Reply to Bogdan et al.: “Cubic ice” in cirrus clouds under dry and wet conditions

Abstract

Bogdan et al. (1) discuss the relevance of surface roughness of vapor-deposited so-called “ice Ic” discovered in ref. 2 for ice crystals formed at low temperatures in cirrus clouds. The authors emphasize that for ice nucleation from solute aerosol droplets, the initial ice crystal is coated by residual freeze-concentrated solutions, and they provide images from laboratory freezing experiments on large H2SO4 and NH4-sulfate solution droplets.