SELECTIVE PRECIPITATION EXTRAPOLATION ENSEMBLE PREDICTION COMBINED WITH CORRECTION SCHEMES

Abstract

 High-resolution Precipitation Nowcasts (HN) provided by JMA (Japan Meteorological Agency) is a state-of-the-art operational short-term precipitation prediction. However, schemes covering uncertainties of prediction are not sufficiently considered in the single prediction. Also, modifications of predictions corresponding to the temporal change in prediction error are not sufficiently considered in the system. Thus, it is necessary to introduce ensemble prediction schemes. In addition, correcting schemes based on the systematic error of the prediction result are also expected. In this study, a precipitation prediction system is installed that the most accurate prediction is selected by the evaluation using scores of previously predicted precipitation among multiple predictions basing on precipitation motion extrapolation with various schemes. We also introduced a scheme to correct predictions based on information of errors in past predictions. The system showed the comparable scores to HN. For the line-shaped rain-band cases, the shapes and amounts of the maximum accumulated precipitation were more accurately predicted in the proposed system for the forecast time of 60 minutes. It showed high responsiveness to the occurrence of rainfall for cases with severe changes in precipitation. Further development of this system is expected in the future.