Long term environmental monitoring at Tokyo bay entrance is important in order to control the current and water quality in Tokyo bay. We installed the environment observation system in a ferry boat which crosses the Tokyo bay mouth. The system is composed of ADCP (Acoustic Doppler Current Profiler), water quality and meteorological observation system. Observation data will be used as the bay mouth boundary condition in numerical simulations of Tokyo bay. In order to predict and control the Tokyo bay environment, this observation data will be also used.
　In this report, the observation system in the ferry and the data obtained from February to June 2003 are introduced.