A parallel implementation of the confined–unconfined aquifer system model for subglacial hydrology: design, verification, and performance analysis (CUAS-MPI v0.1.0)

Abstract. The subglacial hydrological system affects (i) the motion of ice sheets through sliding, (ii) location lakes at margin, and (iii) ocean circulation by freshwater discharge directly grounding line or (iv) via rivers flowing over land. For modeling this hydrology system, a previously developed porous-media concept called confined–unconfined aquifer (CUAS) is used. To allow for realistic simulations sheet scale, we CUAS-MPI, an MPI-parallel C/C++ implementation CUAS (MPI: Message Passing Interface), which employs Portable, Extensible Toolkit Scientific Computation (PETSc) infrastructure handling grids equation systems. We validate accuracy numerical results comparing them with set analytical solutions to model equations, involve two types boundary conditions. then investigate scaling behavior CUAS-MPI show that scales up 3840 MPI processes running Greenland setup on Lichtenberg HPC system. Our measurements also reaches throughput comparable simulations, e.g., Ice-sheet Sea-level System Model (ISSM). Lastly, discuss opportunities modeling, explore future coupling possibilities other consider bottlenecks limits further scaling.