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| The Barents Sea has now less sea-ice-cover than before. Hence, it looses most of the extra heat from stronger ocean currents. Bear Island, between Norway and Svalbard (photo Lars H. Smedsrud). |
The Barents Sea is a robust and effective ocean cooler. Despite its fairly shallow depth of 230 m, it releases more energy to the atmosphere than any other sea around the Arctic. A new study by four oceanographers in Bergen shows how the Barents Sea responds to variation of heat transport by the ocean. Results show that the northwards migration of the sea ice, and the larger open ocean areas in the south, can compensate for much of the increase in ocean heat transport since the mid 1990’s.
The paper, published in Ocean Science, describes a new approach for understanding the Barents Sea. First an overall heat budget had to be produced, including mean monthly ocean transport and atmospheric forcing. New estimates including the Norwegian Coastal Current makes the total transported heat to the Barents Sea about 70TW. The researchers have divided the Barents Sea into a northern and southern area, and show that all of the heat is lost to the atmosphere in the south.
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| Mean temperature of the southern Barents Sea. Red circle is observed summer mean (June – September), and blue star winter mean (December – April). The green line shows a stable yearly cycle resulting from ocean heat transport of 73 TW. Red line shows temperature with increased ocean transport, blue line with decreased ocean transport. (Figure 7 in article). |
The heat is lost by the ocean in the southern Barents Sea through evaporation and sensible fluxes, as there is an approximate balance between the incoming solar, and the outgoing long wave, radiation. The northern Barents Sea receives little ocean heat transport, leading to early sea ice formation during winter.
Reference:
L. H. Smedsrud1, R. Ingvaldsen2,1, J. E. Ø. Nilsen3,1, and Ø. Skagseth2,1: Heat in the Barents Sea: Transport, storage, and surface fluxes, Ocean Science (in press, online 11.02.10)
1Bjerknes Centre for Climate Research, Bergen, Norway
2Institute of Marine Research, Bergen, Norway
3Nansen Environmental and Remote Sensing Centre, Bergen, Norway
The paper is available for download at: http://www.ocean-sci.net/6/219/2010/