In-situ observations of young contrails - overview and selected results from the CONCERT campaign

Lineshaped contrails were detected with the re- search aircraft Falcon during the CONCERT - CONtrail and Cirrus ExpeRimenT - campaign in October/November 2008. The Falcon was equipped with a set of instruments to measure the particle size distribution, shape, extinction and chemical composition as well as trace gas mixing ratios of sulfur dioxide (SO2), reactive nitrogen and halogen species (NO, NOy, HNO3, HONO, HCl), ozone (O3) and carbon monoxide (CO). During 12 mission flights over Europe, nu- merous contrails, cirrus clouds and a volcanic aerosol layer were probed at altitudes between 8.5 and 11.6 km and at tem- peratures above 213 K. 22 contrails from 11 different aircraft were observed near and below ice saturation. The observed NO mixing ratios, ice crystal and soot number densities are compared to a process based contrail model. On 19 Novem- ber 2008 the contrail from a CRJ-2 aircraft was penetrated in 10.1 km altitude at a temperature of 221 K. The contrail had mean ice crystal number densities of 125 cm 3 with effective radii reff of 2.6 µm. The presence of particles with r>50 µm in the less than 2 min old contrail suggests that natural cir- rus crystals were entrained in the contrail. Mean HONO/NO (HONO/NOy) ratios of 0.037 (0.024) and the fuel sulfur con-