Abstract:
Using the daily temperature and precipitation data from 142 national meteorological stations in Sichuan from 1961 to 2022, based on the Meteorological Drought Comprehensive Index (MCI) and its regional drought process identification method, the spatiotemporal variation characteristics of regional drought in Sichuan were analyzed. The results show that: (1) From 1961 to 2022, 239 regional drought processes in Sichuan were identified, with an average of 3.9 times/a, and the comprehensive intensity above the strong level was 49.4%. The process started in November at most and September at least. The process frequency was relatively low in the 1960s and 1990s, and relatively high in the 1970s, 1980s, and 21st century. (2) The comprehensive intensity of regional drought processes in Sichuan Province shows a significant increasing trend, mainly due to the significant increase in the scope of process impact, with an average increase of 3.7 stations every 10 years. However, the trend of changes in process intensity and duration days is not significant. (3) The trend of drought days varies across the Sichuan province, with frequent droughts occurring in the basin and Panxi region. There are four common regional drought types, which are southwest basin type, northeast basin type, northwest basin type, and Panxi basin type. (4) In 2022, four regional drought processes occurred in Sichuan Province, and the frequency was close to the annual level. The comprehensive evaluation of annual drought showed that it was relatively strong in the past 10 years. The identification results of regional drought processes are in good agreement with the business practice and disaster verification. The comprehensive intensity index has a certain characterization ability on the impact of drought events, and can be localized and applied to the monitoring and evaluation of regional drought processes in Sichuan.