Abstract
Abstract. Sustainable aviation fuels can reduce contrail ice numbers and radiative forcing by contrail cirrus. We measured apparent ice emission indices for fuels with varying aromatic content at altitude ranges of 9.1–9.8 and 11.4–11.6 km. Measurement data were collected during the ECLIF II/NDMAX flight experiment in January 2018. The fuels varied in both aromatic quantity and type. Between a sustainable aviation fuel blend and a reference fuel Jet A-1, a maximum reduction in apparent ice emission indices of 40 % was found. We show vertical ice number and extinction distributions for three different fuels and calculate representative contrail optical depths. Optical depths of contrails (0.5–3 min in age) were reduced by 40 % to 52 % for a sustainable aviation fuel compared to the reference fuel. Our measurements suggest that sustainable aviation fuels result in reduced ice particle numbers, extinction coefficients, optical depth and climate impact from contrails.
Highlights
In recent years, the scientific knowledge about climate forcing from global aviation emissions has constantly increased
As ambient conditions have a large impact on microphysical contrail properties (Bräuer et al, 2021), a more comprehensive overview of the contrail ice measurements during Emission and Climate Impact of Alternative Fuels (ECLIF) II/NASA DLR Multidisciplinary Airborne Experiment (NDMAX) is needed to assess the impact of biofuel blends on aviation climate impact
An additional reduction in apparent emission indices (AEIs) of up to 20 % was measured for the sustainable aviation fuels (SAFs) with reduced naphthalene content
Summary
The scientific knowledge about climate forcing from global aviation emissions has constantly increased. T. Bräuer et al.: Reduced ice number concentrations in contrails from low-aromatic biofuel blends uration, the non-volatile, ultra-fine soot particles emitted by the engines serve as condensation nuclei for water droplets. A reduction in contrail ice particle numbers of similar magnitude was first reported by Voigt et al (2021) for semisynthetic and biofuel blends observed during the ECLIF I and ECLIF II/NDMAX experiments for limited conditions near 10 km altitude. As ambient conditions have a large impact on microphysical contrail properties (Bräuer et al, 2021), a more comprehensive overview of the contrail ice measurements during ECLIF II/NDMAX is needed to assess the impact of biofuel blends on aviation climate impact. We contribute to the assessment of the contrail climate impact by deriving optical parameters like the extinction coefficients and contrail optical depths in addition to apparent ice emission indices
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
