This User's Guide accompanies the CCSM4 User's Guide, and is intended
for those who would like to run CICE coupled, on a supported
platform, and "out of the box". Users running CICE fully coupled should first
look at the CCSM4 User's Guide:
http://www.cesm.ucar.edu/models/ccsm4.0/ccsm_doc/book1.html.
http://www.cesm.ucar.edu/models/ccsm4.0/ccsm_doc/book1.html.
It includes a quick start guide for downloading the CCSM4 source code and input datasets, and information on how to configure, build and run the model. The supported configurations and scripts for building the fully coupled model are also described in the CCSM4 User's Guide. The CICE User's Guide is intended for users interested in making modifications to the ice model scripts or namelists or running the uncoupled ice model. Users interested in modifying the source code should see the CICE Code Reference/ Developer's Guide.
CICE4 is the latest version of the Los Alamos Sea Ice Model, sometimes
referred to as the Community Ice CodE. It is the
result of a community effort to develop a portable, efficient sea ice model
that can be run coupled in a global climate model or uncoupled as a stand-alone
ice model. It has been released as the sea ice component of the Community
Climate System Model (CCSM), a fully-coupled global climate model that
provides simulations of the earths past, present and future climate states.
CICE4 is supported on high- and low-resolution Greenland Pole
and tripole grids, which are identical to those used by the Parallel Ocean
Program (POP) ocean model. The high resolution version is best suited for
simulating present-day and future climate scenarios while the low resolution
option is used for paleoclimate simulations and debugging. An uncoupled
version of CICE is available separately from Los Alamos National Laboratory:
http://oceans11.lanl.gov/trac/CICE.
http://oceans11.lanl.gov/trac/CICE.
It provides a means of running the sea ice model independent of the other CCSM components. It reads in atmospheric and ocean forcing, which eliminates the need for the flux coupler, and the atmosphere, land and ocean data models. It can be run on a reduced number of processors, or without MPI (Message Passing Interface) for researchers without access to these computer resources.
The physics in the uncoupled ice model are identical to those in the ice model used in the fully coupled system. CICE is a dynamic-thermodynamic model that includes a subgrid-scale ice thickness distribution ((Bitz et al.(2001)); (Lipscomb(2001))). It uses the energy conserving thermodynamics of (Bitz and Lipscomb(1999)), has multiple layers in each thickness category, and accounts for the influences of brine pockets within the ice cover. The ice dynamics utilizes the elastic-viscous-plastic (EVP) rheology of (Hunke and Dukowicz(1997)). Sea ice ridging follows (Rothrock(1975)) and (Thorndike et al.(1975)). A slab ocean mixed layer model is included. A Scientific Reference is available that contains more detailed information on the model physics.
An attempt has been made throughout this document to provide the following text convention. Variable names used in the code are typewritten. Subroutine names are given in italic, and file names are in boldface.