Goddard Earth Observing System

The Goddard Earth Observing System (GEOS) is an Earth system model and data assimilation system developed at the Global Modeling and Assimilation Office (GMAO) at NASA's Goddard Space Flight Center. The model uses the Earth System Modeling Framework (ESMF), enabling a modular and flexible approach and the investigation of many different aspects of Earth science.

Source: Wikipedia — Goddard Earth Observing System (CC BY-SA 4.0)