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Module thk

This IGM module solves the mass conservation equation for ice to update the thickness based on ice flow (computed by the iceflow module) and surface mass balance (provided by any module that updates smb). The equation is solved using an explicit first-order upwind finite-volume scheme on the 2D working grid. This scheme allows ice mass to move between cells (where thickness and velocities are defined) using edge-defined fluxes (calculated from depth-averaged velocities and ice thickness in the upwind direction).

The scheme is mass-conservative and parallelizable due to its fully explicit nature. However, it is subject to a CFL condition, meaning the time step (defined in the time module) is constrained by the parameter processes.time.cfl. This parameter represents the maximum number of cells crossed in one iteration and cannot exceed one. For more details, refer to the documentation of the time module. Additional information about the scheme can be found in the following paper: (Jouvet et al., 2021)1.

Contributors: Guillaume Cordonnier, Guillaume Jouvet.

Parameters

Default configuration file (thk.yaml): 

thk:
  slope_type: superbee
  ratio_density: 0.910
  default_sealevel: 0.0

Description of the parameters:

Name Description Default value Units
slope_type Type of slope limiter for the ice thickness equation (godunov or superbee). superbee —
ratio_density Density of ice divided by density of water. 0.91 —
default_sealevel Default sea level if not provided by the user. 0.0 m

  1. Jouvet, G., Cordonnier, G., Kim, B., Lüthi, M., Vieli, A., & Aschwanden, A. (2021). Deep learning speeds up ice flow modelling by several orders of magnitude. Journal of Glaciology, 68(270), 651--664. https://doi.org/10.1017/jog.2021.120 ↩