Microphysical and radiative Properties of Contrails detected during the Aircraft Mission CONCERT 2008 (CONtrail and Cirrus ExpeRimenT)

Large uncertainties remain in the assessment of the climate impact from contrails, in part as reliable in-situ measurements of conrails are rare. To this end contrails from a series of aircraft were probed with the DLR research aircraft Falcon during the CONCERT campaign in November 2008 over Europe. During this campaign, the Falcon was equipped with instruments to measure the particle size distribution, extinction and particle shape as well as trace gas distributions of NO, NOy, H2O, CO and O3.

During 5 mission flights contrails were probed at altitudes between 9 and 11.6 km and temperatures between 213 K and 229 K near and slightly below ice saturation. 22 contrails from 11 different aircraft with ages below 10 minutes were detected in the vortex and early dispersion regime. In particular we present new observations of the contrail from a large aircraft (A380). The evolution of the A380 contrail within the first 6 minutes of its lifetime will be discussed. Based on our measurements we investigate the impact of the aircraft type on microphysical and radiative properties of young contrails.

Further, the specific climate impact from each of the measured contrail cases is assessed with the help of a new contrail cirrus prediction tool (CoCiP). The model computes the integral of the radiative forcing of the contrail over the computed life-time of the contrail and is tested with the detected contrails. It will be shown that the climate impact of contrails depends on both aircraft and meteorological parameters.