Research Highlights
Nature Reports Climate Change
Published online: 25 October 2007 | doi:10.1038/ngeo.2007.31
The big melt
Alicia Newton
Geophys. Res. Lett. 34, L19505 doi:10.1029/2007GL031480 (2007)
©2007 AGU
Open ocean waters absorb almost ten times more solar radiation than sea ice — a phenomenon known as the ice-albedo feedback. Recent declines in the extent of Arctic summer sea ice may partly be due to the increase in heat being absorbed by the newly uncovered ocean.
Donald Perovich at the Cold Regions Research and Engineering Laboratory at the US Army ERDC and colleagues used a series of satellite-derived measurements of ice cover and solar radiation in the Arctic from 1979 to 2005 to estimate the amount of heat the ice-free ocean was absorbing. Although scientists have predicted that diminishing sea ice would lead to increasing heat absorption in the ocean, few studies have been able to quantify the effects. The team, led by Perovich, found that most of the Arctic Ocean has steadily been absorbing more heat since 1979. Areas such as the Chukchi Sea near the coast of Alaska have experienced increases of up to 4% per year.
Over the 26 year period, the Arctic Ocean absorbed enough additional heat to melt up to 9,300 km3 of sea ice. Large amounts of energy stored in the upper ocean could also delay or prevent the refreezing of sea ice during the following winter.
