TOGA emphasized the tropical oceans and their relationship to the global atmosphere. Underlying TOGA is the premise that the dynamic adjustment of the ocean in the tropics is far more rapid than at higher latitudes. Thus disturbances emanating from the western Pacific Ocean (such as El Niño) may propagate across the basin on time scales of weeks compared to years for corresponding basin-wide propagation at higher latitudes. The significance of shorter dynamic times scales near the equator is that they are similar to those of highly energetic atmospheric modes. This similarity allows the formation of coupled modes between the ocean and the atmosphere. TOGA was instrumental in developing a comprehensive observing system for the equatorial Pacific Ocean and laid important groundwork for ENSO prediction, data assimilation and understanding of air-sea interaction.