2001 Fiscal Year Final Research Report Summary
Precise Observation of the Secular-Gravity Changes by means of the combination of Absolute and Superconducting Gravimeters.
| Project/Area Number |
11440132
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体地球物理学
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| Research Institution | KYOTO NUNIVERSITY |
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Principal Investigator |
FUKUDA Yoichi Graduate School of Science, Kyoto Univ., Associate Professor, 大学院・理学研究科, 助教授 (30133854)
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| Co-Investigator(Kenkyū-buntansha) |
HIGASHI Toshihiro Graduate School of Science, Kyoto Univ. Research Associate, 大学院・理学研究科, 助手 (90135517)
FUJIMORI Kunio Graduate School of Science, Kyoto Univ. Lecturer, 大学院・理学研究科, 講師 (00025470)
TAKEMOTO Shuzo Graduate School of Science, Kyoto Univ. Professor, 大学院・理学研究科, 教授 (40027256)
IMANISHI Yuichi Ocean Reseach Institute, Univ. of Tokyo, Research Associate, 海洋研究所, 助手 (30260516)
SATO Tadahiro Earth Rotation Devision, National Astro.Obs.,Associate Professor, 地球回転系, 助教授 (10000176)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Absolute Gravimeter / Superconducting Grayimeter / Precise Grayimetry / Satellite Gravity Mission / CHAMP / GRACE / Gravity Variation / Variation of the Earth |
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| Research Abstract |
To obtain so accurate data sets of gravity variations as to be used for the comparison with the satellite gravity data such as GRACE, we studied practical methods to combine superconducting and absolute gravity measurements as well as to improve the accuracies of the individual measurements.
For this purpose, we have continued superconducting gravity observations at the observation stations of Kyoto, Esashi, Matsushiro in Japan and Bandung in Indonesia. We also started groundwater measurements to reveal their gravity effects at Kyoto and Bandung stations: The results show a clear correlation between the groundwater variations and the gravity observations, especially at the Bandung station. We confirmed that the accuracy of the gravity measurements are improved by removing the groundwater effects.
We carried out several absolute gravity measurements in parallel with the superconducting observations at the Esashi and Matsusiro stations in 2000 and 2001 as well as the Kyoto stations where absolute measurements are periodically conducted. The total observation, time in both stations exceeded more than one month which is long enough for purpose of comparison. Moreover, we developed a new method for the data processing, we finally obtained very precise calibration factors for the superconducting gravimeters. We also determined reference gravity values for future studies of secular gravity changes at the stations.
To maintain the accurate absolute gravity measurements, adjustments and validations are very important. We carried out the comparison between the absolute gravity meters in collaboration with Geographical Survey Institute. The comparison also contributed to accumulate the know how of the absolute gravity measurements.
In addition to the actual measurements, we also conducted several simulation studies of satellite gravity mission data and ground base measurements, and we established the basic techniques of future utilization of those data sets.
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