Free and Forced Interannual Variability of the Circulation in the Northern Hemisphere Middle Atmosphere
This paper is an informal review of research relating to the interannual variability of the stratospheric and mesospheric circulation in the northern extratropics. Observations and modelling studies concerning aspects of variability generated internally in the atmosphere are reviewed first, with a particular emphasis on the effects of the tropical quasi-biennial oscillation. Then studies relating to externally forced variability are reviewed, including those that deal with the effects of volcanic aerosols and solar irradiance.