基于水分亏缺指数的陕西冬小麦干旱特征分析

摘要

Based on the observation data collected from 22 weather stations during 1961—2010 ,the winter wheat water requirement ( ETi ) was measured ,the crop water deficit index ( CWDI ) of different classes of drought was deter-mined ,the frequencies of different classes of drought in Shaanxi were calculated ,and the temporal and spatial distribu-tion characteristics of winter wheat water deficit at different growth stages in Shaanxi area were studied .The results indi-cated that drought occurred frequently during the growth period of winter wheat in Shaanxi area .The occurrence frequen-cies of drought during wheat growth followed the following order:jointing-booting stage>filling maturation stage>turning green stage>seeding before winter>growing in winter .The occurrence frequency of severe or worse drought at various growth stages of winter wheat showed a decreasing trend from north to south . For inter-decade change characteristics , drought index fluctuation turned an increasing trend ,reaching high in 1970s and 1990s and becoming mutated in 1968 .%以陕西1961—2010近50 a 22个站点的逐日气象数据为基础资料，计算其冬小麦生育期各旬需水量（ETi ）以及作物缺水指数（CWDI），并根据农业干旱等级计算出研究区干旱频率，分析陕西冬小麦各生育期内干旱指数时空分布特征。结果表明：陕西冬小麦各生育期干旱频率为拔节抽穗期＞灌浆成熟期＞返青期＞冬前生长期＞越冬期；冬小麦重旱以上频率的空间分布由北向南逐渐减少；冬小麦干旱指数的年代际变化呈上升趋势，20世纪70年代和90年代干旱指数较高，1968年为突变年份。