GOLD Mission Eclipse Observations: Comparison with Obscuration Conditions.

The Global Observation of Limb and Disk (GOLD) mission has shown significant daytime composition changes in the thermospheric composition, in terms of column O/N2 ratio, during eclipses. However, questions have been raised if the assumptions made for daytime O/N2 derivation hold during solar eclipse conditions. One potential issue is the relative change in X-ray and EUV spectra incident on the Earth at eclipsed locations because the harder energy portion of the spectra is relatively less blocked within the eclipse shadow. Additionally, any active region on the solar surface could also cause relative change in solar spectra during partially eclipsed condition. In this study, we compare the GOLD observation of OI 135.6 nm and N2 LBH brightnesses, both of which are used for O/N2 derivation, with Eclipse Obscuration Factor (EOF) maps based on actual solar observations at wavelengths of interest. This comparison takes a step to establish the accuracy of GOLD O/N2 derived using current algorithms.