四川盆区冬小麦灌浆结实期阴雨寡照空间分布特征

Spatial distribution of continuous rain disaster on winter wheat during grain-filling in the Sichuan basin

利用1980-2017年四川盆区113个气象站点资料和盆区24个冬小麦(Triticum aestivum L.)农业气象观测站生育期资料,将四川盆区小麦种植区分为5个片区,在分析冬小麦产量构成要素与灌浆结实期气象因子之间相关性的基础上,确定冬小麦灌浆结实期间的平均气温、最高气温、最低气温、日照时间、连阴雨时间为指标因子,根据主成分分析法,构建低温阴雨寡照致灾综合指数(F).选取代表站点,划分等级阈值,确定小麦灌浆结实期连阴雨灾情为轻、中、重3个等级,且各个致灾等级的阈值分别为0.45<F<0.70、0.70≤F<0.87、F≥0.87.通过计算各站点不同等级连阴雨发生的频率,统计分析冬小麦灌浆结实期阴雨寡照轻、中、重度灾害发生频率的空间分布特征.结果表明,四川盆区大部分地区发生连阴雨的概率在30%左右,东南地区的概率较高,西北地区的概率相对较低.

The meteorological data at 113 meteorological stations from 1980 to 2017 and the records of growth stages and yield of winter wheat at 24 agro-meteorological stations were used to determine the correlations between the components of winter wheat yield and meteorological factors during the grain-filling stage,and the wheat growing areas in Sichuan basin were divided into five zones.The average temperature,the maximum temperature,the minimum temperature,the sunshine hours,and the number of continuous rainy days during the grain-filling period of winter wheat were selected as indicator factors to address the effects of continuous rainy weather disaster on winter wheat.The principal component analysis method was used to construct the comprehensive index.The frequencies of continuous rainy weather disaster during the grain-filling stage were calculated and the basin areas were identified as,slight (0.45<F<0.70),moderate(0.70<F<0.87) and severe(F≥0.87) disaster areas according to the index classification.The results showed that the probability of continuous rain disaster in most parts of the Sichuan basin was around 30%,with a higher probability in the southeast and a relatively lower probability in the northwest.