Sea Surface Temperature, Ocean Circulation
The analysis on SST, Ocean Circulation and Ocean heat content has been made
using the data of 1958-2015.
- 1. The tropical Indian Ocean is warming at a faster rate compared to other tropical oceans. The warming trend show a basin scale warming with peak warming in the central equatorial Indian Ocean (0.2 °C per decade).
- 2. There is a strengthening of mean westerly winds over the equatorial Indian Ocean in the recent years. There is also an evidence of strengthening of the mean eastward currents along the equator and westward currents in the equator.
- 3. The upper north Indian Ocean is gaining heat during the recent 60 years or so at an alarming rate, which is supported by the ocean circulation and dynamics.
The analysis on sea level has been made using data of varying lengths.
- 1. The sea level rise over the Arabian Sea and Bay of Bengal from the TOPEX/ Poseidon altimeter observations depict that the rate over the Arabian Sea is about 0.5 mm/year to 3 mm/year and over the Bay of Bengal is 0.75 mm/year to 6 mm/year. The rise is of steric origin and are also driven by short-term climate variability.
- 2. The sea level rise in the Indian ocean over the last 60 years amounts to 1.5 mm/year, which is slightly less than the global average.
- 3. The AR5 projected sea level rise for all the scenarios with the highest emission scenario (RCP8.5) projecting sea-level rise in the range of 0.45-0.82 m for the late twenty-first century (average over 2081-2100) for the Indian Ocean