The impact of aircraft engine emissions and alternative fuels on contrail formation

飞机尾迹是飞机对气候影响的重要组成部分，长寿命的飞机尾迹贡献了航空总辐射强迫的50%或更多。对于长时间存在的尾迹来说尤其如此，随着时间的推移，尾迹会产生相当大的变暖。飞机尾迹是减少航空对气候影响的关键目标。替代燃料被认为是解决航空对气候影响的潜在解决方案，可以减少飞机发动机在生命周期内的二氧化碳排放和颗粒物排放。尽管替代燃料目前只占航空燃油消耗总量的一小部分，但预计未来几年它们将变得更加普遍，一些航空公司已经在商业航班上常规使用它们。此外，不同的飞机发动机可能有不同数量级的颗粒排放，这对轨迹特性的影响尚未使用卫星观测进行研究。虽然不同的飞机发动机颗粒排放已被证明对飞机尾迹的短期特性有影响，但它们对飞机尾迹形成的影响尚不清楚，目前正在使用模型进行评估。这些模型是基于我们对冰晶行为和云过程的理论理解，但存在相当大的不确定性，特别是在轨迹随时间的变化方面。为了通过改进航迹模型来评估替代燃料的影响，需要将航迹生命周期与发电飞机的特性联系起来的新观测结果。这将以使用和利用卫星数据为基础。该项目的总体目标是改进我们对飞机发动机颗粒排放和替代燃料对尾迹形成和发展的影响的模拟。这需要在使用约束模型模拟（O3）之前，了解卫星（O1）应该看到哪些尾迹，在卫星图像（O2）中识别和表征尾迹。EPSRC研究领域：粒子技术和生物物理学

Contrails are an important component of the climate impact of aircraft, with long lived contrails contributing 50% or more of the total radiative forcing from aviation. This is particularly true for long lived contrails, which can generate a considerable warming as they spread out over time. Contrails are a key target for reducing the climate impact of aviation. Alternative fuels have been proposed as a potential solution to aviation's climate impact, by reducing lifecycle CO2 emissions and reducing particulate emissions from aircraft engines. Even though alternative fuels currently account for a tiny percentage of overall aviation fuel burn, they are expected to become more prevalent in the coming years and some airlines are already routinely using them on commercial flights. Furthermore, different aircraft engines can have particle emissions which are different by an order of magnitude and the effect that this has on contrail properties has not yet been studied using satellite observations. While different aircraft engine particle emissions have been shown to have an impact on the short-term contrail properties, their impact on the development of contrails is unclear and is currently assessed using models . These models are based on our theoretical understanding of ice crystal behaviour and cloud processes, but are subject to considerable uncertainty, particularly in the behaviour of the contrail over time. To assess the impacts of alternative fuels through improved contrail modelling, new observations linking the contrail lifecycle to the properties of the generating aircraft are required. This will be based around the use and exploitation of satellite data. The overall aim of this project is to improve our simulations of impact of aircraft engine particle emissions and alternative fuels on contrail formation and development. This requires an understanding of which contrails should be visible to satellite (O1), identification and characterisation of contrails in satellite imagery (O2) before the use for constraining model simulations (O3). EPSRC areas: particle technology and biophysics