Comment on “Empirical relationship between electron precipitation and far-ultraviolet auroral emissions from DMSP observations” by Sotirelis et al.

[1] Sotirelis et al. (2013), which reported on comparisons of Defense Meteorological Satellite Program (DMSP) F16 Special Sensor Ultraviolet Spectrographic Imager (SSUSI) Lyman-Birge-Hopfield short and long (LBHS and LBHL) far ultraviolet (FUV) radiances with Special Sensor J/5 (SSJ/5) in situ particle fluxes, overlooked comparable comparisons of observations made by the same two instruments reported in Knight et al. (2008, 2012). The results are compared, and it is found that the statistical ratio of SSUSI LBHL to SSJ/5 electron energy flux reported by Soterelis et al. is a factor of ~2 greater than would be expected based on Knight et al. (2008, 2012). This difference is mainly caused by a SSUSI calibration change.