1987 Fiscal Year Final Research Report Summary

Developlment of super-deep instrumental housings.

Research Project

Project/Area Number	61840012
Research Category	Grant-in-Aid for Developmental Scientific Research
Allocation Type	Single-year Grants
Research Field	気象・海洋・陸水学
Research Institution	Ocean Resarch Institute, University of Tokyo
Principal Investigator	TAIRA Keisuke Ocean Research Institute, University of Tokyo. Professor, 海洋研究所, 教授 (50013579)
Co-Investigator(Kenkyū-buntansha)	宮崎秀久日油技研工業(株), 開発部, 部長 FUKASAWA Masao Ocean Research Institute, University of Tokyo. Research Assoc., 海洋研究所, 助手 (10143546) MIYAZAKI Hidehisa Nichiyu-Giken, Co. Director of Develpment Section
Project Period (FY)	1986 – 1987
Keywords	Pressure housing for ocean with depth greater than 12 km / Titanium housing / Self-recording current meter / acoustic release / Izu-Ogasawara Trench / Water velocity fluctuatin in a ternch / tidal currents / 慣性振動
Research Abstract	Deepest poritions over the earth are located in the western Notrh Pacific. Usually capcbilty depth of oceanic instruments in limited to be less than 600 m, however, the depth is obviously not enough for Japanese scientist. In this research project, we dovolopod we have developed instrumental nousings for depth greater then 12 km water by using titanium cylinder We developed acoustic release and current meter with titanium housing Acoustic characteristics of the release is improved by a narrow beam transducer pattern of directional, and has been proced the capability of more than 12 km signal transmission, A current meter with titanium housing has been proved to applicapable for a depth greater than 12 km. Deployments of the mooring was made on Jamary 28, and recoveres on mayll,1987. A 104 day long continuous record of current shows that inertial oscilation is increased at bottom layer. A mazimum current speed is greater than 10 cn/sec, which is first shown by the research for the depth of 9205 m in the Izu-Ogasawara Trench.