| Abstract: | Based on the 74 circulation indexes provided by National Climate Center of China(NCC) and the 24 indexes compiled by National Oceanic and Atmospheric Administration(NOAA) of the US, the study used the C4.5 algorithm in data mining to establish a decision tree prediction model to predict whether the spring persistent rains(SPR) of 55 years(from 1961 to 2015) is more than the normal, and obtained 5 rules to determine whether the SPR is more than the normal. The accuracy rate of the test set, namely "whether the SPR is more than the normal", is 98.18%. After the evaluation of the model by conducting ten 10-fold cross validations to take the average value, the test accuracy rate gained is 84%. There are differences between the three types of years with a SPR more than the normal when it comes to intensity and distribution. In spring, they have respective anomalous 850 hPa monthly mean wind fields and water-vapor flux distribution, and 700 hPa forms the zone where the vertical speed is anomalously negative. As indicated by the results, the SPR prediction model based on the C4.5 algorithm has a high prediction accuracy rate, the model is reasonably and effectively constructed, and the decision rules take comprehensive factors into consideration. The anomalous rainfall and circulation distribution characteristics obtained based on the decision classification results provide new ideas and methods for the prediction of SPR. |
