Systematically migrating an operational microphysics parameterisation to FPGA technology
James Stanley Targett, Wayne W. Luk, Michael Lange, Olivier Marsden · 2021
Efficient utilisation of computational resources is one of the critical challenges in Numerical Weather Prediction (NWP) due to tight time constraints and the complexity of the numerical models. Enabling hardware acceleration is therefore of vital interest to the weather and climate modelling community. In this paper, we describe a systematic process to migrate physical parameterisations from sequential code for CPU execution into FPGA designs; a set of conditions that the code must be able to satisfy for the process to be suitable (Single Pass Exclusive Mutability of Current Cell); and describe the steps required to automate the process. We showcase the migration of a cloud microphysics parameterisation which forms a significant portion of the runtime in operational weather models, and show that the design produces results using an order of magnitude less energy than CPU and GPU implementations while achieving significantly higher throughput. We show that when incorporated inside a larger NWP system, a further throughput increase by a factor of five is possible.