Managing Storm Uncertainties for a Safe and Efficient Air Transport System: Storm-Avoidance Aircraft Trajectory Optimization. PID2021-122323OB-C32
Universidad de Sevilla (Seville, Spain)
ABOUT
Within the general objective of StormATS of improving the air traffic system, in terms of efficiency and safety, the objective of this subproject is to develop a methodology to predict probabilistic aircraft trajectories under adverse weather with a time horizon of several hours, using multi-scale convective weather information.
The predicted trajectories in such scenario are of interest for both aircraft operators and air navigation services providers. The former are interested in knowing how to avoid the storm cells efficiently and the associated expected delays, and the latter are interested in knowing the increase in the occupation times of the sectors, the possibility of penetrating adjacent sectors, and the delays in entering the following sectors.
The challenge arises from the integration of the different temporal scales within the extended time horizon of several hours, that is, the integration of different probabilistic meteorological data provided by different meteorological products. In this project two types of meteorological products are considered: ensemble nowcasts, used to forecast thunderstorms at the short-term timescale, and global and regional Ensemble Prediction System (EPS) forecasts, used to retrieve wind and air temperature uncertainties and extract different indicators of the probability of convection for long-term lead times.
To accomplish that objective, in this subproject two different trajectory predictors are developed, one for the short-term time horizon (0-2 hours) and another one for the long-term time horizon (beyond 2 hours, for instance 8 hours, which is of interest for tactical flow management).
The purpose of the short-term trajectory predictor is to predict aircraft trajectories when avoiding thunderstorms in the short term (0-2 hours). To carry out this task, several factors are considered: the three-dimensionality of the weather phenomena, the inherent uncertainty of the weather forecasts (as given by the ensemble nowcasts), the uncertain storm-avoidance strategies, and the uncertainty in the takeoff time for those aircraft that are on-ground at the time of the prediction. To model the uncertainty in the storm-avoidance strategy, one important step is to characterize statistically the main parameters that define the weather hazardous regions that must be avoided.
On the other hand, the purpose of the long-term trajectory predictor is to predict aircraft trajectories when avoiding thunderstorms in the long term (beyond 2 hours), considering the inherent lack of resolution of this time horizon and the same determinant factors mentioned before: three-dimensionality and uncertainties of weather forecasts (as given now by the EPS), storm-avoidance strategies, and take-off times. One important task in this case is to establish the probabilistic relationship between the expected trajectory deviations and the convection indicators provided by the EPS.
The outcome of this subproject will represent a step forward in the understanding of how adverse weather affects the ATM system, which is a necessary step towards the accomplishment of the high-level goals of SESAR of increasing the capacity of the system while maintaining high safety standards and improving the overall performance in terms of cost and environmental impact.
RESEARCH TEAM
Alfonso Valenzuela Romero
avalenzuela@us.es
Antonio Franco Espín
antfranco@us.es
Damián Rivas Rivas
drivas@us.es
WORK TEAM
Juan Manuel Núñez Portillo
jnportillo@us.es
EXPECTED SCIENTIFIC IMPACT
From an economic perspective, the aviation industry is considered a strategic activity given its economic and social impact. Therefore, it is an important asset for Europe and this holds true for other regions around the world. The continuous growth in air traffic and the increasing interest in reducing the environmental impact of aviation are cornering the capacity, safety, and efficiency levels of the ATM system. These challenges demand a paradigm shift that modernizes the ATM system through the close collaboration of all stakeholders.
Across the world, a number of initiatives supporting this modernization have been put in place, such as the Single European Sky ATM Research (SESAR) in Europe. In a nutshell, the high-level goal of SESAR is to increase the capacity of the system while maintaining high safety standards and improving overall performance in terms of cost and environmental impact. Network predictability is another main goal for the future ATM system in Europe.
In this context, a deeper understanding of weather uncertainty in the air traffic system (in the sense of understanding its sources, magnitude, and effects; and in the sense of being able to reduce and/or control it) has been identified as paramount to achieve those highlevel goals. It would certainly empower the necessary technologies to facilitate a future, more automated, safer, economically more efficient, and environmentally friendlier air transportation system.
The coordinated project focuses on the impact of thunderstorms on aviation. Within this broad field, this subproject aims to contribute to the current state-of-the-art in the prediction of aircraft trajectories when crossing thunderstorms, considering different avoidance strategies and timescales, and using multiscale convective weather information. Thanks to an accurate modelling of the uncertainties in the thunderstorms, the pilots avoidance strategy, and the take-off time, the methodologies to be developed in this project will be able to provide more accurate probabilistic predicted trajectories.
These enhanced probabilistic predicted trajectories will be the key enabler of two positive impacts.
On the one hand, from the perspective of airspace users (the airlines), unnecessary fuel added to mitigate flight uncertainty will be reduced. Note that savings of around 0.88 min of extra fuel are had when a 1-min reduction of flight time dispersion is achieved, which translates to hundreds of millions of Euros per year.
On the other hand, from the perspective of the Air Navigation Service Providers, the capacity of Air Traffic Control sectors will be able to be raised thanks to a more predictable entry/occupancy counts and a better situational awareness derived from the probabilistic nature of those predictions. Note that nowadays, the capacity of Air Traffic Control sectors is under-declared due to uncertain entry/occupancy counts (partially due to uncertain weather effects), thus limiting the capacity of the system (this limitation is quantified as around 10%).
Storm-ATS 