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Services - Geoid Repository


Regional Models

Japan (JGEOID2004)


  Authors: Y. Kuroishi, W. Keller     Created: 2004    Resp: T. Yahagi (GSI)  
      Status: PRIVATE    
Description:
The JGEOID2004 model is an improved gravimetric geoid for Japan of the Geographical Survey Institute (http://www.gsi.go.jp). It is constructed on a 1'x1.5' grid in the non-tidal system and it is referred to the GRS80 ellipsoid in the ITRF94 frame (epoch 1997.0). Newly acquired terrestrial gravity data supplemented the data gaps of the previous JGEOID2000 model. The geoid determination is based on the remove-restore technique, using EGM96 as the reference geopotential model and applying a 1D-FFT method. A "semidiscrete" wavelet analysis/reconstruction method with 2D Halo wavelets is applied to a combination of marine gravity data and the KMS2002 altimetric gravity model. The method is used to localize 2D signal components in the spatio-frequency domain and to screen them as a locally adjustable band-pass filter. Compared with 816 GPS/levelling benchmarks, JGEOID2004 shows a significant improvement over JGEOID2000: the standard deviation of the differences from the best fit plane is reduced to 9.2 cm. Substantial localized errors, which are due to systematic errors of the marine gravity data as well as to data gaps on land and in the inland sea, are effectively removed.

References:
Y. Kuroishi, W. Keller (2005). Wavelet approach to improvement of gravity field-geoid modeling for Japan, Journal of Geophysical Research, 110, B03402.


Japan