The sea surface temperature anomaly climatology used for such calculations was published by Reynolds and Smith in 1995.
Sources
- Tropical Pacific Sea Surface Temperature Animation (go.nature.com)
- https://journals.ametsoc.org/view/journals/clim/11/12/1520-0442_1998_011_3320_ahrgss_2.0.co_2.xml (journals.ametsoc.org)
- https://www.ncei.noaa.gov/products/optimum-interpolation-sst (ncei.noaa.gov)
- https://www.ncdc.noaa.gov/oisst/references (ncdc.noaa.gov)
- https://iridl.ldeo.columbia.edu/SOURCES/.IGOSS/.nmc/.Reyn_SmithOIv2/.climatology/.dataset_documentation.html (iridl.ldeo.columbia.edu)
- http://apdrc.soest.hawaii.edu/datadoc/oisst.php (apdrc.soest.hawaii.edu)