Spatial and temporal variations of spring drought in Southwest China and its possible teleconnection with the global climate events

Study region: Southwest China (97.4 degrees E-112.1 degrees E, 21.1 degrees N-34.3 degrees N), including Sichuan, Yunnan, Guizhou, Chongqing, and Guangxi provinces. Study focus: Meteorological droughts were likely to become much more frequent and intensified, posing a huge threat to food security, drinking water supply, ecological environment security, and sustainable development of economy and society. However, the spatial and temporal variations of seasonal droughts and its possible driving forces are still not fully understood. In this work, we deeply explored the spatial and temporal variations of spring drought in Southwest China and its possible teleconnection mechanisms during 1961-2020. New hydrological insights for the region: The rising temperature and reduced precipitation led to a significant worsen trend of spring drought in the eastern parts of Southwest China (ESWC) during 1961-2020. Significant abrupt changes of spring drought occurred in 2003, and spring drought became much more frequent and intensified especially after 2003 in ESWC. Spring drought evolutions were dominated by NAO, and were also affected by the coupling of TNA and AO in ESWC during 1961-2020. However, the significant worsen trend of spring drought during 2003-2020 in ESWC could be largely explained by the coupling influences of NAO, TNA, and PDO. These results can provide valuable information for agricultural production, water resource management, and especially the early warning and prediction of spring drought in Southwest China.