Fig. 5: Spatial distribution of annual trends of the Palmer Drought Severity Index (PDSI) in the West River Basin from 1965 to 2018.

a The annual trends for PDSI at subbasin level (shaded areas with statistically significant trends). b The annual trends for PDSI at hydrological response unit (HRU) level. c The pie chart summarizes the percentages of HRUs showing a drying, wetting, or neutral trend. Source data are provided as a Source Data file.