Gravity wave dynamics influencing ice clouds

Gravity waves (GWs) have a significant influence on the formation,
microphysical properties, and life cycle of ice clouds. However,
understanding how to accurately account for the complex interactions
between GWs and ice physics in atmospheric models remains a
challenge. For instance, some ice nucleation parameterizations
consider only the strong vertical updraft velocities generated by GWs,
which lead to high ice crystal number concentrations. However,
temperature and pressure fluctuations associated with GWs can locally
produce high supersaturation levels, triggering ice crystal nucleation
even when the large-scale saturation ratio is below the critical
threshold or in region where GW vertical velocity is zero.

In this study, we present a testbed for coupling transient GW dynamics
with ice physics used for the development of corresponding
parameterizations. We utilize a model capable of operating in two
modes: one that resolves both wave dynamics and nucleation explicitly,
and another that parameterizes those processes. To test our coupling
strategy, we perform idealized experiments involving the superposition
of wave packets passing through an ice-supersaturated region. We
evaluate the resulting microphysical properties of ice clouds and
cloud cover fraction in different simulations. Our findings suggest
that this approach can be successfully implemented in climate models
equipped with transient GW parameterization.