale processes and typhoon rainfall and intensity change.