Study on the selection of optimal global geopotential models for geoid determination in Kuwait

Abstract

In this study, a thorough validation of the recently released Global Geopotential Models (GGMs) has been carried out by comparing all models with both the free-air (FA) gravity anomaly observations and GPS/Levelling data in Kuwait. First, the gravity functional in terms of FA gravity anomalies and geoid heights that derived from GGMs and compared with the ground-based data before applying the Spectral Enhancement Method (SEM). The findings indicate that the combined GGMs, generally, fit the ground data better than the satellite-only GGMs due to the existing spectral gaps. Second, the FA gravity anomalies and geoid heights, obtained from GGMs at maximum Spherical Harmonics (SH) degree/order (d/o) for the combined models and from spherical harmonics d/o ranging from 100 to their maximum d/o, with a step of 10 d/o for the satellite only GGMs, were compared with the corresponding ones from terrestrial data using the SEM. For the FA gravity signal, the EIGEN-6C4 manifested the best results of combined GGMs with differences characterised with a mean of 0.967 mGal and a Standard Deviation (STD) of 2.845 mGal, while TIM_R5 at SH (d/o) 200 showed the best results with a mean of satellite only GGMs with a mean if 1.008 mGal and a STD of 2.657 mGal. In the case of the evaluation of the geoidal height with GPS/levelling, XGM2016 manifested the best results of combined GGMs with differences characterised with a STD of 0.234 m. For the satellite only GGMs, the best results have been obtained from SPW_R5 at SH d/o 250 with a STD 0.207 m.

Keywords:

• Kuwait
• Global geopotential models
• Geoid
• Gravity anomalies
• GPS/levelling

Acknowledgements

We thank our colleagues from Vision International Co., Kuwait, for having provided us the GPS/levelling observations that greatly assisted the research and we would also like to show our gratitude to Eng. Eid Al-Aadawany CEO of Vision Kuwait for sharing their pearls of wisdom with us during the course of this research. We would also like to thank the reviewers and editors for their comments on this manuscript.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.