摘要
A new method, BDA perturbing, is used in ensemble forecasting of typhoon track. This method is based on the Bogus Data Assimilation scheme. It perturbs the initial position and intensity of typhoons and gets; a series of bogus vortex. Then each bogus vortex is used in data assimilation to obtain initial conditions. Ensemble forecast members are constructed by conducting simulation with these initial conditions. Some cases of typhoon are chosen to test the validity of this new method and the results show that： using the BDA perturbing method to perturb initial position and intensity of typhoon for track tbrecast can improve accuracy, compared with the direct use of the BDA assimilation scheme. And it is concluded that a perturbing amplitude of intensity of 5 hPa is probably more appropriate than 10 hPa if the BDA perturbing method is used in combination with initial position perturbation.
A new method, BDA perturbing, is used in ensemble forecasting of typhoon track. This method isbased on the Bogus Data Assimilation scheme. It perturbs the initial position and intensity of typhoons and gets aseries of bogus vortex. Then each bogus vortex is used in data assimilation to obtain initial conditions. Ensembleforecast members are constructed by conducting simulation with these initial conditions. Some cases of typhoonare chosen to test the validity of this new method and the results show that: using the BDA perturbing method toperturb initial position and intensity of typhoon for track forecast can improve accuracy, compared with the directuse of the BDA assimilation scheme. And it is concluded that a perturbing amplitude of intensity of 5 hPa isprobably more appropriate than 10 hPa if the BDA perturbing method is used in combination with initialposition perturbation.
基金
"The System of Ensemble Forecasting Models for Tropical Cyclones in the South China Sea",a project of the Scientific and Technological Plans for Guangdong Province(2003C32603)
