Toshio Yamagata graduated from the University of Tokyo in 1971. His major professional career includes professor of Department of Earth and Planetary Science of the University of Tokyo and program director of Frontier Research System for Global Change of JAMSTEC and NASDA (now JAXA). After retiring from Dean of School of Science, the University of Tokyo in 2012, he is currently Director of Application Laboratory of JAMSTEC. One of his outstanding scientific achievements is the discovery of the climate mode in the Indian Ocean named Indian Ocean Dipole. For his innumerable contributions to physical oceanography and climate dynamics, he received many national and international honors such as the Sverdrup Gold Medal from the American Meteorological Society, the Prince Albert I Gold Medal from the International Association for the Physical Sciences of the Oceans, and the Medal with Purple Ribbon from Japan.