A new automatic method for estimating the peak auroral emission height from all-sky camera images

This paper presents a new fully automatic method for quickly finding the average peak emission height of an auroral structure from a pair of all-sky camera images with overlapping fields of view. The peak emission height of the aurora must be estimated in order to calculate several other important parameters, such as horizontal spatial scales, optical flow velocities, and ionospheric electric fields. In most cases the height is not measured, but a value is assumed, often about 110 km. It is unclear how accurate this assumption is. A future statistical study of the auroral height in which the method presented here will be applied to many years of observations will lead to more accurate assumptions of the height with quantitative error estimates, and therefore more accurate estimates of parameters derived using these assumed auroral heights. In the present work the performance of the new method is compared to another recent automatic method. It is found that the new method is more suitable for a statistical study, although it would be advantageous to apply both methods to each pair of images. On average the new method produces the correct result, unlike the other recent method, but the new method is less consistent.