ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-12-11943-2012 Selected topics on the interaction between cirrus clouds and embedded contrails Gierens K. 1 Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany 17 12 2012 12 24 11943 11949 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/12/11943/2012/acp-12-11943-2012.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/12/11943/2012/acp-12-11943-2012.pdf

Persistent contrails and natural cirrus clouds often coexist in the upper troposphere and contrails can be embedded within cirrus clouds. The present paper deals with some questions regarding the interaction of cirrus clouds and embedded contrails. I have selected only questions that can be answered by analytical means. I find that (1) the emission index for water vapour is only slightly changed when an aircraft crosses a cirrus cloud, (2) that contrail formation is not affected by an ambient cirrus, (3) that cirrus ice crystals entrained into the trailing wing tip vortex do not efficiently retard the sublimation of contrail ice crystals, and (4) that cirrus can start to dissolve an embedded contrail after a couple of hours by aggregation.

 References Anderson,~B. E., Beyersdorf,~A. J., Hudgins,~C.H., Plant,~J. V., Thornhill,~K. L., Winstead,~E. L., Ziemba,~L.D., Howard,~R., Corporan,~E., Miake-Lye,~R. C., Herndon,~S.C., Timko,~M., Woods,~E., Dodds,~W., Lee,~B., Santoni,~G., Whitefield,~P., Hagen,~D., Lobo,~P., Knighton,~W. B., Bulzan,~D., Tacina,~K., Wey,~C., Vander~Wal,~R., Bhargava,~A., Kinsey,~J., and Liscinsky,~D. S.: Alternative Aviation Fuel Experiment (AAFEX), NASA/TM~2011-217059, 408 pp., 2011. Field,~P. and Heymsfield,~A.: Aggregation and scaling of ice crystal size distributions, J. Atmos. Sci., 56, 544–560, 2003. Gierens,~K.: On the transition between heterogeneous and homogeneous freezing, Atmos. Chem. Phys., 3, 437–446, doi:http://dx.doi.org/10.5194/acp-3-437-200310.5194/acp-3-437-2003, 2003. Heymsfield,~A. and Iaquinta,~J.: Cirrus crystal terminal velocities, J. Atmos. Sci., 57, 916–938, 2000. Heymsfield,~A. and McFarquhar,~G.: Mid-latitude and tropical cirrus: microphysical properties, in: Cirrus, edited by: Lynch,~D., Sassen,~K., Starr,~D., and Stephens,~G., Oxford University Press, New York, USA, 78–101, 2002. Immler,~F., Treffeisen,~R., Engelbart,~D., Krüger,~K., and Schrems,~O.: Cirrus, contrails, and ice supersaturated regions in high pressure systems at northern mid latitudes, Atmos. Chem. Phys., 8, 1689–1699, doi:http://dx.doi.org/10.5194/acp-8-1689-200810.5194/acp-8-1689-2008, 2008. Lewis,~J.S., Niedzwiecki,~R.W., and 30 coauthors: Aircraft technology and its relation to emissions. In: Aviation and the global atmosphere, J.E Penner, D.H Lister, D.J Griggs, D.J Dokken, and M McFarland (eds.), IPCC Special Report, Cambridge University Press, UK, 373 pp., 1999. Iwabuchi,~H., Yang,~P., Liou,~K., and Minnis,~P.: Physical and optical properties of persistent contrails: climatology and interpretation, J. Geophys. Res., 117, D06215, http://dx.doi.org/10.1029/2011JD017020doi:10.1029/2011JD017020, 2012. Kärcher,~B. and Lohmann,~U.: A parameterization of cirrus cloud formation: homogeneous freezing of supercooled aerosols, J. Geophys. Res., 107, 4698, http://dx.doi.org/10.1029/2001JD000470doi:10.1029/2001JD000470, http://dx.doi.org/10.1029/2001JD000470doi:10.1029/2001JD000470, 2002. Kärcher,~B. and Yu,~F.: Role of aircraft soot emissions in contrail formation, Geophys. Res. Lett., 36, L01804, http://dx.doi.org/10.1029/2008GL036649doi:10.1029/2008GL036649, 2009. Kienast-Sjögren,~E., Spichtinger,~P., and Gierens,~K.: Formulation and test of an ice aggregation scheme for two-moment bulk microphysics schemes, Atmos. Chem. Phys. Discuss., 12, 23975–24009, http://dx.doi.org/10.5194/acpd-12-23975-2012doi:10.5194/acpd-12-23975-2012, 2012. Koenig,~L.: Numerical modeling of ice deposition, J. Atmos. Sci., 28, 226–237, 1971. Sassen,~K.: Contrail–cirrus and their potential for regional climate change, B. Am. Meteorol. Soc., 78, 1885–1903, 1997. Schiller,~C., Krämer,~M., Afchine,~A., Spelten,~N., and Sitnikov,~N.: Ice water content of Arctic, midlatitude, and tropical cirrus, J. Geophys. Res., 113, D24208, http://dx.doi.org/10.1029/2008JD010342doi:10.1029/2008JD010342, 2008. Schumann,~U.: On conditions for contrail formation from aircraft exhausts, Meteorol. Z., 5, 4–23, 1996. Schumann,~U.: Contrail cirrus, in: Cirrus, edited by: Lynch,~D., Sassen,~K., Starr,~D., and Stephens,~G., Oxford University Press, chapter 11, 231–255, Oxford, New York, 2002. Schumann,~U. and Graf,~K.: Aviation-induced cirrus and radiation changes at diurnal timescales, J. Geophys. Res., submitted, 2012. Schumann,~U., Schlager,~H., Arnold,~F., Baumann,~R., Haschberger,~P., and Klemm,~O.: Dilution of aircraft exhaust plumes at cruise altitudes, Atmos. Environ., 32, 3097–3103, 1998. Schumann,~U., Mayer,~B., Graf,~K., and Mannstein,~H.: A parametric radiative forcing model for contrail cirrus, J. Appl. Meteorol. Climatol., 51, 1391–1406, 2012. Spichtinger,~P. and Gierens,~K M.: Modelling of cirrus clouds – Part 1a: Model description and validation, Atmos. Chem. Phys., 9, 685–706, doi:http://dx.doi.org/10.5194/acp-9-685-200910.5194/acp-9-685-2009, 2009. Unterstrasser,~S. and Sölch,~I.: Study of contrail microphysics in the vortex phase with a Lagrangian particle tracking model, Atmos. Chem. Phys., 10, 10003–10015, doi:http://dx.doi.org/10.5194/acp-10-10003-201010.5194/acp-10-10003-2010, 2010. Westbrook,~C., Ball,~R., Field,~P., and Heymsfield,~A.: Theory of growth by differential sedimentation, with application to snowflake formation, Phys. Rev. E, 70, 021403, 1–7, 2004.