Properties of In-cirrus Contrails from Airborne Remote-sensing Data

Aviation impacts the Earth's energy balance through non-CO2 effects and emissions of exhaust gases and soot. Planes flying through cirrus clouds can create contrails that might affect the climate effect of these clouds. In this study, we aim to quantify the impact of such embedded contrails based on active remote-sensing observations with the German research aircraft HALO. WALES lidar observations during the ML-CIRRUS campaign indicate that embedded contrails could be identified by a particle backscatter coefficient larger than 4 Mm-1 sr-1 and a particle linear depolarization ratio below 46%. In contrast, cases that don't fulfil these conditions are considered as unperturbed cloud. Identified candidates for embedded contrails are linked to the passage of individual aircrafts for verification. The goal is to detect embedded contrails in WALES observations and to quantify their optical and microphysical characteristics.