Abstract
The Global-scale Observations of the Limb and Disk (GOLD) mission data
contain significant quantitative information about the aurora on a
global scale. Here we present techniques for quantifying such
information, including the temporal development of the structure within
the auroral oval using the GOLD images. These techniques are applied to
auroral observations in the GOLD data, in particular showing an example
of how the longitudinal structure within the aurora varies over the
course of six consecutive days with differing levels of geomagnetic
activity. A simple model of the solar-induced airglow is presented that
is used to remove the sunlight contamination from the dayside auroral
observations. Comparisons to ground-based auroral imaging are used for
the overall auroral context and to make estimates of the proportionality
between the intensities of the green-line (557.7 nm) emission in the
visible and the 135.6 nm emissions in the GOLD data. These observations
are consistent with the intensity of the 135.6 nm auroral emission being
on the same order as the intensity of the 557.7 nm auroral emission.
They were both found to be around 1 kR for a stable auroral arc on a day
with low geomagnetic activity (03 November 2018) and around 10 kR for an
active auroral display on a day with higher levels of geomagnetic
activity (05 November 2018). This could have important implications for
making direct comparisons between space-based UV auroral imaging and
ground-based visible-light auroral imaging and the total energy input
estimates that are derived from them.