Aircraft induced contrail cirrus over Europe

Abstract

Condensation trails (contrails) and aircraft induced cirrus are nowadays a common feature at the mid latitude skies. Previously the impact of aircraft induced cirrus changes has been roughly estimated from observed decadal trends in cirrus cover but the direct attribution of observed cirrus changes to changes in aviation activity remains uncertain. In this paper the amount of additional cirrus induced from spreading contrails in humid air is estimated from the direct correlation between observed cirrus cover derived with suitable methods from METEOSAT data and aviation flight density reported by EUROCONTROL at high spatial and temporal resolution from June 22 to July 27, 1998 and September 27 to October 21, 2000. The results indicate that the aircraft induced cirrus cover over Europe is about ten times larger than that of linear contrails in the same region. Radiative forcing from the additional cirrus may be more than 10 times higher than that of linear contrails and aviation induced CO2 increases.