ASTRA - Atmospheric & Space Technology Research Associates, LLC


Global first-principles fully-coupled ionosphere-thermosphere models have been developed to encapsulate our existing knowledge of atmospheric processes and coupling between the ionosphere and thermosphere. These models fulfill three critical roles:

  • Provide a framework within which to place and analyze atmospheric measurements
  • Provide a laboratory in which to perform numerical experiments
  • Postprocessors provide the ability to unravel the relative importance of different atmospheric processes which can be used to understand the fundamental physics.

ASTRA’s world class modeling capabilities include such a model; the Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (TIME-GCM). The model predicts global 3-D temperature, density, composition and wind fields for the neutral gas, as well as ionospheric electron density and ion distributions from 30 km to about 600 km altitude. The TIME-GCM is the latest in a series of GCMs, which were initially developed at the National Center for Atmospheric Research (NCAR) [Roble and Ridley, 1994]. Dr. Crowley led a team that ported the TIME-GCM code to a workstation environment, and parallelized it [Crowley et al., 1999; Freitas and Crowley, 1999].

The inputs to the TIME-GCM include specifications of the solar flux, the high latitude convection and the particle precipitation, as well as the tides propagating up from the lower atmosphere.

The ability to specify the model inputs makes the TIME-GCM extremely flexible. It can be used for numerical experiments and sensitivity studies, in which the inputs are varied in a simple well-defined manner. However, ASTRA strives to advance the TIME-GCM’s capabilities beyond traditional numerical experiments to the modeling of real “space weather” events in the thermosphere and ionosphere using the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) model. Links to some sample results can be seen below and several others can be seen in Data Analysis .

ASTRA regularly provides collaborators and interested parties with TIME-GCM results. For more information, please feel free to contact us.

Examples of ASTRA’s TIME-GCM capabilities:

Numerical Experiments:

1. Effects of High Latitude Forcing on the Thermosphere
2. Effect of IMF BY on Thermospheric Composition at High and Middle latitudes

Space Weather Events:
3. Response of the Thermosphere and Ionosphere to November 2003 magnetic storm
4. Response of the Thermosphere to the November 2004 magnetic storm
5. GRACE Neutral Density