A numerical study of the western Cosmonaut polynya in a coupled ocean-sea ice model
McClean, Julie L.
Hunke, Elizabeth C.
Semtner, Albert J.
MetadataShow full item record
Employing results from a 0.4° , 40-level fully global, coupled ocean–sea ice model, we investigated the role of physical processes emanating from atmosphere, ocean, and ice in the initiation, maintenance, and termination of a sensible heat polynya with a focus on the western Cosmonaut polynya that occurred during May–July 1999. The Cosmonaut polynya first appeared in early May 1999 in the form of an ice-free embayment, transformed into an enclosed polynya on 5–9 July, and disappeared by late July, when the ice from the surrounding regions began to encircle the embayment. Except for the differences in ice concentrations, the time of appearance, size, and shape of the Cosmonaut polynya simulated by the model are in approximate agreement with the Special Sensor Microwave/Imager (SSM/I) observations. Between May and July 1999 the Cosmonaut Sea experienced two synoptic storms, both lasting 5 days. Followed by the passage of the first storm on 12–19 June, there was a remarkable growth in the size of the embayment by 21 103 km2. Associated with this, the sea surface temperature (SST) rose by 0.15° C, the upward heat flux jumped from 5 to 94 W m(-2), and a net freshwater flux into the ocean increased by 2 cm d(-1). By running the model simulation with a 20% wind speed increase, it is demonstrated that the twofold increase in SST and upward heat flux increased the embayment area by 15 X 10(3) km(2) and decreased the ice concentration by approximately 10% from the control run. A similar, but somewhat weaker wind event that took place on 30 June to 10 July had less influence on the embayment area although the upward heat flux (65 W m(2)) was comparable to the first event. By examining the vertical displacement of the 1.6° C isotherm depth prior to, during, and after these two storms, we demonstrate that the impetus provided by these storms was able to raise the 1.6° C isotherm depth by 30 m through wind-driven mixing, making sufficient oceanic heat input from beneath the mixed layer available to prevent freezing and/or delay ice formation while ice in the adjacent regions continued to grow. A sudden shift in the ice drift direction from southwest to northeast (3 July) followed by the second storm, accompanied by large air-sea temperature differences, caused the enclosure of the embayment, subsequent formation of the polynya, and its termination.
The article of record as published may be found at http://dx.doi.org/10.1029/2004JC002858
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
Lee, Younjoo; Maslowski, Wieslaw; Osinski, Robert; Kinney, Jaclyn Clement; Craig, Anthony; Cassano, John; Nijssen, Bart; Seefeldt, Mark (EGU, 2020);The summer polynya along the northern coast of Greenland has been observed only six months later after the winter polynya in 2018, which has prompted concerns about the stability of some of the thickest sea-ice in the ...
Thornton, E.B.; MacMahan, J.; Sallenger, A.H. (2006-11-01);Dune erosion is shown to occur at the embayment of beach mega-cusps O(200m alongshore) that are associated with rip currents. The beach is the narrowest at the embayment of the mega-cusps allowing the swash of large storm ...
Roth, Mathias K. (Monterey, California. Naval Postgraduate School, 2003-06);The unique properties of the temperature and salinity profiles for polar oceans are critical for high-latitude mixed layer thermodynamics. In the Polar regions the water column is coldest and freshest at the surface where ...