The lifecycle and climate-impact of contrail cirrus

Abstract

The lifecycle of contrails and the related climate impact in terms of radiative forcing (RF) is investigated for contrail cirrus. As a new concept, this study distinguishes between 1) synoptically limited contrail cirrus, where contrails form in moderately ice-supersaturated air, but ice particles stay small and contrails end by sublimation because of drying of the ambient air, e.g., when the ambient air subsides; 2) sedimentation-limited contrail cirrus, where contrails form at high humidity with strong supersaturation or in rising air masses, so that the ice particles grow until their fall speed gets large, and the ice particles finally fall to lower levels (e.g. in fall streaks).