安徽省冬小麦灌浆期连阴雨灾害等级指标的确定

Index Determination of Continuous Rain Disaster During the Filling Stage of Winter Wheat in Anhui

为确定冬小麦灌浆期连阴雨灾害等级指标,利用1980—2012年安徽省冬小麦灌浆期间逐日气象观测数据、连阴雨灾害样本和灾情资料,遴选出连阴雨灾害过程的阴雨日数、累计雨量和日照时数3个主要致灾因子,采用主成分法(PCA)、有序样本最优分割法等数理统计方法,构建了冬小麦灌浆期间连阴雨灾害综合指数(D),并结合危害特征和产量损失情况进行了灾情等级划分。结果表明,冬小麦灌浆期间的连阴雨灾害可由连阴雨综合指数(D)表达,并划分为轻、中、重、严重4个等级,对应的连阴雨综合指数(D)的分级阈值分别为:<0.2、[0.2,0.4)、[0.4,0.6)、≥0.6。经对典型连阴雨年的验证,研究中构建的连阴雨等级指标较单要素指标,对连阴雨灾害具有较高识别能力,可作为冬小麦灌浆期连阴雨灾害监测与评估业务指标使用。

The paper aims to determine the grade index of continuous rain disaster during the filling stage ofwinter wheat. The study was conducted by using the daily meteorological observation data, continuous raindisaster samples and data during the filling stage of winter wheat in Anhui from 1980 to 2012. The authorsselected 3 main disaster causing factors which were the number of rainy day, accumulative rainfall andsunshine hours of rain disaster process. Mathematical statistics method such as the principal componentanalysis method（PCA）, ordered sample optimal segmentation method, etc. were adopted to constructcontinuous rain disaster comprehensive index（D）, and the grade of disaster was determined with thecharacteristics of damage and yield loss. The results showed that continuous rain disaster during the fillingstage of winter wheat could be expressed by the continuous rain disaster comprehensive index（D）, and couldbe divided into 4 levels, which was light, medium, heavy and serious. The classification threshold ofcorresponding continuous rain comprehensive index（D） was： 〈0.2, [0.2, 0.4）, [0.4, 0.6）, ≥ 0.6. At the sametime, the morphological characteristics of each grade of continuous rain disaster were given. Through theverification of typical continuous rainy years, the continuous rain index had higher recognition ability than thesingle factor index, which could be used as the monitoring and evaluation business index of continuous raindisaster during the filling stage of winter wheat.