Özet:

High-degree geopotential models of spherical harmonic coefficients are used for modelling the exterior gravity field of the Earth. These coefficients are derived from satellite tracking data, altimeter data, and terrestrial and airborne gravity data. Hundreds of thousands of coefficients and standard deviation values for these coefficients are estimated from millions of measurements. The geopotential model accuracy is affected by the amount, the distribution and the type of measurements. The satellite gravity field missions have provided accurate data forming geopotential models since 1960’s. The geopotential models related to the satellite gravity field missions are experienced by interior validation (estimated error degree variances of fully-normalized coefficients) or outer validation (comparison of model based gravity anomalies and geoid heights with terrestrial measurements). In this paper, recent high-degree geopotential models are primarily explained and evaluated by GNSS/levelling data of a selected study area. The objective of this evaluation is to determine the high-degree geopotential model giving a better fit to the GNSS/levelling data over the study area for the contribution to the regional geoid determination studies in Turkey.

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