NBP09-01 Cruise Report - British Oceanographic Data Centre

Figure 29: Water column thickness (m) over the model domain.the ice shelf draft was altered by an increment that varied sinusoidally transverse to the longitudinal axis ofthe ice shelf. This alteration modified the ice shelf draft (contours in figure 30) by up to ∼100 meters.7.2 Model ForcingThe model simulation was initialized with a meridionally uniform temperature and salinity profile correspondingto NBP09-01 CTD 14. Flow was initiated and maintained by buoyancy fluxes at the ice-oceaninterface. No winds or tides were prescribed. During the simulation, the hydrography was restored to theinitial conditions in the western 15 km. The model was integrated for 20 days, at which point the kineticenergy of the flow stabilized. The strong restoring may have limited accurate representation of the locationof inflow as well as ice front hydrography. When more computational resources are available, that sensitivitywill be explored.7.3 Preliminary ResultsGiven our still limited knowledge of ice shelf basal topography, sub-shelf bathymetry, and forcing, modelresults are primarily qualitative. However, there is encouraging agreement between the observed and modeledocean circulation and melting patterns. In figure 30, heightened melt rates occur in three distinct locationsdriven by differing dynamics: near the deepest parts of the ice shelf grounding line, near the ice shelf front,and in inverted channels at the ice shelf base.The depth integrated flow illustrated in figure 30 obscures vertically sheared currents underneath the iceshelf. Heat used for melting is derived primarily from the densest, warmest waters respresented in thesimulation (CDW); virtually all heat entrained into the mixed layer occurs within 10 km of the groundingNBP09-01 Cruise Report (p. 47 of 83) Revised February 27, 2009