SCALE-RM is a regional atmospheric model using the SCALE library.

Brief Description


  • The three-dimensional (3D) Cartesian grid system based on actual distance
  • 2D domain decomposition by Message Passing Interface (MPI) communication
  • Several map projections commonly used
  • Domain nesting system ( one-way, i.e., data transfer from parent domain to child domain. )
    • On-line nesting: concurrent execution of multiple domains).
    • Offline nesting: execution of computation in an inner domain after that in an outer domain.
  • Collective execution system of multiple cases, i.e., bulk job system
  • netCDF file I/O based on CF (Climate and Forecast) convention
    • Selection of netCDF 3 and netCDF 4 formats
  • Generation of initial data for an ideal experiment
  • Generation of topographical and land-use data, converted from external data
  • Generation of initial and boundary data from external data
    • Supporting inputs from the WRF-ARW and GrADS formats.

Dynamical core

  • Grid system : Arakawa-C type
  • Governing equations: 3D fully compressible non-hydrostatic equations
  • Spatial descretization: finite volume method
    • 2nd-, 4th-, and 6th-order central differences
    • 3rd- and 5th-order upwind differences
  • Time integration: selection from the “fully explicit method” or the “horizontally explicit and vertically implicit methods”
    • Heun-type 3rd-order RungeKutta scheme
    • Wicker and Skamarock (2002)’s 3-step RungeKutta scheme
    • 4th-order RungeKutta scheme
  • Guarantee of non-negative value:
    • Flux corrected transport method (Zalesak, 1979)
    • Koren (1993)’s filter: available only with the use of the 3rd-order upwind scheme
  • Numerical filter: 4th-order hyper-viscosity and diffusion
  • Topography: expressed using terrain-following coordinates

Physical processes

  • Turbulence process: selectable from among the following
    • Smagorinsky (1963) & Lilly (1962)-type sub-grid model corrected by Brown et al. (1994) and Scotti et al. (1993)
    • Deardorff (1980) sub-grid model
    • MYNN level 2.5 boundary scheme (Mellor and Yamada 1982; Nakanishi and Niino 2004, 2009)
  • Cloud microphysics: selectable from among the following
    • 3-class 1 moment bulk scheme (Kessler 1969)
    • 6-class 1 moment bulk scheme (Tomita 2008)
    • 6-class 2 moment bulk scheme (Seiki and Nakajima 2014)
    • spectral bin scheme (Suzuki et al. 2010)
  • Radiation process
    • a k-distribution-based broadband radiation transfer model (Sekiguchi and Nakajima 2008)
  • Land model: heat diffusion/bucket model
  • Ocean model: selectable from among the following
    • fixed to initial condition
    • input from external data
    • slab model
  • Urban model: a single-layer canopy model (Kusaka et al. 2001)
  • Surface models
    • The bulk method using the universal function (Beljaars and Holtslag 1991; Wilson 2001; Nishizawa and Kitamura 2018)
    • Louis-type bulk method (Uno et al. 1995)


The description for SCALE-RM is available at SCALE Document page