Emissions and impacts of supersonic business jets on the atmosphere
Prof David Lee, Dr Ruben Rodriguez De Leon
Omega: Higher Education Funding Council for England (HEFCE)
2007 – 2009
The environmental impact of any supersonic aircraft will be of significant public concern, as research dating back to the late 1960s highlights concerns over their effects on ozone depletion and climate change. Thus, the sensitivity, even to a potentially small fleet of
supersonic business jets (SSBJs), will be high.
SSBJs are under initial design consideration by a number of manufacturers, including Aerion and Gulfstream, possibly adapting existing engine technologies. The European
Commission has funded a technology design programme, ‘HISAC’ to investigate the technical feasibility of an environmentally compliant SSBJ.SSBJs are ‘on the table’ as a serious technological and commercial proposition.
Previous studies (e.g. IPCC, SCENIC) have highlighted that flying in the stratosphere can result in potentially large radiative impacts from water vapour, injected into the dry stratosphere. In this respect, ‘impact’ through residence time is vitally controlled by cruising altitude and, to a lesser degree, speed. Ozone depletion issues also need to be
considered.
No evaluation of the atmospheric impacts of SSBJs is currently being undertaken.
The objective of this project is:
to deliver parametric studies of the impacts of additional emissions of NO x, water vapour and CO 2 on the mid-stratosphere
and to determine the sensitivities to height of emissions.
Study outputs and benefits. The study will bring together technologists, emissions specialists, climate scientists and policy developers. Exposure and examination of study work by the industry is planned to involve the stakeholder community.
In addition, the study will be of importance to UK Government policy developers involved in the international ICAO-CAEP forum as a better understanding of the acceptability of second-generation supersonic aircraft is needed.
An understanding of the cruise height implications of SSBJ emissions will also assist the design of this new generation of aircraft.
This initual study has developed a capacity for studying supersonic aviation-climate effects. A chemistry tranport and radiative transfer model were setup and tested to calculate the effect of stratospheric emissions of NOx, water vapour and contrails. A radiative contrail parameterization was produced and a contrail cover model is under development.
The CTM (Chemistry Transport Model) is currently up and running at MMU, providing coupled troposphe-stratospheric chemistry traffic calculations that allow the inclusion of supersonic traffic. The RTM (radiative transfer modelling) provides radiative forcing calculations for the CTM’s output and for water vapour emissions in the stratosphere. A sophisticated parameterization was developed for the microphysical properties of contrails that can realistically predict the impact of stratospheric clouds.
The sensitivity studies performed indicated negligible radiative forcing differences with respect to subsonic aircraft with respect to linear contrails. The corresponding increase in the radiative forcing linked to the injected water vapour into the stratosphere requires further studies based on SSBJ engine performance and efficiency. The engine performance and fuel flow information will also allow the inclusion opf SBBJ traffic into the contrail cover model in order to quantify the reduction with respect to subsonic traffic.
References:
Brasseur, G.P., D.A. Hauglustaine, S. Walters, P.J. Rash, J.-F. Muller, C. Granier, and X.-X. Tie, MOZART: A global chemical transport model for ozone and related chemical tracers, PART 1: Model description, J. Geophys. Res., 103, 28265-28289, 1998
Donovan, D. P., Ice-cloud effective particle size parametrization based on combined lidar, radar reflectivity, and mean Doppler velocity measurements, (2003) J. Geophys. Res., 108(D18), 4573.
Edwards, J.M. and Slingo A. 1996. Studies with a flexible new radiation code 1: Choosing a configuration for a large-scale model. Q.J.R. Met. Soc., 122: 689-719.
Myhre et.al, Quantifying the uncertainity associated with radiative forcing of stratospheric water vapour and contrails. (Submitted to Meteorolishe Zeitschrift) Bakan, S., M. Betancor, V. Gayler, and H. Grassl, 1994: Contrail frequency over Europe from NOAA-stallite images. Annales Geophysicae 12(10-11), 962-968
Schiffe, R.A., and W.B. Rossow, 1983: The international Satellite Cloud Climatology Project (ISCCP): The first project of the World Climate Research Programme. Bull. Amer. Meteor. Soc., 64, 779-784
Schiller, C., Kramer, M., Afchine A., Spelten N., (Submitted to JGR) An in-situ climatology of ice water content in Arctic, mid latitude and tropical cirrus.