Simulating contrail formation within cirrus in the high-resolution ICON-LEM model

Abstract

Contrail ice formation in ice supersaturated region and their impact on climate is often studied. However, contrail ice formation within cirrus and their impact on cirrus cloud properties are overlooked therefore, their climate impact is unknown. Contrail formation within natural cirrus can introduce a large perturbation in ice crystal numbers modifying the microphysical and optical properties of the natural cirrus. Therefore, in this thesis work, the impact of contrail ice formation within cirrus on cirrus properties is analysed. In order to study contrail formation within cirrus a high-resolution ICON-LEM (ICOsahedral Non-hydrostatic- Large eddy simulation model) at a horizontal resolution of 625m is used. A parameterization for contrail formation within cirrus is implemented and modified to include the impact of pre-existing cirrus on contrail ice formation. The presented work provides insights into the effect of pre-existing cirrus on contrail ice formation within cirrus and the effect of contrail formation within cirrus on cirrus microphysical and optical properties