Klimawirkung von Kondensstreifen: Untersuchungen mit einem globalen atmosphärischen Zirkulationsmodell

A parameterization of line-shaped contrails for use within the
framework of a general circulation model (ECHAM) was developed for
the first time. Contrail coverage, optical properties and radiative
forcing are calculated at any model time step depending in a
physically based manner on the respective conditions in the ambient
air. In addition, possible effects on atmospheric parameters can be
simulated, allowing for the determination of a climate sensitivity
parameter especially for line-shaped contrails. Regional contrail
cover as well as the large range of simulated optical depth values
show a fair qualitative and quantitative agreement with
observations. Sensitivity studies result in a lower global
radiative forcing of line-shaped contrails than estimated by the
Intergovernmental Panel on Climate Change (1999). Remaining
uncertainties are mainly associated with poor knowledge of
microphysical properties such as ice water content, particle shape
and size. Considering future changes in air traffic density, and
aircraft technology, as well as anthropogenic climate change, an
increase of global contrail cover and radiative forcing by roughly
a factor of four between 1992 and 2050 is simulated.