Interaction of Hurricane Georges (1998) with Orography on the Island of Hispaniola and Its Impacts upon Excessive Orographic Rainfall

On 22 September 1998 Hurricane Georges made landfall on the island of Hisponiola and caused the worst natural disasters in the history of the Domincian Republic. The big casulty and devastation are largely the result of the excessive rainfall, not extreme winds or storm surge along the coast. Interaction of the hurricane's circulation and the mountainous island (with the peak of 3.1 km) is believed to have great impact upon the excessive orographic rainfall.

Nemerical experiments are carried out using non-hydrostatic, mesoscale model MM5. The recently developed hurricane initialization technique, variational bogus data assimilation (BDA), is employed to generate the hurricane initial conditions. NOAA aircraft data, including GPS dropsondes and Doppler reflectivity and radial velocity, are assimilated into the model initial conditions during BDA procedure. The MM5 simulated structure of Hurricane Georges (1998) during its landfall on the island of Hisponiola is investigated. Interaction of the landfalling hurricane and the island orography is analyzed. Sensitivity experiments will be also conducted to assess the impact of the island orography upon the excessive rainfall caused by Hurricane Georges (1998).