Uncertainty assessment of drought characteristics projections in humid subtropical basins in China based on multiple CMIP5 models and different index definitions

This study presents an assessment of projection and uncertainty drought characteristics (frequency DF, area Da) using three indices (Palmer Drought Severity Index, PDSI; Standardized Precipitation SPI; Evapotranspiration SPEI) in the humid subtropical Pearl River basin southern China during period 2021–2050. The is based on 13 CMIP5 general circulation models (GCMs) under Representative Concentration Pathway scenarios (RCP2.6, RCP4.5 RCP8.5). Specifically, SPI derived by precipitation simulations GCMs, whereas PDSI SPEI are computed from Variable Infiltration Capacity (VIC) model forced GCMs. projected (PDSI, due to various GCMs RCPs quantified variance-based sensitivity analysis approach. results indicate that sign magnitude changes DF Da highly dependent index definition at regional scale, tends underestimate compared with SPEI. There a large spread (especially for all RCP scenarios, larger more extreme events. Uncertainty shows GCM contributes than 90% total projections, while rather limited (< 10%) GCM. spatially unevenly distributed variability interannual scale. highlights projections as well spatial–temporal sources projections.