Idealized modeling of Tropical easterly disturbances

Tropical easterly disturbances that originate over Africa have been shown in the literature to be linked to tropical cyclone formation in the Atlantic and eastern Pacific regions. It is, therefore, of interest to study the behavior of these disturbances as they traverse across the Atlantic Basin. In this study, a linearized shallow water model is used with the aim of simulating some of the observed characteristics of Tropical easterly disturbances. Two types of background states are chosen: (1) Idealized background states that are exact solutions to the model equations (2) Background states derived from ECMWF reanalyses. In this case a suitable forcing function is used such that the basic state is an exact solution to the model equations. A hierarchy of numerical experiments is performed to study the effect of these background states on various perturbation fields chosen to represent the Tropical easterly disturbances. The evolution of the disturbances is documented and compared with some of the past theoretical and observations-based diagnostics.