Using the meteorological data of 15 stations in Longdong area, the reference crop evapotranspiration ( ET0) , crop water requirement of main crops ( ETC) , and crop water deficit index ( CWDI) of each station were calculated . The temporal and spatial distribution characteristics of winterwheat water deficit at different growth stages in Longdong area were studied to provide science gist for mastering law of drought and making rational distribution to avoid disadvantages in agricultural production. The results indicated that the drought especially severe drought occurred frequently in the growth period of winter wheat in Longdong area. The drought frequency was higher in vegetative growth stage while lower in reproductive growth stage. In space, drought occurred with the highest frequency in north Longdong, followed by west and north middle parts, and the lowest area located in south and east parts. In annual changes, the CWDI of winter wheat in critical period of water fluctuated with a slight increase in recent 40 years generally, and increased obviously in the years after 2005 .%利用陇东地区15个县(区)气象资料,计算各县(区)1967～2008年冬小麦生长期间逐旬参考作物蒸散量( ET0)、需水量(ETc)和作物水分亏缺指数(CWDI),确定农业干旱等级,研究陇东地区冬小麦生育期间水分亏缺时空分布特征.结果表明,陇东冬小麦生长期间各类干旱尤其是重旱发生频繁.冬小麦营养生长阶段干旱频率低,生殖生长阶段干旱频率高；从空间分布看,陇东北部干旱频率最高,其次是西部及中部偏北地区,陇东南部及东部干旱频率相对较低；从年际变化看,冬小麦近40a来水分临界期CWDI总体多波动变化略有增加,2005年后的最近几年CWDI增大,干旱加重明显.
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