Vorticity, momentum and divergence budgets of synoptic-scale wave disturbances in the tropical eastern Atlantic.

Abstract

Budgets of vorticity, momentum and divergence are evaluated for the average, synoptic-scale wave composited by Thompson et al. (1979) from Phase III data of the GARP Atlantic Tropical Experiment (GATE). The data are analyzed into a Phase III mean component and a time-varying wave component. The geopotential field which is required for the momentum and divergence budgets is obtained from vertical integration of the hydrostatic equation. It is found that nonlinear terms in all wave budgets tend to be small, so that the disturbances are governed by linear dynamics. Each of the large-scale budgets has a significant residual imbalance, suggesting subsynoptic scale circulations strongly affect the wave dynamics. -from Author