Tropical cyclone energy dispersion in a three-timension model: upper tropospheric influence

A wave train pattern associated with the tropical cyclone energy dispersion is simulated in a 3D model. The northwest-southeast oriented wave train bears many similarities with the observed. The physical mechanism that leads to the generation of the wave train is further studied. The new process, which emphasizes the upper tropospheric influence, is different from the traditional view of barotropic Rossby wave energy dispersion. It is noted that the upper outflow jet of TC has a preferred orientation, attributing to the result of dynamic instabilities. This jet plays an important role in the generation of wave train pattern. A stronger cyclonic shear vorticity or positive PV anomaly area associated with the outflow jet can propagate into lower levels, resulting in a significant change in the planetary boundary layer (PBL) circulation. The PBL cyclonic circulation further feedbacks to the upper tropospheric flow through the WISHE or CISK theory. As a result, a wave train pattern will be generated in the wake of pre-existing TC. The results may have implications for development of new platforms for improving the understanding and prediction of TC genesis.