Abstract:

Based on meteorological observation data during 1981 －2010 and the Digital Elevation Model，population density，social e-
conomy，etc，the normalized weighting regression model of drought was built，firstly． Then，the sensitivity of disaster － formative envi-
ronments，the danger of disaster － causing factors and the exposure of disaster － affected bodies of drought in Dingxi city were analyzed
and evaluated by using the powerful spatial analysis abilities of Geographic Information System (GIS)． Finally，the risk division of
drought disaster considering the weight of the above three factors was put forward． The results showed that the frequencies of drought in-
creased from 1981 to 2010 in Dingxi，and spring drought occurred annually in three counties or above after 1999． The high risk regions
of drought disaster were located from the north to the central of Dingxi，which was spatially distributed in a“D”shape on the whole，
and the low risk regions of drought disaster were located in the south of Dingxi． The crops were more susceptible to water stress in
northern and central part of Dingxi，so the planting crop types should be given priority to autumn crop in order to make the growth peri-
od and critical period of water requirement of crops to stay away from main drought periods in the first half of a year．

Key words: drought disaster, risk assessment, GIS, Dingxi city

摘要：

利用 1981 ～2010 年各类干旱统计资料，结合地形特征、人口密度、社会经济等资料，构建加权归一化回归模型，借助 GIS 强大的空间分析功能，对定西市干旱灾害孕灾环境的敏感性、致灾因子的危险性与承灾体的暴露度进行分析与评估，最后给出了基于孕灾环境、致灾因子与承灾体 3 个条件的干旱灾害风险区划。结果表明，定西市干旱灾害频率呈增加趋势，1999 年后 3 县及以上区域的春旱每年均有发生;干旱灾害的高风险区在定西市北部到中部，大体上呈 D 字形分布，南部为干旱灾害低风险区。定西市中北部易受干旱威胁，在农作物结构布局上应以大秋作物为主，尽量使农作物在生长及需水关键期避开前半年的主要干旱时段。

关键词: 干旱灾害, 风险评估, GIS, 定西市