Preparing NASA Global Modeling and Assimilation Systems for Future HPC Applications/Arhitectures

The Global Modeling and Assimilation Office (GMAO) at NASA's Goddard Space Flight Center maintains a near-realtime operational analysis and forecast model, and regularly produces retrospective reanalyses of the satellite era (post 1979). As with other operational centers, our software must continually prepare for the demands of future assimilation systems and computing environments. One aspect of this preparation is to adapt our codes to run on new technologies, such as GPUs and MICs, even though they are not yet available to our operational systems. Another aspect is to run early versions of our most advanced systems on current platforms, but at resolutions currently not affordable for operational work. We present our experience in both aspects of this development strategy, with an emphasis on our attempts to run a 1.5-km GEOS-5 global atmospheric model (a circa 2030 deterministic forecast system) on today's computing architectures. We conclude with an assessment of the future of observation driven modeling at NASA.