Modelling subglacial drainage with GlaDS on GPUs

The Subglacial Drainage System model (GlaDS) is one of the most widely used advanced glacier drainage models, with implementations in several ice sheet models. Here we present a new version of this model capable of execution on graphics processing units (GPUs) programmed in Julia. The aim is for the model to run on meshes larger than 10,000² grid points, which would allow, for instance, to simulate Antarctica at 500m resolution. Unlike the original GlaDS implementation, this is based on a finite difference scheme on a structured grid. Together with a matrix-free solver, this allows us to leverage the full performance capabilities of GPUs. We present model runs of the SHMIP test cases, show the model's scalability and provide an outlook towards higher-resolution continental-scale applications and inversion schemes.