1.School of Geography and Tourism, Chongqing Normal University;2.Chongqing Normal University;3.College of Chemistry, Chongqing Normal University
National Natural Science Foundation(42201124);Chongqing Natural Science Foundation(cstc2021jcyj-msxmX0523);Chongqing PhD
Under the influence of global warming, drought events are becoming more frequent in China. Moreover, the dividing line between China’s semi-arid and semi-humid areas has generally moved southward in the past half-century, and the arid area had an increasing trend. Thus, understanding the trend of drought change in China is of great significance for protection of the regionally ecological environment. Based on the GLASS dataset and ERA5-Land data, the characteristics of drought events (drought duration, drought severity, drought intensity, etc.) were explored from 1982 to 2018 at different timescales (SPEI-1, SPEI-3, SPEI-6 and SPEI-12) using run theory and multiple linear regression model. Then, the changing trend of vegetation productivity was investigated in the study. Further study revealed the cumulative effect of drought on vegetation change. The results showed that severe drought was observed in Xinjiang, the Qinghai-Tibet Plateau and southeast China based on drought indicators at multiple timescales, while mild drought or no drought was identified in most of central and eastern China. Drought events with high severity and long duration have occurred in Xinjiang; The drought intensity in the Qinghai-Tibet Plateau is relatively high; In southeast China, there are fewer drought events, but their severity and intensity are higher. The overall vegetation productivity of China improved from 1982 to 2018. The areas with significant improvement were mainly distributed in the central China, while the areas with significant degradation were concentrated in the southeastern China, the Inner Mongolia and southern Tibet. A positive correlation between vegetation and drought was investigated in most areas of China, especially in the arid and semi-arid zones. With the increase in vegetation coverage, the correlation between vegetation and short-term drought increased. The correlation between vegetation and drought at the short-term timescale increased gradually from the arid area to the humid area. Drought at the medium timescale of SPEI-6 had the significantly cumulative impact on vegetation with slight changes, whereas drought at the long-term timescale of SPEI-12 had the strongest cumulative impact on vegetation with significant changes. Most of the impacts of drought on vegetation in China are cumulative. For example, Inner Mongolia, located in the northeastern part of the semi-arid region, has a close relationship between vegetation degradation and medium-term drought. Vegetation in the Qinghai-Tibet Plateau is sensitive to long-term drought, which is not only affected by precipitation, but also by ice and snow melt water in the early stage and frozen soil freezing and thawing. This study will help to deeply understand the cumulative impact of drought on vegetation and improve the effectiveness of vegetation degradation prevention and control measures. This paper can provide the scientific basis for achieving the land degradation neutrality initiative.
刘海,姜亮亮,刘冰,刘睿,肖作林.近40年中国干旱特征及其对植被变化影响研究.生态学报,,(). http://dx. doi. org/10.5846/stxb202206061601复制