北方农牧交错带干旱脆弱性时空格局演变

The Spatio-temporal Evolution of Drought Vulnerability in the Ecotone between Agriculture and Animal Husbandry in the North of China

干旱脆弱性研究为北方农牧交错带人地系统的"整合"研究提供了新思路与分析框架。论文运用VSD脆弱性评估框架,将系统脆弱性分解为暴露度、敏感性、适应能力3个维度,以北方农牧交错带112个县域为研究单元,以2000、2008、2015年社会经济统计数据、气象数据、遥感影像数据为研究基础,运用模糊层次分析、空间热点探测分析和变异系数分析等方法,对各县域干旱脆弱性时空演变特征进行分析与总结。研究结论:1)研究区干旱脆弱性指数逐步降低,整体呈现东北地区低脆弱、西南地区高脆弱的空间格局。2)研究区暴露度指数先上升、后下降,且由东北向西南逐渐增高;敏感性指数先下降、后上升,呈现空间碎片化特征;适应能力指数逐步提高,呈现中部高度适应、东部中度适应、西部低度适应的格局。3)研究区干旱脆弱性差异度先增大、后减小,且呈现西、南部差异度大,东、北部差异度小的格局。4)研究区干旱脆弱性冷、热点个数增加明显,2000—2008年冷热点个数增加最明显;空间上,热点先由中部向西部蔓延,冷点由东部边界区向西部、南部扩展,形成了东部边界冷点集聚带和中、西部热点集聚区。

Drought vulnerability researches provide a new idea and an analytical framework for the study on the integration of human-land relations in the ecotone between agriculture and animal husbandry in the north of China. This paper divides the system vulnerability into three dimensions with VSD（Vulnerability Scoping Diagram） vulnerability assessment framework,namely exposure, sensitivity and adaptive capacity. Taking 112 counties（cities） in the ecotone between agriculture and animal husbandry in northern China as research units, the temporal and spatial evolution characteristics of drought vulnerability in counties（cities） are analyzed and summarized by methods of fuzzy analytic hierarchy process, spatial hotspot detection analysis and variation coefficient analysis based on socio-economic statistics, meteorological data and remote sensing image data in 2000, 2008 and 2015. The results show that： 1） The drought vulnerability index of human-land system in the ecotone between agriculture and animal husbandry in the northern China decreased gradually, and the drought vulnerability was low in northeast and high in southwest. 2） The degree of drought exposure increased first and then decreased, and it presented gradually increasing trend from northeast to southwest. The sensitivity decreased first and then increased, showing fragmentation features in space; the adaptive capacity has been improved year by year, forming a spatial pattern that it is high in the middle, moderate in the east and low in the west. 3） The differentiation of the drought vulnerability in the study area is obvious that the vulnerability difference degree is big in the west and south and small in eastern and northern regions. 4） The number of cold and hot spots of drought vulnerability increased obviously in the study area. The number of cold and hot spots increased significantly during 2000-2008. In space, the distribution of hot spots extended from central region to western region, and the cold spot area extended from the eastern boundary to west and south, forming a spatial pattern of＂cold-hot-hot＂from east to west.