A New Approach for Coupled Regional Climate Modeling Using More than 10,000 Cores

  • Marcus Thatcher
  • John McGregor
  • Martin Dix
  • Jack Katzfey
Conference paper
Part of the IFIP Advances in Information and Communication Technology book series (IFIPAICT, volume 448)


This paper describes an alternative method for coupling atmosphere-ocean regional climate models that communicates momentum, radiation, heat and moisture fluxes between the atmosphere and ocean every time-step, while scaling to more than 10,000 cores. The approach is based on the reversibly staggered grid, which possesses excellent dispersive properties for modeling the geophysical fluid dynamics of both the atmosphere and the ocean. Since a common reversibly staggered grid can be used for both atmosphere and ocean models, we can eliminate the coupling overhead associated with message passing and improve simulation timings. We have constructed a prototype of a reversibly staggered, atmosphere-ocean coupled regional climate model based on the Conformal Cubic Atmospheric Model, which employs a global variable resolution cube-based grid to model the regional climate without lateral boundary conditions. With some optimization, the single precision, semi-implicit, semi-Lagrangian prototype model achieved 5 simulation years per day at a global 13 km resolution using 13,824 cores. This result is competitive with state-of-the-art Global Climate Models than can use more than 100,000 cores for comparable timings, making CCAM well suited for regional modeling.


geophysical fluid dynamics MPI regional climate modeling 


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Copyright information

© IFIP International Federation for Information Processing 2015

Authors and Affiliations

  • Marcus Thatcher
    • 1
  • John McGregor
    • 1
  • Martin Dix
    • 1
  • Jack Katzfey
    • 1
  1. 1.CSIRO Ocean and Atmosphere FlagshipMelbourneAustralia

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