HR: 08:45h
AN: C41A-04 INVITED     [PDF]
TI: Seasonal Ventilation of the Cavity Beneath Filchner-Ronne Ice Shelf Simulated With an Isopycnic Coordinate Ocean Model
AU: * Jenkins, A
EM: ajen@bas.ac.uk
AF: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET United Kingdom
AU: Holland, D M
EM: holland@cims.nyu.edu
AF: Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012 United States
AU: Nicholls, K W
EM: kwni@bas.ac.uk
AF: British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET United Kingdom
AU: Schr\"{o}der, M
EM: mschroeder@awi-bremerhaven.de
AF: Alfred-Wegener-Institut f\"{u}r Polar- und Meeresforschung, Postfach 120161, Bremerhaven, 27515 Germany
AB: The ocean cavity beneath Filchner-Ronne Ice Shelf is observed to respond to the seasonal cycle of water mass production on the continental shelf of the southern Weddell Sea. Here we use a numerical model to investigate the propagation of newly-formed shelf waters into the cavity. We find that the model reproduces the most distinctive features of the observed seasonality and offers a plausible explanation for those features. The most saline shelf waters are produced in the far west, where the inflow to the cavity peaks twice each year. The major peak occurs during the short period around mid-winter when convection reaches full-depth and the densest waters are generated. Once the surface density starts to decline, dynamic adjustment of the restratified water column leads to a gradual fall in the salinity at depth and a secondary peak in the inflow that occurs in summer at the western coast. Beneath the ice shelf, the arrival of the wintertime inflow at the instrumented sites is accompanied by a rapid warming, while the slower decline in the inflow leads to a more gradual cooling. Water brought in by the secondary summer peak flows mainly to the eastern parts of the cavity. Here the seasonality is suppressed because the new inflows mix with older waters that recirculate within a topographic depression. This pooling of waters in the east, where the primary outflow of Ice Shelf Water is generated, dampens the impact of seasonality on the local production of Weddell Sea Bottom Water.
DE: 1863 Snow and ice (1827)
DE: 4207 Arctic and Antarctic oceanography
DE: 4255 Numerical modeling
SC: Cryosphere [C]
MN: 2003 Fall Meeting