Vortex Initialization Scheme in GRAPES-TCM Model:

A vortex initialization scheme has been developed and implemented in a newly updated version of GRAPES-TCM (Global/Regional Assimilation and Prediction System-Tropical Cyclone Model) by following the principle of HWRF (Hurricane Weather Research and Forecasting Model), in which correction for the vortex is as small as possible. The new scheme applies a small correction in the storm vortex to maintain a certain consistency with the model. Arbitrariness in the modification of the vortex is largely reduced, and the resultant vortex holds related dynamical and thermodynamical balance. Results indicate that the initial vortex from the new scheme possesses an intensity that is considerably closer to the observed intensity and increased structural detail. Hindcast shows that the new vortex scheme can effectively improve the accuracy of typhoon tracking and intensity forecasting.