STUDIES OF THE MOTION AND DEVELOPMENT OF LONG WAVES IN THE WESTERLIES

Abstract

Abstract In order to subdue small scale irregular features of the atmospheric circulation and emphasize the large-scale flow patterns, five-day mean charts showing the pressure distribution at 10,000 feet are presented. It is shown qualitatively that the long waves of the westerlies which appear on these charts seem to behave in a manner suggested by a theoretical formula developed by Rossby. Examples are shown wherein complex combinations of troughs and ridges are brought about by different speeds of motion in different latitude belts. Some indications for the development of new troughs are discussed, wherein a rapid readjustment of circulation patterns becomes necessary over most of the hemisphere. Cases of blocking are described where an unexplained disturbance in the atmosphere moves slowly westward, bringing with it increases in mass and diminutions of the speed of the westerlies. In the second portion of the report evidence is presented to show that Rossby's formula for trough displacement is also v...