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SUMMARY:Fine-scale ocean processes in the basal melting of Antarctic ice s
 helves - Madi Rosevear\, University of Tasmania
DTSTART:20201202T100000Z
DTEND:20201202T110000Z
UID:TALK150730@talks.cam.ac.uk
CONTACT:Dr Irena Vankova
DESCRIPTION:The Antarctic Ice Sheet\, which comprises the largest volume o
 f ice on our planet\, is losing mass due to ocean-driven melting of its fr
 inging ice shelves. Efforts to represent the effects of basal melting in s
 ea level projections are undermined by poor understanding of the turbulent
  ice shelf-ocean boundary layer (ISOBL)\, a meters-thick band of ocean tha
 t regulates heat and salt transfer between the ambient ocean and the ice. 
 Ocean-climate models cannot resolve the ISOBL and rely on parameterisation
 s to predict melting. However\, observations suggest that common ISOBL par
 ameterisations only perform well in cold\, energetic ocean environments.\n
 \nIn this talk I will summarise some of the main findings of my PhD thesis
 \, which uses both observational data and turbulence-resolving model simul
 ations to characterise melting and ISOBL dynamics across a broad range of 
 ocean states. The observational data comprises unique ocean and in situ ba
 sal melt rate observations from beneath the Amery Ice Shelf. The modelling
  focuses on the ISOBL and is performed using resolved large-eddy simulatio
 n. The model domain consists of a horizontal ice-ocean interface underlain
  by a stratified ocean\, and is forced by a steady flow in geostrophic bal
 ance. Using these model simulations\, I investigate the coupled ISOBL and 
 melting response to ocean temperature and current forcing. Depending on th
 e relative strength of the thermal and current forcing\, I find that the I
 SOBL may be characterized as either “well-mixed” \, “stratified” o
 r “double-diffusive”. I use these results to develop a novel regime di
 agram for the ISOBL\, which provides new insight into the varied and nonli
 near melting responses expected around Antarctica\, depending on the local
  conditions. Comparison to observed sub-ice shelf conditions and melt rate
 s is favorable and demonstrates the relevance of these regimes over a broa
 d range of realistic conditions.
LOCATION:British Antarctic Survey\, Zoom
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