Better Contrails Mitigation

Project Information

BeCoM

Grant agreement ID: 101056885

DOI

10.3030/101056885

Project closed

EC signature date 4 May 2022

Start date 1 June 2022

End date 31 May 2026

Funded under

• Climate, Energy and Mobility

Total cost

€ 4 457 338,75

EU contribution

€ 4 457 334,00

Coordinated by

TECHNISCHE UNIVERSITEIT DELFT
Netherlands

Periodic Reporting for period 2 - BeCoM (Better Contrails Mitigation)

Reporting period: 2023-12-01 to 2025-05-31

Summary of the context and overall objectives of the project

Civil aviation contributes to ~4% of the total anthropogenic radiative forcing, including the effects from CO2, NOx, water vapor and persistent contrails/contrail cirrus. The climate impact of contrails is significant and large uncertainties exist due to sparse relative humidity measurements at cruise levels and modeling inadequacies. Furthermore, one most critical aspect, which limits the projections of aviation’s climate impact, is the vast weather-induced variability of the radiative effect of individual contrails. This is the quantity, BeCoM will predict better since the knowledge of the individual radiative forcing is the basis for avoiding just those contrails that dominant the overall climate impact. Once this is accurate, BeCoM will formulate adequate mitigation measures and develop policy-driven implementation schemes for non-CO2 emissions/climate effects. The goal of BeCoM is to largely reduce or eliminate the global mean contrail radiative forcing, hence a substantial reduction of aviation’s global warming effects to be achievable on a much shorter time horizon.
BeCoM comprises six specific objectives:
• Objective O1: enhance the routine measurements of atmospheric humidity at the cruise altitude.
• Objective O2: improve the treatment of ice supersaturation conditions in numerical weather prediction models.
• Objective O3: develop appropriate AI algorithms for data assimilation, contrail detection, contrails classification, and uncertainties of contrail prediction (WP3).
• Objective O4: minimize overall cost when implementing climate optimized trajectories.
• Objective O5: develop non-CO2-based measures to be applied for ATM strategies for climate impact mitigation.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The work performance and main achievements in the reporting period 2 are summarized as below corresponding to the project objectives described above:
1) Water vapor measurements:
• The first water vapor measurement campaign has been successful conducted to obtain the water vapor profile at the upper troposphere.
• Lidar measurements are calibrated via comparison with M10 radiosondes (GRUAN) and ERA5.
• The outcome is published in a journal publication of Alraddawi et al., 2025.
2) Numerical weather prediction model improvements:
• Technical realisation using three different data assimilation methods (classical, AI/ML – and ensemble based) to use satellite-borne cloud measurements and direct camera images finished and a first assimilation cycle was successfully carried out using all three methods.
• The quality of IAGOS humidity observations has been investigated using the local DA system of DWD. Corresponding investigations using the global DA system have been started.
• The investigation of quality and use of operational aircraft humidity measurements (AMDAR WSVII system) of the U.S and Europe have been started using the global DA system of DWD
• A redesign of the super saturation formulation within the DQ system and the ICON model has been started.
3) Data collection for AI algorithm development:
• Two annotated datasets for machine learning were identified.
• Contrail detection algorithms over Europe using domain adaptation were developed.
• A method to identify the minimum annotated dataset size for robust algorithm evaluation was created.
4) Minimize cost impact when implementing climate optimized trajectories:
• The analysis on weather pattern predicted by a climate model EMAC over the North Atlantic Flight Corridor shows the dependency of contrail avoidance on different winter weather types, mainly driven by the jet stream.
• A subset of European flight plans was used to perform flight trajectory optimization considering contrail distance versus fuel burn. Analysis is ongoing on the contrail avoidance potential when considering different fuel burn increases.
5) Non-CO2 based market measures for flight optimization:
• The focus of the current reporting period is to assess the effectiveness of the policy-driven flight planning approach regarding climate impact mitigation potential and feasibility based on the algorithmic cost functions for climate changes incorporating non-CO2 effects.
• The methodology for integrating non-CO2 effects into flight planning was finalized (T5.2 in M24, Deliverable D5.1).
• Currently the assessment of the policy driven flight planning approach is ongoing and is expected to be finalized in M46 with Deliverable 5.2.
• One publication has been submitted on the non-CO2 pricing concept and is under review.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

• The exploration of assimilating different datasets, e.g. IAGOS humidity measurements or satellite images, will improve the predictivity of the humidity forecast at cruise altitude, which is critical to contrail formation condition.
• The new concept of a one-moment ice cloud scheme has a potential to improve the ice supersaturation forecast quality within numerical weather models with less expensive computational load compared to the two-moment scheme method.
• The constructed database from various identified sources focuses on open access so that it serves the scientific community to predict contrail formation.
• The newly developed CO2e accounting will allow cost optimized flight planning while reducing the climate impact.

BeCoM Flyer