摘要
不同方向垂直风切变对热带气旋强度变化的影响存在明显差异,但对热带气旋无维强度变化的影响却差异较小.研究发现不同方向垂直风切变对无维强度变化的影响的细微差异与热带气旋周围的高层西风槽,倒槽,低层季风槽等天气系统配置有关.这一结果表明,在研究不同方向切变对热带气旋强度变化的影响时,除了下垫面热力作用外,还应考虑与切变相关的天气尺度系统的热,动力作用.
The effect of vertical wind shear(VWS)directions on the change in western North Pacific tropical cyclone(TC)intensity is revisited in this study.Results show that the differences in the correlations between VWS in different orientations and the change in TC nondimensional intensity highly diminish,although slight differences are still present.The subtle differences in the correlations are likely associated with different synoptic-scale patterns at upper and lower levels.This result suggests that,in addition to thermodynamic effects,dynamic roles of the synoptic-scale patterns associated with the VWS should also be taken into account when the authors examine how VWS in different directions affects TC intensity change.
基金
This work was jointly supported by the National Key Research and Development Program of China[grant numbers 2018YFC1507103 and 2017YFC1501601]
the Key Program of the Ministry of Science and Technology of China[grant number 2017YFE0107700]
National Natural Science Foundation of China[grant numbers 41875054,41730961,41730960,and 41775065].
关键词
热带气旋
强度变化
垂直风切变方向
大尺度形式
Tropical cyclone
Intensity change
Vertical wind shear direction
Large-scale pattern