The High Altitude Observatory at the National Center for Atmospheric Research has developed a series of numeric simulation models of the earth's upper atmosphere, including the upper Stratosphere, Mesosphere, and Thermospere. The Thermospheric General Circulation Models (TGCM's) are three-dimensional, time-dependent models of the EARTH's neutral upper atmosphere. The models use a finite differencing technique to obtain a self-consistent solution for the coupled, nonlinear equations of hydrodynamics, thermodynamics, continuity of the neutral gas and for the coupling between the dynamics and the composition.

Recent models in the series include a self-consistent aeronomic scheme for the coupled Thermosphere/Ionosphere system, the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIEGCM), and an extension of the lower boundary from 97 to 30 km, including the physical and chemical processes appropriate for the Mesosphere and upper Stratosphere, the Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Model (TIME-GCM). A global mean, or column model, has also been developed in parallel with the TGCM's. The global mean model is used as a time-dependent, one-dimensional platform from which new chemical, dynamic and numeric schemes are developed and tested before being introduced into the 3-d GCM's.

What's New

June 23, 2008: Announcing the release of TIEGCM version 1.9

Release notes, model source code, post-processors and documentation are available for download (email registration required).

Documentation

User's Guide to the Models and Post-processors (updated June, 2008): [html] [pdf]
Draft TIEGCM Model Description [pdf]

Simulations

Graphics of selected results

Comparisons of TIEGCM (v1-82) with empirical models MSIS, HWM, and IRI
TIEGCM (v1-83) test results including Weimer and Heelis potential models, and IMF data import.

Plot Of The Day:

Nitric Oxide (mmr): ZP=-4, SLT=12, Days 1-180, 2002 (Daily histories)