Fig. 2: Sustained freshening of Arabian Sea High Salinity Water (ASHSW) driven by freshwater input.

Time-latitude plots of anomalies in a salinity in the upper 50 m and b precipitation, averaged in the eastern Arabian Sea (60°–75°E). c Time-series of cumulative anomalies in salinity (psu) in the upper 50 m (black line) and precipitation (mm d⁻¹) (red line) averaged over the region 60°–75°E, 5°–25°N. Cumulative precipitation anomalies excluding all cyclones during 2019–2023 (blue dashed line) and both extreme precipitation events (July–August of 2020 and 2022), combined with cyclones (green dashed line) are also shown (see “Methods”). The two extreme precipitation events in 2020 and 2022 are marked with green boxes. Salinity data are from the monthly EN4 dataset⁴⁵, and precipitation data are from the monthly IMERG dataset⁴⁶. Anomalies are calculated relative to the 2000–2023 period by subtracting the long-term monthly climatology. Cyclone occurrences are marked in panel c: circles indicate very severe to super cyclones, and diamonds indicate cyclones to severe cyclones. Cyclones penetrating north of 15°N are marked in red.