Skip to main content
Log in

Daytime Ionosphere Retrieval Algorithm for the Ionospheric Connection Explorer (ICON)

  • Published:
Space Science Reviews Aims and scope Submit manuscript


The NASA Ionospheric Connection Explorer Extreme Ultraviolet spectrograph, ICON EUV, will measure altitude profiles of the daytime extreme-ultraviolet (EUV) OII emission near 83.4 and 61.7 nm that are used to determine density profiles and state parameters of the ionosphere. This paper describes the algorithm concept and approach to inverting these measured OII emission profiles to derive the associated \(\mathrm{O}^{+}\) density profile from 150–450 km as a proxy for the electron content in the F-region of the ionosphere. The algorithm incorporates a bias evaluation and feedback step, developed at the U.S. Naval Research Laboratory using data from the Special Sensor Ultraviolet Limb Imager (SSULI) and the Remote Atmospheric and Ionospheric Detection System (RAIDS) missions, that is able to effectively mitigate the effects of systematic instrument calibration errors and inaccuracies in the original photon source within the forward model. Results are presented from end-to-end simulations that convolved simulated airglow profiles with the expected instrument measurement response to produce profiles that were inverted with the algorithm to return data products for comparison to truth. Simulations of measurements over a representative ICON orbit show the algorithm is able to reproduce hmF2 values to better than 5 km accuracy, and NmF2 to better than 12% accuracy over a 12-second integration, and demonstrate that the ICON EUV instrument and daytime ionosphere algorithm can meet the ICON science objectives which require 20 km vertical resolution in hmF2 and 18% precision in NmF2.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3

Similar content being viewed by others


  • D. Bilitza, International Reference Ionosphere 2000. Radio Sci. 36(2), 261–275 (2001). doi:10.1029/2000RS002432

    Article  ADS  Google Scholar 

  • D. Bilitza, B.W. Reinisch, International Reference Ionosphere 2007: improvements and new parameters. Adv. Space Res. 42, 599–609 (2008). doi:10.1016/j.asr.2007.07.048

    Article  ADS  Google Scholar 

  • P.D. Feldman, D.E. Anderson Jr., R.R. Meier, E.P. Gentieu, The ultraviolet dayglow. IV: The spectrum and excitation of singly ionized oxygen. J. Geophys. Res. 86(A5), 3583–3588 (1981). doi:10.1029/JA086iA05p03583

    Article  ADS  Google Scholar 

  • H.E. Hinteregger, K. Fukui, B.R. Gilson, Observational, reference and model data on solar EUV from measurements on AE-E. Geophys. Res. Lett. 8, 1147–1150 (1981). doi:10.1029/GL008i011p01147

    Article  ADS  Google Scholar 

  • T. Holstein, Imprisonment of resonance radiation in gases. Phys. Rev. 72, 1212–1233 (1947). doi:10.1103/PhysRev.72.1212

    Article  ADS  MATH  Google Scholar 

  • T.J. Immel et al., The Ionospheric Connection Explorer Mission: mission goals and design. Space Sci. Rev. (2017, this issue)

  • W.C. Martin, V. Kaufman, A. Musgrove, A compilation of energy levels and wavelengths for the spectrum of singly-ionized oxygen (OII). J. Phys. Chem. Ref. Data 22, 1179 (1993). doi:10.1063/1.555928

    Article  ADS  Google Scholar 

  • R.P. McCoy, D.E. Anderson Jr., S. Chakrabarti, \(\mathrm{F}_{2}\) region ion densities from analysis of \(\mathrm {O} ^{+} 834-\mathrm{A}\) airglow: a parametric study and comparisons with satellite data. J. Geophys. Res. 90(A12), 12257 (1985). doi:10.1029/JA090iA12p12257

    Article  ADS  Google Scholar 

  • R. Meier, The scattering rate of solar 834 Å radiation by magnetospheric \(\mathrm{O}^{+}\) and \(\mathrm{O}^{++}\). Geophys. Res. Lett. 17(10), 1613–1616 (1990). doi:10.1029/GL017i010p01613

    Article  ADS  Google Scholar 

  • R.R. Meier, J.M. Picone, Retrieval of absolute thermospheric concentrations from the far UV dayglow: an application of discrete inverse theory. J. Geophys. Res. 99(A4), 6307–6320 (1994). doi:10.1029/93JA02775

    Article  ADS  Google Scholar 

  • R.R. Meier et al., Remote sensing of Earth’s limb by TIMED/GUVI: retrieval of thermospheric composition and temperature. Earth Space Sci. 2, 1–37 (2015). doi:10.1002/2014EA000035

    Article  ADS  Google Scholar 

  • J.M. Picone, Influence of systematic error on least squares retrieval of upper atmospheric parameters from the ultraviolet airglow. J. Geophys. Res. 113, A09306 (2008). doi:10.1029/2007JA012831

    Article  ADS  Google Scholar 

  • J. Picone, R. Meier, O. Kelley, D. Melendez-Alvira, K. Dymond, R. McCoy, M. Buonsanto, Discrete inverse theory for 834-Å ionospheric remote sensing. Radio Sci. 32(5), 1973–1984 (1997a). doi:10.1029/97RS01028

    Article  ADS  Google Scholar 

  • J. Picone, R. Meier, O. Kelley, K. Dymond, R. Thomas, D. Melendez-Alvira, R. McCoy, Investigation of ionospheric of remote sensing using the 834-Å airglow. J. Geophys. Res. 102(A2), 2441–2456 (1997b). doi:10.1029/96JA03314

    Article  ADS  Google Scholar 

  • M.M. Sirk et al., Design and performance of the ICON EUV spectrograph. Space Sci. Rev. (2017). doi:10.1007/s11214-017-0384-2

    Google Scholar 

  • A.W. Stephan, Advances in remote sensing of the daytime ionosphere with EUV airglow. J. Geophys. Res. Space Phys. 121, 9284–9292 (2016). doi:10.1002/2016JA022629

    Article  ADS  Google Scholar 

  • A.W. Stephan, J.M. Picone, S.A. Budzien, R.L. Bishop, A.B. Christensen, J.H. Hecht, Measurement and application of the O II 61.7 nm dayglow. J. Geophys. Res. 117, A01316 (2012). doi:10.1029/2011JA016897

    Article  ADS  Google Scholar 

  • D.E. Strickland, J. Bishop, J.S. Evans, T. Majeed, P.M. Shen, R.J. Cox, R. Link, R.E. Huffman, Atmospheric Ultraviolet Radiance Integrated Code (AURIC): theory, software architecture, inputs, and selected results. J. Quant. Spectrosc. Radiat. Transf. 62(6), 689–742 (1999). doi:10.1016/S0022-4073(98)00098-3

    Article  ADS  Google Scholar 

Download references


ICON is supported by NASA’s Explorers Program through contracts NNG12FA45C and NNG12FA42I. We acknowledge the input and feedback from the entire ICON team. AWS acknowledges the many contributions and productive discussions with J. Michael Picone, Kenneth F. Dymond, Robert R. Meier, and Douglas Drob.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Andrew W. Stephan.

Additional information

The Ionospheric Connection Explorer (ICON) mission

Edited by Doug Rowland and Thomas J. Immel

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Stephan, A.W., Korpela, E.J., Sirk, M.M. et al. Daytime Ionosphere Retrieval Algorithm for the Ionospheric Connection Explorer (ICON). Space Sci Rev 212, 645–654 (2017).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: