Multidecadal Changes in Meteorological Drought Severity and Their Drivers in Mainland China

This study analyzes the multidecadal changes in the severity of extreme meteorological droughts at the regional scale in China during 1951-2017. Dominance analysis is applied to multiple linear regression models to quantify the relative influence of global warming and internal variability on the meteorological drought severity in nine climate regions of China to understand which drivers are the most significant for each region and how they are likely to influence the severity of droughts in the near future (10-20 years). The influence of internal variability is represented by the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). The PDO and global warming are found to have a stronger influence on the multidecadal variability of drought severity in China than the AMO. Global warming is found to be the more dominant driver of multidecadal variability of drought severity in the western parts of China, whereas the PDO is found to have a more dominant influence in the eastern parts of China. In the near future, global warming and the PDO are both likely to contribute to reduction of drought severity in Xinjiang, Northwest, and Tibet regions. The positive phase of the PDO is also expected to reduce the severity of droughts in Inner Mongolia and South China. On the other hand, both the PDO and global warming are expected to contribute to increase in drought severity in North and Southwest China in the near future.