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

尾迹是飞机气候影响的重要组成部分，长寿命的尾迹占航空辐射强迫总量的50%或更多。对于寿命较长的痕迹来说尤其如此，随着时间的推移，它们会产生相当大的变暖。尾迹是减少航空对气候影响的关键目标。替代燃料已经被提出作为航空气候影响的潜在解决方案，通过减少生命周期的二氧化碳排放和减少飞机发动机的颗粒物排放。尽管替代燃料目前只占航空燃料总消耗量的很小比例，但预计它们将在未来几年变得更加普遍，一些航空公司已经在商业航班上例行使用它们。此外，不同的飞机发动机的粒子排放可能相差一个数量级，这对轨迹特性的影响尚未通过卫星观测进行研究。虽然不同的飞机发动机颗粒排放已被证明对轨迹的短期特性有影响，但它们对轨迹发展的影响尚不清楚，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，但受到相当大的不确定性，特别是随着时间的推移轨迹的行为。为了通过改进的轨迹模型评估替代燃料的影响，需要将轨迹生命周期与产生的飞机的特性联系起来的新的观察。这将以卫星数据的使用和利用为基础。这个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轨迹形成和发展影响的模拟。这需要了解哪些轨迹对卫星(O1)是可见的，在用于约束模型模拟(O2)之前识别和描述卫星图像中的轨迹(O2)。EPSRC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