Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
clear differences in the calculated perturbations caused by aircraft emissions, all model calculations show significant increases in NO x concentration in the UT (up to
100% above those calculated without aircraft) in the latitude band where traffic is most frequent (30-60°N). Corresponding increases in O 3 concentration in the UT are
up to 10% above those calculated without aircraft. Comparisons revealed significant differences in calculated O 3 perturbations among models, both in magnitude and
in seasonal variation.
A projected fleet of high speed civil transport (HSCT) aircraft would fly at supersonic speeds in the LS at altitudes where stratospheric O3 concentrations are large and
particularly vulnerable to emissions from these aircraft. The effects of NOx and H2O emissions from this projected fleet on stratospheric ozone were thought to be most
important when NASA's Atmospheric Effects of Stratospheric Aircraft (AESA) program started in 1989 (Prather et al., 1992). Projected changes in the O3 column as a
result of aircraft emission of NOx and H2O from six 2-D models were presented by Stolarski et al. (1995) for various scenarios of fleet size and EI(NOx ) in g NO2 kg-1 fuel. The model predictions in Stolarski et al. (1995) showed generally that supersonic fleet sizes of 500-1,000 aircraft would result in some depletion of Northern
Hemisphere averaged total column O3 . More recently, the role of SO2 aircraft emissions has been studied carefully and found to have a potentially major influence on
resultant O 3 perturbation computed in models (Weisenstein et al., 1996, 1998).
The new model studies in this chapter focus on the impact on atmospheric chemical composition from a current and future fleet of subsonic aircraft flying in the UT and
LS, and include a fleet of supersonic aircraft flying in the LS in one of the technology options. In the case of subsonic traffic, the estimated impact on atmospheric
composition is based on 3-D CTMs; in the case of supersonic transports, the estimated impact is based on a combination of 2-D and 3-D CTMs.
Table 4-1: Description of models used in the subsonic assessment.
Model Institution References
ECHAm 3 /CHEM German Aerospace Research Establishment, Germany Roeckner et al. (1992); Steil et al. (1998)
HARVARD Harvard University, USA Wang et al. (1997a,b)
IMAGES/BISA Belgian Institute for Space Aeronomy, Belgium Müller and Brasseur (1995); Brasseur et al. (1996)
Tm 3 /KNMI
Royal Netherlands Meteorological Institute,
The Netherlands
Wauben et al. (1997a,b)
UKMO United Kingdom Meteorological Office, UK Collins et al. (1997); Stevenson et al. (1997)
UiO University of Oslo, Norway Berntsen and Isaksen (1997); Jaffe et al. (1997)
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