Extended Abstract (68K)2D.4
Control Parameters for Track Continuity and Deflection Associated with Tropical Cyclones over a Mesoscale Mountain
Yuh-Lang Lin, North Carolina State University, Raleigh, NC; and S. Y. Chen and C. M. Hill
In this study, we employ a simple mesoscale model (GFDM) to investigate the dominant control parameters for track continuity associated with the passage of a tropical cyclone over an idealized, mesoscale mountain. The influences of three potential control parameters, which include Vmax/Nh, Vmax/U, and U/Nh, where Vmax, N, h, and U are the maximum tangential wind of the cyclone, Brunt-Vaisala frequency, mountain height, and basic wind speed, respectively, on the track continuity associated with a tropical cyclone passing through a mesoscale mountain are examined by performing a series of numerical experiments. We found that when Vmax/Nh>1.25 the track is continuous; Otherwise, it is discontinuous. The track continuity is more or less independent of the other two parameters. Thus, we conclude that the track continuity associated with a tropical cyclone passing through a mesoscale mountain range is correlates best with the non-dimensional parameter, Vmax/Nh. The tropical cyclone is deflected to the north when the Froude number associated with the basic flow (U/Nh) is very small. Otherwise, it will be deflected to the south. The track deflection of a tropical cyclone influenced by the mesoscale mountain range is also explained by the induction mechanism, which is closely related to the formation and movement of the secondary vortices.
Session 2D, Tropical Cyclone Motion (Parallel with Sessions 2A, 2B, & 2C)
Monday, 29 April 2002, 2:00 PM-3:15 PM
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