WRF benchmark for regional applications

Despite parallelisation, scalable performance of WRF is often not achieved. Although the WRFV3 Parallel Benchmark Page provides valuable scaling information, this one-domain configuration is often not typical of the general application of WRF to nested domains of varying sizes and shapes. This study is a first step in providing a centralised WRF performance repository for a variety of typical configurations and environments that might be found in general NWP environments. Here, a real-world scenario that comes close to the ones used in regional climate studies in complex topographical areas is evaluated. The performance of WRF V3.2.1 is analysed in several multi-nest configurations varying vertical levels and parameterisations and tested for scalability on different platforms. Initial insight shows that multi-nest configurations make realization of desired scalabilities more difficult. In many real-world cases, the outer nest has substantially fewer grid points than the inner nests, and this can be problematic in that large-scale domain decomposition of the inner nests where the great majority of computations take place is limited by “over-decomposition” of the outer nest.