Center for Coastal Physical Oceanography & ODU Resilience Collaborative



Spring 2017 Seminar Series

"PROCESSES CONTROLLING BOTTOM WATER FORMATION AND SUB-ICE-SHELF MELTING
IN IDEALIZED SIMULATIONS OF ANTARCTIC MARGINS"


Gustavo Marques
Geophysical Fluid Dynamics Lab, Princeton University

Monday, March 20, 2017
3:30 PM
Conference Center, Innovation Resarch Building II
4211 Monarch Way, Norfolk, VA 23508

Abstract

In the first part of the talk, a set of numerical experiments will be used to illustrate that Antarctic outflows can trigger topographic vorticity waves. It will be shown that the properties of these waves are controlled by the ambient stratification, the buoyancy force exerted by the outflow, and the along-slope flow magnitude. For weak stratification and weak westward along-slope flows typical of the Antarctic slope, wave energy propagates eastward, in the opposite direction from phase velocity. The second part of the talk will focus on idealized ocean/sea-ice simulations coupled with a thermodynamically active ice shelf. These simulations were designed to study the sensitivity of sub-ice-shelf melting to (1) wind forcing; (2) surface heat fluxes; (3) presence/absence of topographic features; (4) ice shelf geometries; and (5) horizontal grid resolution. Sub-ice-shelf melting is mostly sensitive to changes in wind pattern over the continental shelf slope when a topographic trough is present. As the prevailing easterly winds change direction, an undercurrent develops near the upper part of the slope. The interaction of this undercurrent with a topographic trough allows warm waters to penetrate into the sub-ice-shelf cavity, leading to high melting rates near the grounding line. This result is consistent with previous studies that highlight the link between undercurrent strength and wind forcing, with important consequences to sub-ice-shelf melting. The talk will end with a short demonstration of key novel capabilities to model ice shelf/ocean interaction that were recently included in the GFDL's ocean model (MOM6).


Biography

Gustavo Marques is a Postdoctoral Research Associate at the Atmospheric and Oceanic Sciences Program at Princeton University, working with scientists from the Ocean and Ice-Sheet Processes Group at the Geophysical Fluid Dynamics Laboratory (GFDL). He received a B.S. in Oceanography from the University of Sao Paulo in 2007, a M.S. in Physical Oceanography from the University of Massachusetts Dartmouth in 2010, and a Ph.D. in Meteorology and Physical Oceanography from the University of Miami in 2015. Gustavo is an active developer of GFDL's ocean model (MOM6) and he is responsible for GFDL's participation in the 2nd Ice Shelf-Ocean Model Intercomparison Project (ISOMIP+).


Reception before seminar at 3:00 PM


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