Vulnerability assessment of ecological drought in Northwest China

To understand the spatial distribution and evolution trend of ecological drought vulnerability in Northwest China, the concept of ecological drought vulnerability and its quantitative characterization methods were proposed in terms of exposure, sensitivity and impact. Entropy weight method is adopted to develop the ecological drought vulnerability indices. Moran index is adopted to evaluate the correlation of drought vulnerability indices in spatial distribution and accumulation of vulnerability in local space. The regional distribution, vulnerability degree and trend of ecological drought vulnerability in Northwest China during 1985-2014 were analyzed. The results showed that ecological drought highly vulnerable areas in Northwest China were mainly distributed in Tianshan Mountains, southern Qinghai, the area near Qinghai Lake, central Gansu, northern Shaanxi and central Shaanxi, while the rest of the areas are moderate or low vulnerable. The spatial distribution pattern of ecological drought vulnerability index is relatively concentrated, showing a “large aggregation and small dispersion” pattern. Ecological drought vulnerability shows a trend of increasing and then decreasing during the studied period. The ecological drought vulnerability in Yili Basin, Turpan Basin and Hexi Corridor has improved significantly, while that in areas including southern Qinghai and northern Shaanxi still show a trend of increase. The ecological protection works in these areas need to be strengthen in the future.