华北地区冬小麦主要气象灾害风险评价

为了对华北地区冬小麦生育期内遇到的主要气象灾害(干旱和干热风)的综合风险进行评价,根据气象灾害发生机理及区域环境特征建立危险性、暴露性和脆弱性评价模型,并构建综合风险模型,具体分析各地区综合风险的大小及主导风险因子,该文利用华北地区48个农气站冬小麦发育期资料(1981-2010年)和气象资料(1961-2010年)以及近50 a产量资料,将冬小麦全生育期划分为前期(播种期-起身期)、中期(拔节期-开花期)、后期(灌浆期-成熟期)3个阶段,并充分考虑了底墒形成期(播种当年7-9月)内的降水,分别基于水分亏缺指数和加权干热风日数构建了干旱、干热风等级指数,对华北地区冬小麦干旱、干热风灾害以及综合气象灾害风险进行分析。结果表明:危险性、脆弱性和暴露性的权重分别为0.3272、0.3116和0.3612。华北地区冬小麦农业气象灾害风险值有2个高值中心,一个位于冀鲁豫交汇处,一个位于河北省泊头、黄骅等地,风险值由中心向四周逐渐降低。根据该文构建的综合风险评估模型,将华北冬小麦种植区划分为5个不同风险等级区。评价结果具有较强的针对性,可以为华北各地区农业气象灾害风险管理提供参考。

Risk assessment of main meteorological disasters of winter wheat in North China

North China Plane is one of the most important area for winter wheat planting, but meanwhile it is severely influenced by meteorological disasters, which may lead to serious reduction in yield. This research is carried out to evaluate the integrated risk for winter wheat in North China Plane through establishing the comprehensive risk model, which is made up of the integration of hazard, exposure and vulnerability models. The meteorological data in 1961-2010 and the winter wheat developmental stages data and yield data in 1981-2010 from 48 agro-meteorological observatories and MODIS data are employed to establish the risk model. According to the growth and development characteristics of winter wheat, the whole growing period is divided into three stages, which are early stage (from sowing to standing stage), middle stage(from jointing to flowering stage) and late stage (from filling to mature stage),respectively. In addition to the climatic conditions in the three stages, the precipitation in the period before sowing is also taken into account in the impact analysis for periodical disasters toyield reduction of winter wheat in North China. Disaster hazards in different growing stages are analyzed based on the drought index and dry hot wind index. According to the embryology mechanism of meteorological disasters and the regional environmental characteristics, the hazard, exposure and vulnerability models are established and thus the integrated risk model come into being, with which the integrated risk of meteorological disasters for winter wheat in North China Plain is evaluated, and then the risk distribution is demonstrated based on GIS technology. Results showed that, 1) According to the hazard model, in the stage before sowing, the hazard weights were generally low. Weights of drought hazard in early stage and middle stage were generally high, and middle stage had the highest weights in most area. The highest weight of dry hot wind hazard located in middle and south of Hebei Province. In late stage, the weights ratio of drought to dry hot wind could explain the main meteorological disaster locally, it showed that drought dominated in middle and western part of Henan Province, and its impact decreased from south to north, thus the impact of dry hot wind increased. According to the vulnerability model, the highest value area sat in Huanghua and Botou of Hebei Province, Juxian in south of Shandong, Lushi and Sanmenxia in Henan Province. According to the exposure model, the highest exposed area lie in southwest of Shandong and northeast of Henan. The weights of hazard, exposure and vulnerability were 0.3272, 0.3116 and 0.3612, respectively. 2) There were two high risk value centers in North China Plain, one of them lay in the junction of Hebei, Shandong and Henan province. The other one lay in Huanghua and Botou, Hebei province. Risk values decreased from center to surroundings. 3) North China Plain was divided into 5 parts according to the integrated risk value. In conclusion, in the whole growing period, the highest hazard value appears in the middle stage, for the late stage, differences in dominant meteorological disasters exist over the research domain, which could be coped by local measures according to their risk features. Vulnerability occupies the biggest component in the risk index. In the study, county is the smallest unit in carrying out the risk assessment, which means the result is more targeted and typical, so that it can provide reference in the management of agro-meteorological disasters for winter wheat in North China Plane.