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Voigt C.,German Aerospace Center | Voigt C.,Johannes Gutenberg University Mainz | Schumann U.,German Aerospace Center | Jurkat T.,German Aerospace Center | And 32 more authors.
Atmospheric Chemistry and Physics | Year: 2010

Lineshaped contrails were detected with the research 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, numerous contrails, cirrus clouds and a volcanic aerosol layer were probed at altitudes between 8.5 and 11.6 km and at temperatures 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 November 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 cirrus crystals were entrained in the contrail. Mean HONO/NO (HONO/NOy) ratios of 0.037 (0.024) and the fuel sulfur conversion efficiency to H2SO4 (εs) of 2.9 % observed in the CRJ-2 contrail are in the range of previous measurements in the gaseous aircraft exhaust. On 31 October 2010 aviation NO emissions could have contributed by more than 40% to the regional scale NO levels in the mid-latitude lowest stratosphere. The CONCERT observations help to better quantify the climate impact from contrails and will be used to investigate the chemical processing of trace gases on contrails. © 2010 Author(s).


Schauble D.,German Aerospace Center | Voigt C.,German Aerospace Center | Karcher B.,German Aerospace Center | Stock P.,German Aerospace Center | And 10 more authors.
DLR Deutsches Zentrum fur Luft- und Raumfahrt e.V. - Forschungsberichte | Year: 2010

This is a short version of Schäuble et al. (2009) published in ACPD. In November 2006 cirrus clouds and almost 40 persistent contrails were probed with in situ instruments over Germany and Northern Europe during the CIRRUS-III campaign. At altitudes between 10 and 11.5 km and temperatures of 211 to 220 K contrails with ages up to 8 hours were detected. These contrails had a larger ice phase fraction of total nitric acid (HNO3,ice/HNO3,tot = 6 %) than the ambient cirrus layers (3 %). The differences in ice phase fractions between developing contrails and cirrus are likely caused by high plume concentrations of HNO3 prior to contrail formation and large ice crystal number densities in contrails. The observed decrease of nitric acid to water molar ratios in ice with increasing mean ice particle diameter suggests that ice-bound HNO3 concentrations are controlled by uptake of exhaust HNO3 in the freezing plume aerosol in young contrails and subsequent trapping of ambient HNO3 in growing ice particles in older (age > 1 h) contrails.

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