Search

A recent analysis of winds in the upper atmosphere, as revealed by sodiumvapor trails, led its authors to the conclusion that all the observed winds could be explained on the basis of prevailing and tidal components. Irregularly varying winds were attributed to ‘phase anomalies’ in the tidal oscillations, and the thesis that they were due instead to internal atmospheric gravity waves was excluded. In the present paper the steps that led to these conclusions are examined critically. It is shown that little, if any, weight can be placed in the arguments that were presented, and that there are substantial reasons for rejecting them. The relevance of prevailing and tidal components may be readily accepted, and indeed is supported in a companion paper, but the thesis that these components account for all the winds is simply not in accordance with the available evidence.

In two earlier articles the authors have shown that if atmospheric ozone is considered as existing in a photochemical steady state depending on solar radiation, calculations involving certain assumptions regarding the absorption-coefficients yield a distribution of the ozone with height which is sufficiently similar to the distribution that is deduced from experimental observations to suggest that the photochemical picture is adequate to account for atmospheric ozone. At the end of the first paper the disturbance of the steady state by atmospheric circulation was briefly discussed, and it was pointed out that the known variations in the existing vertical ozone path over any point on the Earth's surface might be explained as due to such disturbance. In order to estimate the quantitative importance of circulation in the photochemical picture, it is necessary to have some idea of the rates at which the steady state is maintained at the various heights. It is one of the purposes of the present paper to estimate the approximate values of these rates.

This paper describes a study of the average contour length changes and trough developments at the 300-mb level following geomagnetic disturbances from October 1956 through March 1957. A ‘contour length index’ and a ‘trough index’ were developed to measure the degree of disturbance of the 300-mb circulation over western North America and the eastern Pacific Ocean and the intensity of troughs in this circulation. Three trough classifications were defined and the development of all troughs appearing in the Aleutian Island-Gulf of Alaska area were analyzed by class. The results suggest that troughs which appeared in the Aleutian Island-Gulf of Alaska area a few days after an abrupt increase in geomagnetic activity subsequently developed a stronger average cyclonic curvature than other troughs. The largest trough developments and the maximum contour lengths occurred, on the average, eight to nine days after the magnetic disturbance. Added studies will be needed to determine whether the suggested relationships are general ones.

The Symposium on Atmospheric Trace Constituents and Atmospheric Circulation, held in Heidelberg, Germany, September 8–13, 1969, was organized by the Commission on Atmospheric Chemistry and Radioactivity of the International Association of Meteorology and Atmospheric Physics. The symposium was sponsored jointly by the World Meteorological Organization and IAMAP. The University of Heidelberg was host organization. More than 100 scientific papers were presented in symposium sessions on the following topics: A. Tracers and Transport Processes B. Radioactive Aerosol Transport and Fallout C. Radiocarbon and Tritium Distribution D. Aerosol Formation and Removal Processes E. Atmospheric Trace Gas Distribution F. Aerosol Distribution and Composition G. Upper Atmosphere Constituents H. Atmospheric Geochemistry I. Emanations and Daughters as Tracers J. Air and Precipitation Chemistry K. Cosmogenic Radioisotopes as Tracers