Editing Sea surface temperature (section)

==Definitions==
{{See also|Ocean temperature}}
[[File:SST 20131220 blended Global.png|thumb|upright=1.2|Global map of sea surface temperature, showing warmer areas around the equator and colder areas around the poles (20 December 2013 at 1-km resolution). ]]
Sea surface temperature (SST), or ocean surface temperature, is the water [[temperature]] close to the [[ocean]]'s surface. The exact meaning of ''surface'' varies according to the measurement method used, but it is between {{convert|1|mm|in|sigfig=1}} and {{convert|20|m|ft|sigfig=1}} below the [[sea]] surface. 

For comparison, the [[sea surface skin temperature]] relates to the top 20 or so [[micrometres]] of the ocean's surface.

The definition proposed by [[Intergovernmental Panel on Climate Change|IPCC]] for ''sea surface temperature'' does not specify the number of metres but focuses more on measurement techniques: Sea surface temperature is "the subsurface bulk temperature in the top few metres of the ocean, measured by ships, buoys and drifters. [...] Satellite measurements of skin temperature (uppermost layer; a micrometre thick) in the infrared or the top centimetre or so in the microwave are also used, but must be adjusted to be compatible with the bulk temperature."<ref>IPCC, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_AnnexVII.pdf Annex VII: Glossary] [Matthews, J.B.R., V. Möller, R. van Diemen, J.S. Fuglestvedt, V. Masson-Delmotte, C. Méndez, S. Semenov, A. Reisinger (eds.)]. In [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 2215–2256, doi:10.1017/9781009157896.022.</ref>{{rp|2248}} 

The temperature further below that is called ''ocean temperature'' or ''deeper ocean temperature''. [[Ocean temperature|Ocean temperatures]] (more than 20 metres below the surface) also vary by region and time, and they contribute to variations in [[ocean heat content]] and [[ocean stratification]].<ref name="AR6_WG1_Chapter9" /> The increase of both ocean surface temperature and deeper ocean temperature is an important [[Effects of climate change on oceans|effect of climate change on oceans]].<ref name="AR6_WG1_Chapter9" />

=== Extent of "surface" ===
{{See also|Ocean stratification|Photic zone}}
The extent of the ''ocean surface'' down into the ocean is influenced by the amount of mixing that takes place between the surface water and the deeper water. This depends on the temperature: in the tropics the warm surface layer of about 100&nbsp;m is quite stable and does not mix much with deeper water, while near the [[Polar regions of Earth|poles]] winter cooling and storms makes the surface layer denser and it mixes to great depth and then [[Ocean stratification|stratifies]] again in summer. This is why there is no simple single depth for ''ocean surface''. The [[Photic zone|photic depth of the ocean]] is typically about 100 m and is related to this heated surface layer. It can be up to around 200 m deep in the [[open ocean]].<ref name=":11">{{Cite book |last1=Emerson |first1=Steven |url=https://www.cambridge.org/core/product/identifier/9780511793202/type/book |title=Chemical Oceanography and the Marine Carbon Cycle |last2=Hedges |first2=John |date=2008-04-24 |publisher=Cambridge University Press |isbn=978-0-521-83313-4 |edition=1 |chapter=Chapter 4: Carbonate chemistry |doi=10.1017/cbo9780511793202}}</ref><ref name=":5">{{Cite book |last1=Chester |first1=R. |url=https://www.wiley.com/en-us/Marine+Geochemistry%2C+3rd+Edition-p-9781118349090 |title=Marine geochemistry |last2=Jickells |first2=Tim |date=2012 |publisher=Wiley/Blackwell |isbn=978-1-118-34909-0 |edition=3rd |location=Chichester, West Sussex, UK |chapter=Chapter 9: Nutrients, oxygen, organic carbon and the carbon cycle in seawater |oclc=781078031}}</ref>