Ionospheric characterization from SSULI OII 83.4 nm dayglow measurements during the ascending phase of solar activity
Abstract
We present an analysis of the OII 83.4 nm airglow measurements made to-date by the Special Sensor Ultraviolet Limb Imager (SSULI) on the Defense Meteorological Satellite Program (DMSP) F18 satellite. SSULI has been making measurements since early 2010, providing an ongoing monitor of this airglow feature as solar activity climbs from the last minimum toward the upcoming maximum. The 83.4 nm emission is created in the lower thermosphere by solar photoionization of atomic oxygen atoms and the subsequent transition of the resulting excited ions back to their ground state. The 83.4 nm photons given off in this process undergo multiple resonant scattering by O+ in the ionosphere before they reach the SSULI sensor. Thus the observed intensity reflects a combination of changes in the characteristics of the ion density profile and solar ionizing flux. While individual 83.4 nm altitude profiles can be inverted to produce ion density profiles, the lack of knowledge about the ionization source term can introduce a bias to the results. A broader compilation of this extensive SSULI data set provides a unique visualization of the relative variability in this daytime airglow emission over the changing phase of solar activity. We will discuss the patterns observed in this emission, inferences that can be made about ionospheric change driven by solar activity, as well as the utility of such a data set for identifying and correcting biases in the inversion of individual profiles to improve the accuracy of ionospheric retrievals.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMSA11A2125S
- Keywords:
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- 0310 ATMOSPHERIC COMPOSITION AND STRUCTURE / Airglow and aurora;
- 2494 IONOSPHERE / Instruments and techniques;
- 7999 SPACE WEATHER / General or miscellaneous