BeCoM · Better Contrails Mitigation

Aviation contributes to about 5% of the total anthropogenic climate change when including non-CO2 effects, e.g., contrail formation and the impact of NOx emissions on ozone and methane. Among various non-CO2 effects, the contrail-cirrus radiative forcing is the largest (~2/3) with large uncertainties. The most critical affecting factor is the huge weather-induced variability of the radiative impact of individual contrails. This is the quantity, BeCoM will predict better since the knowledge of the individual radiative forcing is the basis for avoidance of just those contrails that contribute most to the overall climate impact. Once this is standard, it will be possible to formulate adequate mitigation measures and develop policy-driven implementation schemes. BeCoM will address the uncertainties related to the forecasting of persistent contrails and their weather-dependent individual radiative effects. BeCoM focuses on: 1) obtaining a larger and higher resolution database of relative humidity and ice supersaturation at cruise levels for assimilation into numerical weather prediction (NWP) models; 2) providing more adequate representation of ice clouds in their supersaturated environment in the NWP models; and 3) validation of the predictions to determine and reduce the remaining uncertainties of contrail forecasts. To facilitate the assimilation and validation process, BeCoM will develop a novel hybrid artificial intelligence algorithm. Based on the contrail prediction, BeCoM will develop a policy framework for effective contrail avoidance through a trajectory optimization approach. BeCoM will enable a better understanding of contrail’s climate impact and formulate recommendations on how to implement strategies to enable air traffic management to reduce aviation's climate impact. The BeCoM consortium builds on its knowledge and expertise covering a wide spectrum from atmospheric science and climate research to aviation operations research and policy development.