WarmWorld - “Hail Mary” Collaborative Project - Subproject 1: Development of the ICON model for global simulations on hectometer scales through performance-portable software, reduced memory requirements, and a new grid and software infrastructure
Hail Mary is developing the technical foundations to enable, for the first time, global simulations using the ICON model with a horizontal resolution down to the hectometer scale. The goals are simulations with a grid spacing of up to approximately 150 m over time periods ranging from days to weeks. This is intended to open up a new modeling domain in which important processes of cloud and convective dynamics can be represented more explicitly and their interactions with large-scale circulation can be investigated.
To this end, ICON is undergoing a fundamental modernization. Key model components are being ported from Fortran/OpenACC to a performance-portable C++/Kokkos implementation. At the same time, memory requirements are being significantly reduced through lower numerical precision and improved memory management. New libraries for grid and nesting management eliminate existing infrastructural limitations for extremely large model grids. In addition, the build, test, and CI/CD infrastructure is being modernized. These developments not only enable hectometer-scale simulations but also increase ICON’s efficiency, portability, and maintainability at coarser resolutions, thereby making it available for broader climate and Earth system modeling.
