The Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM)

The NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) is a series of numeric simulation models of the Earth's upper atmosphere, including the upper Stratosphere, Mesosphere, and Thermosphere, from ~100 to ~500 km altitude. TIE-GCM are three-dimensional, time-dependent models of the Earth's neutral upper atmosphere.

Winds and temperature at 300 km altitude simulation image
Winds and temperature at 300 km altitude simulated by the NCAR TIE-GCM v. 2.0, during the ramp-up to a geomagnetic storm

TIE-GCM is based on a long history of model development initiated by Ray Roble, Bob Dickinson, and Cicely Ridley, and carried on by Art Richmond, Ben Foster, and the Geospace section of the NCAR High Altitude Observatory (HAO). The entire section has been involved in its public release as an open-source community model, and in the recent development and release of TIE-GCM v. 2.0. The new version supports higher resolution (2.5° horizontal), extends to higher altitude, uses parallel computations for the electrodynamics, and produces a more accurate description of ionospheric structure. It is used by researchers in the University community and worldwide. Making the code stable, fixing problems, documenting, and enabling installation on a variety of platforms from supercomputers to laptops, has been a major endeavor during the last several years, culminating in official release in March 2016 (see This work is the basis for new development of a thermosphere-ionosphere capability in the NCAR Whole Atmosphere Community Climate Model - eXtended (WACCM-X). The next step for ionosphere modeling is to fully couple the ionosphere to the entire atmosphere, using the WACCM-X platform, thus making it a component of the Community Earth System Model. This will enable studies of the weather and climate in near-Earth space as it responds to the complex interactions between solar events and atmospheric variability.