IJERPH, Vol. 18, Pages 7967: VCI-Based Analysis on Spatiotemporal Variations of Spring Drought in China

In this study, the spring vegetative drought conditions in China were analyzed by using the vegetation condition index (VCI) as an indicator to reveal the drought characteristics in China from 1981–2015. The results suggest that spring vegetative drought (especially moderate drought) occurs frequently in China, and drought conditions have obvious geographical differences and are highly affected by monsoons. The frequency of spring vegetative drought is relatively high in the southern and northern regions, which are greatly affected by monsoons, and is relatively low in the northwestern and Qinghai-Tibet regions, which are less affected by monsoons. During 1981–2015, the spring VCI in China showed an overall upward trend. In addition, the trend was not a single change but a wave-like increasing trend that can be divided into four stages: (1) a stage of slow growth from 1981–1990, (2) a stage of intense fluctuations from 1991–2000, (3) a stage of steady growth from 2001–2010, and (4) a stage of slow descent after 2010. The Mann–Kendall test confirmed that the spring VCI in China was increasing, and the changes in the southern, northwestern, and Qinghai-Tibet regions reached significant levels. The time point of mutation in the southern region was 2000, and that in the northwestern and Qinghai-Tibet regions was 1992. Wavelet time series analysis showed that spring vegetation drought in China has a short-period oscillation of 5–7 years and a long-period oscillation ...
Source: International Journal of Environmental Research and Public Health - Category: Environmental Health Authors: Tags: Article Source Type: research