HR: 1330h
AN: G32A-0734    [PDF]
TI: Collocated Observations with a Superconducting Gravimeter and an Absolute Gravimeter FG5 at Esashi Station
AU: * Tamura, Y
EM: tamura@miz.nao.ac.jp
AF: National Astronomical Observatory, Mizusawa, 2-12 Hoshigaoka, Mizusawa, 023-0861 Japan
AU: Sato, T
EM: tsato@miz.nao.ac.jp
AF: National Astronomical Observatory, Mizusawa, 2-12 Hoshigaoka, Mizusawa, 023-0861 Japan
AU: Fukuda, Y
EM: fukuda@kugi.kyoto-u.ac.jp
AF: Graduate School of Science, Kyoto University, Oiwake Kitashirakawa Sakyo-ku, Kyoto, 606-8502 Japan
AU: Higashi, T
EM: higashi@kugi.kyoto-u.ac.jp
AF: Graduate School of Science, Kyoto University, Oiwake Kitashirakawa Sakyo-ku, Kyoto, 606-8502 Japan
AB: Continuous gravity change observations with a superconducting gravimeter (SG) are carried out for more than 12 years at Esashi Earth Tides Station, NAO, Japan. The objects of the observations are the studies of earth tide, core dynamics, secular change of gravity, and so on. Collocated absolute gravity measurements with an FG5 gravimeter of Kyoto University are regularly carried out once a year since 2000. The purposes of the collocated observations are, 1) to determine the scale factor of the SG at Esashi Station, 2) to constraint secular gravity change at the Station, and 3) to monitor long term stability of the SG. The SG has a high resolution in gravity changes, but it has a drift (even it is small) in the long term phenomena. The collocated observations of SG and FG5 reinforce their capabilities each other, and enable high resolution and long term stable gravity change observations. About the determination of the scale factor of the SG, it was estimated within the accuracy of 0.07%. The accuracy of at least 0.1% is required to compare observed tidal factors with theoretical ones. About the long term phenomena, annual change and pole tide are discussed already until now. The absolute gravity measurements give more constraint in the studies of such long term gravity changes.
DE: 1200 GEODESY AND GRAVITY
DE: 1244 Standards and absolute measurements
DE: 1249 Tides--Earth
SC: Geodesy [G]
MN: 2003 Fall Meeting