The effect of crustal density heterogeneity on determining gravimetric geoid: Example in Central Anatolia, Türkiye

Abstract

Accurate geoid height determination are crucial for achieving high precision in geospatial measurements. In this context, one key challenge is accounting the density for the Earth's topography, which varies considerably across different regions. The assumption of a homogeneous crustal density value of 2.67 g/cm3 has traditionally been employed in geoid determination using Stokes’ formula. However, recent studies have underscored the need to consider the actual density variations, which can deviate by up to ±20% from this assumed value. Such deviations can lead to substantial discrepancies in geoid height calculations, especially in regions characterized by significant topographic variations, such as mountainous areas. In this study, we address this issue by developing a local density model specifically tailored to Central Anatolia, Türkiye, using Bouguer gravity anomalies. By incorporating this refined density model, we aim to improve the accuracy of gravimetric geoid determination in the mountainous terrain of the study area. To achieve this objective, we employ the Least Squares Modification of Stokes’ Formula (LSMS) approach, implemented via the LSMSSOFT software package. Through numerical analysis, our results demonstrate noteworthy geoid height differences, sometimes exceeding a few decimeters, between the local density model and the conventional homogeneous crustal model. These disparities point out the significance of considering local density variations, particularly when striving for centimeter-level accuracy in geoid determination, especially in topographically complex regions. In conclusion, this study highlights the critical impact of density variations on geoid determination and emphasizes the necessity of adopting local density models, particularly in mountainous areas. © 2024 Elsevier Ltd