华北平原夏玉米干旱灾害的时空变化特征及危险性评估

气候变化背景下，农业气象灾害呈面积逐年扩大、发生频率增加的趋势，且旱灾较其他灾害对农业的影响范围更广、历时更长，为了科学应对夏玉米干旱，保障夏玉米高产稳产，利用1980—2019年华北平原43个站点的气象数据，基于水分亏缺指数作为干旱指标，采用频次和站次比阐明了夏玉米主要生育阶段干旱灾害变化规律；利用信息扩散理论和层次分析法评估了夏玉米干旱危险性。结果表明：(1)华北平原夏玉米干旱以轻旱为主，阶段性差异明显，抽雄—乳熟阶段受旱严重，40年间平均各站点发生28次干旱，干旱站次比平均值为69.5%。(2) 2010—2019年是夏玉米受旱影响加重阶段，呈现干旱连年发生、范围明显扩大的特征。(3)夏玉米干旱的危险性整体呈西高东低趋势，河南大部及河北南部是干旱危险性高值区和次高值区，面积占比分别为12.1%,23.4%。综上，华北平原夏玉米干旱有加重和扩散趋势，抽雄—乳熟阶段受旱可能性较大，河南大部及河北南部干旱危险性较高，需加强对干旱的预报、监测及风险防控工作。

Temporal and Spatial Variation Characteristics and Risk Assessment of Summer Maize Drought Disasters in the North China Plain

Agro-meteorological disasters tended to expand year by year and occurred more frequently in the context of climate change. Drought not only covers a wider range but also lasts longer compared with the other agro-meteorological disasters, which has the greatest impact on agricultural production. In order to scientifically cope with summer maize drought and ensure high and stable yield of summer maize, the characteristics and risk of drought of summer maize were analyzed by using the crop water deficit index(CWDI), based on the meteorological data from 43 weather stations in the North China Plain from 1980 to 2019. The characteristics of drought in the different growth period of summer maize were identified by the frequency and the stations ratio. Moreover, the risk of drought was evaluated by using the theory of information diffusion and the analytic hierarchy process. The results indicated that:(1)the slight drought was the main drought type in the North China Plain with obvious differences in stages; the tasseling-milking stage was severely affected by drought, with an average of 28 droughts occurring at each station during 40 years, and the average drought station ratio was 69.5%;(2)summer maize suffered more serious effects of drought in the period from 2010 to 2019, and the characteristics of drought showed successive occurrence and spatial expansion;(3)the risk of drought was higher in the west and lower in the east; the high-risk and the second-high-risk areas of drought happened in most of Henan Province and southern Hebei Province, and their proportions of areas were 12.1% and 23.4%, respectively. In summary, the drought of summer maize in the North China Plain has a trend of aggravation and diffusion, and the drought is likely to occur in the tasseling milking stage, most of Henan and the south of Hebei are high drought risk areas, so drought prediction, monitoring and risk prevention and control should be strengthened.