[P-EM09] Vertical coupling in the atmosphere and Ionosphere

[PEM09-08] Observations of the Thermosphere and Ionosphere by the NASA GOLD Mission

★Invited Papers

*Stanley C Solomon¹, Alan G. Burns¹, Richard W. Eastes², William E. McClintock² (1.National Center for Atmospheric Research, 2.University of Colorado)

Keywords:Thermosphere, Ionosphere, Ultraviolet Imaging

The new Global-scale Observations of the Limb and Disk (GOLD) mission is an imaging spectrograph deployed in geostationary orbit on the SES-14 communications satellite. GOLD measures airglow emitted by the Earth in the far-ultraviolet region of the spectrum from 132 to 164 nm, notably including the 135.6 nm doublet of atomic oxygen (O), and most of the LBH bands of molecular nitrogen (N₂). During the day, the ratios of the oxygen to nitrogen emissions indicate the relative column densities of O and N₂, and temperature can be inferred from the spectral shape of the LBH bands. During the night, radiative recombination emissions by the O doublet indicate the density of the ionosphere, particularly the equatorial ionization anomalies and the structured instabilities that form within them. GOLD also measures exospheric temperatures on the limb, it infers molecular oxygen densities from stellar occultations, and it can also see northern hemisphere aurora. SES-14 was launched in January 2018, the satellite achieved geostationary orbit in, and GOLD observations commenced in October. We will give an overview of the GOLD mission and show preliminary results from its first months of operations. Despite the recent quiet conditions with low solar activity, composition images reveal daily and seasonal variations, indicative of global vertical wind patterns. The equatorial ionization anomalies are seen to be surprisingly variable and dynamic, with instabilities forming on most nights, even at solar minimum. We will compare GOLD results with global general circulation models and airglow emissions modeling, and discuss how these data could be used in assimilation models of the upper atmosphere and ionosphere.