CESM Models

CESM1.0: Coupler, version 7


The CESM coupled model is based on a framework which divides the complete climate system into component models that are connected by a coupler component. The coupler controls the execution and time evolution of the complete system by synchronizing and controlling the flow of data between the various components. It also communicates interfacial states and fluxes between the various component models while ensuring the conservation of fluxed quantities.



What's New in CESM1.0

The version 7 coupler (cpl7) found in CESM1.0 is basically identical to the coupler in CCSM4. The cpl7 version does have some significant changes compared to CCSM3/cpl6 and previous versions. Component models are no longer implemented as multiple executables running concurrently, but rather as a single executable. The coupler's main program is now the main program for the entire coupled model. As before, the coupler main program coordinates the interaction and time evolution of the component models, but now component models appear as subroutines with standard init, run, and finalize methods. The coupler also has new functionality to arrange that component models run sequentially, concurrently, or in some mixed sequential/concurrent layout. Because it contains this type of control functionality, the main program is also called the driver. As before, the coupler also has functionality to carry out flux calculations, mapping (regridding), diagnostics, and other calculations -- this type of functionality can be run on a subset of the total processors. The name cpl7 refers to the driver functionality as well as this other type of functionality.