碩士 / 國立成功大學 / 測量及空間資訊學系碩博士班 / 95 / In period 2000-2002, a new leveling height system of first order, class I, with 1010 benchmarks in Taiwan was measured by precise electric leveling instruments. The Global Positioning System (GPS) measurements and terrestrial gravity measurements were carried out for the orthometric corrections
. In addition, collimation error, refraction error, earth’s curvature, rod temperature and other systematic errors were also corrected in the Taiwan Vertical Datum, TWVD2001. But the influences of earth’s tides were not reduced.
The purpose of this study is to discuss the effects of the earth’s tides, namely solid tides and ocean tides, on the leveling measurements. The oceanic loading model developed by Mr. Wang’s tilt factors derived by global ocean tide model CSR4.0 and the China offshore data are adopted for the reductions, and the deformable earth’s model are used for solid earth’s tidal correction. The positions of Sun and Moon are obtained from DE200 ephemeris. After corrected the leveling data, the leveling network of first order, class I are re-adjusted. The results show that the corrections of the solid earth’s tides range from -0.185 mm to 0.247 mm, while the corrections of oceanic tide loading range from -0.185 mm to 0.097 mm. In total, the tidal effects on the leveling measurements range from -0.185 mm to 0.225 mm in the leveling network of first order, class I. The sigma-naught is not improved and is estimated to be plus or minus 0.73mm. However the change of the adjusted heights is significant and most of the height variations are under 3mm in the northern of Taiwan, and the maximum value is about 9mm in the southern of Taiwan. The effects of the earth’s tides are so significant that the corrections are necessary.
| Identifer | oai:union.ndltd.org:TW/095NCKU5367003 |
| Date | January 2007 |
| Creators | Yao-ping Chang, 張耀屏 |
| Contributors | Rey-Jer You, 尤瑞哲 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 73 |
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