Newton's
Bulletin
Issue n. 4, April 2009 - External Quality Evaluation Reports of EGM08 [pp. 99-109]
Evaluation of EGM2008 and PGM2007A over Sweden
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Abstract
An important part of the work performed bythe IAG/IGFS Joint Working Group “Evaluation of Global Earth Gravity Models” is to test the new Earth Gravitational Model EGM2008 and its preliminary versions. The purpose of thispaper is to present the evaluation of the preliminary PGM2007A and final model EGM2008 over Sweden. The evaluation is done by comparing the model to 195 high quality GPS/leveling observations, to the best regional quasigeoid model presently available and finally to observed gravity anomalies. The regional (gravimetric) quasigeoid model in question has previously been computed in cooperation between Lantmäteriet and the Royal Institute of Technology inStockholm (KTH) using least squares (stochastic) kernel modification with additive corrections. The most important result is that EGM2008 agree with the Swedish GPS/leveling data with a RMS of 2.7 cm after a 1-parameter transformation. This is comparable to the corresponding RMS value of 2.2 cm obtained for the regional quasigeoid model. Thus, EGM2008 agrees well with the GPS/levelling data and the regional quasigeoid model in Sweden.