A set of 12 mean monthly reference atmospheres, which describes the seasonal changes in the distribution of the thermodynamic properties of the atmosphere, is provided for the North Pole for altitudes up to 55 km. Additional atmospheric models for arctic and subarctic regions are presented to describe the large variations that occur in the vertical distributions of atmospheric temperature, density, and pressure during typical warmings and coolings of the winter stratosphere and mesosphere.

Sets of mean monthly reference atmospheres that describe seasonal changes in the vertical distributions of temperature, density, and pressure up to 90 km are presented for 15 intervals of latitude between the equator and pole. Specialized atmospheres are included that portray longitudinal variations in monthly median values of temperature, density, and pressure during winter months. Other models illustrate the magnitude of the changes in the vertical distributions of these atmospheric properties during winter warmings and coolings of the stratosphere and mesosphere in arctic and subarctic regions. Estimates of the day-to-day variations around the monthly median values of temperature and density are provided for each set of models. (Author).

PAGEOPH, stratosphere, these differences provide us with new evidence, interpretation of which can materially help to advance our understanding of stratospheric dynamics in general. It is now weil established that smaller-scale motions-in particular gravity waves and turbulence-are of fundamental importance in the general circulation of the mesosphere; they seem to be similarly, if less spectacularly, significant in the troposphere, and probably also in the stratosphere. Our understanding of these motions, their effects on the mean circulation and their mutual interactions is progressing rapidly, as is weil illustrated by the papers in this issue; there are reports of observational studies, especially with new instruments such as the Japanese MV radar, reviews of the state of theory, a laboratory study and an analysis of gravity waves and their effects in the high resolution "SKYHI" general circulation model. There are good reasons to suspect that gravity waves may be of crucial significance in making the stratospheric circulation the way it is (modeling experience being one suggestive piece of evidence for this). Direct observational proof has thus far been prevented by the difficulty of making observations of such scales of motion in this region; in one study reported here, falling sphere observations are used to obtain information on the structure and intensity of waves in the upper stratosphere.

"Meteorological soundings of the upper stratosphere and mesosphere, conducted with in situ rocket techniques during all seasons of the year from several sites, ranging in latitude from 8 deg S to 71 deg N, are analyzed. The resulting data are compiled into mean monthly and seasonal profiles of temperature, pressure, density, and wind for each site and are presented in graphical and tabular form. Analyses of these mean values produced time cross sections, quasi-meridional cross sections, and constant level maps which are included."--NTIS abstract.