| Project/Area Number |
14540403
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MICHIDA Yutaka The University of Tokyo, Ocean Research Institute, Associate Professor, 海洋研究所, 助教授 (20323628)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | ocean surface / diffusion / drifters / GPS / water exchange / drift prediction / eddy diffisivity |
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| Research Abstract |
GPS tracked surface drifters have been developed for observations of fine structure of ocean surface curent field. A compact GPS data logger manufactured by Koden Electronics Co. Ltd., which was originally designed for tracking migrating birds such as albatross, is installed in a container made of strengthening glass. The container is put on the top of a oval float that is drogued with a holey sock to reduce the wind slip effect. This is very low cost drifter comparing with others, because all the parts but GPS are quite common things. A series of preparatory experiments carried out in Tokyo and others, because all the parts but GPS are quite common things. A series of preparatory experiments carried out in Tokyo and other test sites in Japan shows that the accuracy of GPS positioning with the logger is estimated at 5m in average. It means that the accuracy of current measurement with the drifter is expected to be less than 2 cm/s, when the interval of positioning is set to be 5minutes. Four to six drifters were applied to an investigation on the dispersion process of particles on the sea surface. We deployed them in the Otsuchi Bay and tracked them for a couple of hours, in July 2002, January 2003 and July 2003. Although we have still been analyzing the data including error estimations, a preliminary calculation has given estimation for diffusivity in the Bay. We also describe the trajectories of these drifters that provide information on detailed motions of water paticles resulting in the estimated diffusion coefficients. Our experiments have demonstrated the effectiveness of the drifter in observing detailed variability of surface current and applicability to visualization of the coastal current field.
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