The researchers set a speed performance record for a U.S. weather model running on the Cray XT4 "Franklin" supercomputer at the Department of Energy's National Energy Research Computing Center (NERSC) at Lawrence Berkeley National Laboratory. Running on 12,090 processors of this 100 peak teraflops system, they achieved the important milestone of 8.8 teraflops - the fastest performance of a weather or climate-related application on a U.S. supercomputer, the group said. One teraflops is one trillion, or a thousand billion, calculations per second. It would take a person operating a hand-held calculator more than 30,000 years to complete one trillion calculations.
The team also set a record for "parallelism," or harnessing many computer processors to work together to solve a large scientific problem, running on 15,360 processors of the 103 peak teraflops IBM Blue Gene/L supercomputer at Brookhaven National Laboratory, jointly operated by Brookhaven and Stony Brook University, the group said in a statement.
The input data to initialize the run was more than 200 gigabytes, and the code generates 40 gigabytes each time it writes output data, the group said.
For the highly detailed weather simulations, a team of researchers from the National Center for Atmospheric Research (NCAR), the San Diego Supercomputer Center (SDSC) at UC San Diego, Lawrence Livermore National Laboratory (LLNL), and IBM Watson Research Center used the sophisticated Weather Research and Forecast (WRF) model, widely used for weather forecasting by government, military, and commercial forecasters.
With this power the researchers were able to create "virtual weather" on a detailed 5 kilometer horizontal grid covering one hemisphere of the globe, with 100 vertical levels, for a total of some two billion cells - 32 times larger and requiring 80 times more computational power than previous simulation models using the WRF code, the group said. Weather simulations of greatly enhanced resolution and size will serve as a key benchmark for improving operational forecasts and basic understanding of weather and climate prediction, the group said.
Team members include John Michalakes, Josh Hacker, and Rich Loft of NCAR; Michael McCracken, Allan Snavely, and Nick Wright of SDSC; Tom Spelce and Brent Gorda of Lawrence Livermore; and Robert Walkup of IBM. The research is supported by the National Science Foundation and the Department of Energy.