边界层高度和动量粗糙度的不确定性对台风“天鸽”(1713)模拟的影响

基于中国气象局区域台风数值预报系统(CMA-TYM),通过一系列敏感性试验,分析研究了台风“天鸽”(1713)生命过程中不同时间阶段的移动路径及强度的数值模拟对模式参数化方案中边界层高度(h)和动量粗糙度(z₀)的敏感性。试验结果表明,使用不同参数化方案计算的h在“天鸽”(1713)初期的热带风暴阶段对热带气旋的移动路径有较明显的影响,在台风成熟后对热带气旋的移动路径影响不显著 ；台风中心附近最大10 m风速对h的变化不敏感,而最低海平面气压对h的变化却非常敏感。同时发现在台风发展初期阶段,边界层过薄或过厚都不利于台风强度的发展加强。这表明边界层高度h在热带气旋数值模拟和预报中是非常重要的,尤其是在台风发展的初期阶段。动量粗糙度z0的变化对台风“天鸽”的影响主要体现在台风增强阶段,台风中心附近10 m风速最大值在台风增强阶段对z₀敏感,尤其是在台风发展的初期阶段

Influence of uncertainty of boundary layer height and momentum roughness on Typhoon Hato (1713) simulation

Based on the CMA-TYM model, through sets of sensitivity experiments, the sensitivities of the simulated moving track and intensity of Typhoon Hato (1713) to the boundary layer height h and momentum roughness z₀ in different life stages are studied. The experiment results show that the boundary layer height h from different parameterization schemes has significant influence on the moving track during the tropical storm stage, while there is no obvious influence on the moving track after Hato gets mature. The maximum 10-m wind speed near the typhoon center is not sensitive to the change of h, while the minimum sea-level pressure is very sensitive to the change of h. The study also finds that, in the early stage, it is not beneficial for the development of typhoon intensity whether h is too thin or thick. It shows that h is very important in the numerical simulation and prediction of tropical cyclones, especially in the early stage of Typhoon Hato. The influence of the change of momentum roughness z₀ on Typhoon Hato is mainly reflected in the typhoon intensification stage. The maximum 10-m wind speed near the typhoon center is sensitive to z₀ in the typhoon intensification stage, especially in the early stage of typhoon.