Ocean Utilization Group

It is well known that resources and energy, such as sea-floor hydrothermal deposit and methane hydrate, are present in EEZ of Japan. EEZ can be also utilized for natural energy conversion, such as wind power and tidal and ocean-current energy conversion. Offshore aqua-farming can contribute to the increase of self-sufficiency in food. Our laboratory aims to present a technology policy for industrialization of these marine technologies. Prediction of key-technology in the future is most important for making the effective technology policy. This can be achieved only by studying typical marine technologies, finding key-technologies and predicting future aspect by ourselves. Specifically, the following three themes are studied. 1) Sailing-type offshore wind-power plant. 2) GHG reduction in marine transportation. 3) Exploration and observation technology in deep sea by advanced deep sea robot.

In order to solve the global problems like supplies-reduction in natural resources and food, climate changes, etc.,
the sustainable development of the ocean has been laid hope on increasingly. As a certain big volume is essential
for the real effect on every problem, the industry-based activity would be necessary. The existing ocean industries such as fishery, shipping, offshore oil & gas industry, shipbuilding, etc. hold good human resources and specific infrastructures now, and have built up their own technologies, skills, experiences over many years. Based on such resources, and making collaborations among the conventional industries, it is expected that some new
business to solve the global problems will emerge and hopefully a new ocean industry will grow. Our researches are aimed at the new business producing. Technical feasibilities of novel proposals which will, we believe, contribute to the progress of human society are pursued, and social-economical issues are addressed with every branch of knowledge. At present, our interests are system for; CO2 capture & storage in the field of ocean, deep ocean mining, mobile power supply to very deep water, ultra-deep ocean drilling, etc.

One of the key challenges of human society in the 21th century is to establish sustainable society. Development of new type of resources and energies which reduce global warming and environmental impact is a key issue. Ocean provides such opportunities. Development renewable ocean energy such as wind, ocean current, thermal, wave and solar which is actively investigated in the world is a research area of our laboratory. Ocean also provides other chances such as mineral resources, CO2 ocean sequestration and space utilization for transportation and storage, and these are also research area of our laboratory.
Research and development project is proposed and function and platform related technologies such as riser, floating platform, station keeping and material are investigated.

More than ten seafloor massive sulfide (SMS) deposits, enriched with Au and Ag and containing varying amounts of Cu, Zn, Pb and Ba, are distributed within the Japanese Exclusive Economic Zone (EEZ). These deposits have recently become the focus of attention as a potential source of economically and socially valuable mineral resources in the near future. However, a great deal of research will be necessary to enable the exploration and exploitation of these resources. Ongoing surveys of SMS deposits within the Japanese EEZ are presently being conducted. Our laboratory aims, by means of field surveys and land-based studies, to investigate the genesis of SMS deposits and potential methods for their exploration, and to propose environmentally friendly methods for their development.

Ocean Environment Group

Our current research theme is numerical modelling and predictions, field and satellite observations of sea ice, which is very sensitive to climate change and has significant effects on global environment. Recent global warming stimulates human activities of resource development and transportations in cold regions such as the Arctic Ocean and the Okhotsk Sea. We should realize sustainable development by integrating various ocean data. Since there are not complicated vested interests in cold regions, our latest wisdom should achieve sustainable developments in cold regions earlier than the other regions. In addition, this result leads to the further research to develop technologies on the overall management and the providing technique of ocean information. The one to control information rules the world!

To utilize intelligently and to understand the Ocean, we conduct observational, numerical and predictability research. We conduct forecasting and hindcasting of the Kuroshio to utilize its enormous energy and to support safe navigation and operation in the sea. The wave climate near Japan shows an increasing trend. We perform observational, experimental and simulation research of the ocean wave to clarify the mechanism of its decadal change and also the mechanism of freak wave generation.
Wave and current fore- and hind-casting products will be utilized for fisheries, disaster prevention research, and assisting sail racing as well. All the collected and originally
produced data will be archived and will be distributed by use of a user-friendly data server
(waseda2.t.u-tokyo.ac.jp).

Our researches are aimed to form concepts of environmentally harmonizing systems, which coexist with natural environments for the global sustainability. For this purpose, we are developing computational models of environments using physics, chemistry, and biology, etc. Then these models are synthesized into simulation systems in order to predict environmental impacts and construct public acceptance. Our research interests are CO2 storage in deep ocean and in subsea underground, biological CO2 fixation, decomposition of methane hydrate, development of high performance photobioreactors, development of multi-scale ocean model, modelling of flashing light effect of photosynthesis and the effects of CO2 on fish and zooplankton, etc.

We conduct researches on the technologies for preservation and recovery of marine environment as well as on the methods for grasping, understanding, and predicting marine environmental changes. For example, material cycle and ecosystem dynamics are studied by both approaches of field observations and numerical modelling, for not only coastal areas which are greatly influenced by human activities but also marginal seas which are important for global environment or natural resources. The comprehensive assessment of ecosystem and socioeconomic systems are also carried out for the technologies such as coastal mitigation, ocean fertilization, and so on.

Ocean Sensing Technology Group

The URA laboratory is actively involved in the development and application of Autonomous Underwater Vehicles (AUV) as a platform for exploring our oceans, emphasizing the pursuit of new ideas, innovative technology and always pursuing actual application of our robots at sea. The robot “r2D4”, constructed in 2003, explored vast lava plains at a depth of 2,700 m in the Central Indian Ridge. The robot “Tri-Dog 1”, constructed in 1999, took photo mosaics in the Kagoshima bay area at a depth of 100 m to map the distribution of Tube worm colonies and reveal information concerning their underwater ecology. The robot “TUNA-SAND”, constructed in 2007, discovered a hydrothermal vent at 200 m depth in Kagoshima bay. Furthermore, we apply the underwater acoustic technology used by underwater robots to study the behavior of whales and dolphins, in particular developing monitoring instruments in collaboration with Indian researchers to perform long-term acoustic surveys on river dolphins such as the endangered Ganges river dolphin.

Under the sea/seafloor, there is a big new world which is not yet explored and exploited including its vast space, and it is eagerly expected to visit there without any burden. The shallow part of the sea has been explored frequently, but the deep part of the sea is still not because of its large water pressure. The world under the sea floor is really an un-explored world except small number of points of drilling for oil/gas. In order to visit this world freely, TAKAGAWA laboratory is developing new technology of ceramic pressure vessel which shall become basement for any robots and sensors. Also, new method to grasp the detailed distribution of deposits under the seafloor is under development and a new and simple mechanism of drilling different from the conventional rotating system is under development in order to extend our capability to this new world. Integrating these works, total design of recovery system of resources is also underway.

On the Japanese coasts, there are so many important facilities which can be exposed to the threats of terror attacks. So, we built an acoustic video system, modifying a dual-frequency acoustic camera DIDSON and developing an optimum underwater surveillance method and software. In succession, a Wharf Installed Security Sonar was developed. Recently, we have developed an effective moving surveillance method employing a consisting of three transducers, each with a different frequency. With the embedded software we developed for overlaying aerial photo maps on sonar images. Furthermore, intending to capture sea-bottom crustal deformations with high accuracy, we have been developing new technologies for seafloor geodetic observations with an AUV. This has led to the development of a small high-performance geodetic observation system and an ideal spherical acoustic transducer, both to be mounted on an AUV, and the tuning and evaluation tests of them have yielded good results.

To exploit persistently marine resources while preserving their environments, we are required to acquire more underwater information. In our laboratory, we are making a study of the underwater information acquisition and transmission by using the acoustic wave that is efficiently propagative in the water as well as the underwater information processing and visualization, which are, for example, applicable to fisheries acoustics, high speed underwater acoustic communication and network, and underwater information measurement technologies. As one of the main targets of our laboratory, we are also developing the unique and advanced application measurement systems by integrating the latest technologies covering such various fields as fisheries, marine navigation, oceanographic survey, underwater acoustics, data processing, electronics etc. The new USB-based 3D digital echo sounder system for mapping and assessing fish and aquatic plants, the multi-frequency floating mud measurement system and the sand drift measurement sonar system have been developed, all of which are directly useful for the environmental preservation purpose. Moreover, in order to acquire underwater information in the wide sea area on a real time basis, we are developing a new acoustic adaptor by using DSP which can as easily be handled as the ordinary internet adaptor used on land. This will certainly enable the systemization of the underwater acoustic network to be put in a practical use.

The ocean has always fluctuated. Causes of oceanic fluctuation are various such as sea surface wind, sea-level pressure, seawater density and the topography. Generally states of oceanic fluctuation are represented by flow such as oceanic general circulation and ocean current, and wave to express sea surface configuration. All things in the ocean take influence of waves and flows, are drifted and swayed. Ocean engineering starts from figuring out oceanic fluctuation and comes down to assessment of the influence of them. Main research subjects of the laboratory are as follows, 1) Sea surface measurement by using active microwave remote sensing, 2) Prediction of sea ice and oil spill behavior in ice covered sea, 3) Dynamics of underwater line structure, 4) Motion reduction of very large floating structure. The figure shows a concept of sea surface measurement system by using active microwave remote sensing.

Marine Research and Development System Group

This Laboratory conducts observational study aimed to understand marine environments. The distribution and transport of heat and chemical tracers (e.g. CO2) in the ocean are investigated and thus to clarify their variations by analyzing the data obtained by various observations; free-drifting autonomous profiling floats (Argo floats), the highest accurate basin-scale hydrographic observations of the temperature, salinity and chemical tracers, and buoy monitoring of air-sea heat flux by mooring buoys in the Kuroshio Extension region. The developments of the observation techniques to maintain the quality of data are also studied.

Climate variations and change have huge impacts on our lives. Japan and most parts of Asia are influenced by the seasonal monsoon variability and the interannual climate modes such as Indian Ocean Dipole, El Nino and El Nino Modoki. Our research objectives are therefore related to understand the physical and dynamical processes of tropical oceans and atmosphere, to predict climate variations on time scales of months to years, and to understand the mechanisms of that predictability. Besides data analyses, we rely on the computer simulation results because of data scarcity in large parts of oceans. Our state of the art global ocean-atmosphere coupled models not only simulate ocean and climate processes accurately but also predict climate fluctuations at long lead times. In addition to the understanding of climate impacts on societies, we also aim to study climate impacts on regional ocean processes. The inter-relation between climate and small-scale ocean processes is not only a key to ocean and climate predictions but also important for sustainable management of marine resources.