Simulating Contrails with COSMO-ART Based on Real Time Flight Tracks

Kurzfassung

Condensation trails (contrails) from aircrafts are among the most obvious indications showing anthropogenic activities impacting the atmosphere. A parameterization to simulate the formation and life cycle of contrails has been implemented into the high resolution regional numerical model system COSMO-ART (Baldauf et al., 2011; Vogel et al., 2009). Depending from the Schmidt-Appleman criterion (Schumann, 1996), that decides whether the environmental conditions are favorable for the formation of contrails, the parameterization computes additional ice water content and number concentrations. The following life cycle, consisting of processes like advection, deposition of water vapor and sublimation is described using the two moment cloud microphysical scheme of Seifert and Beheng (2006), in which the new parameterization scheme is embedded. This method allows also the treatment of so called contrail cirrus that is basically aged contrails which more and more develop into wide spread and optical thin cirrus. A basic data set provided by the German Aerospace Center - Institute of Air Transport and Airport Research contains the spatial and temporal high resolved trajectories of a limited number of sample flights over Central Europe. First model results are compared with satellite pictures for the simulated days. Besides the conditions for formation and the life cycle of contrails and contrail cirrus, the influence on the upper troposphere cloud coverage of these man-made clouds over Germany is examined.