摘要
Bilis (0 0 10 )是一个登陆后长久维持的热带气旋 ,其维持期间与一条西南风低空急流水汽通道长时间保持联结。用中尺度模式MM5V3对其维持过程进行模拟 ,并通过多个敏感性试验 ,研究不同方向水汽输送对热带气旋在陆上维持和降水的影响。结果表明 :外界持续的水汽输送有利于热带气旋气旋性环流在陆地上维持 ,减缓其登陆后的强度衰减。水汽输送通过影响热带气旋的热力结构来影响热带气旋强度 ,充沛的水汽供应有利于热带气旋暖心维持。外界水汽输送有助于热带气旋雨带中的强对流活动 ,使雨量加强。而对流活动过程中水汽凝结潜热释放是热带气旋获得能量继续维持的重要条件。结果还表明 ,南边界水汽输送对热带气旋维持和降水的影响最为明显 ,其次是东边界。来自北界和西界水汽的影响微弱。
Tropical cyclones are mainly driven by the energy from the release of latent heat which has a close relation to the moisture supply. As to the landfalling tropical cyclone, the moisture transportation plays an important role in its sustention over land. Bilis was sustained over land with 3 days long. The major characteristic of Bilis is that there existed a moisture transportation channel connected with the right circle of Bilis. This process would keep Bilis supplied with water vapor after it landed.Numerical experiments are is performed with PSU/NCAR MM5V3 to study the impact of moisture transportations from different directions on Bilis'sustention and precipitation. Results demonstrate that moisture supply is favorable for maintaining Bilis’circulation over land. It is found that (1)Bilis would decrease obviously without the moisture transportation from all lateral boundaries,(2)moisture transportation affects the thermodynamic structure of typhoon to a great extent and plentiful water vapor is helpful to maintain Bilis'warm core,(3)plentiful moisture supply contributes to typhoon rainfall and convective activities which play a major role in typhoon sustention due to moisture condensation and latent heat release,(4)the moisture transportation from the south lateral boundary has the most distinct impact on Bilis'intensity and rainfall rather than from the other three boundaries.
出处
《大气科学》
CSCD
北大核心
2005年第1期91-98,共8页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金项目 40 1 750 1 9
国家科技部公益重点项目 2 0 0 1DIA2 0 0 2 6
