基于年际增量法的华西秋雨预测模型建立及检验

Establishment and Test of Huaxi Autumn Rain Forecasting Model Based on Interannual Increment Method

利用1962—2018年华西地区301个气象台站秋季降水量资料和国家气候中心整理的130项气候系统指数,采用年际增量法建立了华西秋雨预测模型。首先通过相关分析挑选了4个与华西秋雨年际增量前3主模态密切相关的影响因子,进而采用多元线性回归方法进行建模,拟合时段和后报时段分别选为1962—1991年和1992—2018年。华西秋雨年际增量前3主模态累积值的预测模型通过了α=0.01的显著性水平检验,表明该模型具有较高的拟合预测能力。然后用相同的预测因子分别建立华西地区301个气象站点的华西秋雨年际增量预测模型,大部分模型都通过了显著性检验。用PS评分指标对预测效果进行检验,结果显示后报期年平均PS评分达74.5分。从空间分布来看后报期大部分站点的PS评分都超过60分,其中四川盆地南部、贵州东部和湖南西部等地超过80分。与华西各省和国家气候中心发布的近6年秋季降水预测PS评分进行比较,发现模型后报结果有显著优势。总体来看,用年际增量法建立的华西秋雨预测模型具有较高的预测技巧和实际应用价值。

Based on the autumn precipitation data of 301 meteorological stations in West China from 1962 to2018 and 130 climatic system indices compiled by the National Climate Center,the autumn rainfall prediction model in West China is established by using the interannual incremental method.Four influencing factors closely related to the first three main modes of the annual increment of Huaxi autumn rainfall are selected through correlation analysis.The multivariate linear regression method is used to establish the model,and the fitting and the hindcast periods are selected as 1962-1991 and 1992-2018,respectively.The main-mode prediction model of interannual increment of Huaxi autumn rainfall has passed the significance test ofα=0.01,which shows that the model has a high capability of fitting and forecasting. The interannual incremental forecasting models of Huaxi autumn rainfall for 301 meteorological stations are established with the same forecasting factors,and most of the models have passed the significance test.The results are checked by two indicators:symbol consistency rate and PS score.The results show that the average annual PS score is 74.5 in the hindcast test period.In terms of spatial distribution,the PS scores of all stations in the hindcast test period exceeds 60,and more than 80 points are scored in the southern of Sichuan Basin,Eastern Guizhou and Western Hunan.Compared with the PS scores of autumn precipitation forecast published by the western provinces and the National Climate Center in recent 6 years,it is found that the results of the model have significant advantages.Generally,the Huaxi autumn rain prediction model based on the interannual increment method has high prediction skills and practical application value.