CONTRAIL OBSERVATIONS BY GROUND-BASED SCANNING LIDAR - CROSS-SECTIONAL GROWTH

The spatial growth of individual contrails of commercial aircrafts in the time range from 1 min to 60 min behind the aircraft is investigate d by means of a ground-based scanning backscatter lidar. The growth in width varies between 18 m/min and 140 m/min, and the growth of the cr oss-section between 3500 m2/min and 25000 m2/min. These values cover t he findings of model calculations and former investigations. The verti cal growth is often limited by boundaries of the humid layer at flight level, but values up to 18 m/min were observed. In a single case a ve rtical growth of 4.5 m/s during the early vortex regime was derived fr om video images.