CESM Models

CCSM4: Notable Improvements

Atmosphere

1. New treatments of cloud and ice-phase processes;
2. Improved representation of the interactions among water vapor, solar radiation, and terrestrial thermal radiation;
3. New treatment of the effects of aerosols, including prognostic sulfate, on the reflection and absorption of solar radiation; and
4. New dynamical frameworks suitable for modeling atmospheric chemistry.

Coupler

1. Improved performance and scalability on parallel supercomputers;
2. Faster multi-way communication among the component models; and
3. New communications infrastructure.

Land

1. New methods to enable simulation of the terrestrial carbon cycle;
2. New methods to enable simulation of dynamic vegetation; and
3. Improvements in land-surface physics to reduce temperature biases; and
4. New load balancing implementation results in substantial performance improvement.

Ocean

1. Improvements to the representation of the ocean mixed layer;
2. Inclusion of solar heating by chlorophyll; and
3. New infrastructure for studying vertical mixing in the ocean.

Sea-ice

1. New advanced sea ice rheology;
2. Explicit ice-thickness distribution physics;
3. Explicit treatment of brine pockets; and
4. Improved scheme for horizontal advection of sea ice.

Complete System

1. New portability for vector and Linux supercomputers;
2. New, easy-to-use methods to run IPCC climate-change experiments;
3. Flexibility to simulate climate over a wide range of spatial resolutions with greater fidelity; and
4. New built-in test facilities suitable for validating installation and verifying some types of model changes.