NICAM-DC : NICAM dynamical core package

What’s NICAM-DC?

NICAM-DC is the dynamical core package, which is a part of NICAM full model. The development of NICAM with full physics has been co-developed mainly by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Atmosphere and Ocean Research Institute (AORI) at The University of Tokyo, and RIKEN / Advanced Institute for Computational Science (AICS). A reference paper for NICAM is Satoh et al. (2008). See

This distribution package (NICAM-DC) is released for the purpose of widespread use of NICAM. The license is according to BSD 2 Clause. Have lots of fun!

Numerical techniques for NICAM-DC

NICAM-DC is constructed by many original numerical techniques as below. The overview of dynamical core development is summarized in Tomita et al. (2011). You may easily construct a clone of NICAM-DC by reviewing them.

Grid generation and accurate differential operators

Spring dynamics and gravitational center relocation make the default grid be more homogeneous and smoothed. The 2nd order accuracy is guaranteed over the globe. The detailed techniques are described in Tomita et al. (2001, 2002). Recent improvement of grid generation is developed by Iga and Tomita (2014).

Non-hydrostatic scheme

The prognostic variable for thermodynamics is internal energy instead of potential temperature. The conversion between internal energy, potential energy, and kinetic energy is considered by the numerically consistent way. This technique is described in Satoh (2002, 2003).

Prototype of three dimensional dynamical core and benchmark tests

The first NICAM dynamical core was made by techniques of Tomita et al. (2001, 2002) and Satoh (2002, 2003). The detailed description and basic tests are summarized in Tomita and Satoh (2004).

The higher order advection scheme with monotonicity

The 3rd order advection scheme based on conservative semi-Lagrangian like technique was developed by Miura (2007) with the flux limiter proposed by Thuburn (1996). Now. this advection scheme is a default scheme in NICAM-DC.

Satisfaction of Consistency with Continuity

The Consistency With Continuity (CWC) is a necessary constraint for precise advection of tracer. Based on Miura (2007)’ scheme, current NICAM-DC guarantees the CWC. The detailed description appears in Niwa et al. (2011).

Stretched grid

The icosahedral grid is one of homogeneous grids and used for global model. On the other hand, for regional model with seamless grid, the horizontally stretched grid is also available. The Schmidt transformation is enabling for the homogeneous grid to stretch it without any skewness of grid. The stretched grid based on the icosahedral grid by a modified Schmidt transformation is available. See Tomita (2008) for the detail formulation.

Computational performance and parallelization techniques

The computational performance on the vector machine such as Earth Simulator and its comparison with spectral transform model is evaluated in Tomita et al. (2008). For massively parallel computing, mapping the region to nodes is one of key issues for scalability. The special configuration for the torus topology of network is now prepared (Kodama et al., 2013).


  1. Satoh, M., T. Matsuno, H. Tomita, H. Miura, T. Nasuno and S. Iga (2008) : Nonhydrostatic Icosahedral Atmospheric Model (NICAM) for global cloud resolving simulations. J. Comp. Phys., the special issue on Predicting Weather, Climate and Extreme events, 227, 3486-3514.
  2. Tomita, H., M. Satoh, H. Miura and Y. Niwa (2011) : Current status of nonhydrostatic modeling at NICAM. ECMWF Workshop on Non-hydrostatic Modelling, page 171-182, ECMWF.
  3. Tomita, H., M. Tsugawa, M. Satoh, and K. Goto (2001) : Shallow Water Model on a Modified Icosahedral Geodesic Grid by Using Spring Dynamics. J. Comp. Phys., 174, 579-613.
  4. Tomita, H., M. Satoh, and K. Goto (2002) : An Optimization of the Icosahedral Grid Modified by Spring Dynamics. J. Comp. Phys., 183, 307-331.
  5. Iga, S. and H. Tomita (2014) : Improved smoothness and homogeneity of icosahedral grids using the spring dynamics method, J. Comp. Phys., 258, 208-226.
  6. Satoh, M. (2002) : Conservative scheme for the compressible non-hydrostatic models with the horizontally explicit and vertically implicit time integration scheme. Mon. Wea. Rev., 130, 1227-1245
  7. Satoh, M. (2003) : Conservative scheme for a compressible nonhydrostatic model with moist processes. Mon. Wea. Rev., 131, 1033-1050
  8. Tomita, H. and M. Satoh (2004) : A new dynamical framework of nonhydrostatic global model using the icosahedral grid. Fluid Dyn. Res., 34, 357-400.
  9. Miura, H. (2007) : An upwind-biased conservative advection scheme for spherical hexagonal–pentagonal grids. Mon. Wea. Rev., 135, 4038-4044.
  10. Thuburn, J. (1996) : Multidimensional flux-limited advection schemes. J. Comput. Phys. 123, 74-83.
  11. Niwa, Y., H. Tomita, M. Satoh and R. Imasu (2011) : A three-dimensional icosahedral grid advection scheme preserving monotonicity and consistency with continuity for atmospheric tracer transport. J. Meteor. Soc. Japan, 89, 3, 255-268.
  12. Tomita, H. (2008) : A stretched grid on a sphere by new grid transformation. J. Meteorol. Soc. Japan, 86A, 107-119.
  13. Tomita, H., K. Goto, and M. Satoh (2008) : A new approach of atmospheric general circulation model: Global cloud resolving model NICAM and its computational performance. SIAM J. Sci. Comput. 30, 2755-2776.
  14. Kodama, C., M. Terai, A. T. Noda, Y. Yamada, M. Satoh, T. Seiki, S. Iga, H. Yashiro, H. Tomita, K. Minami (2013) : Scalable Rank-Mapping Algorithm for an Icosahedral Grid System on the Massive Parallel Computer with a 3-D Torus Network, Parallel Computing, in revision.