Contrail formation in mid-latitudes: Estimating the climate effect of contrails with climate change functions in EMAC using a Lagrangian approach.

Aviation has long been linked to environmental problems, including pollution, noise, and climate change. Although CO2 emissions are the primary focus of public discussion, non-CO2 emissions from aviation, such as contrails, nitrogen oxides, or cloud cover caused by aviation, can have comparable impacts on the climate. Previous studies have investigated the impact of different weather conditions on aviation and identified regions that are sensitive to climate change. They have also created data products, such as 4-dimensional climate change functions (CCFs), which enable air traffic management (ATM) to plan for climate-optimized trajectories. However, these functions were only derived for specific regions, seasons, and weather situations 1,2. The presented research focuses on developing methods to determine the sensitivity of the atmosphere to aviation emissions in relation to climate effects. This is necessary to describe spatially and temporally dependent distributions, which are required to determine climate-optimized aircraft trajectories. While previous studies have focused on characterizing the North Atlantic Flight Corridor region 2, this study aims to extend the geographic scope by performing Lagrangian simulations for the extratropical regions of the northern hemisphere. The modular global climate model EMAC was used in this study to investigate contrail evolution on Lagrangian trajectories. The study analyzed the effects of contrails on the temporal evolution of key contrail formation parameters along these trajectories, as well as their effects on radiation in terms of the radiative forcing concept. With this comprehensive model, we can investigate the physical processes that determine the effects of contrails on climate and study their spatial and temporal variations. The project leading to this study was funded by the European SESAR programme under Grant Agreement No. 101114785 (CONCERTO). High performance supercomputing resources were used from the German CARA Cluster in Dresden and the DKRZ Cluster in Hamburg. References: 1 Matthes, S., Lhrs, B., Dahlmann, K., Grewe, V., Linke, F., Yin, F., Klingaman, E. and Shine, K. P.: Climate-Optimized Trajectories and Robust Mitigation Potential: Flying ATM4E, Aerospace 7(11), 156, 2020. 2 Frmming, C., Grewe, V., Brinkop, S., Jckel, P., Haslerud, A. S., Rosanka, S., van Manen, J., and Matthes, S.: Influence of weather situation on non-CO2 aviation climate effects: the REACT4C climate change functions, Atmos. Chem. Phys., 21, 91519172, https://doi.org/10.5194/acp-21-9151-2021, 2021.