This paper presents a global view of relationships between large-scale tropical wave activity and the formation of tropical cyclones. Although the climatological conditions associated with tropical cyclogenesis have been well known for several decades, the conditions present at the time and place of individual events of storm formation vary widely and are not well understood. Since 85-90% of all tropical cyclones form within 20o of the equator, the family of equatorial and near-equatorial waves may play a role in many tropical cyclogenesis events.

In principle, the waves could cause cyclones to form by organizing deep convection and/or by altering the flow in preferred areas. This paper examines relationships between tropical cyclogenesis events and tropical wave activity. Ten years of storm formations are compared with analyses of tropical wave activity derived from spectrally filtered satellite imagery and analysis wind fields. The results provide a global climatology of the relationships between wave activity and cyclogenesis as well as composite analyses of the wave-related circulation at the time of genesis.