Resumen
The typhoon Damrey that hit Jiangsu the populous coastal province of China on 2 August 2012 is a rarely seen tropical cyclone in that it has a higher latitude origin, and it is part of a twin typhoon. In this study, a recently developed analysis tool?multiscale window transform (MWT) and the MWT-based localized multiscale energy and vorticity analysis (MS-EVA)?is applied to investigate its genesis and maintenance. The fields are reconstructed onto three scale windows: large-scale, tropical cyclone?scale, and cumulus convection?scale windows. It is found that the track of Damrey is well along the edge of the subtropical high. Its birth is mainly caused by a strong barotropic instability in the lower troposphere around 24°?25° N. Its later amplification, however, is quite different, related to a baroclinic instability in the upper troposphere. Also discovered in this study is that a strong center of upscale canonical transfer exists over the East China Sea at the mouth of Yangtze River, which accounts for the rapid decay of Damrey before landing.