High-performance computing for climate change impact studies with the Pasture Simulation model

• We simulate grassland processes over large areas for climate change impact studies.
• We parallelize simulations with pixel-based Pasture Simulation model (PaSim).
• We perform simulations with 8 × 8 km resolution for metropolitan France (∼10,000 pixels).
• We report 25 h (speedup of 200) for the simulation on a 200-processor cluster.

High-performance computing technology permits to efficiently achieve high-performance throughputs for intensive CPU load applications. We describe the development of an integrated tool for climate change impact studies on grassland ecosystems running with pixel-wise data. The pixel-based Pasture Simulation model (PaSim) is suited to work with a NetCDF format of input and output files. It includes the parallel job launcher, which dispatches individual jobs to execute simulations. In a case study covering metropolitan France, we demonstrate how this approach is configured and used to evaluate the impact of climate change on grassland productivity. Over ∼10,000 pixels of 8 × 8 km resolution, we report ∼25 h to complete the simulation on a cluster machine (TITANE) with 200 processors, which is a speedup of 200.