Arctic Report Card 2020: Sea Surface Temperature Sea Surface Temperature

Summer sea surface temperatures (SST) in the Arctic Ocean are driven mainly by the amount of incoming solar radiation absorbed by the sea surface. Solar warming of the Arctic surface ocean is influenced by the distribution of sea ice (with greater warming occurring in ice-free regions), cloud cover, ocean optical properties, and upper-ocean stratification. Discharge of warm Arctic river waters can provide an additional source of heat to the surface marginal seas. In the Barents and Chukchi Seas, there is also a contribution to ocean heat by the advection of warm water from the North Atlantic and North Pacific Oceans, respectively. Arctic SSTs are an essential indicator of the role of the ice-albedo feedback mechanism in any given summer melt season. As the area of sea ice cover decreases (see essay Sea Ice), more incoming solar radiation is absorbed by the ocean and, in turn, the warmer ocean melts more sea ice. In addition, warmer SSTs are associated with delayed autumn freeze-up and increased ocean heat storage throughout the year. Marine ecosystems are influenced by SST, which affects the timing and development of primary and secondary production cycles, as well as available habitat for upper trophic and temperature-sensitive species. Finally, with respect to carbon cycling, warmer SSTs increase the surface-ocean partial pressure of CO2 (pCO2), which reduces the air-ocean pCO2 gradient and therefore the ocean uptake of CO2 from the atmosphere. A study published this year indicates that increased SSTs in recent years may have reduced air-ocean exchange of CO2 by as much as 50% (DeGrandpre et al. 2020). 2020 OAR (Oceanic and Atmospheric Research) CIRES (Cooperative Institute for Research in Environmental Sciences) Submitted https://doi.org/10.25923/v0fs-m920 Public Domain 1876