Changes in Temperature-Precipitation Compound Extreme Events in China During the Past 119 Years

This study analyzes the change characteristics of compound extreme events (CEEs) of temperature and precipitation (including warm-wet, warm-dry, cold-wet and cold-dry) in China on interannual and interdecadal scales between 1901 and 2019. The results demonstrate a long-term increasing trend and interdecadal oscillations in CEEs total frequency. However, the frequency of each type of CEEs changes in a different manner compared with total CEEs frequency. There are fewer CEEs but increasing warm-dry during 1901-1950. The period 1951-1995 are characterized by frequent cold CEEs (cold-wet and cold-dry), cold-wet are largely distributed in most areas except for northeast and coastal areas of China, while cold-dry are distributed in most areas except for the northwest regions of China. There are frequent warm CEEs (warm-wet and warm-dry) and fewer cold CEEs during 1996-2019. Warm-wet frequently occurs in the Tibetan Plateau and northwest China, and warm-dry mainly concentrates in southwest and northern China during this period. The frequency of warm-dry and cold-wet were higher than that of warm-wet and cold-dry over the past 119 years, whereas warm-wet increased fastest in the northwest region after 1996, consistent with the warming and wetting characteristics in the northwest region of China. Further study show that long-term change and low frequency oscillations have the greatest impact on CEEs among different time scale factors. Furthermore, the temperature rise caused by climate change affects the interdecadal characteristics of CEEs in China through the changes of circulation fields such as East Asian trough and subtropical high and the configuration between them.