EGU2020-19856
https://doi.org/10.5194/egusphere-egu2020-19856
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Ice front blocking of ocean heat transport to an Antarctic ice shelf

Anna Wåhlin1, Nadine Steiger2, Elin Darelius2, Karen Assmann1, Mirjam Glessmer3, Ho Kyung Ha4, Laura Herraiz-Borreguero5, Celine Heuzé6, Adrian Jenkins7, Tae Wan Kim8, Aleksandra Mazur1, Joel Sommeria9, and Samuel Viboud9
Anna Wåhlin et al.
  • 1Department of Marine Sciences, Univeresity of Gothenburg, Sweden (anna.wahlin@marine.gu.se)
  • 2Geophysical Institute, University of Bergen, Norway
  • 3Leibniz Institute of Science and Mathematics Education, Kiel, Germany
  • 4Inha University, South Korea
  • 5Commonwealth Scientific and Industrial Research Organisation (CSIRO), Hobart, Australia
  • 6Department of Earth Sciences, Univeresity of Gothenburg, Sweden
  • 7Northumbria University, Newcastle upon Tyne, UK
  • 8Korea Polar Research Institute, South Korea
  • 9Laboratoire des Ecoulements Geophysiques et Industriels Domaine Universitaire, Grenoble, France

Shoreward oceanic heat flux in deep channels on the continental shelf typically far exceeds that required to match observed ice shelf melt rates, suggesting other critical controls.  IN the present study we study the depth-independent (barotropic) and the density-driven (baroclinic) components of the flow of warm ocean water towards an ice shelf. Using observations from the Getz Ice Shelf system as well as geophysical laboratory experiments on a rotating platform, it is shown that the dramatic step shape of the ice front blocks the barotropic component, and that only the baroclinic component, typically much smaller, can enter the sub-ice cavity.  A similar blocking of the barotropic component may occur in other areas with comparable ice-bathymetry configurations, which may explain why changes in the density structure of the water column have been found to be a better indicator of basal melt rate variability than the heat transported onto the continental shelf. Representing the step topography of the ice front accurately in models is thus important for simulating the ocean heat fluxes and induced melt rates.

How to cite: Wåhlin, A., Steiger, N., Darelius, E., Assmann, K., Glessmer, M., Ha, H. K., Herraiz-Borreguero, L., Heuzé, C., Jenkins, A., Kim, T. W., Mazur, A., Sommeria, J., and Viboud, S.: Ice front blocking of ocean heat transport to an Antarctic ice shelf, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19856, https://doi.org/10.5194/egusphere-egu2020-19856, 2020

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Display material version 1 – uploaded on 08 May 2020
  • CC1: Comment on EGU2020-19856, Krissy Reeve, 08 May 2020

    Hi Anna, thanks for answering my question in the live chat :-) 
    I was just wondering, do you think it would be feasible (and worthy) experiment to incorporate your results into a model to estimate the amount of heat that actually reaches the ice shelves for the whole of Antartica, assuming adequate information on bathymetry?

    We actually chatted about your research back in Davos in the Polar science conference a few years back; I really enjoyed it then too - I was a PhD student of Torsten's at AWI at the time, now a post-doc... hi! :-) 

    • AC1: Reply to CC1, Anna Wåhlin, 09 May 2020

      Hi Krissy, and big congratulations to your post-doc! It seems a long time ago since we last met - a different world. The short answer to your questionn is YES. I definitely think that would be a worthy study and I would very much like to see the results. Using only bathymetry and hydrographic boundary conditions of the source water it should be technically possible to get a theoretical upper limit of the ocean heat flux to the ice shelves. As such it could serve as 'sanity check' or maybe even a new reference case for more complex regional models. If you are interested in pursuing this I would be more than willing to help if you think there is anything (besides cheering on) that I can do :)

      Good luck with all your research!

      Anna

      • CC2: Reply to AC1, Krissy Reeve, 12 May 2020

        Hi Anna, thanks for your response! And I agree, it does seem like an age away! Crazy times we live in!

        It would be very interesting, and I think could be very useful for modellers to have that as a reference level too! While I would love to be involved in such a study, I don't think I'm really the right person for it given my lack of experience with models... maybe its a potential project for a student though, given the right support? 

        Take care and I hope you had a nice EGU week!