The MIGHTI Wind Retrieval Algorithm: Description and Verification

Brian J. Harding, Jonathan J. Makela, Christoph R. Englert, Kenneth D. Marr, John M. Harlander, Scott L. England, Thomas J. Immel

Research output: Contribution to journalReview article

Abstract

We present an algorithm to retrieve thermospheric wind profiles from measurements by the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument on NASA’s Ionospheric Connection Explorer (ICON) mission. MIGHTI measures interferometric limb images of the green and red atomic oxygen emissions at 557.7 nm and 630.0 nm, spanning 90–300 km. The Doppler shift of these emissions represents a remote measurement of the wind at the tangent point of the line of sight. Here we describe the algorithm which uses these images to retrieve altitude profiles of the line-of-sight wind. By combining the measurements from two MIGHTI sensors with perpendicular lines of sight, both components of the vector horizontal wind are retrieved. A comprehensive truth model simulation that is based on TIME-GCM winds and various airglow models is used to determine the accuracy and precision of the MIGHTI data product. Accuracy is limited primarily by spherical asymmetry of the atmosphere over the spatial scale of the limb observation, a fundamental limitation of space-based wind measurements. For 80% of the retrieved wind samples, the accuracy is found to be better than 5.8 m/s (green) and 3.5 m/s (red). As expected, significant errors are found near the day/night boundary and occasionally near the equatorial ionization anomaly, due to significant variations of wind and emission rate along the line of sight. The precision calculation includes pointing uncertainty and shot, read, and dark noise. For average solar minimum conditions, the expected precision meets requirements, ranging from 1.2 to 4.7 m/s.

Original languageEnglish (US)
Pages (from-to)585-600
Number of pages16
JournalSpace Science Reviews
Volume212
Issue number1-2
DOIs
StatePublished - Oct 1 2017

Keywords

  • Interferometry
  • Inverse theory
  • Limb imaging
  • Thermospheric winds

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Harding, B. J., Makela, J. J., Englert, C. R., Marr, K. D., Harlander, J. M., England, S. L., & Immel, T. J. (2017). The MIGHTI Wind Retrieval Algorithm: Description and Verification. Space Science Reviews, 212(1-2), 585-600. https://doi.org/10.1007/s11214-017-0359-3