西北典型雨养农业区冬小麦干旱致灾阈值及风险影响机制研究

Northwestern China is one of the high frequency drought disaster and the serious loss region, and the drought disaster seriously threat the local food safety. However, the study on winter wheat dynamic risk of the regional scale is scare in the different growth period. This project focus on the drought disaster risk characteristic of winter wheat and affected mechanism, comparing the adaptability of the drought monitoring index, identifying the drought disaster hazard index. Based on the long term drought disaster and production data, selecting the occurring drought samples in the winter wheat growth period and calculating reduction rate, building the relationship between production and drought disaster index, based on the reduction rate to quantify the hazard index critical value and grading, quantify the contribution degree of the drought in different growth period to production. Based on the theory of coupled risk simulation, which including the hazard factor, disaster-forming environments, and disaster-bearing objects, building the drought disaster dynamic risk assess model of the winter wheat. Describing the drought disaster hazard factor and its critical values, the characteristics of dynamic risk, and change rule in the rain-fed agriculture region, analyzing the resist capability to drought in different growth period, finding the risk key period. Mixing the field observation data, revealing the contribution of key physical factor to risk and it physical mechanism to happen. Providing the control measurement to winter wheat drought disaster risk, promoting the drought disaster risk management level.

西北是我国干旱灾害最频发和损失最严重的地区之一，干旱灾害严重威胁西北的粮食安全。目前针对西北冬小麦不同生育期的干旱灾害动态风险研究较少。本项目围绕西北典型雨养农业区冬小麦干旱致灾阈值及风险影响机制开展研究。基于长序列产量、气候和灾损资料，采用遥感反演、野外调查、数理统计和建模相结合的方法，对比分析4种干旱指数的适应性，识别干旱监测指标。建立干旱致灾指标与减产率的定量关系，确定不同等级干旱强度致灾阈值和等级。综合致灾因子危险性、孕灾环境脆弱性和承灾体暴露性耦合模拟风险的理论，构建冬小麦关键生育期干旱灾害风险评估模型。阐明冬小麦不同等级干旱致灾阈值、风险演变特征和区域差异性，明确风险关键影响期。揭示冬小麦关键生育期动态风险激发的物理机制，为提升风险管理水平提供科技支撑。

西北是我国干旱灾害最频发和损失最严重的地区之一，干旱灾害严重威胁西北的粮食 安全。目前针对西北冬小麦不同生育期的干旱灾害动态风险研究较少。本项目围绕西北典 型雨养农业区冬小麦干旱致灾阈值及风险影响机制开展研究。基于长序列产量、气候和灾 损资料，采用遥感反演、野外调查、数理统计和建模相结合的方法，对比分析4种干旱指 数的适应性，识别干旱监测指标。建立干旱致灾指标与减产率的定量关系，确定不同等级 干旱强度致灾阈值和等级。综合致灾因子危险性、孕灾环境脆弱性和承灾体暴露性耦合模 拟风险的理论，构建冬小麦关键生育期干旱灾害风险评估模型。阐明冬小麦不同等级干旱 致灾阈值、风险演变特征和区域差异性，明确风险关键影响期。揭示冬小麦关键生育期动 态风险激发的物理机制，为提升风险管理水平提供科技支撑。主要研究结果：系统认识了中国干旱时空变化特征、演变规律和区域差异性；改进作物水分盈亏指数，确定了西北干旱半干旱区干旱监测评估等级指标，明确了甘肃省冬小麦干旱时空分布特征，建立了冬小麦产量要素定量评估模型和减产率预测模型。基于干旱灾害致灾因子、危险性和暴露度等风险因子耦合法，构建了综合农业干旱灾害风险评估模型，并在中国甘肃和西南地区进行案例研究；利用干旱灾情资料统计分析，构建灾害风险指数-综合损失率，揭示了中国农业干旱灾损率变化特征、南北区域差异及其对气候变暖的响应；阐明气候变化背景下中国西北、华北等七个子区域干旱灾害损失变化规律；探讨了干旱对中国主要粮食作物产量的影响；明确了中国农业干旱灾害风险关键影响期。