气候变化背景下山东省夏玉米极端高温灾害风险研究

Extreme high temperature events are much more frequently during recent years under climate change, it is one of the most important agricultural meteorological disasters at present. Corn as one of the most important cereal crops, it is meaningful for food security to study the impacts of extreme high temperature on corn at present and future. Taking Shandong province as the study area and based on natural disaster risk formation theory to study risk of extreme high temperature disaster of summer corn from the aspects of hazard, vulnerability and exposure. The threshold of extreme high temperature in each corn growing stage is determined by the data of field experiment and statistical analysis based on historical observation data. The hazards of extreme high temperature in different corn growing stages were assessed by their frequency and density. Vulnerability curves of extreme high temperature disaster at each corn growing stage were built to assess vulnerability. Data of typical high temperature disasters events in history were used to build the statistical model between risk and corn yield losses. This model can be used to predict the potential corn yield losses in different climate change scenarios in the future. The results can provide a strong scientific basis for release and management agriculture disasters in an uncertain climate.

在以变暖为主要特征的气候变化背景下，近年来极端高温事件日渐频发，已经成为影响农业最主要的气象灾害之一。玉米作为主要粮食作物，了解当前及未来不同气候变化情景下极端高温对玉米产量的影响对于保障粮食安全有重要意义。本项目拟以山东省为案例研究区，基于自然灾害风险形成理论，从危险性、脆弱性、暴露度三方面研究玉米极端高温灾害风险。利用大田试验和对历史数据的统计分析确定玉米不同生育阶段极端高温事件的阈值，评估研究区玉米各个生育阶段极端高温危险性；完善作物模型的极端高温影响模块，构建玉米极端高温脆弱性曲线，评估脆弱性；分析研究区玉米极端高温灾害风险时空分布和形成机理。利用典型案例年灾情数据，构建极端高温灾害风险与玉米减产统计关系模型，预估2050-2080年RCP8.5、RCP4.5、RCP2.6 排放情景下玉米因极端高温减产情况。研究结果可为进一步制订我国农业防灾减灾规划和应对气候变化对策提供科学依据。

在以变暖为主要特征的气候变化背景下，近年来极端高温事件日渐频发，已经成为影响农业最主要的气象灾害之一。玉米作为主要粮食作物，了解当前及未来不同气候变化情景下极端高温对玉米产量的影响对于保障粮食安全有重要意义。本研究以山东地区夏玉米为研究对象，针对极端高温灾害，以自然灾害风险形成理论为基础，确定极端高温危险与夏玉米减产关系模型，结合未来气候模式预估数据实现对当前及未来不同情景下山东地区夏玉米受极端高温影响情况的预估，为国家制定农业适应气候变化政策、保障粮食安全提供科学依据。基于夏玉米产量及发育期逐日最高最低气温数据，采用积温产量模型方法，确定了山东地区夏玉米拔节前、后及全生育期极端高温阈值分别35.2℃、34.5℃、35.3℃，并通过田间试验进行检验；以前面得到的高温阈值为基础，结合夏玉米生育期极端高温发生的频率、强度，夏玉米对高温敏感情况综合评估研究区夏玉米极端高温灾害危险的空间分布情况，在研究区西部地区危险较高；基于观测数据构建极端高温与夏玉米减产关系模型，极端高温日数每增加1 d将会带来226.62 kg/ha 的夏玉米产量损失，两者之间的相关系数为0.563达到了0.01的极显著水平；采用NEX-GDDP高时空分辨率降尺度数据集对未来2021-2050年夏玉米因极端高温减产情况进行预估，RCP8.5和RCP4.5情景下夏玉米平均产量较1976-2005年分别减少了9.1%和27.3%。本项目的研究结果可为整个华北地区夏玉米生产提供借鉴，为制定农业适应气候变化政策、指导防灾减灾工作、保障粮食安全提供科学依据。此外夏玉米极端高温阈值还可以用于当地农业气象指数保险产品的制作。