We successfully developed a set of technical methods constructing fine climatic analysis field for regional precipitation considering terrain influence based on PRISM monthly climatic precipitation analysis field and ...We successfully developed a set of technical methods constructing fine climatic analysis field for regional precipitation considering terrain influence based on PRISM monthly climatic precipitation analysis field and DEM. By using harmonic analysis and Shepard inverse distance interpolation,we quantitatively analyzed precipitation observation data at 68 reference weather stations of Zhejiang Province in recent 50 years,and established climatic analysis field of daily precipitation at 1 km grid of Zhejiang Province considering terrain influence. Systemic cross-examination of the method was conducted. Result showed that the established fine climatic field for precipitation could reproduce rapid seasonal evolution characteristics of precipitation induced by monsoon migration and typhoon landing with better quantitative accuracy.展开更多
This study investigates multi-model ensemble forecasts of track and intensity of tropical cyclones over the western Pacific, based on forecast outputs from the China Meteorological Administration, European Centre for ...This study investigates multi-model ensemble forecasts of track and intensity of tropical cyclones over the western Pacific, based on forecast outputs from the China Meteorological Administration, European Centre for Medium-Range Weather Forecasts, Japan Meteorological Agency and National Centers for Environmental Prediction in the THORPEX Interactive Grand Global Ensemble(TIGGE) datasets. The multi-model ensemble schemes, namely the bias-removed ensemble mean(BREM) and superensemble(SUP), are compared with the ensemble mean(EMN) and single-model forecasts. Moreover, a new model bias estimation scheme is investigated and applied to the BREM and SUP schemes. The results showed that, compared with single-model forecasts and EMN, the multi-model ensembles of the BREM and SUP schemes can have smaller errors in most cases. However, there were also circumstances where BREM was less skillful than EMN, indicating that using a time-averaged error as model bias is not optimal. A new model bias estimation scheme of the biweight mean is introduced. Through minimizing the negative influence of singular errors, this scheme can obtain a more accurate model bias estimation and improve the BREM forecast skill. The application of the biweight mean in the bias calculation of SUP also resulted in improved skill. The results indicate that the modification of multi-model ensemble schemes through this bias estimation method is feasible.展开更多
基金Supported by Nonprofit Technology Application and Research Item of 2011,Zhejiang Science and Technology Department,China(2011C33G1610011)
文摘We successfully developed a set of technical methods constructing fine climatic analysis field for regional precipitation considering terrain influence based on PRISM monthly climatic precipitation analysis field and DEM. By using harmonic analysis and Shepard inverse distance interpolation,we quantitatively analyzed precipitation observation data at 68 reference weather stations of Zhejiang Province in recent 50 years,and established climatic analysis field of daily precipitation at 1 km grid of Zhejiang Province considering terrain influence. Systemic cross-examination of the method was conducted. Result showed that the established fine climatic field for precipitation could reproduce rapid seasonal evolution characteristics of precipitation induced by monsoon migration and typhoon landing with better quantitative accuracy.
基金Special Research Program for Public Welfare(Meteorology)of China(GYHY200906009,GYHY201006015,GYHY200906007)National Natural Science Foundation of China(4107503541475044)
文摘This study investigates multi-model ensemble forecasts of track and intensity of tropical cyclones over the western Pacific, based on forecast outputs from the China Meteorological Administration, European Centre for Medium-Range Weather Forecasts, Japan Meteorological Agency and National Centers for Environmental Prediction in the THORPEX Interactive Grand Global Ensemble(TIGGE) datasets. The multi-model ensemble schemes, namely the bias-removed ensemble mean(BREM) and superensemble(SUP), are compared with the ensemble mean(EMN) and single-model forecasts. Moreover, a new model bias estimation scheme is investigated and applied to the BREM and SUP schemes. The results showed that, compared with single-model forecasts and EMN, the multi-model ensembles of the BREM and SUP schemes can have smaller errors in most cases. However, there were also circumstances where BREM was less skillful than EMN, indicating that using a time-averaged error as model bias is not optimal. A new model bias estimation scheme of the biweight mean is introduced. Through minimizing the negative influence of singular errors, this scheme can obtain a more accurate model bias estimation and improve the BREM forecast skill. The application of the biweight mean in the bias calculation of SUP also resulted in improved skill. The results indicate that the modification of multi-model ensemble schemes through this bias estimation method is feasible.
