基于CWSI的贵州省干旱时空变化特征及影响因素分析

Analysis of Temporal and Spatial Variation Characteristics of Drought in Guizhou Province and Its Influencing Factors Based on CWSI

为了促进贵州省农业和生态环境可持续发展,基于作物缺水指数(Crop Water Stress Index,CWSI),结合气象、植被指数等数据,采用Theil-Sen Median趋势分析、Mann-Kendall检验、变异系数和相关性分析等方法,对贵州省2000—2019年的干旱时空变化特征、趋势及影响因素进行了分析。研究表明:(1)贵州省CWSI多年均值为0.43,整体处于轻旱等级,空间分布为东南湿润,西北干旱,多年旱情变化呈缓解趋势;(2)从地貌类型来看,非喀斯特地貌CWSI多年均值为0.37,整体处于无旱等级,喀斯特地貌均值为0.47,处于轻旱状态;(3)从植被类型来看,除针叶林整体处于无旱状态外,其他植被类型都处于轻旱等级,且针叶林的变异系数(CV)值较其他林地高,说明其对气候因子的敏感性高,抗旱能力强;(4)贵州省CWSI与降水和气温均呈负相关,负相关面积占比为95%和54%,说明降水对CWSI的影响较大。综合分析得出,贵州省东南部湿润,西北地区干旱,全省干旱受喀斯特地貌、降水的影响较大。

To promote the sustainable development of agriculture and ecological environment in Guizhou Province,based on the crop water stress index(CWSI),meteorological and vegetation index data,we used Theil-Sen Median trend analysis,Mann-Kendall test,and coefficient of variation and correlation analysis to analyze the spatial and temporal variation characteristics of drought in Guizhou Province from 2000 to 2019.The analysis was conducted to provide a scientific basis for drought research and water resources management in Guizhou Province by analyzing the characteristics,trends and influencing factors of drought from 2000 to 2019.The results show that:(1)the multi-year average value of CWSI in Guizhou Province was 0.43,with an overall light drought level,and the spatial distribution was wet in the southeast and dry in the northwest,and the multi-year drought changes were in a relieving tendency;(2)in terms of landscape types,the multi-year average value of CWSI in non-karst landscapes was 0.37,with an overall drought-free level,while the average value of karst landscapes was 0.47,with a light drought status;(3)from the perspective of vegetation types,except for coniferous forests,all other vegetation types were in light drought status,and the coefficient of variation values of coniferous forests were higher than those of other woodlands,indicating their high sensitivity to climatic factors and strong drought resistance;(4)CWSI in Guizhou Province was negatively correlated with NDVI and precipitation,and the areas of negative correlation was 93%and 95%,respectively;it was both positively and negatively correlated with temperature,and the area of negative correlation was 54%.The comprehensive analysis concluded that the southeastern part of Guizhou Province was wet and the northwestern part was dry,and the drought in the province was influenced by the karst landscape,precipitation and vegetation.