Observational Analysis And Numerical Study Of Typhoon Haitang (2005)

The influences of different time-scale circulations on the westward-moving tropical cyclone Haitang(2005) are analyzed by filtering the synoptic-scale and low-frequency-scale circulations from FNL data. From the study, we can infer that typhoon can generate propagation which may induce the typhoon move northeastward by the interaction between typhoon and low-frequency scale circulation.Haitang's track is also influenced by the low-frequency circulation which changes slowly beyond the synopcic-scale circulation. Haitang's track can separate into two stage in the study. In the first stage, the anti-cyclone west to Haitang in synoptic-scale circulation and subtropical high in low-frequency scale circulation lead the cyclone to a southwestward moving, while in the beginning of second stage, the northward deflection of Haitang is inhibited by synoptic-scale circulation but co-steered by cyclone west of cyclone in QBW circulation and subtropical high in MJO circulation. In the late stage of movement, the genesis and development of wave train are resulted from the interaction between Haitang and low-frequency cyclone and lead to the propagation of tropical cyclone. It also causes the tendency of Haitang to move to the northeast but the TC finally makes a westward movement due to the northward migration of subtropical high in the MJO fields and QBW-scale cyclone.A serial simulations are carried out by the WRF-ARW for study the whole track of Haitang. Althought the track and the intensity of Haitang is simulated well in the control experiment as the large-scale circulation is similar with the observation, the structure of the inner core is not like the observation.An experiment which without the Taiwan's topography is carried out in the paper for examine the effect of the topography on Haitang's track. The result illustrates that Taiwan's terrain affects typhoon's track when it approach the central mountain range, but not affects the whole track of typhoon which infer that the main reason influence on the whole Haitang's track is the large-scale circulation.