Post date: 15-sep-2014 10:50:37

Title: An Aviation Environmental Fingerprint Mitigation Strategy: Flight Trajectory Design in the Presence of Contrails

Date: 25-Oct-2013

Material: slides pdf

Speaker: Manuel Soler

Abstract: Air transportation contributes a small but growing share of global anthropogenic climate change impact. As aviation grows to meet increasing demand, the United Nations Intergovernmental Panel on Climate Change (IPCC) forecasted in 1999 that its share of global man made CO2 emissions will increase to around 3% to 5% in 2050 (in 1999 it was estimated to be 2%). Moreover, the United Kingdom (UK) Royal Commission of Environmental Pollution (RCEP) has estimated that the aviation sector will be responsible for 6% or the total anthropogenic radiative forcing by 2050.

CO2 is the most widely perceived greenhouse gas agent in aviation. However, emissions from aircraft engines include other constituents that contribute, via the formation or destruction of atmospheric constituents, to climate change. Emissions of NOx tend to increase tropospheric ozone and reduce methane. The increase in radiative forcing associated with ozone is largely offset by the methane reduction, resulting in a relatively small net positive NOx impact compared to the CO2 impact. Another source of aviation-induced climate change comes from the formation of persistent contrails, which are composed of ice particles and formed in the wake of jet aircraft at high altitude where the ambient temperature is very low.

Quantifying the climate impact of persistent contrails is an area that has attracted considerable research interests over the past decades. While consensus has yet to be achieved, the general conclusion is that the magnitude of contrail climate impact is non-negligible compared to that of CO2. Accounting for the formation of persistent contrails, therefore, should be indispensable when one wants to mitigate the overall aircraft induced climate impact.

In this work, flight trajectory design in the presence of contrails is analyzed using multiphase mixed-integer optimal control techniques. The problem subject to study can be described as follows: given an aircraft point mass dynamical model, a route composed by a sequence of waypoints, and the airspace’s flight level structure, find the control inputs that steer the aircraft from the initial fix to the final fix following the horizontal route of waypoints and performing the permitted step climbs to change flight level, while minimizing the fuel consumption, CO2 emissions, and contrail formation impact during the flight.