Noctilucent clouds and polar mesospheric summer echoes are both manifestations of ice particles near the summer polar mesopause. These ice particles are believed to form mainly on pre-existing ice condensation nuclei. The characteristics and especially the concentrations of such nuclei have been considered important factors in determining ice properties. But to what extent is this true?

Results from Megner (2011) suggest that the observable mesospheric ice properties are fairly independent of the condensation nuclei characteristics. These results have been questioned by Wilms et al (2015) who do observe a sensitivity. I here compare the two studies with the aim to determine under which conditions the two seemingly opposing conclusions apply.