Detection of young contrails – selected results from the CONCERT (CONtrail and Cirrus ExpeRimenT) campaign

Kurzfassung

Large uncertainties remain in estimating the climate impact from contrails. In particular it is unknown, whether the aircraft type has an influence on contrail properties. Therefore, microphysical and radiative properties of contrails were detected with the DLR research aircraft Falcon during the CONCERT campaign in October/ November 2008. During 12 mission flights over Western Europe 22 contrails from 11 different aircraft were probed and the ice particle number density, size, extinction, contrail dimension as well as trace gas fields were measured. Here we focus on the 14 minutes sampling of the contrail of an A319. The 1 to 3 min old contrail was detected in the vortex regime. It was observed at an altitude of 10.6km and a temperature of 216K in ice subsaturated air (82%<RHI<98%). Particle concentration, extinction, and ice water content decrease within the sampling period due to contrail ageing and dilution. A vertical contrail depth of 122m has been estimated from the measurements and agrees with vortex descent simulations. Micro- and macro-physical contrail observations allow for the quantification of the contrail optical depth, playing a crucial role for the estimate of contrail radiative forcing.