Air travel and its associated emissions are growing faster than other sectors. These emissions are predicted to contribute a significant warming of climate over the coming century. One of aviation?s largest effects is likely to be that due to contrails and especially aviation induced cirrus, but these effects remain more-or-less unquantified (Forster et al., 2007). The two previous estimates have relied on correlating air traffic with cirrus coverage and have both large uncertainties and methodological problems. The ultimate aim of this project is, for the first time, to build a physically based parameterization of aviation induced cirrus to determine its role in climate change.

The project aims to conduct studies of water vapour, ice crystal habit, turbulence and radiative properties of contrail as it either spreads into cirrus or dissipates. Boundary conditions for LEM studies of contrail lifecycles will be delivered and Measurements of radiative forcing from spreading contrail taken for comparison to other cases. Case studies for testing later contrail cirrus parameterization in the Unified Model will be also be considered