21. Modelling and Evaluation of Persistent Contrail Formation Regions for Offline and Online Strategic Flight Trajectory Planning

This chapter presents a contrail mapping algorithm developed for integration into a Multi-objective Trajectory Optimisation (MOTO) software framework, targeting the mitigation of environmental impacts associated with aviation-induced cloudiness. The presented linear contrail mapping algorithm exploits analytical and empirical models to determine the formation, persistence and radiative properties of contrails along a defined flight trajectory. In order to determine the contrail formation and persistence, the algorithm takes into account aircraft characteristics as well as relative humidity, temperature, pressure as well as the speed and shear of winds aloft, derived from suitable weather forecast data inputs. The linear contrail mapping algorithm generates an accurate mapping of the contrail persistence and associated Radiative Forcing (RF) along a flight trajectory based on inputs of weather data and aircraft state. A 3D contrail mapping algorithm is developed by executing the linear contrail mapping algorithm along an arbitrary number of virtual sounding trajectories. These virtual trajectories are constructed radially around a centre position, at individual flight levels. Multiple 3D mappings are exploited to characterise time variations, ultimately leading to a 4-dimensional (4D) mapping in space and time of contrail formation, persistence and RF properties. These 4D contrail mappings can be exploited in a MOTO software framework to assess and minimise the environmental impacts associated with contrails.