Potential impacts on ozone and climate from a proposed fleet of supersonic aircraft

There has been renewed interest in developing commercial supersonic transport aircraft due to the increased overall demands by the public for air travel, the aspiration for more intercontinental travel, and the desire for shorter flight times. Various companies and academic institutions have been actively considering the designs of such supersonic aircraft. As these new designs are developed, the environmental impact on ozone and climate of these fleets need to be explored. This study examines one such proposed commercial supersonic fleet of 55-seater that is projected to fly at Mach 2.2, corresponding to cruise altitudes of 17-20 km, and which would burn 122.32 Tg of fuel and emit 1.78 Tg of NOx each year. Our analyses indicate this proposed fleet would cause a 0.74% reduction in global column ozone (similar to 2 Dobson Units), which is mainly attributed to the large amounts of nitrogen oxides released in the atmosphere from the supersonic aircraft. The maximum ozone loss occurs at the tropics in the fall season, with a reduction of -1.4% in the total column ozone regionally. The stratospheric-adjusted radiative forcing on climate from this fleet was derived based on changes in atmospheric concentrations of ozone (59.5 mW/m(2)), water vapor (10.1 mW/m(2)), black carbon (-3.9 mW/m(2)) and sulfate aerosols (-20.3 mW/m(2)), resulting in a net non-CO2, non-contrail forcing of 45.4 mW/m(2), indicating an overall warming effect.