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The Thermospheric General Circulation Models (TGCM's)

Announcing Release of TIEGCM v3.0: TIEGCM 3.0 Principle Paper



Introduction

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 Thermosphere. 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.

For an introduction to the TIEGCM Community Model, and several examples of upper atmosphere research using this model, please see Astrid Maute's presentation to students at the 2013 CEDAR Workshop and Stan Solomon's presentation at the the 2016 CEDAR workshop. Also see Haonan Wu’s tutorial at the 2024 CEDAR student day workshop.

Notice

Updated IGRF: The public release of TIEGCM v2.0 doesn't produce correct results after 2015 due to the incorrect IGRF coefficients. If you would like to perform TIEGCM v2.0 simulations after 2015, please replace the apex.F90 code under the src/ directory with the updated one (https://github.com/NCAR/tiegcm/blob/master/src/apex.F90) in the TIEGCM v3.0 code repository (https://github.com/NCAR/tiegcm). Or directly use TIEGCM v3.0 for all simulations after 2015.

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References:

The TIE-GCM and related models are developed at the NCAR High Altitude Observatory by Ray Roble and colleagues, with support from the National Science Foundation and NASA. Some of the primary references are given below.

  • Dickinson, R. E., E. C. Ridley and R. G. Roble, A three-dimensional general circulation model of the thermosphere, J. Geophys. Res., 86, 1499-1512, 1981.
  • Dickinson, R. E., E. C. Ridley and R. G. Roble, Thermospheric general circulation with coupled dynamics and composition, J. Atmos. Sci., 41, 205-219, 1984.
  • Roble, R. G., and E. C. Ridley, An auroral model for the NCAR thermospheric general circulation model (TGCM), Annales Geophys., 5A, 369-382, 1987.
  • Roble, R. G., E. C. Ridley and R. E. Dickinson, On the global mean structure of the thermosphere, J. Geophys. Res., 92, 8745-8758, 1987.
  • Roble, R. G., E. C. Ridley, A. D. Richmond and R. E. Dickinson, A coupled thermosphere/ionosphere general circulation model, Geophys. Res. Lett., 15, 1325-1328, 1988.
  • Richmond, A. D., E. C. Ridley and R. G. Roble, A Thermosphere/Ionosphere General Circulation Model with coupled electrodynamics, Geophys. Res. Lett., 19, 601-604, 1992.
  • Roble, R. G., and E. C. Ridley, A thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM): equinox solar cycle minimum simulations (30-500 km), Geophys. Res. Lett., 21, 417-420, 1994.
  • Roble, R. G., Energetics of the mesosphere and thermosphere, AGU, Geophysical Monographs, eds. R. M. Johnson and T. L. Killeen, 87, 1-22, 1995.
  • Wang, W., M. Wiltberger, A. G. Burns, S. Solomon, T. L. Killeen, N. Maruyama, and J. Lyon, Initial results from the CISM coupled magnetosphere-ionosphere-thermosphere (CMIT) model: thermosphere ionosphere responses, J. Atmos. Sol.-Terr. Phys., 66, 1425-1442, doi:10.1016/j.jastp.2004.04.008, 2004.
  • Solomon, S. C., and L. Y. Qian, Solar extreme-ultraviolet irradiance for general circulation models, J. Geophys. Res., 110, A10306, doi:10.1029/2005JA011160, 2005.
  • Lei, J., J. P. Thayer, W. Wang, X. Luan, X. Dou, and R. Roble (2012), Simulations of the equatorial thermosphere anomaly: Physical mechanisms for crest formation, J. Geophys. Res., 117, A06318, https://doi.org/10.1029/2012JA017613
  • Wang, W., E. R. Talaat, A. G. Burns, B. Emery, S. Hsieh, J. Lei, and J. Xu (2012), Thermosphere and ionosphere response to subauroral polarization streams (SAPS): Model simulations, J. Geophys. Res., 117, A07301, https://doi.org/10.1029/2012JA017656
  • Qian, L., A. G. Burns, B. A. Emery, B. Foster, G. Lu, A. Maute, A. D. Richmond, R. G. Roble, S. C. Solomon, and W. Wangm, The NCAR TIE-GCM: A community model of the coupled thermosphere/ionosphere system, in Modeling the Ionosphere-Thermosphere System, AGU Geophysical Monograph Series, 2014.
  • Sutton, E. K., J. P. Thayer, W. Wang, S. C. Solomon, X. Liu, and B. T. Foster (2015), A self-consistent model of helium in the thermosphere, J. Geophys. Res. Space Physics, 120, 6884–6900, https://doi.org/10.1002/2015JA021223
  • Liu, J., W. Wang, M. Oppenheim, Y. Dimant, M. Wiltberger, and S. Merkin (2016), Anomalous electron heating effects on the E region ionosphere in TIEGCM, Geophys. Res. Lett., 43, 2351–2358, https://doi.org/10.1002/2016GL068010
  • Dang, T., Lei, J., Wang, W., Zhang, B., Burns, A., Le, H., et al. (2018). Global responses of the coupled thermosphere and ionosphere system to the August 2017 Great American Solar Eclipse. Journal of Geophysical Research: Space Physics, 123, 7040–7050. https://doi.org/10.1029/2018JA025566
  • Jones, M. Jr., Drob, D. P., Siskind, D. E., McCormack, J. P., Maute, A., McDonald, S. E., & Dymond, K. F. (2018). Evaluating different techniques for constraining lower atmospheric variability in an upper atmosphere general circulation model: A case study during the 2010 sudden stratospheric warming. Journal of Advances in Modeling Earth Systems, 10, 3076–3102. https://doi.org/10.1029/2018MS001440
  • Lei, J., Dang, T., Wang, W., Burns, A., Zhang, B., & Le, H. (2018). Long-lasting response of the global thermosphere and ionosphere to the 21 August 2017 solar eclipse. Journal of Geophysical Research: Space Physics, 123, 4309–4316. https://doi.org/10.1029/2018JA025460
  • Maute, A. Thermosphere-Ionosphere-Electrodynamics General Circulation Model for the Ionospheric Connection Explorer: TIEGCM-ICON. Space Sci Rev 212, 523–551 (2017). https://doi.org/10.1007/s11214-017-0330-3
  • Dang, T., Zhang, B., Lei, J., Wang, W., Burns, A., Liu, H., Pham, K., and Sorathia, K. A.: Azimuthal averaging–reconstruction filtering techniques for finite-difference general circulation models in spherical geometry, Geosci. Model Dev., 14, 859–873, https://doi.org/10.5194/gmd-14-859-2021, 2021
  • Lin, D., Sorathia, K., Wang, W., Merkin, V., Bao, S., Pham, K., et al. (2021). The role of diffuse electron precipitation in the formation of subauroral polarization streams. Journal of Geophysical Research: Space Physics, 126, e2021JA029792. https://doi.org/10.1029/2021JA029792
  • Cai, Y., Yue, X., Wang, W., Zhang, S.-R., Liu, H., Lin, D., et al. (2022). Altitude extension of the NCAR-TIEGCM (TIEGCM-X) and evaluation. Space Weather, 20, e2022SW003227. https://doi.org/10.1029/2022SW003227
  • Pham, K. H., Zhang, B., Sorathia, K., Dang, T., Wang, W., Merkin, V., et al. (2022). Thermospheric density perturbations produced by traveling atmospheric disturbances during August 2005 storm. Journal of Geophysical Research: Space Physics, 127, e2021JA030071. https://doi.org/10.1029/2021JA030071
  • Wu, H., Lu, X., Wang, W., & Liu, H.-L. (2023). Simulation of the propagation and effects of gravity waves generated by Tonga volcano eruption in the thermosphere and ionosphere using nested-grid TIEGCM. Journal of Geophysical Research: Space Physics, 128, e2023JA031354. https://doi.org/10.1029/2023JA031354
  • Lu, X., & Wu, H. (2025). Evaluating nudging techniques in implementing the lower atmosphere variability induced by tides and gravity waves into the TIEGCM. Journal of Geophysical Research: Space Physics, 130, e2024JA033517. https://doi.org/10.1029/2024JA033517
  • Wu, H., Wang, W., Pham, K. H., Lin, D., Rao, N., Wiltberger, M. J., et al. (2025). The NCAR-TIEGCM Version 3.0. Journal of Geophysical Research: Space Physics, 130, e2025JA034219. https://doi.org/10.1029/2025JA034219