Explicit habit-prediction in the Lagrangian super-particle ice
microphysics model McSnow
Abstract
The Monte-Carlo ice microphysics model McSnow is extended by an explicit
habit prediction scheme, combined with the hydrodynamic theory of
\citeauthor{Boehm1992a}.
\citeauthor{Boehm1992a}’s original cylindrical shape
assumption for prolates is compared against recent lab results, showing
that interpolation between cylinder and prolate yields the best
agreement.
For constant temperature and supersaturation, the predicted mass, size,
and density agree well with the laboratory results, and a comparison
with real clouds using the polarizability ratio shows regimes capable of
improvement.
An updated form of the inherent growth function to describe the primary
habit growth tendencies is proposed and combined with a habit-dependent
ventilation coefficient.
The modifications contrast the results from general mass size relations
and significantly impact the main ice microphysical processes. Depending
on the thermodynamic regime, ice habits significantly alter depositional
growth and affect aggregation and riming.