UV limb‐scatter spectra of noctilucent clouds consistent with mono‐modal particle size distribution

Abstract

Limb‐backscatter spectra of noctilucent clouds (NLCs) are retrieved from limb measurements made with the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) on the Envisat satellite. The spectral dependence of many hundred sun‐normalized NLC spectra measured during the 2005 NLC season in the northern hemisphere can be well approximated with a power‐law in the 240–300 nm spectral range. In particular, no spectral signatures indicative of the presence of a second particle mode at radii exceeding 200 nm are found, in contradiction to recent studies. The results presented are consistent with a mono‐modal NLC particle size distribution.