Evidence of the Existence and Eastward Motion of Superclusters at the Equator

A numerical experiment with an atmospheric general model (GCM) indicate that moist convection in the equatorial region is spontaneously organized into a form of “supercluster” which is an area of precipitation with a spatial extent of about 2000 km and an eastward propagation speed of about 1 5 m s−1. In this article, the existence of superclusters in the real atmosphere is shown through a comparison between satellite observations and the GCM results. It is argued that eastward motion of convective activity occurs not only as the well-known property of the 30–60 day oscillation, but as a property of synoptic-scale disturbances at the equator.