A new way to initialize operational NWP system for tropical cyclone forecast

A Balanced Tropical Cyclone Bogus scheme is presented to improve the representation of a tropical cyclone in the initial field of a mesoscale model. In the proposed method, a vortex that extracted from the mesoscale model forecast result valid at the initial time of the new run is putted in the first guess field of the model. The vortex formed by this method is asymmetric and well adapted to the prediction model. This method has been tested in the operational numerical weather prediction system in Center for Coastal and Atmospheric Research, Hong Kong University of Science and Technology. It can be easily used in an operational system. Read-data cases study and statistic of operational performance are presented here. Comparison of the forecast results using balanced TC bogus, no tropical cyclone bogus (NTCB) and Rankin vortex tropical cyclone bogus technique show that this balanced TC bogus method can improve both the intensity and track forecast of tropical cyclones.