Improvement in seafloor geodetic measurements by means of evaluation of sound speed variation in ocean

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K13557
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Solid earth and planetary physics
• Research Institution: Tohoku University
• Principal Investigator: Kido Motoyuki 東北大学, 災害科学国際研究所, 教授 (10400235)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 海中音速場 / 海底地殻変動観測 / GPS-A / 内部重力波 / XBT / CTD

Outline of Final Research Achievements

It is crucial for improvement in seafloor geodetic measurement to evaluate sound speed variation in ocean. In order to construct a proper ocean model, we conducted intensive continuous measurement of temperature profile in ocean using XBT, which is an expandable thermistor. Based on its obtained data, we proved that short-period variation is mainly caused by internal gravity waves. Using internal wave model, we construct correction method for sound speed, which leads improvement in detecting horizontal movement and even vertical one.

Free Research Field

海底測地学