In 2021, the aviation industry saw a notable reduction in air traffic due to the COVID-19 pandemic. Seizing this unique opportunity, a research team led by Robert Sausen from the DLR Institute of Atmospheric Physics and Rudiger Ehrmanntraut from MUAC conducted an analysis of the upper airspace over north-west Germany and the Benelux countries.
The key innovation explored in this study was the 'avoidance' procedure, implemented on alternate days when weather forecasts indicated the potential formation of long-lasting contrails at typical flight altitudes. During these days, flights were redirected either higher or lower by 2000 feet (approximately 660 meters). The researchers then used satellite imagery to assess the presence of long-lasting contrails. Comparing these days to the reference days when flights followed their usual paths, the research team found that long-lasting contrails occurred less frequently.
Aviation's climate impact extends beyond carbon dioxide emissions, encompassing what are known as non-carbon-dioxide effects. These effects are particularly pronounced in air transport because aircraft emit pollutants at altitudes where their impact differs from ground emissions and can significantly affect the climate.
Among these effects, contrails and contrail cirrus clouds play a pivotal role. They can either warm or cool the atmosphere, with a warming effect prevailing. The extent of their climate impact depends on various factors, including geographical location, altitude, emission timing, solar positioning, and weather conditions. This complexity presents an opportunity to mitigate aviation's climate impact by optimizing flight routes and altitudes, a concept known as climate-optimized flight trajectories.
Several prerequisites must be met to implement climate-optimized flight trajectories successfully:
+ Reliable Climate Impact Prediction: Weather services must accurately predict the climate impact of individual flights to ensure that rerouting air traffic leads to a genuine reduction in climate impact.
+ Integration into Flight Planning Tools: Non-carbon-dioxide effects must be integrated into operational tools and flight planning processes, requiring a system capable of calculating the climate impact of flights with precision during the planning phase.
+ Capacity and Safety: When rerouting flights in higher airspace for climate considerations, it's essential to ensure the continued safe and orderly handling of authorized air traffic, as these adjustments can potentially lead to airspace capacity constraints and delays.
Unlike other non-carbon-dioxide effects, controlling the formation of long-lasting contrails is feasible through sophisticated statistical methods. The collaborative effort between DLR and EUROCONTROL/MUAC has demonstrated the practical viability of contrail avoidance in real air traffic. This promising development marks a significant step towards more climate-friendly air travel.
The findings from this research hold substantial implications for the aviation industry and environmentalists alike. As the world seeks ways to mitigate the climate impact of air travel, the ability to reduce the formation of contrails by merely adjusting flight altitudes presents a practical and immediate solution. Further research and integration into aviation practices could lead to a more sustainable future for the industry.
Research Report:'Can we successfully avoid persistent contrails by small altitude adjustments of flights in the real world?
Related Links
DLR Institute of Atmospheric Physics
Aerospace News at SpaceMart.com
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