EGU21-12846
https://doi.org/10.5194/egusphere-egu21-12846
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Turbulent dynamics and ice-shelf basal melt rates from large-eddy simulations

Carolyn Branecky Begeman, Xylar Asay-Davis, and Luke Van Roekel
Carolyn Branecky Begeman et al.
  • Los Alamos National Laboratory, Los Alamos, NM, United States of America (cbegeman@lanl.gov)

Large-eddy simulations are used to investigate boundary layer turbulence and its control on ice-shelf basal melt rates in Antarctic settings. We present simulations at relatively low thermal driving and low ice-shelf basal slopes, resulting in simulated melt rates from 10s cm/yr to several m/yr. Our results are broadly consistent with the linear relationships between far-field thermal driving and melt rate and between ice-shelf slope and melt rate reported by previous studies. The simulated thermal exchange coefficient is lower than recommended values; thermal exchange becomes less efficient as stratification increases.  In our simulations, shear production of turbulent kinetic energy outweighs buoyant production, as found below Larsen C Ice Shelf through recent microstructure measurements. We also find that turbulent intensity and melt rate vary significantly with the orientation between the ice-shelf slope and the far-field flow, even at low ice-shelf slopes. Our results suggest that numerical ocean models employing the standard ice-shelf melt parameterization will underestimate slope effects on ice-shelf melt rates even if they capture the mean buoyancy effects on boundary layer flow. The proposed slope effects would modify feedbacks between ocean circulation and ice-shelf geometry and tidal variability in ice-shelf melt rates.

How to cite: Begeman, C. B., Asay-Davis, X., and Van Roekel, L.: Turbulent dynamics and ice-shelf basal melt rates from large-eddy simulations, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12846, https://doi.org/10.5194/egusphere-egu21-12846, 2021.

Display materials

Display file

Comments on the display material

to access the discussion