The Advanced Earth Observing Satellite-II (ADEOS-II), the successor to ADEOS, has been developed to advance Earth observation technologies. It acquires data to help researchers understand the mechanism of the global environmental changes such as global warming and to support meteorology and fishery activities. It is equipped with two JAXA sensors: AMSR for quantitatively observing various geophysical data concerning the water cycle, and GLI for observing oceans, land and clouds with high accuracy. It also carries three sensors provided by international and domestic partners. ADEOS-II is expected to provide the data necessary for us to understand the circulation of water, energy, and carbon in order to contribute to studies on global environmental changes.