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| Titel |
Geoid determination with different density hypotheses in the Xinjiang and Tibetan regions |
| VerfasserIn |
Jiancheng Han, WenBin Shen |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077789
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| Zusammenfassung |
| A 5′×5′ regional gravimetric geoid, XTG2013, has been developed for the Xinjiang and Tibetan regions (25~50° N, 70~100° E). The realization of XTG2013 follows an original method, namely, the shallow-layer method (Shen, 2006), which is quite different from the classical ones (Stokes’ method, Molodensky’s method, etc.) and takes full advantage of the precise Earth gravity field model EGM2008, digital topographic model DTM2006.0 and global crust density model CRUST2.0. In this study, we have taken the lateral and radial density variations into account by making use of CRUST2.0. In order to investigate the effects of the density variations in the test regions, we computed another gravimetric geoid in the same region using the same reference gravity filed, digital topographic model and processing procedures, but with a constant density hypothesis (2.67g/cm3 for rock, 1.0g/cm3 for water and 0.92g/cm3 for ice). This “Constant-density based geoid” is then referred to as XTG2013c for convenience. XTG2013, XTG2013c as well as the EGM2008 geoid (in which a constant topographic density is adopted) are compared with the GPS/leveling benchmarks (GPSBMs). The validations show that (1) the accuracy of EGM2008 geoid in the test region is ~20cm, (2) XTG2013c fits the GPSBMs slightly better than the EGM2008 geoid, (3) XTG2013 outperforms the other models significantly, and its accuracy is ~16cm in contrast to ~20 cm for the XTG2013c and the EGM2008 geoid, (4) the differences in geoid undulations in the test region due to different density hypotheses, namely the differences between XTG2013 and the XTG2013c can reach a magnitude of ~4cm, which is significant and could not be negligible in the precise geoid determination with centimeter accuracy. This work was supported partly by the NSFC (grant No. 41174011), National 973 Project China (grant No. 2013CB733305), NSFC (grant No. 41210006, 41128003, 41021061, 40974015). |
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