A Climatological Study of the Atmospheric Circulation in the Southern Hemisphere during the IGY, Part II

Abstract

The seasonal variations during the IGY of sea-level pressures, 500-mb heights, and 1000-500 mb thickness in the Southern Hemisphere are examined to see if they conform to patterns which are deemed intrinsic to the hemisphere. These are: 1) the arrangement of the annual temperature range in four concentric zones of alternating low and high range; 2) the coldness of the lower and middle troposphere over Australasia in winter compared with South America and Africa; 3) the positive temperature isanomals in middle and high latitudes over the South Pacific Ocean in both summer and winter; and 4) the sea-level pressure and 500-mb height variations of opposite sign in middle and high latitudes which give rise to a second harmonic of large amplitude in temperature and height gradients, and in winds and sea-level pressure. The speed of movement of lows between 30 and 70S was, on the average, only slightly lower in the IGY summer than in the winter. A comparison between the standard deviations of daily sea-level pressures and 500-mb heights in the two hemispheres shows that the variability is nearly the same in the northern and southern winters, but that the standard deviations in the latitudes near 50N in summer are only two-thirds of those in the same latitudes in the southern summer.