Exploring the Interaction between Aircraft Emissions and Cirrus Clouds: Through Simulation Techniques and Satellite retrievals

Aviation outflow is the only anthropogenic source of pollution that is directly emitted into the upper troposphere and potentially alters cloud patterns by creating linear contrails. These contrail cirrus formations can either increase high-cloud cover in supersaturated, cloud-free air or modify the microphysics of existing natural cirrus clouds. Despite the likelihood of aircraft intersecting natural cirrus, the extent of their impact remains uncertain.

Our study interests using the ICON_NWP model, integrated with a two-moment cloud microphysical scheme, to simulate contrail formation and dynamics. Central to this research is examining how aviation aerosols and emitted water vapor influence contrail development within already existing cirrus clouds.

The number of surviving nucleated ice crystals after the jet phase depends on engine and fuel parameters as well as on the ambient atmosphere (Kärcher et al 2015) and displays large regional variation (Bier & Burkhardt, 2019).  Bier and Burkhardt (2022) demonstrated that the concentration of ice crystals after the jet phase varies, ranging in terms of ice particle concentrations from 160 to 200 cm-3 over the North Pacific.

We assume a suggestive fixed-wing span of 50 meters, typical of aircrafts such as Airbus 300 and Boeing 737, correlating to a water vapor emission rate of 10 g per meter of flight. In our simulations, contrail formation is initiated at 450 seconds, marking the end of the vortex phase. Beyond this point, the remaining ice crystals are predominantly influenced by atmospheric conditions. Within each grid box, our initial step involves assessing the critical contrail temperature according to the Schmidt-Appleman criterion. Depending on whether these criteria are met, we then proceed to either introduce ice crystals or add the corresponding amount of water vapor.

Ultimately, we compare our simulation results with corresponding aircraft data, utilizing the DARDAR-NICE dataset that offers height-resolved measurements within cirrus clouds, to validate the imprints of aircraft emissions.