Behaviour of nitric oxide trails deposited in the mesosphere and stratosphere

The transient behavior of a nitric oxide trail deposited at approximately 60 km altitude is studied by the solution of the appropriate multidimensional diffusion equation which includes terms representing the effects of wind shear. Similar analysis is then carried out for the situation in the stratosphere. Trail behavior is found to be relatively independent of altitude and background ozone, but strongly dependent on the magnitude of eddy diffusity and the initial nitric oxide concentration. The nitric oxide trail reacts with ambient ozone to form nitrogen dioxide. For a trail 100 m initial radius, an ozone hole will form to a maximum size in 4 to 6 hours and then decay. The overall recovery time of the atmosphere following the creation of the trail is less than 12 hours.