Arctic Ocean Mixing. Influence of changing ice cover on internal waves and mixing.
Mixing in the stratified ocean is related to internal wave energy, which tends to be low under the Arctic Ocean ice cover. Consequently, as ice cover declines, background mixing may increase and, among other changes, bring more Atlantic Water heat to the surface to melt ice, a potentially important positive climate feedback. To understand the influence of background mixing and to improve models of the changing Arctic Ocean, we take advantage of the latest analysis techniques to examine existing internal wave and mixing data and thereby develop a database with which to track changes in the internal wave and mixing environments. We combine new observations with recent and historical data, including data from ocean areas in the Norwegian Arctic and the US Arctic, to explore the energetics of Arctic internal waves and mixing under changing ice conditions.
The study is collaboration with James Morison (University of Washington, Polar Science Center).
Our approach is to
1) examine existing data to assemble an internal wave and mixing database,
2) examine the relation of mixing to internal waves in the Arctic Ocean,
3) compare historical data with recent (2007 and on) and new data, and
4) examine the relation of internal wave energy to the ice cover. Data set recently collected by Fer includes current measurements and dissipation rate measurements
i) in the upper 500 m in the Amundsen Basin (Barneo drift April 2007 and 2008),
ii) near the Yermak Plateau (summer 2007) and
iii) 30 day long hourly profiles during the drift of icebreaker Oden (2008, summer).
Additionally, Morison continues with the NPEO program including 10 XCP (expendable current profiler) deployments per year. Through ARCOM, we supplement this by another 15 XCPs each year.
Available data and plots can be found here.
Funding: 900 kNOK, NFR
Contact at GFI: Ilker Fer