M. G. McPhee,1
S. F. Ackley,2
B. A. Huber, 4
D. G. Martinson, 4
J. H. Morison,5
R. D. Muench,6
L. Padman, 7
T. P. Stanton3:
The Antarctic Zone Flux Experiment,
(submitted) Bulletin of the American Meteorological Society
In winter the eastern Weddell Sea in the Atlantic sector of the Southern Ocean hosts some of the most dynamic air-ice-sea interaction found on earth. Sea ice in the region is kept rleatively thin by heat flux from below, maintained by upper ocean stirring associated with the passage of intense, fast moving cyclones. Ocean stratification is so weak that the possibility of deep convection exists, and indeed, satellite imagery from the Weddell Sea in the 1970s shows a large expanse of open water (the weddell Polynya) that persisted through several seasons and may have significantly altered global deep water production. Understanding what environmental conditions could again trigger widespread oceanic overturn may thus be an important key in determining the role of high latitudes in deep ocean ventilation and global atmospheric warming. During the Antarctic Zone Flux experiment in July and August, 1994, response of the upper ocean and its ice cover to a series of storms was measured at two drifting stations supported by the NSF research icebreaker, Nathniel B.Palmer. This article describes the experiment, in which fluxes of heat, mass, and momentum were measured in the upper ocean, sea ic, and lower atmospheric boundary layer. Initial results illustrate the importance of oceanic heat flux at the ice undersurface for determining the character of the sea ice cover. They also show how the heat flux depends both on high levels of turbulent mixing during intermittent storm events, and on large variability in the stratified upper ocean below the mixed layer.
A postscript file of the entire paper is available at the NPS ANZFLUX site.