Additional Evidence for Quasi-biennial Variations in Tropospheric Parameters

During the years 1899-1967, in temperate latitudes of the Northern Hemisphere, there has been a significant quasi-periodic fluctuation (hereafter denoted as periodicity) of about 16 yr. in the even minus odd (even-odd) year difference in sea level zonal geostrophic wind for the months January through May. No such periodicity is evident for the months July through November. For the winter and spring months there is also a significant correlation between even-odd year difference in sea level zonal wind around the hemisphere (at the appropriate latitude) and the evenodd year difference in surface temperature in western Europe. On the basis of this periodicity and correlation, long-range prediction of surface temperatures in western Europe during winter and spring should exhibit modest skill. Sparse pressure data suggest that similar periodicities in sea level zonal wind are present in the Southern Hemisphere and that, a t least a t lat. 30” during the period January-May, the periodicities in the two hemispheres are basically in phase. In the Northern Hemisphere winter and spring, at 500 mb., evidence is presented for periodicities of about 16 yr. in the even-odd year differences of zonal wind, temperature, and meridional momentum and heat flux. These periodicities, as well as the one for the sea level zonal wind, tend to be in phase. There is a strong out-of-phase relation between the even-odd year difference in sea level zonal wind in midlatitudes and the total ozone a t Arosa, and a strong in-phase relation between this wind and the evenodd year difference in temperature in the tropical stratosphere 1 yr. earlier.