近60年河北省冬小麦干旱风险时空规律

Spatial and temporal patterns of drought risk for winter wheat grown in Hebei province in past 60 years

干旱是造成作物减产的主要自然灾害,开展作物干旱成因机制和时空特征研究,对于稳定区域粮食生产有重要意义。本研究基于河北省内18个国家标准气象站点1958—2016年的长时间序列观测资料,采用水分亏缺指数(CWDI)作为干旱评价指标,分析了近60年来河北省冬小麦的干旱风险时空格局;通过CWDI对不同气象因子的敏感性分析,进一步探究了冬小麦干旱的成因机制。研究表明,冬小麦生育期需水量和干旱风险呈先增后减再增加的特征,在拔节抽穗阶段的干旱风险最高,其次是抽穗-成熟阶段。冬小麦全生育期间干旱等级以重旱和特旱为主,特别在其产量形成的关键生长中后期,河北省东南部黑龙港地区面临较高的旱灾风险。冬小麦干旱受降水、气温、湿度等多种因素的影响,其中影响最大的是降水;气温是影响冬小麦生育后期干旱程度的关键因子,伴随近几十年气候变化冬小麦生长期内温度明显升高,将增加冬小麦生长期的耗水量和灌溉需求。本研究揭示了气候变化影响下河北省冬小麦干旱风险的时空演变规律,识别出了干旱灾害的高风险区和关键生育期阶段,可为优化冬小麦灌溉管理和农田防灾减灾提供参考依据。

Drought is a major natural disaster that causes crop yield losses.Study on the cause mechanism and spatio-temporal patterns of drought is of great significance for regional food security.Based on long-term climate data during 1958–2016,we analyzed the spatial and temporal patterns of drought risk of winter wheat in Hebei province in the past 60 years by calculating Crop Water Deficit Index (CWDI).The water requirement and drought risk during the growth period of winter wheat increased at first,then decreased and then increased.Drought risk was the highest in jointing-heading stage,followed by heading-maturity stage.Winter wheat suffered severe drought during the whole growing periods,particularly in the middle and late stages of yield formation.The Hei-long-gang region in southeastern Hebei faced an extreme high drought risk.Drought risk of winter wheat was affected by various factors such as precipitation,temperature,humidity.The most important impact factor was precipitation,and temperature was the key factor affecting the CWDI of winter wheat in the later stage.With climate changed in recent decades,the temperature during crop growth season showed a clear upward trend,increasing the water consumption of winter wheat.The results of this study reveal the spatio-temporal patterns of drought risk of winter wheat,identify high drought risk areas and key growth stages,and provide a reference for regional water irrigation management and drought disaster mitigation in a changing climate.