Appraising standardized moisture anomaly index (SZI) in drought projection across China under CMIP6 forcing scenarios

Abstract

Study region: Seven climatic regions of China. Study focus: This study compared and assessed the Standardized Moisture Anomaly Index (SZI), Standardized Precipitation Evapotranspiration Index (SPEI), and self-calibrated Palmer Drought Severity Index (scPDSI) over seven climatic regions of China based on simulations from General Circulation Models (GCM) participated in the 6th Coupled Model Intercomparison Project (CMIP6) under climate change. Then, SZI was calculated using downscaled and multi-model ensemble (MME) simulations for drought projection, and drought characteristics were determined based on SZI from 1985 to 2100. New hydrological insights for the region: Results showed that SZI was more robust and performed better in identifying and projecting multi-scalar and multi-category drought, especially in comprehensive drought identification, in different climatic regions under global warming. The performance of scPDSI in identifying multi-category drought decreased with the increase of time scales beyond 12 months. The SZI series calculated with downscaled and MME simulations showed that most parts of China (arid, semi-arid, and semi-humid regions) were projected to become wetter over the 21st century, however, drought is expected to be more widespread in southern humid regions of China under a warmer climate in the future. The results provide a new choice for future drought projection and valuable information for regional drought mitigation under climate change.

Keywords

• Climate change
• CMIP6
• Multi-category drought
• Drought projection
• China