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Regional Models

Japan (JGEOID2000)


  Author: Y. Kuroishi     Created: 2000    Resp: T. Yahagi (GSI)  
      Status: PUBLIC    
Description:
The JGEOID2000 model is an improved gravimetric geoid for Japan of the Geographical Survey Institute (http://www.gsi.go.jp). It is referred to the GRS80 ellipsoid in the ITRF94 frame (epoch 1997.0) and it is constructed on a 1'x1.5' grid with newly acquired land gravity data. About 6.5 times as many data as those used for the previous models are collected and merged with marine data. The geoid determination method is based on the remove-restore technique and EGM96 is used as the reference geopotential model. De-trending is applied to the residual gravity anomalies at sea, for reducing long-wavelength distortion in the local application of Stokes integral. The least squares spectral combination is tested for evaluating the effects of Stokes kernel modification. Comparisons with the nationwide GPS/levelling network reveal a substantial improvement over the previous geoid models: the standard deviation of the differences after fitting the best plane is equal to 14.3 cm. Effectiveness of the de-trending to marine data is confirmed in the reduction of long wavelength distortion.

References:
Y. Kuroishi (2002). A New Geoid Model for Japan, JGEOID2000. In: M.G. Sideris (ed.), Gravity, Geoid and Geodynamics 2000, IAG Symposia Series, vol. 123, pp. 329-333, Springer Verlag.

Japan