Ultraviolet plume instrument imaging from the LACE satellite: Analysis of broadband UV auroral limb data

Abstract

Southern auroral limb images have been recorded by the wide‐angle UV camera of the Ultraviolet plume instrument on board the Low‐power Atmospheric Compensation Experiment satellite. Tangent altitudes within each image have been determined using recorded stars along with the known position of the satellite. Range to the observed aurora has been determined by stereoscopic techniques using images of the same auroral forms collected over several seconds. An auroral model has been used in conjunction with simulated annealing techniques to fit two limb profiles taken from a single image. The auroral model provides altitude profiles of volume emission for the relevant features based on electron transport calculations starting with a user‐specified precipitating electron spectrum. Volume emission is then distributed within the observing region, followed by line‐of‐sight integration producing limb profiles. The fitting procedure provides distributions of the energy characteristics of the aurora over the relevant observing region. The results of the fitting process suggest that a quantitative description of the aurora has been achieved in terms of the most probable precipitating electron spectral characteristics and the spatial distribution of this precipitation.

<title>Recent progress in UV remote sensing</title>

“…The same group also has an imager on the Freja satellite, launched in October, 1992, and results are being reported, Lundin, eta!., 1994. A broadband look at the aurora! limb in the mid UV using the UVPI instrument on the LACE satellite has been reported, Evans, et a!., 1994. A sounding rocket study of the aura, called ARIA I, has also used a FTJV spectrometer to help analyze the aurora!…”