Sea surface temperature
Also called: SST · Topic: Oceans: Hydrological Cycle, Relief of the Ocean Floor, Temperature and Salinity · NCERT: Beyond NCERT
Meaning
Sea surface temperature (SST) is the temperature of the ocean's top layer. Tropical cyclones need SST above about 26.5°C, because warm water supplies the heat and moisture that power them. Changes in SST patterns drive ENSO, which is the El Niño and La Niña swings in the Pacific, and the IOD (Indian Ocean Dipole), a see-saw in SST between the western and eastern Indian Ocean. Both shape India's monsoon.
Example
The warmer Bay of Bengal produces more cyclones than the Arabian Sea. The Arabian Sea is warming, however, and now produces more severe storms. INCOIS in Hyderabad and the satellite Oceansat-3 (EOS-06, launched 2022) track SST and issue Potential Fishing Zone advisories to fishers.
Don't confuse with
- Marine heatwave: a marine heatwave is an extreme event. SST stays above the 90th percentile, meaning warmer than 90% of past readings, for at least five days. SST itself is simply the temperature reading.