南盘江流域主汛期降雨量年(代)际变率研究及趋势预测

利用二次多项式平滑和Morlet小波分析,研究了南盘江流域主汛期降雨量的年(代)际周期变化;并挑选了相关性较好的预测因子,利用最优子集回归方法对主汛期降雨量建立预测模型.结果显示:①从线性趋势来看,19612014年南盘江流域主汛期降雨量是逐步减少的,减少幅度为每年2.7mm;②南盘江流域主汛期降雨量在年代际尺度上以准14a和准18a周期为主,而在年际尺度上则以准3a、准6a和准9a为主,并且显示出年际变化的年代际差异;③最优子集回归模型回归值和实况值距平百分率符号一致率为70%,回归准确率为87.5%;而试预报值与实况值的距平百分率符号一致率为71.4%,预报准确率为85.7%,显示出较好的趋势预测效果.

Interannual/interdecadal variabilities and trend forecasting on Nanpanjiang Basin in the major flooding season

By using binomial smoothing and Morlet wavelet transform, we have researched the interannual/interdecadal variabilities on Nanpanjiang Basin in the major flooding season.Meanwhile, predictors about correlation surpassing 99% have been selected, on this basis, the forecasting model of optimal subset regression on Nanpanjiang Basin in the major flooding season has been established.The results show that firstly, from the linear trend, the precipitation of Nanpanjiang Basin in the major flooding season from 1961 to 2014 was decreasing, and the decreasing trend is 2.7mm yearly.Secondly, in interdecadal variability, the main period is quasi 14 and 18 years, but in interannual variability, the main period is quasi 3, 6 and 9 years, and interannual variability presents interdecadal variances.What is more, the consistent symbol rate of precipitation anomaly percentage observations and regression values of optimal subset regression is 70% ; regression accuracy is 87.5%; the consistent symbol rate of precipitation anomaly percentage observations and predicted values is 71.4%, and the forecast accuracy is 85.7%.It shows that the precipitation trend prediction level is sound.