Understanding the history of complex ice crystal habits deduced from a
holographic imager
Abstract
The sizes and shapes of ice crystals influence the radiative properties
of clouds, as well as precipitation initiation and aerosol scavenging.
However, ice crystal growth mechanisms remain only partially
characterized. We present the growth processes of two complex ice
crystal habits observed in Arctic mixed-phase clouds during the NASCENT
campaign. First, are capped-columns with multiple columns growing out of
the plates’ corners that we define as columns on capped-columns (CCC).
These ice crystals originated from cycling through the columnar and
plate temperature growth regimes, during their vertical transport by
in-cloud circulation. Second, is aged rime on the surface of ice
crystals having grown into faceted columns or plates depending on the
environmental conditions. Despite their complexity, the shapes of these
ice crystals allow to infer their growth history and provide information
about the in-cloud conditions. Additionally, these ice crystals exhibit
complex shapes and could enhance aggregation and secondary ice
production.