Demonstrating the capability of instrumental synergy to characterize contrails at the SIRTA observatory in Paris

As part of the Climaviation project, which is funded by the French Direction Générale de l’Aviation Civile (DGAC) aiming to quantify the non-CO2 effect of civil aviation in the warming climate, this study aims to characterise the optical, macro and microphysical properties of contrails at the SIRTA observatory in Palaiseau, France. To detect contrail occurrence over the site, a co-localised instrumental synergy comprising the IPRAL Lidar (a multi-longwave lidar), a total sky camera, Sentinel-2 satellite data, and aircraft flight altitudes is used. The particular integration method is applied to the lidar backscatter coefficient to estimate the optical depth of contrails after their geometrical characteristics (base height and thickness) have been defined. The optical depth estimated with this method is validated using a CIMEL sun-photometer. The Trappes radiosoundings are used to characterise the atmospheric conditions in with the contrails form. The colour ratio and the volume and particle depolarisation ratios from the analog and photo counting signals are used to qualitatively estimate the crystal size distributions within the contrails. An analysis of ten identified contrails observed on 5 July 2019, will be presented.