HR: 14:15h
AN: OS42J-04 [PDF]
TI: A Model Study of Circulation and Biogeochemical Processes on the West Antarctic Peninsula
AU: * Klinck, J M
EM: klinck@ccpo.odu.edu
AF: Center for Coastal Physical Oceanography, Old Dominion University
Crittenton Hall, Norfolk, VA 23529
United States
AU: Dinniman, M S
EM: msd@ccpo.odu.edu
AF: Center for Coastal Physical Oceanography, Old Dominion University
Crittenton Hall, Norfolk, VA 23529
United States
AU: Hofmann, E E
EM: hofmann@ccpo.odu.edu
AF: Center for Coastal Physical Oceanography, Old Dominion University
Crittenton Hall, Norfolk, VA 23529
United States
AB:
Circumpolar Deep Water (CDW) is a relatively warm, salty and nutrient rich
water mass which flows across the shelf break of the west Antarctic
Peninsula. This water mass moderates the ice cover through heat flux,
provides a relatively warm subsurface environment for some animals and
provides nutrients to stimulate primary production. CDW exchange is known
to be episodic, but persistent, and is thought to occur at specific
locations due to bottom topography. A circulation study using an eddy
permitting 3D numerical circulation model analyzes the exchange of
CDW. Macro-nutrients and estimated biological uptake processes are included
to analyze nutrient pathways and selection processes that result in diatoms
or algae blooms.
We use the Rutgers/UCLA Regional Ocean Model System (ROMS) with a grid
resolution of 5 km horizontally and 24 levels vertically. A gridded
bathymetry is derived from the Smith and Sandwell bathymetry with
modifications around Marguerite Bay from digitized nautical charts
(Beardsley). Initial temperature, salinity, nitrate and silicate are
derived from the World Ocean Atlas (WOA98). Monthly climatological ECMWF
reanalysis wind stress is applied to the top three layers of the model. Ice
concentrations are specified using the SSM/I climatology. The COARE bulk
flux algorithms are used to compute the model surface heat and salt fluxes,
as modified by the sea ice. Vertical mixing in the interior and surface
boundary layer uses the K profile parameter (KPP) scheme (modified for the
presence of ice). An annual climatology of depth averaged volume transport
was estimated from the Orsi et al. (1995) frontal locations. A radiation
boundary condition with adaptive nudging (Marchesiello 2000) to monthly
climatologies of the tracers and the estimated volume transport is used on
open boundaries.
The model circulation compares favorably to general schematics of the flow.
The Antarctic Circumpolar Current (ACC) flows along the shelf break,
although the model has stronger and less variable circulation than is shown
by recent ADCP measurements. A weak, southward coastal flow, which turns
into Marguerite Bay and flows cyclonically around the bay, matches the
general pattern of recent ADCP measurements (Muench and Padman).
Subpycnocline temperature shows evidence of intrusion of warm water from the
ACC onto the shelf.
DE: 4207 Arctic and Antarctic oceanography
DE: 4219 Continental shelf processes
DE: 4255 Numerical modeling
SC: OS
MN: 2002 Ocean Sciences Meeting