MinSIA v1: a lightweight and efficient implementation of the shallow ice approximation

Abstract. Simulations of ice flow have recently been boosted to an unprecedented numerical performance by machine learning techniques. This paper aims at keeping classical numerics competitive in this field. It introduces a new numerical scheme for the shallow ice approximation. Key features are a semi-implicit time-stepping scheme in combination with a dynamic smoothing of the nonlinearity in the slope-dependence of the flow velocity. As a first step, the software MinSIA presented here provides a lightweight implementation of the new scheme in MATLAB. An implementation in Python is under development. MinSIA is designed for simulations with several million nodes on standard desktop PCs and allows for spatial resolutions of 25 m or even finer. The numerical scheme performs particularly well for heavily glaciated topographies with moderately inclined ice surfaces. In turn, the advantage of the scheme decreases slightly for alpine topographies with steep walls during phases of moderate glaciation.