Radiative forcing from particle emissions by future supersonic aircraft G. Pitari1, D. Iachetti1, E. Mancini1, V. Montanaro1, N. De Luca1, C. Marizy2, O. Dessens3, H. Rogers3, J. Pyle3, V. Grewe4, A. Stenke4, and O. A. Søvde5 1Dipartimento di Fisica, Università L'Aquila, Italy 2AIRBUS, Toulouse, France 3Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Cambridge, UK 4Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, 82230 Wessling, Germany 5Department of Geoscience, University of Oslo, Norway
Abstract. In this work we focus on the direct radiative forcing (RF) of black carbon (BC)
and sulphuric acid particles emitted by future supersonic aircraft, as well as
on the ozone RF due to changes produced by emissions of both gas species (NOx, H2O)
and aerosol particles capable of affecting stratospheric ozone chemistry. Heterogeneous
chemical reactions on the surface of sulphuric acid stratospheric particles (SSA-SAD)
are the main link between ozone chemistry and supersonic aircraft emissions of sulphur
precursors (SO2) and particles (H2O–H2SO4). Photochemical O3 changes are
compared from four independent 3-D atmosphere-chemistry models (ACMs), using as input the
perturbation of SSA-SAD calculated in the University of L'Aquila model, which includes on-line
a microphysics code for aerosol formation and growth. The ACMs in this study use aircraft
emission scenarios for the year 2050 developed by AIRBUS as a part of the EU project SCENIC,
assessing options for fleet size, engine technology (NOx emission index), Mach number,
range and cruising altitude. From our baseline modeling simulation, the impact of supersonic
aircraft on sulphuric acid aerosol and BC mass burdens is 53 and 1.5 μg/m2,
respectively, with a direct RF of −11.4 and 4.6 mW/m2 (net RF=−6.8 mW/m2).
This paper discusses the similarities and differences amongst the participating models
in terms of changes to O3 precursors due to aircraft emissions (NOx, HOx,Clx,Brx)
and the stratospheric ozone sensitivity to them. In the baseline case, the calculated global ozone
change is −0.4 ±0.3 DU, with a net radiative forcing (IR+UV) of −2.5± 2 mW/m2.
The fraction of this O3-RF attributable to SSA-SAD changes is, however, highly variable among
the models, depending on the NOx removal efficiency from the aircraft emission regions by large scale transport.
Citation: Pitari, G., Iachetti, D., Mancini, E., Montanaro, V., De Luca, N., Marizy, C., Dessens, O., Rogers, H., Pyle, J., Grewe, V., Stenke, A., and Søvde, O. A.: Radiative forcing from particle emissions by future supersonic aircraft, Atmos. Chem. Phys., 8, 4069-4084, doi:10.5194/acp-8-4069-2008, 2008.