Fig. 2: Drought characteristics and variability modes.

Top three rows show the drought characteristics from CHIRPS and bottom four rows show the four SST indices from National Oceanic and Atmospheric Administration (NOAA) Optimum Interpolation (OI) SST dataset version 2 (V2) in each year (1981–2018). The white dots indicate years with severe droughts (row 1), widespread droughts (row 2) and compound droughts (row 3). White dots in the bottom four rows indicate years with positive SST anomalies (≥0.5σ) over Niño3.4 and IOD regions and negative (≤−0.5σ) SST anomalies over TNA and AtlNiño regions.