基于干旱灾害风险综合评估指数的西藏主要农区青稞干旱时空格局

为研究西藏主要农区青稞的干旱时空变化特征,笔者从干旱灾害的致灾因子危险性、承灾体易损性、灾损脆弱性、防灾减灾能力等4个风险因子考虑,采用专家打分法和熵权法确定各因素权重,构建干旱灾害风险综合评估模型,并进行干旱灾害时空格局分析。结果表明：干旱灾害综合风险整体呈现中间低、两边高的态势,高风险区分布比较分散,次高风险区多集中在研究区的边缘地带,中等风险区以左斜H型分布在拉萨、山南、林芝市部分区域,而次低和低风险区零星分布在加查、索县、比如、林芝等站;且干旱灾害风险较高年份出现在1999、2005、2006、2007、2009、2010、2012、2014、2015年。西藏主要农区青稞各个干旱风险因子的分布具有明显的区域差别和一定的连片性,研究区和分区的干旱趋势随年份递增而加重。

Temporal and Spatial Patterns of Barley in Tibet Major Agricultural Areas Based on the Comprehensive Assessment Index of Drought Disaster Risk

To study the spatiotemporal changes of drought of barley in the main agricultural areas of Tibet, the authors took four risk factors, including the danger of drought disaster, the vulnerability of disaster victims, the vulnerability of disaster, and the ability to prevent and mitigate disaster, and adopted the expert score method and entropy weight method, to determine the weight of each factor to construct a comprehensive assessment model for drought risk and analyze the spatial and temporal pattern of drought disaster. The results showed that: the overall risk of drought disasters was generally low in the middle and high on both sides. The distribution of high-risk areas was relatively scattered. The sub-high-risk areas were mostly concentrated in the marginal zones of the study area. The middle-risk areas were distributed with left-sloping H-shape in parts of Lhasa, Shannan, and Linzhi, while the sub-low-risk and low-risk areas were scattered in Jiacha, Suoxian, and Linzhi stations; and the years with higher risk of drought disaster appeared in 1999, 2005, 2006, 2007, 2009, 2010, 2012, 2014, and 2015. The distribution of drought risk factors for barley in major agricultural areas in Tibet has obvious regional differences and a certain degree of continuity, and the drought trend in the study area and subdivision increases with each year.