National Oceanic and Atmospheric Administration
https://psl.noaa.gov/data/gridded/data.ncep.reanalysis.html

National Oceanic and Atmospheric Administration
https://www.ncdc.noaa.gov/data-access/marineocean-data/extended-reconstructed-sea-surface-temperature-ersst-v4

National Oceanic and Atmospheric Administration
https://www.psl.noaa.gov/data/gridded/data.20thC_ReanV3.html