The effect of the 135.6 nm emission originated from the ionosphere on the TIMED/GUVI O/N₂ ratio

AMS Citation:
Kil, H., W. -chau Lee, J. Shim, L. J. Paxton, and Y. Zhang, 2013: The effect of the 135.6 nm emission originated from the ionosphere on the TIMED/GUVI O/N₂ ratio. Journal of Geophysical Research-Space Physics, 118, 859-865, doi:10.1029/2012JA018112.
Date:2013-02-01
Resource Type:article
Title:The effect of the 135.6 nm emission originated from the ionosphere on the TIMED/GUVI O/N₂ ratio
Abstract: The column number density ratio of atomic oxygen to molecular nitrogen (O/N₂ ratio) provided by the Global Ultraviolet Imager (GUVI) onboard the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) satellite has been used as a diagnostic of the thermospheric neutral composition. However, a recent study claimed that the GUVI O/N2 ratio is not a pure thermospheric parameter in low latitudes during periods of low geomagnetic activity. This study quantifies the O/N₂ ratio contamination by the ionosphere using the GUVI observations and model ionosphere acquired from 31 August to 2 September 2002. During this period, the local time of the GUVI observation was near 1500 and the average Kp index was 2°. The 135.6 nm emission originated from the ionosphere is estimated using the electron density profiles provided by the Utah State University-Global Assimilation of Ionospheric Measurements model. Our results show that the 135.6 nm emission originated from the equatorial ionization anomaly (EIA) contributes 5-10% to the total 135.6 nm intensity and O/N₂ ratio. The EIA feature and longitudinal wave patterns in the GUVI 135.6 nm intensity maps are identified above an altitude of 300km and show a good agreement with those in the F region plasma density. However, the EIA feature and longitudinal wave patterns do not appear in the GUVI 135.6 nm intensity maps below an altitude of 300km and in the GUVI N₂ Lyman-Birge-Hopfield band intensity maps in any altitude. These observations indicate that the longitudinal wave patterns in the GUVI O/N₂ ratio represent the ionospheric phenomenon.
Peer Review:Refereed
Copyright Information:Copyright 2013 American Geophysical Union.
OpenSky citable URL: ark:/85065/d78s4qrm
Publisher's Version: 10.1029/2012JA018112
Author(s):
  • H. Kil
  • Wen-chau Lee - NCAR/UCAR
  • J. Shim
  • L. Paxton
  • Y. Zhang
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