I don't know but it cooencideds with the start of satellite monitoring. Half a century of satellite remote sensing of sea-surface temperature (2019) https://ww

I don't know but it cooencideds with the start of satellite monitoring. Half a century of satellite remote sensing of sea-surface temperature (2019) https://www.sciencedirect.com/science/article/pii/S0034425719303852 https://www.sciencedirect.com/science/article/pii/S003442571... I haven't looked but there will probably be references somewhere explaining the dat sources.