Abstract
The vertical flux of geopotential at 100 mb in the wavenumber domain is examined for the 5-year period January 1964-December 1968. It is deduced that a significant correlation exists between this term and the circulation pattern at 10 mb as measured by an appropriate circulation index. A maximum correlation is found when the vertical flux precedes the circulation index by several days. In line with this result the existence of a wave 1 pattern above ∼30 mb as a semi-permanent feature during the winter is associated with generally increased tropospheric forcing at this same wavenumber.
In addition, year-to-year variations of the energy flux are examined. The best correlation between the upward flux of kinetic energy and the quasi-biennial oscillation of the tropical zonal wind at 10 mb is found in wavenumber 1 with maximum flux occurring 4–6 months previous to the maximum easterly winds. The amplitude of this variation in energy flux is the same order of magnitude as current estimates of the yearly energy convergence between 100 and 30 mb.
