中文摘要：

选取我国粮食重要生产区——北方冬麦区作为研究区,基于干旱灾害对作物产量的影响开展冬小麦干旱灾害风险评估和区划。在确定干旱灾害危险性指标过程中,通过对比分析MCI、CWDIa、CI、Pa及Ma干旱指数的适应性,确定了干旱灾害风险危险性指数;在分析北方冬麦区干旱背景和脆弱性时,考虑了冬麦区的地形、土壤类型、土壤有效持水量、河网水系、灌溉条件、降水量及干燥度等环境因素,以及冬小麦的耕地面积、播种面积、主要生育期的水分敏感系数、历史产量等。与以往致灾因子危险性分析方法不同,本文首先建立了干旱指标与冬小麦减产率之间的关系,通过减产率等级来确定干旱致灾临界阈值,在此基础上计算分析了冬小麦全生育期和6个关键生育期不同等级干旱发生的频率。综合考虑干旱发生的危险性、不同地区干旱背景和脆弱性,建立了我国北方冬麦区全生育期和6个关键生育期的干旱灾害风险评估模型和区划方法,实现了我国北方冬麦区干旱灾害的风险评估和区划。结果表明,MCI更能反映北方冬麦区干旱的特征,故以MCI指数作为干旱灾害风险危险性指数;我国北方冬麦区中北部的干旱灾害风险较高,应该加强防旱抗旱能力建设,南部地区包括苏皖和河南东南部的干旱灾害风险较小。本文建立的北方冬麦区不同生育期干旱灾害风险评估模型可应用于干旱灾害风险动态评估实时业务中。

英文摘要：

This paper carried out the drought risk assessment and zonation of winter wheat in northern China based on the impact of drought on crop yield by focusing on China＇s Grain Producing Areas. The adaptability of drought indices including MCI,CWDIa,CI,Paand Mawere compared,and on this basis the drought risk index was determined. Many critical environmental and agricultural factors were selected to analyze the background and drought vulnerability in winter wheat region of northern China,such as topography,soil type,soil available water holding capacity,drainage network,irrigation,precipitation,aridity index,cultivated land area,grain planting area,water sensitive coefficient in major growth period,and historical yield,etc. The relationship between the drought risk index and the yield reduction rate of winter wheat was built,the drought risk index was graded by using the yield reduction rate of winter wheat,and then the frequencies beyond the different drought disaster thresholds were calculated. Based on that,the different levels of drought frequency during the whole growth period and six critical growth stages were analyzed. At last,a comprehensive regional drought risk evaluation model and division method were established combining with the risk of drought,drought vulnerability of different backgrounds and regions. The results showed that MCI could well reflect the characteristics of drought in winter wheat region of northern China,which was determined as the drought risk index. The drought risk in north- central region of winter wheat area was higher than that in other regions of northern China,so the capacity of drought management should be strengthened. In comparison,the drought risk in southern region was lower,including Jiangsu,Anhui and southeastern of He＇nan. Drought disaster risk assessment models of winter wheat in different growth stages could be applied to the real- time drought disaster risk assessment operation system.