On the dynamics of the formation of multiple tropical disturbances

Summer 1994.Also issued as author's dissertation (Ph.D.) -- Colorado State University, 1994.Includes bibliographical references.A nonlinear shallow water model on the sphere is used to study the early stages of tropical cyclone genesis, namely, the formation of tropical disturbances. Two particular cases in which one or more tropical disturbances are produced are studied: the ITCZ breakdown and the formation of disturbances that lead to twin tropical cyclones. The ITCZ breakdown is seen to be a plausible mechanism for the formation of tropical disturbances. This mechanism also offers an explanation for the observations of easterly waves outside the Atlantic basin. In the Eastern Pacific, in particular, the time and space clustering of tropical cyclone genesis lend support to the hypothesis that the ITCZ breakdown plays a role in their formation. Tropical cyclone twins are observed exclusively in the Indian Ocean and in the West Pacific near the dateline. They are believed to form in association with super cloud clusters that straddle the equator in those regions. Shallow water model results presented herein corroborate this hypothesis. The existence of preferred regions for their formation is proposed to be associated with the life cycle and movement of their parent super cloud clusters. The shallow water model proved to be a useful simple tool for investigating barotropic dynamical aspects of the formation of tropical cyclone disturbances