MPAS-Albany Land Ice Model User's Guide v6.0

The MPAS-Albany Land Ice (MALI) is an unstructured-mesh land ice model (ice sheets or glaciers) capable of using enhanced horizontal resolution in selected regions of the land ice domain. MALI is built using the Model for Prediction Across Scales (MPAS) framework for developing variable resolution Earth System Model components and the Albany multi-physics code base for solution of coupled systems of partial-differential equations, which itself makes use of Trilinos solver libraries. MALI includes a three-dimensional, first-order momentum balance solver (“Blatter-Pattyn”) by linking to the Albany-LI ice sheet velocity solver, as well as an explicit shallow ice velocity solver. Evolution of ice geometry and tracers is handled through an explicit first-order horizontal advection scheme with vertical remapping. Evolution of ice temperature is treated using operator splitting of vertical diffusion and horizontal advection and can be configured to use either a temperature or enthalpy formulation. MALI includes a mass-conserving subglacial hydrology model that supports distributed and/or channelized drainage and can optionally be coupled to ice dynamics. Options for calving include “eigencalving”, which assumes calving rate is proportional to extensional strain rates. MALI has been evaluated against commonly used exact solutions and community benchmark experiments and shows the expected accuracy. It has been used in land ice evolution experiments estimating potential for future sea-level rise from ice sheets.  This User's Guide describes the model configuration and underlying physics.