Aircraft induced effects on Arctic polar stratospheric cloud formation

Abstract

Stratospheric chemical transport models (CTM) have been used to calculate perturbations in HNO 3 and H 2 O due to stratospheric supersonic aircraft emissions of nitrogen oxides and water vapour. The perturbations were used as input to a detailed microphysical model to study the effects on Arctic polar stratospheric cloud (PSC) formation. Actual winter 1989/90 temperature histories from domain filling trajectories were used to calculate PSC particle types and surface areas, allowing the inherent temperature hysteresis in the life cycles of different PSC particle types to be taken into account. Increased concentrations of water vapour, caused by stratospheric aircraft emissions, imply higher freezing temperatures for ice in supercooled ternary solution liquid type PSC particles, required for the formation of solid type PSCs. A potential exists that the enhanced H 2 O concentrations may lead to more solid type PSC formation and thereby more widespread denitrification.