Recorded presentation8.3
The impacts of increased open water on Arctic summer storms
Will Perrie, Bedford Institute of Oceanography, Dartmouth, NS, Canada; and Z. Long
It is important to understand the impacts of increased open water on storm intensity, storm tracks, and the surface winds that drive coastal ocean processes. For example, in the Beaufort Sea, coastal erosion is often related to coastal ocean processes such as waves and nearshore currents, driven by strong surface winds generated by intense storms.
The role of sea surface fluxes in Arctic storm development was investigated using a coupled atmosphere-ice-ocean model to simulate a summer storm that moved from the Chuckchi Sea into the Beaufort Sea in late July 2008. The coupled model system consists of the Canadian Regional Climate Model two-way coupled to an ice-ocean model, consisting of the Hibler ice model and POM, the Princeton Ocean Model. The coupled model system is shown to simulate the storm track, intensity, maximum wind speed and the ice cover well, compared to Canadian Meteorological Centre (CMC) analyses and QSCAT-NCEP analysis data. In addition, the model also simulates well the observed ice edge and open water expanse along the Chuckchi and Beaufort Seas at the time of the storm, in late July 2008. At this time, the open water expanse was quite large.
Significant ocean surface responses were simulated over the open water of the Chuckchi and Beaufort Seas during the storm. The maximum surface current is estimated at about 0.7m/s while the surface cooling due to the storm is as much as 2 degrees C. However, no significant ocean surface responses were found in the model domain covered with sea ice, suggesting that sea ice prevents the surface momentum exchange between the atmosphere and the underlying water. The significantly warmer SSTs simulated in the coupled run compared to the uncoupled run (up to 6 degrees C) are due to the high albedo of sea ice; the warmer SSTs further increase the downward kinetic energy transport through enhanced boundary turbulence. The coupled run suggested winds that were typically 3-4m/s stronger than those of the uncoupled simulation.
Session 8, High Latitude Air-Sea Interaction, Including Air-Sea-Ice Interaction
Wednesday, 29 September 2010, 3:30 PM-5:00 PM, Capitol AB
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