Developing a Research Agenda on Contrails and Their Climate Impacts (2025)
Chapter: Appendix C: Recommendations
C
Recommendations
SHORT-TERM PRIORITY RECOMMENDATIONS
Recommendation: NASA should support the development, testing, and certification of advanced and accurate commercial-aircraft-capable humidity and temperature sensors for contrail-forming regions as well as onboard contrail-detecting cameras and automated contrail detection image recognition algorithms. (Chapter 3)
Recommendation: NASA should support research and observational studies to improve the understanding of the extent and frequency of ice-supersaturated regions (ISSRs) and the level of skill in simulating ISSRs and contrails. (Chapter 3)
Recommendation: NASA should apply its current Earth system modeling efforts in support of simulating ice-supersaturated regions and contrails as a pathway to demonstrate the use of observations and advanced modeling tools for developing a contrail forecast and prediction system and estimating contrail radiative forcing. (Chapter 5)
LONG-TERM PRIORITY RECOMMENDATIONS
Recommendation: NASA, in coordination with the Federal Aviation Administration, the Department of Energy, and the Department of Defense, should support laboratory and engine research studies to improve the understanding of how fuel composition, combustor technology, and engine operating conditions impact particulate emissions (volatile and non-volatile) and contrail properties. (Chapter 2)
Recommendation: NASA should continue to collect in-flight observational data of contrails, cruise emissions (CO2, NOx, and ice-nucleating particles) from aviation that advance the understanding of the factors that influence contrail properties. (Chapter 2)
Recommendation: NASA should identify and enable a minimum set of key aerosol instruments that can be flown on multiple missions with the goal of characterizing the aerosol composition of the upper troposphere and uncovering the contribution of aviation emissions relative to other sources. (Chapter 3)
Recommendation: NASA, in coordination with the Federal Aviation Administration, the Department of Energy, the Department of Defense, other relevant federal agencies, and the private sector, should support development of low-particle-emitting combustion technologies, as well as sustainable aviation fuels with inherently low particulate-formation tendencies. (Chapter 2)
Recommendation: NASA should support observing system simulation experiments to define widespread water vapor sensor deployment to best inform contråail forecasts systems and individual verification and avoidance efforts. (Chapter 3)
Recommendation: NASA should support satellite remote sensing research for diagnosing persistent contrails and ice-supersaturated regions to develop readiness for the next-generation geostationary sounders and imagers. (Chapter 3)
Recommendation: As part of a national strategy, NASA should support development and assessment of models for all scales of contrail prediction. These models range from wake vortex to global climate to contrail plume to ice-supersaturation forecasting. (Chapter 4)
Recommendation: NASA should support development of a global contrail observing system as a foundation for research, analysis, and future verification. (Chapter 5)
Recommendation: NASA, in collaboration with airline operators and Air Navigation Service Providers, should continue research, development, and operational evaluation of advanced high-altitude air traffic control concepts of operations to enable flexibility to accommodate fuel efficient and contrail avoidance flight trajectories. (Chapter 6)
