This is the first volume in a set of four volumes which depict the upper air climatology of the world, covering selected climatic conditions in the Southern Hemisphere. Volume I gives mean monthly isopleth charts of sea-level pressure and of height, temperature and dew point at selected upper levels, together with smoothed gridpoint values produced by computer analysis from these charts. The emphasis in the present volume is on mean atmospheric circulation, for which the temperature distribution and the humidity are vital. The charts are intended to show the long-term mean monthly distributions of the elements and are a fair approximation of the long-term conditions. 128 charts contained in this volume detail the complete monthly sequences for the surface and 500 millibars and for the 200-mb heights, in addition to the midseason charts for the remaining levels. They form a framework in which few significant features can escape attention. Therefore, it was decided not to draw the remaining charts for publication in this volume but to derive them by computer methods.
