ANALYSIS OF KINETIC ENERGY FEATURE OF ABRUPT INTENSITY CHANGE OF SUPER TYPHOON SAOMAI(0608)

An energy diagnostic analysis is applied in the abrupt intensity change stage of super typhoon Saomai(0608),especially concerning the kinetic energy feature.The results show that the total kinetic energy and the rotational kinetic energy(KR) in the lower troposphere increase suddenly during the rapid intensification(RI) stage of the typhoon.Meanwhile,these two kinds of energy in the upper levels significantly decrease while the divergent kinetic energy(KD) rises.The downward transport of the upper tropospheric kinetic energy is a major cause of the RI phenomenon.The conversion of the KR and KD reaches the maximum in the RI stage,kinetic energy for the interaction of divergent wind with rotational wind stays high in the RI stage.Each kinetic energy distribution trend of the whole layer is out-of-phase in a rapid weakening(RW) stage,with an upward transport of the lower tropospheric kinetic energy.There may be a 6 h to 18 h response time for the total kinetic energy and its three components to reach their max.or min.when the RI or RW occurs.