Based on five years of satellite brightness data the year-to-year variations in convective activity are investigated over the GATE area.
The monthly-mean brightness data suggest that in the B-scale region, centered at 8.5N, 23.5W, the probability of intense convective activity during the summer of 1974 (the GATE period) is quite large. During the majority of the summer months investigated the intertropical convergence zone was found close to the latitude of the B-scale network.
The daily brightness records show that one may expect a high day-to-day variability with a predominant period of about 4 to 5 days. This may limit the range of extrapolative predictability of cloud clusters in the B-scale area to only a few days.