HR: 1330h
AN: C12A-0876    [PDF]
TI: A Reanalyis of the Contribution of Meteoric Ice, Flooding and Snow Ice Formation to the Mass Balance of Antarctic Sea Ice
AU: Maksym, T
EM: maksym@usna.edu
AF: Department of Oceanography, United States Naval Academy, 572 Holloway road, Annapolis, MD 21402 United States
AU: * Jeffries, M
EM: martin.jeffries@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive Box 757320, Fairbanks, AK 99775-7320 United States
AB: Sea ice core data from five autumn to early spring cruises in the Ross, Amundsen, and Bellingshausen Seas from 1993 to 1998 are reanalyzed to determine the role of meteoric ice, flooding and snow ice formation in the mass balance of Antarctic Sea Ice. Previous analysis of crystal texture and oxygen isotope data have determined that 15% to 38% of the total ice thickness has a meteoric ice component. This suggests a substantial component of the sea ice mass balance in the Southern Ocean during the growth season is due to flooding and snow ice formation. We show that although determining the meteoric component is relatively straightforward, attributing a mechanism of formation to this ice is more difficult. A number of post-genetic changes can occur that may significantly alter the isotopic signature of the ice, making definitive attribution of genesis difficult. Here, the oxygen isotope and crystal structure data is reanalyzed, and using a variety of models of ice growth and compositional evolution, we suggest that the true contribution of flooding and refreezing to the mass balance may be significantly lower, at 6% to 18% of the total ice thickness. However, we show that such estimates are highly dependent on the thermophysical behavior of the vertical exchange of brine in the ice, about which little is known quantitatively. The uncertainty in these estimates suggest that our understanding of the mass balance of Antarctic sea ice and its snow cover remains incomplete and awaits a better understanding of the ice permeability evolution and other small scale sea ice processes. Lastly, recent evidence from flooding experiments on Arctic sea ice is presented that demonstrate the importance of the vertical exchange of brine in determining the compositional properties of the ice.
DE: 4207 Arctic and Antarctic oceanography
DE: 4540 Ice mechanics and air/sea/ice exchange processes
SC: Cryosphere [C]
MN: 2003 Fall Meeting