release_elmerice_9.0.md

Elmer/Ice Release Notes for version 9.0

Previous release: 8.4

Period covered: 18 Dec 2018 - 30 Aug 2020

Number of commits: ~110 (excluding merges of other branches)

These release notes provide information on most essential changes in Elmer/Ice functionalities. Starting from the uppermost directory of the source tree, you can inquire changes inside the elmerice-directory using

git log --since="2018-12-18" -- elmerice

Overview of changes/enhancements

• Documentation of new solvers from now on is placed using MarkDown under elmerice/Solvers/Documentation/

• Improvements to inversion methods:

  • Introduced new directory structure to distinguish general Adjoint solver routines (elmerice/Solvers/Adjoint), solvers solely needed for inversions using SSA (elmerice/Solvers/AdjointSSA) and solvers solely needed for invesions using Stokes (elmerice/Solvers/AdjointStokes). As there have been a lot of changes/new files introduced, we do not list those below but rather refer the user to the new documentation in MarkDown, which is to be found under (elmerice/Solvers/Documentation/).

• Coupling of the GlaDS solvers with the calving solvers in a two-mesh, 3D simulation. Includes a new plume solver that currently relies on the external ODEPack library (not included in the Elmer distribution).

• New thermodynamically consistent model for permafrost with saturated aquifers

New Solver/Userfunction Modules

• Calving3D_lset.F90: Return calving as a level set function (work in progress).

• CalvingRemeshMMG.F90: Cut a calving event directly out of a 3D mesh without external gmsh or mesh extrusion. Initial work on allowing calving margins to migrate.

• PlumeSolver.F90 - associated ODEPack library files: opkda1.F, opkda2.F, opkdmain.F(not included in Elmer repository): Provides plume melt rates across the calving front of a glacier. Fed by output from GlaDS solvers. Simulates a continuous sheet-style plume across entire front, split up into segments defined by frontal nodes and mesh resolution.

• CalvingHydroInterp.F90: Interpolates required variables between 3D ice mesh and 2D hydrology mesh, if using a multi-mesh approach. This is more complicated than it sounds.

• HydroRestart.F90: Allows separate 2D hydrology mesh to be restarted in a multi-mesh simulation.

• USF_SourceCalcCalving.F90: User function that calculates the source term for GlaDS as a combination of surface melt (provided in some user-specified variable or input file) and basal melt (worked out automatically from the residual of the TemperateIce solver)

• BasalMelt3D.F90: Solver that works out basal melt on ungrounded portions of a glacier.

• GMValid.F90: Solver that discriminates between ungrounded areas that are connected to the fjord and isolated ungrounded patches inland.

• Permafrost.F90: Collection of solvers for permafrost simlations of a saturated aquifer including heat transfer and phase change as well as solute transport and mechanical deformation (the latter involving the linear elasticity solver)

• PermafrostMaterials.F90: Module for material functions given by either a thermodynamically consistent model by Hartikainen or a simplified model by Andersson. Reads default values from permafrostsolutedb.datand permafrostmaterialdb.dat.

• SurfaceBuondaryEnthalpy: Surface Boundary Condition for steady state thermal regime

Enhanced Solver/Userfunction Modules

• GlaDSCoupledSolver.F90: Modified to work on a secondary hydrology mesh (as opposed to the primary ice mesh) and to discriminate properly between fjord-connected ungrounded areas and isolated ungrounded patches inland. Also should work on the basal boundary of an internally extruded 3D mesh.

• GlaDSchannelSolver.F90: Changes to achieve the same outcome as above.

• CalvingRemesh.F90 and Calving3D.F90: Changed to avoid interpolating hydrology-specific solvers to the ice mesh after calving. Also changed to allow ice solvers and calving to run at different timestep to hydrology.

• GroundedSolver.F90: Minor tweak to allow frontal grounded basal nodes to be listed as grounding-line nodes, so that the plume solver knows where to stick plumes. Introducing the possibility to use lower surface variable (instead of node coordinate - which is still default)

ElmerSolver library functionality

• Added Zoltan repartitioning capabilities to permit continuous runtime load balancing and to assist with calving remeshing.

• Added support for MMG3D remeshing/mesh adaptation.