It is also possible that the group originated in the Neotropics and subsequently dispersed eastwards to Africa via the Intertropical Convergence Zone.
Upwelling at the equator is associated with the Intertropical Convergence Zone (ITCZ) which actually moves, and consequently, is often located just north or south of the equator.
The Twilight Zone | The Twilight Zone (1959 TV series) | Negative Zone | Panama Canal Zone | Eastern Time Zone | Twilight Zone | Korean Demilitarized Zone | The Dead Zone (TV series) | The Dead Zone | Pacific Time Zone | Hardiness zone | Central Time Zone (North America) | Ponce Historic Zone | Metekel Zone | Arsi Zone | The Twilight Zone (2002 TV series) | O-Zone | Mirab Welega Zone | Hadiya Zone | Gamo Gofa Zone | Debub Omo Zone | Zone | Semien Omo Zone | The Ultra Zone | Rapti Zone | Karnali Zone | Debub Wollo Zone | Dawro Zone | Central Time Zone | Agew Awi Zone |
There are a number of explanations of the asymmetry of the Intertropical Convergence Zone (ITCZ), known by sailors as The Doldrums.
The seventh named storm of the 1996–97 South-West Indian Ocean cyclone season, Gretelle developed within the intertropical convergence zone on January 19, and gradually intensified while moving southwestward.