“…The MLT ice particles in summer reveal sizes of tens of nanometers to 100 nm diameter (e.g., Berger and von Zahn, 2002;Bailey et al, 2015) and consist of water ice. In winter the sizes of MSPs are significantly smaller, i.e., up to some nanometers (e.g., Strelnikova et al, 2007;Kero et al, 2008;La Hoz and Havnes, 2008;Belova et al, 2008;Havnes and Kassa, 2009;Fentzke et al, 2009;Robertson et al, 2014;Rapp et al, 2010Rapp et al, , 2012Strelnikov et al, 2012). Hence, in winter Sc will be much smaller as it is connected to the radius by Sc ∼ r 2 (Lübken et al, 1998, and Sect.…”