P36     IBM GRAF: A rapidly-updating global NWP system.

Hutchinson, Todd, Brett Wilt, James Cipriani, John Wong, Ken Dixon,
The Weather Company, an IBM Business, Rich Loft, Bill Skamarock, and Michael Duda, National Center for Atmospheric Research

The Weather Company (TWC), an IBM Business, is nearing release of a global weather prediction system that will run at convective-allowing scales over large parts of the world.  The system, referred to as IBM GRAF (Global high-Resolution Atmospheric Forecast System), will be driven by MPAS for the NWP and the Gridpoint Statistical Interpolation (GSI) software for the data assimilation.  GSI will be used to assimilate a variety of observations, including, conventional (METARs, SYNOPs, cell-phone pressures, radiosondes), and radar.  MPAS will integrate the GSI analyses forward in time to provide rapidly-updating global forecasts for the day ahead time period.  Horizontal resolution will vary from 3km over 30-40% of the world to 15km over the rest of the world. 

TWC, IBM Research, and NCAR have partnered to develop a GPU-accelerated software port of MPAS and to integrate this port into a future MPAS release.  The Weather Company will run MPAS operationally on a cluster of IBM Power9 systems containing a total of 296 nVidia GPUs.  As of April 2019, MPAS is running nearly 3x faster on one nVidia Volta 100 GPU as compared to 2 Intel Broadwell CPUs.  Further details on GPU performance will be provided at the Workshop.