EGU2020-6572
https://doi.org/10.5194/egusphere-egu2020-6572
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Estimating Antarctic Ice Sheet Contributions to Future Sea Level Rise Using a Coupled Climate-Ice Sheet Model

Jun-Young Park1,2, Fabian Schloesser3, Axel Timmermann1,2, Dipayan Choudhury1, June-Yi Lee1,2,4, Arjun Babu Nellikkattil1,2, and David Pollard5
Jun-Young Park et al.
  • 1Center for Climate Physics, Institute for Basic Science, Busan, South Korea
  • 2Department of Climate System, Pusan National University, Busan, South Korea
  • 3International Pacific Research Center, University of Hawaii, Honolulu, Hawaii, USA
  • 4Research Center for Climate Sciences, Pusan National University, Busan, South Korea
  • 5Earth and Environmental Systems Institute, Penn State University, University Park, Pennsylvania, USA

One of the largest uncertainties in projecting future global mean sea level (GSML) rise in response to anthropogenic global warming originates from the Antarctic ice sheet (AIS) contribution. Previous studies suggested that a potential AIS collapse due to the Marine Ice Sheet Instability (MISI) and Marine Ice Cliff Instability (MICI) may contribute up to 1m GMSL rise by the year 2100. However, these estimates were based on uncoupled ice sheet models that do not capture interactions between the AIS and the ocean and atmosphere. Here, we explore future GMSL projections using a three-dimensional coupled climate-ice sheet model (LOVECLIP) that simulates ice sheet dynamics in both hemispheres. The model was forced by increasing CO2 concentrations following the Shared Socioeconomic Pathway (SSP) 1-1.9, 2-4.5 and 5-8.5 scenarios. Over the next 80 years, the corresponding GMSL contribution from AIS amounts to about 2cm, 8cm and 11cm, respectively. Additional sensitivity experiments show that AIS meltwater flux in response to the SSP 5-8.5 CO2 concentrations causes subsurface Southern Ocean warming which leads to an additional 20% AIS melting and a reduction in Southern Hemispheric future warming.

How to cite: Park, J.-Y., Schloesser, F., Timmermann, A., Choudhury, D., Lee, J.-Y., Nellikkattil, A. B., and Pollard, D.: Estimating Antarctic Ice Sheet Contributions to Future Sea Level Rise Using a Coupled Climate-Ice Sheet Model, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6572, https://doi.org/10.5194/egusphere-egu2020-6572, 2020

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Display material version 1 – uploaded on 04 May 2020
  • CC1: Comment on EGU2020-6572, User deleted account, 05 May 2020

    Hi Jun-Young Park, Nice work. We're trying similar type of experiments with iLOVECLIM at the VU Amsterdam together with Didier Roche. How do you couple the models, every year? Do you use anomaly methods for Temperature and/or precipitation, how do you calculate SMB?

    Model seems well calibratied for the present, what did you use as initial ice sheets? Do you include a glacial spin-up?

    Again nice work, hope you can answer my questions.

    Best.

    • AC2: Reply to CC1, Axel Timmermann, 05 May 2020

      Hi Bas,

      We use bias corrections -- additive for temperature, multiplicative for precipitation. See https://www.clim-past-discuss.net/cp-2020-46/ for more information. We also did glacial-> present-day coupled transient simulation. SMB is also described in Dipayan's CPD paper.

       

      Which ice-sheet model are you using, Bas?

      • CC4: Reply to AC2, User deleted account, 05 May 2020

        using GRISLI (LSCE, French model). coupling was already set up for NH (Roche, 2014), also working together with Aurelien. Have a Display tomorrow in CR5.4. Will upload pdf today.

  • CC2: Comment on EGU2020-6572, Yue Wu, 05 May 2020

    Hi Jun-Young, I’m curious about what you mentioned larger contribution to the GMSL rise from the GrIS. Did you also do the same work on the GrIS as you did in slides 5 and 6? Did you find similar (or intensified) results as we see on the AIS? 

    And another question, I was wondering about larger SLE of the AIS while contributing less to the GMSL rise. Do you have any explanation of mechanism on this? 

    • AC3: Reply to CC2, Axel Timmermann, 05 May 2020

      LOVECLIM is coupled to  Penn State ice-sheet model in both hemisphere (Antarctica, Greenland and Laurentide, Eurasian for paleo). Antarctic ice-sheets is marine-based => SLE is much larger than SL, because ice-shelves and ice-sheet volume below sealevel (50-60% of WAIS) do not contribue to GMSL.

      • CC5: Reply to AC3, Yue Wu, 05 May 2020

        Thanks Axel! That makes sense to me. 

  • CC3: Comment on EGU2020-6572, Nicolas Jourdain, 05 May 2020

    Hi Jun-Young. Thank you for your presentation. Given the low horizontal and vertical resolution in the ocean component of LOVECLIM, how do you calculate ice-shelf basal melting?

    • AC1: Reply to CC3, Axel Timmermann, 05 May 2020

      ... by interpolating the 400 m subsurface temperatures from the nearest ocean points. There is no ocean cavity under the ice-shelf