Development of a Simple Coupler (Scup) for Earth System Modeling
Papers in Meteorology and Geophysics
We have developed a simple general-purpose coupler "Scup" (Simple coupler) which is usable in earth system modeling with flexible coupling among component models, such as atmosphere and ocean general circulation models and chemical transport models. Scup provides sufficient functions required for efficient development of the earth system model at Meteorological Research Institute (MRI), and its fundamental design is also applicable for other earth system models. Each process of the component
... of the component models communicates with each other directly by calling the Scup library, which is necessary for efficiently exchanging a large amount of grid data among the processes of the component models. Scup supports grid transformation for three-dimensional data in addition to that for two-dimensional data with accurate local and global conservation, which is necessary for coupling component models with different coordinates or grids. Simplicity and easiness to use are the strong points of Scup. All the source 2 code of Scup is described in Fortran and can be compiled on various platforms with a Fortran 95 compiler and MPI (Message Passive Interface) library, which contributes to good portability of Scup. 1. Introduction An earth system model has been developed at Meteorological Research Institute (MRI) as a next generation model for climate change projection. The earth system model should represent interactions among climate system components, for example, atmosphere, land, ocean and sea ice, and their subsystem components, such as atmospheric chemical processes and biogeochemical processes. To represent their interactions, field variables and fluxes must be exchanged among the component models. Since each component model is developed as an independent program, a coupler is needed to exchange the variables and fluxes with keeping the independency of each component model in the earth system model. A coupler should include following functions for general purposes: Exchange of data among the component models; Management of data to be exchanged; Operations on data, such as time average and spatial interpolation. There are several general-purpose open-source couplers with these functions, for example, OASIS3 (Valcke et. al.