This computation involved: April 2008 experimental version of the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) deployed on Oak Ridge Leadership Computing Facility's (OLCF) 'Jaguar' system Cray XT5 supercomputer. The April 2008 experimental version of the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) was used to generate the 20th Century Reanalysis (Version 2) Project reanalysis dataset.

For the production of the reanalysis data from the 20th Century Reanalysis (Version 2) Project the April 2008 experimental version of the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) on the US Department of Energy's massively parallel system at the National Energy Research Scientific Computing Center.

For specific details of the complete suite of physical parameterisations used in the model runs refer to the citation given in the "Documentation and Links to Further Information and References section".

The Twentieth Century Reanalysis Project used resources of the National Energy Research Scientific Computing Center managed by Lawrence Berkeley National Laboratory and of the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory, which are supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and Contract No. DE-AC05-00OR22725, respectively. Support for the Twentieth Century Reanalysis Project dataset is provided by the U.S. Department of Energy, Office of Science Innovative and Novel Computational Impact on Theory and Experiment (DOE INCITE) program, and Office of Biological and Environmental Research (BER), and by the National Oceanic and Atmospheric Administration Climate Program Office.

The Oak Ridge Leadership Computing Facility's (OLCF) 'Jaguar' Cray XT5 supercomputer system delivers 2.33 petaflop/s (peak) of parallel processing compute with access to 326 terabytes of high-speed memory.

The Oak Ridge Leadership Computing Facility (OLCF), part of the US National Center for Computational Sciences, brought its 'Jaguar' system Cray XT5 supercomputer online in 2009, providing access to 2.33 Petaflops/s peak processing power to the research community.

The 'Jaguar' system Cray XT5 supercomputer consists of an 84 cabinet quad-core Cray XT4 system and 200 upgraded Cray XT5 cabinets, using six-core processors. The XT4 has 8 gigabytes of memory per node while the XT5 has 16 gigabytes per node, giving the users a total of 362 terabytes of high-speed memory in the combined system. The two systems are connected to the Scalable I/O Network (SION), which links them together and to the Spider file system. The XT5 system has 256 service and I/O nodes providing up to 240 gigabytes per second of bandwidth to SION and 200 gigabits per second to external networks. The XT4 has 116 service and I/O nodes providing 44 gigabytes per second of bandwidth to SION and 100 gigabits per second to external networks.