Technology for research on the ocean
   Water quality analysis at the ocean

海とかもめThere are two methods for analyzing the chemical composition of seawater. One is to analyze directly in seawater and the other one is to analyze on the observation ship using the water sampling equipment. However, since these methods are performed only on the several ship points in the wide ocean, it is true that research area is limited. It would be almost impossible to keep track with all the phenomenon of ocean surface vessels that vary on a scale between from hours to months.

To make a future plan for water pollution and global warming that are currently on the problem, it is important to study the features and dynamics of the ocean used by long-lasting and global observation of ocean currents and temperature change.


 The role of satellite remote sensing

It is not visible, but the structure of the ocean has several layers like as the atmosphere. The factors that alter the structure of near sea level are, in large-scale, difference of thermal supply caused by the seasonal variation of solar radiation and , in medium and small-scale, wind, cooling, passage of the vortex, and ocean currents change. These processes vary by ocean area or season and have sometimes constant variation pattern. For the purpose to reveal marine material circulation associated with biological activity, it is important to study processes of mixing and flow in each ocean area and characteristics of biological or chemical processes caused by these processes in the whole ocean area.

The role that is expected to remote sensing (telemetry), is to complement the discrete vessel observation. Remote sensing by satellite, because it can be repeatedly measured the broad ocean areas at the same time, is likely ideal for compliments of the ship observing.

 Development of satellite image analysis software

We have been working on and developed a system to analyze satellite picture data automatically and provides water quality of the ocean. We have made accomplishments such as systems to analyze data from LANDSAT, SPOT of France and IRS of India, or ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor and contributed to develop processing algorithms for the analysis of water temperature distribution, turbidity distribution, density distribution of aquatic plants and so on.


Turbidity distribution in Tokyo-Bay, October 1998. Water surface temperature distribution in Tokyo-Bay, November 1998.