In order to establish grid scale model of agricultural drought early warning, according to the theory of natural disaster system, integrating features of dry pregnant disaster environment, hazards factors and disaster bodies, selecting the DEM, slope, aspect, soil type, history of drought risk index, agricultural inputs as influence factors of the geo-hazards stability, selecting the pre-drought, crop water satisfaction rate as hazard risk factors, selecting crop type,crop development of water sensitive coefficient, irrigation, crop yields as vulnerability factors in the drought system, the agricultural drought early warning model for Ningxia region was established by the AHP method with quantization influence coefficient based on GIS and spatial interpolation. Test results showed that compared with the measured values,more than 90％ of model output levels of drought were consistent. The early warning model could accurately predict future trends and distribution of droughts. Compared with current climatic drought index prediction model, the spatial resolution of agricultural drought early warning model was significantly improved, and could better reflect the occurrence of agricultural drought and its development process. It can be used for regional drought early warning and drought trend forecast.%为建立格点尺度上的农业干旱预警模型,根据自然灾害系统理论,综合干旱孕灾环境、致灾因子、承灾体的特征,选择DEM、坡度、坡向、土壤类型、历史干旱风险指数、农业投入量作为孕灾环境稳定性影响因子,选择前期干旱程度、作物水分满足率、作为致灾危险性因子,选择作物种类、作物发育期水分敏感系数、灌溉条件、作物单产水平等作为承灾体脆弱性因子,在干旱灾害系统分析的基础上,采用层次分析法(AHP)量化影响因子的影响系数,建立基于GIS和空间插值的宁南区域农业干旱预警累乘模型.检验结果表明,预警模型输出干旱等级与实测符合率达到90%以上,能准确预测未来干旱发展趋势和分布范围,比现有基于气候干旱指数的预警模型空间分辨率明显提高,模型输出结果更能反映农业干旱的发生、发展过程,模型可用于区域干旱预警和干旱趋势预测.
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