It is widely known that there exists substantial variability in the annual frequency of tropical cyclogenesis across the North Atlantic basin; records indicate that as many as 21 and as few as 1 named storms have formed in particular seasons. Our understanding of the physical mechanisms which control this variability is limited by the sparse in situ observational network in the tropics. However, it is clear that the structure of the large-scale tropical general circulation is important. Because tropical deep convection is intimately linked to the structure of the large-scale, tropical general circulation, it seems natural to expect some relationship between its spatial and temporal distribution and the frequency of tropical cyclogenesis. To the best of our knowledge, no one has addressed this issue.
Our study seeks to answer the following question: Are there relationships between the spatial and temporal distributions of deep convective activity over North Atlantic tropical and subtropical waters and the spatial and temporal distributions of North Atlantic tropical cyclogenesis? To answer this question, we use the ISCCP C2 and D2 (2.5 degree x 2.5 degree) and the NHC 'best' track data sets. Monthly and seasonal maps of "deep convective" cloud and IR brightness temperature for time periods with markedly different tropical cyclone activity are constructed from the ISCCP data sets and are used as proxies for the spatial distribution of deep convective activity. These maps are then compared to identify whether there are relationships between changes in the spatial distribution of convective activity on monthly and seasonal time scales and changes in tropical cyclone activity.