On large-scale quasi-stationary waves

Abstract

The large-scale quasi-stationary waves have been demonstrated to depend essentially on the vorticity production at the intermediate levels of the atmosphere (La Vallee Celentano, 1975). The present study of the vorticity production at Ps/2 during four months of the I.G.Y. over the northern hemisphere indicates that orography explains about 20% of vorticity production over sloped ground, while temperature advection and diabatic heating in the lower half of the atmosphere account for 50% of the vorticity production over or flat land.