On the colour of noctilucent clouds

Abstract. The high-latitude phenomenon of noctilucent clouds (NLCs) is characterised by a silvery-blue or pale blue colour. In this study, we employ the radiative transfer model SCIATRAN to simulate spectra solar radiation scattered NLCs for ground-based observer and assuming spherical NLC particles. To determine resulting colours in an objective way, CIE (International Commission on Illumination) colour-matching functions chromaticity values are used. Different processes parameters potentially affecting colour investigated, i.e. size particles, abundance middle atmospheric O3 importance multiply radiation. We affirm previous research indicating that absorption Chappuis bands can have significant effect NLCs. A new result study sufficiently large optical depths specific viewing geometries, plays only minor role blueish simulations also show particles affects clouds. Cloud unrealistically sizes lead reddish Furthermore, contribution multiple scattering total importance, providing additional justification earlier studies topic, which were all based single-scattering approximation.