Top: Typhoon MORAKOT (2009) with forecast track. Down: Streamline plot of typhoon MORAKOT (2009).
The challenges in developing ensemble prediction include the selection of a good set of ensemble members, improving model physics and the initial/boundary conditions.
The experiment was designed to examine the sensitivities of numerical models to uncertainties in initial conditions and model physical parameterizations. As a result, the ensemble forecasts reduced the typhoon track forecast errors, and also improved the QPFs for five typhoons for which warnings were issued by CWB in 2010.
Although the ensemble forecast performed quite well for the rainfall distribution and typhoon tracks, the extremely heavy rainfall over a very short duration - which was related to mesoscale convective systems (MCS) - could still not be well predicted by the models. However, TTFRI continues to improve the ensemble forecast as the results may contribute to disaster reduction.