The Community Earth System Model (CESM) is a fully coupled, global climate model that provides state-of-the-art computer simulations of the Earth's past, present, and future climate states. Please post your question to the most appropriate forum topic.
This forum is for technical and scientific questions related to the simpler model configurations within CESM, such as aquaplanet, dynamical core, SCAM etc
http://www.cesm.ucar.edu/models/simpler-models/The Community Terrestrial Systems Model and river runoff models including the Community Land Model (CLM5.0 and CLM4.5), RTM and MOSART of the Community Earth System Model. Descriptions and details are available at https://www.cesm.ucar.edu/models/cesm2/land/ and https://www.cesm.ucar.edu/models/cesm2/river
This forum is also for help with CTSM in other atmosphere models, such as WRF via LILAC