Radiative forcing by persistent contrails and its dependence on cruise altitudes

[1] The expected increase of global air traffic raises concern over the impact of aviation on climate, for instance via the creation of persistent contrails that influence the radiative budget of the Earth. Here the radiative forcing due to persistent contrails due to potential new aircraft, which are added to the present fleet, is studied as a function of cruise altitudes. A sophisticated radiative transfer model is used to calculate the forcing, assuming a contrail cover derived from ECMWF analyses combined with information on air traffic from the AERO2k inventory for 2002. The global net forcing of the 2002 fleet is found to be 6 mW/m2 with a large uncertainty of about 50%, mainly due to the sparseness of contrail cover observations, assumptions about the optical depth of the contrails, and the small size of the net forcing, which results from a large cancellation of longwave and shortwave forcings of opposite signs. By increasing air traffic by, e.g., 10% in 2000 ft thick horizontal global layers in turn, it is found that contrails produced around 10 km have the largest impact on the radiative forcing per flown kilometer. A clear linear behavior was observed: in the most sensitive layer each percent of increase in air traffic leads to a 0.25% increased radiative forcing. A comparison between using ECMWF model outputs with different cloud schemes, allowing for or neglecting ice supersaturation, is presented.

[1]  Q. Fu.  An Accurate Parameterization of the Infrared Radiative Properties of Cirrus Clouds for Climate Models , 1996 .

[2]  H. Mannstein,et al.  Contrail observations over Southern and Eastern Asia in NOAA/AVHRR data and comparisons to contrail simulations in a GCM , 2007 .

[3]  U. Schumann,et al.  Radiative forcing by contrails , 1999 .

[4]  D. F. Young,et al.  Transformation of contrails into cirrus during SUCCESS , 1998 .

[5]  Patrick Minnis,et al.  Contrail coverage derived from 2001 AVHRR data over the continental United States of America and surrounding areas , 2005 .

[6]  Robert B. Noland,et al.  Variability of Contrail Formation Conditions and the Implications for Policies to Reduce the Climate Impacts of Aviation , 2005 .

[7]  Q. Fu,et al.  Parameterization of the Radiative Properties of Cirrus Clouds , 1993 .

[8]  R. Hogan,et al.  A Sensitivity Study of the Effect of Horizontal Photon Transport on the Radiative Forcing of Contrails , 2007 .

[9]  U. Schumann.  Über Bedingungen zur Bildung von Kondensstreifen aus Flugzeugabgasen , 1996 .

[10]  Geraint Vaughan,et al.  Water vapour and ozone profiles in the midlatitude upper troposphere , 2004 .

[11]  R. Sausen,et al.  Future Development of Contrail Cover, Optical Depth, and Radiative Forcing: Impacts of Increasing Air Traffic and Climate Change , 2003 .

[12]  Robert Sausen,et al.  The impact of cruise altitude on contrails and related radiative forcing , 2005 .

[13]  E. Schmidt.  Die Entstehung von Eisnebel aus den Auspuffgasen von Flugmotoren , 1941 .

[14]  W. Rossow,et al.  Advances in understanding clouds from ISCCP , 1999 .

[15]  Klaus Gierens,et al.  A distribution law for relative humidity in the upper troposphere and lower stratosphere derived from three years of MOZAIC measurements , 1999 .

[16]  Klaus Gierens.  Are fuel additives a viable contrail mitigation option , 2007 .

[17]  Keith P. Shine,et al.  Impact of perturbations to nitrogen oxide emissions from global aviation , 2008 .

[18]  Robert Sausen,et al.  A Diagnostic Study of the Global Distribution of Contrails Part I: Present Day Climateast; , 1998 .

[19]  Patrick Minnis,et al.  Contrail Frequency over the United States from Surface Observations , 2003 .

[20]  Claudia J. Stubenrauch,et al.  Retrieval of effective ice crystal size in the infrared: Sensitivity study and global measurements from TIROS‐N Operational Vertical Sounder , 2003 .

[21]  T. Ackerman,et al.  A simple formulation of the delta-four-stream approximation for radiative transfer parameterizations , 1988 .

[22]  R. Betts,et al.  Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2 , 2007 .

[23]  Q. Fu,et al.  On the correlated k-distribution method for radiative transfer in nonhomogeneous atmospheres , 1992 .

[24]  R. Sausen,et al.  Contrails in a comprehensive global climate model: Parameterization and radiative forcing results , 2002 .

[25]  Patrick Minnis,et al.  Global distribution of contrail radiative forcing , 1999 .

[26]  Patrick Minnis,et al.  Contrail properties over the eastern North Pacific from AVHRR data , 2005 .

[27]  U. Schumann,et al.  Impact of air traffic on cirrus coverage , 2005 .

[28]  Gunnar Myhre,et al.  On the tradeoff of the solar and thermal infrared radiative impact of contrails , 2001 .

[29]  H. Appleman.  The Formation of Exhaust Condensation Trails by Jet Aircraft , 1953 .

[30]  J. Thepaut,et al.  Assimilation of MIPAS limb radiances in the ECMWF system. I: Experiments with a 1‐dimensional observation operator , 2007 .

[31]  B. Strauss,et al.  On the regional climatic impact of contrails: microphysical and radiative properties of contrails and natural cirrus clouds , 1997 .

[32]  Damian R. Wilson,et al.  A microphysically based precipitation scheme for the UK meteorological office unified model , 1999 .

[33]  C S Peirce,et al.  The numerical measure of the success of predictions. , 1884, Science.

[34]  Robert Sausen,et al.  A Diagnostic Study of the Global Distribution of Contrails Part II: Future Air Traffic Scenarios , 1999 .

[35]  Hermann Mannstein,et al.  Aircraft induced contrail cirrus over Europe , 2005 .

[36]  K. Shine,et al.  Evaluation of the use of radiosonde humidity data to predict the occurrence of persistent contrails , 2007 .

[37]  K. Atkinson,et al.  AERO2k Global Aviation Emissions Inventories for 2002 and 2025 , 2004 .

[38]  Ulrich Schumann,et al.  Regional radiative forcing by line-shaped contrails derived from satellite data , 2002 .

[39]  Patrick Minnis,et al.  Contrails, Cirrus Trends, and Climate , 2004 .

[40]  Q. Fu,et al.  Multiple Scattering Parameterization in Thermal Infrared Radiative Transfer , 1997 .

[41]  S. Bakan,et al.  Contrail frequency over Europe from NOAA-satellite images , 1994 .

[42]  Anu Vedantham,et al.  Aviation and the Global Atmosphere: A Special Report of IPCC Working Groups I and III , 1999 .

[43]  Klaus Gierens,et al.  Ice supersaturation in the ECMWF integrated forecast system , 2007 .

[44]  Nicola Stuber,et al.  The importance of the diurnal and annual cycle of air traffic for contrail radiative forcing , 2006, Nature.

[45]  David S. Lee,et al.  Aviation radiative forcing in 2000: an update on IPCC (1999) , 2005 .

[46]  Klaus Gierens,et al.  A note on how to avoid contrail cirrus , 2005 .

[47]  U. Schumann.  On conditions for contrail formation from aircraft exhausts , 1996 .

[48]  P. Forster,et al.  The impact of diurnal variations of air traffic on contrail radiative forcing , 2007 .

[49]  B. Strauss,et al.  On the Transition of Contrails into Cirrus Clouds , 2000 .