Comparative Assessment of Global Models of the Earth’s Gravity Field

—Empirical comparative study of the modern global models of the Earth’s gravity field (EGF) in the form of geopotential spherical harmonics is carried out. The importance and topicality of this study is associated with the growing number of models and strengthening the requirements to the modeling results. The obtained comparative characteristics are based on the results of statistical processing of model quasi-geoid heights and gravity anomalies on global and regional scale (by the example of the Arctic region and territory of Russia). A large and diverse array of the examined models and the study method determine the novelty of the obtained results. Overall, 103 models have been studied, among which three are Russian and others are developed by foreign authors. The studied models include those with low-, medium-, high-, and super-high spatial resolution. The effect of convergence (nonparallelism) of meridians at the calculation points on the statistical characteristics of EGF models is estimated which, according to the obtained estimates, can be significant. It is shown that this effect can be taken into account by a modified approach that involves introducing the weighting factors. The discrepancies between models in different combinations are analyzed. Based on this analysis, the contribution of the new satellite geodetic data obtained with the use of satellite-to-satellite systems and satellite gradientometry is estimated. The importance of taking into account the intragroup, intergroup, and inter-regional differences between the studied models is shown.