Valentina Schüller is presenting her midway report for the PhD degree in Computational Science, with opponent Paul Kuberry (Sandia National Laboratories).

The seminar consists of a 20 minute talk presenting the midway report, followed by a scientific discussion moderated by the opponent.

Title: Waveform Relaxation for Coupled Environmental Problems

Abstract:

In environmental and climate science, simulations are a central tool to improve our understanding of the Earth system and guide decision-making. We consider two applications, namely surface-subsurface flow for hydrological simulations and atmosphere-ice-ocean coupling in climate models. In both cases, it is common to use separate codes for distinctly modeled physics components, which are coupled to determine the evolution of the full system. The goal of this thesis project is to develop novel coupling algorithms for these applications that reduce numerical errors while being energy-efficient.

We view surface-subsurface and atmosphere-ice-ocean coupling through the theoretical lens of domain decomposition and waveform relaxation methods. This framework provides analysis tools with which we study simplified, linearized models for the applications at hand. The analysis is not considered in isolation, but in relation to numerical results obtained with production(-like) codes: a surface-subsurface flow solver based on the DUNE-FEM and preCICE libraries, as well as the EC-Earth coupled atmospere-ocean single column model. The talk presents this methodological approach, select research results, and implications for model development. It concludes with a brief overview of three subprojects planned for the second half of the thesis project.