The Tropical Waves: Studies of Easterly Waves and Equatorial Waves Stimulated by Prof. Yanai's Scientific Contributions

Prof. Yanai's career in the tropical meteorology started with a study of the typhoon formation from the easterly waves. The discovery of the Yanai-Maruyama wave or the mixed Rossby gravity wave in the lower stratosphere with his student, coincident with the development of equatorial wave theory in the same years, stimulated the studies of tropical waves. A series of spectral analyses and energy budget analyses in his group indicated the prominence of large-scale waves in the troposphere as well as in the stratosphere, and their tight interactions with tropical cumulus convections. Based on these studies, Prof. Yanai made a substantial contribution to a design of the GARP Atlantic Tropical Experiment (GATE) through the diagnostics with Q1 and Q2 of their own invention, which further enabled his group to reveal the wave-convection interactions. Prof. Yanai and his students further expanded the analysis of equatorial waves from various viewpoints including their enhancement through a mid-latitude forcing. In this presentation, recent scientific outcomes on the easterly waves, equatorial waves, and satellite data contributions on these topics are reviewed in relation to Prof. Yanai's profound perspectives.