Extended Abstract (76K)P1.15
Modeliong Track Deflection For Tropical Cyclones Passing Over a Mesoscale Mountain and its Potential Application to Track Prediction
Yuh-Lang Lin, North Carolina State University, Raleigh, NC; and N. C. Witcraft and S. Y. Chen
A simple prediction system has been developed for potential use on tropical cyclones passing over a mesoscale mountain. In this study, we use observed tropical cyclones and a simple mesoscale model (GFDM), along with a control parameter, Vmax/Nh, on track continuity associated with the passing of modeled tropical cyclones over a mesoscale mountain proposed in a parallel study, to examine the validity of this control parameter and the model predicted tracks. The data set includes Typhoon Nari (2001) and Supertyphoon Bilis (1999) during their passage over Taiwan, Hurricane Michelle (2001) over Cuba, and Hurricane Georges (1998) over Hispaniola. Simulated tracks using the GFDM compare reasonably well with the observed tracks. Results from the simulation show that the track of the low-level wind center is often different from the low pressure center. Observations support this phenomenon, which can make cyclones passing over a mesoscale mountain very difficult to track. We also compare rainfall distributions using the moisture flux model, in which the rainfall is predicted by the vertical moisture flux estimated by the lower boundary condition, proposed in a previous study to observations. In this study, we examine rainfall in Typhoons Lokima (2001) and Nari and Supertyphoon Bilis over Taiwan, Hurricane Georges over Hispaniola, and Hurricane Michelle over Cuba. Sounding data from locations near and in the circulation of the tropical cyclones are used in conjunction with the wind field simulated by the simple model (GFDM). We compare the flux model amounts to observations, and show that variations in the moisture profile can lead to a wide range of rainfall amounts.
Poster Session 1, Tropical Cyclones, Large-scale Dynamics and Convection
Monday, 29 April 2002, 11:00 AM-12:30 PM
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