Polar Stratospheric Clouds

Abstract

Polar Stratospheric Clouds (PSCs) form during the winter and early springtime inside the cold polar vortexes. Beautifully colored PSCs have long been observed but did not draw attention from the broader public until the 1980s when scientists found they were critical elements for Arctic and Antarctic ozone depletion and that some contain nitric acid. Heterogeneous chemistry occurring on PSCs converts chlorine and bromine reservoir species into photochemically active species, which drive the springtime loss of Arctic and Antarctic ozone via catalytic cycles. Large PSC particles denitrify and dehydrate the lower stratosphere through sedimentation, which also affects polar ozone chemistry.