河北省冬小麦旱灾风险评估和区划方法研究

Study on methodology for risk assessment and division of winter wheat drought hazard in Hebei Province

分别以冬小麦年雨量平均值±0.5倍样本标准差和平均值±1.5倍样本标准差界定不同等级的干旱年份,以气象产量减产大于等于3%界定冬小麦受灾年份,分析了河北省各市冬小麦旱年的平均减产率及其空间分布,研究了冬小麦不同旱灾强度的频率分布规律。提出了冬小麦干旱灾害风险指数的概念和计算方法,分析了河北省冬小麦干旱灾害风险指数的区域分布规律,并以旱年平均减产率、干旱灾害风险指数和冬小麦年雨量等因子为指标,利用地理信息技术将全省冬小麦种植区区划为干旱灾害高、中、低3种风险区,并探讨了各类风险区不同旱灾年景的平均减产率和防灾减灾措施。

Different levels of dry years was defined respectively by the ±0.5 times and ±1.5 times standard deviational sample variance of the mean values of annual precipitation,and then winter wheat dry disaster year was confirmed by whether the meteorological equivalent yield reduction rate was greater than 3%.In addition,analysis was made of the average winter wheat yield reduction rate in dry years and its spatial distribution in various areas of Hebei Province,and study was also made on the frequency distribution law of the winter wheat drought hazard with different intensities.From point of view on risk analysis of disasters,it presented a methodology for risk assessment and division of winter wheat drought hazard in Hebei Province,including the concept,calculation method and regional distribution of the disaster risk index.The average decreasing rate,drought hazard risk indexes and annual precipitation were selected as factors dominating insurance of drought hazard,based on which,the winter wheat growing zone might be divided into three grades,such as light,moderate and severe under the support of GIS.The average decreasing rate,the disaster prevention and mitigation measures of dry year with different intensities and loses were also dicussed in different kind of risk areas.