Planetary-scale characteristics of the atmospheric circulation during January and February 1979

The global scale mass and wind fields observed during FGGE special observing period (SOP) are studied, with attention given to the time variation and vertical structure of the ultralong waves. A spherical harmonic representation is developed for the global fields. The tropical circulation is found to imprint more amplitude on the lower-order components than the midlatitude circulation does. High amplitude oscillations are determined to be present in the divergent fields on all time scales, i.e., diurnal to monthly. The global scale wind was found to change on scales approaching a week. Good agreement with teleconnection predictions was demonstrated for the cross-equatorial divergent and zonal rotational flow changes. The global scale was concluded to resemble force modes of linear tidal theory, with important contributions from longitudinal heating gradients.