Abstract -- To improve the capability of typhoon forecast and to reduce the damages due to the destructive typhoons are the top ranked research topics of the Disaster Mitigation Research Program. The “Technical Development Studies on the Observations and Forecasts of Heavy Rains and Strong Winds Associating with Typhoons” is one of the integrated researches under the Program. This year, the integrated research contains a general and seven individual studies. The goals of the studies are to improve the typhoon rainfall and strong winds forecasts and to examine the feasibility of applying the Aerosonde in the observation of the environmental and typhoon structures.
During this year, the studies have been will conducted according to the original plan. Several results have been achieved. Those include: (1) several rainfalls forecast models based on the regression formulas have been completed and the verifications show that those models are more accurate than the Climatologic Average Method. (2) Analyses of the heavy rainfall cases caused by the typhoon accompanying with northeasterly monsoon were conducted. (3) Numerical model, MM5, was employed to study the sensitivity of the model forecast (such as track, sea level pressure) to the different cumulus parameterization, cloud, or planetary boundary layer schemes. The results showed that the forecasts are sensitively depend on the schemes included. The ensemble technique will be applied later to improve the model guidance for typhoon rainfall prediction. (4) The events of major aircraft accidences and the situation of cases of close down the Taipei airport were reviewed. Results show that weather is an important factor to the safety of air transportations. (5) Aerosonde test fights and field observations have been conducted. Data sets were collected for later studies. Some procedures, such as control the aerosonde in Central Weather Bureau, also have been examined as feasible for being applied during the operation. (6) The wind spend observations of the stations in Taiwan have been collected. Some basic statistical method have also been developed and verified for wind speed forecast when typhoon in nearby Taiwan. Those methods have been implemented in Central Weather Bureau. In next typhoon season, those methods can be applied to provide objective guidance for station wind speed forecasts when a typhoon in nearby.