Abstract:

 Based on the surface intensive observed meteorological data, the TBB data from FY-2E satellite and the NCEP 1°×1°reanalysis data, the characteristics of the asymmetric structure of the typhoon Damrey (code 1210) and its forming reason were analyzed. The results indicate that the cloud system structure, precipitation falling area and upper and lower wind fields for the typhoon Damrey are all asymmetric after landfall. The heavy rainstorm mainly appears in the northern and northeastern sides of the center of typhoon Damrey. The evolution of the asymmetric structure could be found obviously by the FY-2E water vapor images. The dark area located in the western side of typhoon cuts off the southwestern transfer of water vapor, which makes advective cloudsystem in the western and southern sides of typhoon center weakened and disappeared, while water vapor plume from the southeast goes into typhoon circulation and provides water vapor and energy for typhoon. At the same time, strong upper divergence, weakly vertical wind shear and evident upward movement are all favorable for enhancement and maintenance of advective cloudsystem to the northeastern side of the typhoon Damrey, which could trigger torrential rain. Cold air brought by upper trough intrudes into inside of typhoon and destroys its warm-core structure, which makes typhoon Damrey disappear on the Bohai Sea.

Key words: Landfalling typhoon, Asymmetric structure, Water vapor image, Cold air, θ_se field