Numerical simulations of contrail-to-cirrus transition – Part 1: An extensive parametric study
Other literature type
(issn: 1680-7324, eissn: 1680-7324)
Simulations of contrail-to-cirrus transition over up to 6 h were performed
using a LES-model. The sensitivity of microphysical, optical and geometric
contrail properties to relative humidity RH<sub><i>i</i></sub>, temperature <i>T</i> and
vertical wind shear <i>s</i> was investigated in an extensive parametric study.
The dominant parameter for contrail evolution is relative humidity.
Substantial spreading is only visible for RH<sub><i>i</i></sub>≳120%. Vertical
wind shear has a smaller effect on optical properties than human observers
might expect from the visual impression. Our model shows that after a few
hours the water vapour removed by falling ice crystals from the contrail
layer can be several times higher than the ice mass that is actually present
in the contrail at any instance.