The NATO Advanced Research Workshop on "Dynamics, Transport am. Photochemistry in the Middle Atmosphere of the Southern Hemisphere" was held in San Francisco, California, U.S.A., 15-17 April 1989. In addition to NATO, the workshop was supported by the University of California, Los Angeles, and by the National Aeronautics and Space Administration, U.S.A. (NASA). The American Meteorological Society was a co-operating organization. The venue for the workshop was the Lone Mountain Conference Center of the University of San Francisco. The workshop was organized and directed by Dr A.O'Neill (Hadley Centre for Climate Prediction and Research, Meteorological Office, Bracknell, U.K.) and Prof C.R. Mechoso (Dept of Atmospheric Sciences, University of California, Los Angeles, U.S.A.). The workshop was the third one held as part of the Middle Atmosphere in the Southern Hemisphere (MASH) project, an international effort (under the auspices of the Middle Atmosphere Program) to learn more about dynamics, transport and photochemistry in the middle atmosphere of the southern hemisphere. Before the discovery that, during recent years, a dramatic thinning of the ozone layer takes place over Antarctica in spring - the "ozone hole" - the middle atmosphere of the southern hemisphere had received much less attention than that of the northern hemisphere from meteorologists and atmospheric chemists. The MASH project was instituted to remedy this comparative lack of interest.

The NATO Advanced Research Workshop on Coupling Processes in the Lower and Middle atmosphere held in Loen, Norway in May 1992 was, in the estimation of apparently all participants, an enormous success. The 18 invited speakers included many of the leaders in the field and resulted in the attendance of a large number of contributing speakers and observers. The subject of the workshop was itself very timely, given the increasing awareness within the international community of the sensitivity of the atmosphere to coupling between adjacent layers, different latitudes, and various scales of motion. It was also very beneficial to bring together researchers with different approaches to the same or similar problems. For example, experimentalists benefitted from the inputs of modelers and theoreticians concerning the needs of current models and the most pressing problems and unknowns. Likewise, theoreticians were challenged to apply themselves to realistic problems and saw their theories tested against geophysical data. These discussions led to meaningful exchanges of ideas and challenges to or displacement of conventional wisdom in some areas. Indeed, possibly the greatest benefit of the workshop was the exposure of many participants to other areas of research or approaches to problems relevant to their own work. Workshop topics were confined to dynamical coupling processes in order to examine progress in a relatively focussed area. Nevertheless, the results presented spanned spatial scales from molecular to global and temporal scales from seconds to decades.

"[...] an interesting and well-written overview of the current status of our knowledge of the composition of the middle atmosphere and the basic radiative, dynamical and photochemical processes which maintain it." (Bulletin American Meteorological Society)