Limited-area GAME (L-GAME)

L-GAME is a numerical weather prediction (NWP) model. It is the application of the theory behind GAME to a regional quadrilateral grid. Properties:

non-hydrostatic
Eulerian
(rotated) latitude-longitude grid
C-grid
uses a hybrid of finite volume and finite difference methods
time stepping: two-time-level predictor-corrector scheme, modified into a HEVI (horizontally explicit, vertically implicit) and forward-backward scheme for stability, horizontal pressure gradient extrapolated and kept constant
radiation: coupled to RTE+RRTMGP
uses the Poisson bracket formulation by Gassmann and Herzog (2008) and Gassmann (2013)
assigns individual mass densities to all tracers and calculates interactions

Installation

It is recommended to run the model on Linux. These installation instructions are tested for Ubuntu, for other Linux distributions they might have to be modified.

Dependencies

Everything is easy and quick to install.

sudo apt-get install gfortran make cmake wget python3-pip libnetcdff-dev

Clone the RTE+RRTMGP repository: git clone https://github.com/earth-system-radiation/rte-rrtmgp

For using the plotting routines

The following packages are additionally required if you want to make use of the plotting routines:

Python visualization library scitools-iris (installation manual: https://scitools-iris.readthedocs.io/en/latest/installing.html#installing-from-source-without-conda-on-debian-based-linux-distros-developers)

Download and compilation

git clone https://github.com/OpenNWP/L-GAME.git
cd L-GAME
./compile.sh -f

Execution

Modify the variable lgame_home_dir in the run scripts (files in the directory run_scripts). Then you can use these files to execute certain model runs, for example:

./run_scripts/schaer.sh

Output will be placed in the directory output.

Fundamental literature

Thuburn, John. (2008). Numerical wave propagation on the hexagonal C-grid. Journal of Computational Physics. 227. 5836-5858. 10.1016/j.jcp.2008.02.010.
Gassmann, Almut & Herzog, Hans-Joachim. (2008). Towards a consistent numerical compressible non‐hydrostatic model using generalized Hamiltonian tools. Quarterly Journal of the Royal Meteorological Society. 134. 1597 - 1613. 10.1002/qj.297.
Thuburn, John et al. “Numerical representation of geostrophic modes on arbitrarily structured C-grids.” J. Comput. Phys. 228 (2009): 8321-8335.
Ringler, Todd & Thuburn, John & Klemp, J. & Skamarock, W.C.. (2010). A unified approach to energy conservation and potential vorticity dynamics on arbitrarily structured C-grids. J. Comput. Physics. 229. 3065-3090. 10.1016/j.jcp.2009.12.007.
Gassmann, A. (2013), A global hexagonal C‐grid non‐hydrostatic dynamical core (ICON‐IAP) designed for energetic consistency. Q.J.R. Meteorol. Soc., 139: 152-175. doi:10.1002/qj.1960

OpenNWP / L-GAME