Dynamic evolution analysis and risk assessment of drought processes: A case study in Shaanxi, China

Drought disasters are long-term, and their risks evolve over time. Understanding the dynamic changes in drought risk is crucial for drought prevention and reducing losses. This study uses ten cities in Shaanxi Province as examples and establishes a drought risk evaluation index system based on precipitation and statistical data. PCA was used to determine index weights, and the TOPSIS method was employed for static risk assessment. A drought intensity-disaster loss rate curve was constructed using historical disaster data to represent risk changes during droughts. By combining static analysis results with risk changes, a dynamic risk analysis of the study area was conducted. The results show: (1) The drought severity based on SPI shows that mild droughts occur most frequently in Shaanxi, followed by moderate droughts. (2) There are significant differences in static drought risk across different areas. Yulin and Weinan have the highest drought risks. (3) The speed of dynamic risk development varies across regions. In the middle and late stages of droughts, the severity of risk shows significant differences. This study helps adjust disaster relief plans promptly during drought events and provides a reference for disaster management and risk reduction.