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Regional Models

Japan (JGEOID98)


  Author: Y. Kuroishi     Created: 1998    Resp: T. Yahagi (GSI)  
      Status: PRIVATE    
Description:
The JGEOID98 model is an improved gravimetric geoid for Japan of the Geographical Survey Institute (http://www.gsi.go.jp). It is constructed on a 3'x3' grid in the non-tidal system and it is referred to the GRS80 ellipsoid in the ITRF89 frame. About 570000 ship gravity data are improved by adjusting them for about 50000 cross-over errors. The geoid determination is based on the remove-restore technique, using EGM96 as the reference geopotential model and applying a 1D-FFT method. Compared with GPS/levelling benchmarks, JGEOID98 shows improvement over JGEOID93 by 29 % in short wavelength, and a significant tilt reduction. The remaining trend can be partly explained by gravity errors: overestimation of gravity induced from EGM96 east off Hokkaido and underestimation south off Taiwan.

References:
Y. Kuroishi (2001). An improved gravimetric geoid for Japan, JGEOID98, and relationships to marine gravity data. Journal of Geodesy, 74(11), pp. 745-755.


Japan