%0 Journal Article
%A De Leon, R.R.
%A Krämer, M.
%A Lee, D.S.
%A Thelen, J.C.
%T Sensitivity of radiative properties of persistent contrails to the ice water path
%J Atmospheric chemistry and physics
%V 12
%@ 1680-7316
%C Katlenburg-Lindau
%I EGU
%M PreJuSER-22462
%P 7893 - 7901
%D 2012
%Z This work was supported by the United Kingdom Department for Transport. The authors wish to thank a number of people for providing us with the data used in this study. Christine Fromming for providing the contrail cover distribution data calculated during the TRADEOFF project. (TRADEOFF was a project in the European Fifth Framework Programme, http://www.iac.ethz.ch/tradeoff/); Prof. Piers Forster for the climatology of the monthly atmospheric composition, cloud cover and surface albedo, and Dr. Anthony Baran for the hexagonal prisms database. We thank our colleague, Dr Michael Bennett for valuable discussions and his help to improve the readability of the manuscript. We also thank two anonymous referees and the editor for their helpful comments and suggestions.
%X The dependence of the radiative properties of persistent linear contrails on the variability of their ice water path is assessed in a two-stream radiative transfer model. It is assumed that the ice water content and the effective size of ice crystals in aged contrails do not differ from those observed in natural cirrus; the parameterization of these two variables, based on a correlation with ambient temperature derived from in situ observations, allows a more realistic representation than the common assumption of fixed values for the contrail optical depth and ice crystal effective radius.The results show that the large variability in ice water content that aged contrails may share with natural cirrus, together with an assumed contrail vertical thickness between 220 and 1000 m, translate into a wider range of radiative forcings from linear contrails [1 to 66 m Wm(-2)] than that reported in previous studies, including IPCC's [3 to 30 m Wm(-2)]. Further field and modelling studies of the temporal evolution of contrail properties will thus be needed to reduce the uncertainties associated with the values assumed in large scale contrail studies.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000308753800002
%R 10.5194/acp-12-7893-2012
%U https://juser.fz-juelich.de/record/22462