HR: 1340h
AN: G33B-0050    [Abstracts]
TI: Illustrating the improved global geopotential models by use of local gravimetric geoids
AU: * Omang, O C
EM: ove.omang@umb.no
AF: Department of Mathemathical Sciences and Technology, Drøbaksveien 31 POBox 5003 UMB, Å s, 1432 Norway
AB: New global geopotential models (GGM) have been computed by several different institutes, e.g. GFZ and CSR, based on data from the satellite missions GRACE and CHAMP. These new models may be divided into two subgroups, models based on satellite data only and models based on a combination of satellite and surface gravity data. In this work we investigate whether the new GGMs give better representation of the long wavelength part of the Earth's gravity field. This is done by comparing local gravimetric geoid models to a synthetic geoid model. The local gravimetric geoid models are computed using local gravity data with a selected GGM as reference field. The Stokes kernel is also modified using the Wong-Gore approach. Local gravimetric geoid models using GGMs based on GRACE data as reference field give significantly better results than using either EGM96 or CHAMP. The best results are obtained in combination with a modified Stokes kernel truncated at degrees 90 - 95. Using EGM96 as a reference field smallest standard deviation is obtained with Stokes kernel truncated at degree 30. This indicates that the new GGMs give a better representation of Earth's gravity field.
DE: 1200 GEODESY AND GRAVITY
SC: Geodesy [G]
MN: Fall Meeting 2005