Observational Analysis of Tropical Cyclone Formation. Part I: Basic Description of Data Sets

Abstract Twelve composite data sets are constructed from rawinsonde data in the tropical northwest Pacific and tropical northwest Atlantic Oceans. Each data set is a composite average of approximately 80 individual disturbances. Four different types of non-developing oceanic tropical disturbance are composited. For comparison, disturbances in each ocean are composited at four different stages of intensification from pre-hurricane to hurricane and pre-typhoon to typhoon. In total, 912 different tropical weather systems go into the composites and approximately 40 000 rawinsonde observations are used. Details are presented on data density, number of individual weather systems averaged and mean position for each composite system. The basic thermodynamic and dynamic properties of the systems are discussed as well as regional differences between the Pacific and the Atlantic. The analyses presented here form a framework for Part II and subsequent papers which use these composite data sets to investigate the gene...