信息流因果理论在分析双台风相互作用中的应用

Application of information flow causality theory in analyzing the interaction of binary typhoons

利用上海台风研究所热带气旋最佳路径数据以及ERA5再分析资料,以台风天鹅(0907)和莫拉克(0908)为例,应用Liang-Kleeman信息流因果理论分析了双台风的相互作用机理。结果表明:(1)台风天鹅强度的变化是造成莫拉克强度变化以及经向移动的部分原因,而台风莫拉克强度的变化在一定程度上造成了天鹅的南北移动;(2)台风天鹅主要是通过双台风间的"连体"通道向莫拉克输送位涡以及水汽,进而影响后者强度的变化,影响时段主要在莫拉克的发展初期以及登陆阶段;(3)台风莫拉克对天鹅移动路径变化的贡献不仅包括双台风互旋的直接作用,还包括其调整大尺度环流形势的间接影响。

Based on the best path data of tropical cyclone and ERA5 reanalysis data of Shanghai Typhoon Research Institute,taking Typhoon Goni(0907)and Morakot(0908)as examples,this paper analyzed the interaction mechanism of binary typhoons by using Liang-Kleeman information flow causality theory.The results show that(1)the intensity change of Goni is part of the reason for the intensity change of Morakot,which caused the north or south movement of Goni to a certain extent.(2)Goni mainly transported potential vorticity and water vapor to Morakot through the conjoined channel between the two typhoons,which affected the intensity change of Morakot;the impact period was mainly in the early development stage and landing stage of Morakot.(3)The contribution of Morakot to the change of Goni’s moving path included not only the direct effect of mutual rotation of binary typhoons,but also the indirect effect of adjusting the large-scale circulation situation.