Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.585 IF 1.585
  • IF 5-year value: 1.698 IF 5-year
    1.698
  • CiteScore value: 1.62 CiteScore
    1.62
  • SNIP value: 0.820 SNIP 0.820
  • IPP value: 1.52 IPP 1.52
  • SJR value: 0.781 SJR 0.781
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 83 Scimago H
    index 83
  • h5-index value: 24 h5-index 24
Volume 22, issue 2
Ann. Geophys., 22, 441–452, 2004
https://doi.org/10.5194/angeo-22-441-2004
© Author(s) 2004. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 22, 441–452, 2004
https://doi.org/10.5194/angeo-22-441-2004
© Author(s) 2004. This work is distributed under
the Creative Commons Attribution 3.0 License.

  01 Jan 2004

01 Jan 2004

Variations of thermospheric composition according to AE-C data and CTIP modelling

H. Rishbeth1, R. A. Heelis2, and I. C. F. Müller-Wodarg4,3 H. Rishbeth et al.
  • 1School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
  • 2William B. Hanson Center for Space Sciences, The University of Texas at Dallas, P. O. Box 830688, Richardson, Texas 75083-0588, USA
  • 3Atmospheric Physics Laboratory, University College London, 67-73 Riding House Street, London W1W 7EJ, UK
  • 4now at: Space and Atmospheric Lab, Imperial College London, Prince Consort Road, London SW7 2BW, UK

Abstract. Data from the Atmospheric Explorer C satellite, taken at middle and low latitudes in 1975-1978, are used to study latitudinal and month-by-month variations of thermospheric composition. The parameter used is the "compositional Ρ-parameter", related to the neutral atomic oxygen/molecular nitrogen concentration ratio. The midlatitude data show strong winter maxima of the atomic/molecular ratio, which account for the "seasonal anomaly" of the ionospheric F2-layer. When the AE-C data are compared with the empirical MSIS model and the computational CTIP ionosphere-thermosphere model, broadly similar features are found, but the AE-C data give a more molecular thermosphere than do the models, especially CTIP. In particular, CTIP badly overestimates the winter/summer change of composition, more so in the south than in the north. The semiannual variations at the equator and in southern latitudes, shown by CTIP and MSIS, appear more weakly in the AE-C data. Magnetic activity produces a more molecular thermosphere at high latitudes, and at mid-latitudes in summer.

Key words. Atmospheric composition and structure (thermosphere – composition and chemistry)

Publications Copernicus
Download
Citation