Articles | Volume 14, issue 5
Atmos. Chem. Phys., 14, 2713–2733, 2014
Atmos. Chem. Phys., 14, 2713–2733, 2014

Research article 14 Mar 2014

Research article | 14 Mar 2014

Dimension of aircraft exhaust plumes at cruise conditions: effect of wake vortices

S. Unterstrasser1, R. Paoli2, I. Sölch1, C. Kühnlein3, and T. Gerz1 S. Unterstrasser et al.
  • 1Deutsches Zentrum für Luft- und Raumfahrt (DLR) – Institut für Physik der Atmosphäre, Oberpfaffenhofen, 82234 Wessling, Germany
  • 2Centre Europeen de Recherche et Formation Avancee en Calcul Scientifique, CNRS/CERFACS URA1875, Toulouse, France
  • 3European Centre for Medium-Range Weather Forecasts, Reading, UK

Abstract. The dispersion of aircraft emissions during the vortex phase is studied using a 3-D LES model with Lagrangian particle tracking. The simulations start with a fully rolled-up vortex pair of a type B747/A340 airplane and the tracer centred around the vortex cores. The tracer dilution and plume extent is studied for a variety of ambient and aircraft parameters until aircraft-induced effects have ceased. For typical upper tropospheric conditions, the impact of stratification is more dominant compared to turbulence intensity or vertical wind shear. Moreover, the sensitivity to the initial tracer distribution was found to be weak. Along the transverse direction, the tracer concentrations can be well approximated by a Gaussian distribution, along the vertical a superposition of three Gaussian distributions is adequate. For the studied parameter range, the vertical plume expansion ranges from 400 m to 550 m and cross-sectional area from 4.0 × 104 m2 to 6 × 104 m2 after six minutes. For validation, selected simulations were compared to an alternative LES model and to in-situ NO-measurements.

Final-revised paper