The middle atmosphere

The last 50 years have seen enormous advances in our knowledge and understa nding of the stratosphere and mesosphere, which together comprise the middl e atmosphere. Beginning from a phase of basic discovery, we have now reache d the stage where most observed phenomena can be modelled from first princi ples with a reasonable degree of fidelity, and where there is an overall th eoretical framework which can be tested against measurements and models. Th is review surveys a number of major surprises in middle atmosphere science over the past 50 years. A phenomenological and historical approach is adopt ed in each case, leading up to the current literature. Along the way, a com mon thread emerges: the central role of waves, of various types, in redistr ibuting angular momentum within the atmosphere, and the global nature of th e atmospheric response to such redistribution. (C) 2000 Elsevier Science Lt d. All rights reserved.