One of the options of the GEOS- 5 GCM is the GEOS- 5 Chemistry Transport Model ( GEOS- 5 CTM), which is an offline simulation of chemistry and constituent transport driven by a specified meteorology and other model output fields. The Goddard Earth Observing System version 5 ( GEOS- 5) General Circulation Model (GCM) makes use of the Earth System Modeling Framework (ESMF) to enable model configurations with many functions. GEOS- 5 Chemistry Transport Model User's Guide
