How to avoid contrail cirrus

Abstract

Aircraft induced cirrus clouds have a major effect on climate. These clouds are triggered by air-traffic, if the ambient air is super-saturated with respect to ice. Operational radiosonde data with high vertical resolution is used to estimate the effect of small changes in flight altitudes on contrail and cirrus formation. It is demonstrated that a substantial fraction of contrails and contrail induced cirrus could be avoided by relatively small changes in flight level,if the actual atmospheric conditions are known. Due to the shallowness of ice-super-saturation layers in most cases only small deviations from optimal flight profiles and routes are necessary, to avoid the formation of persistent contrails and contrail cirrus.