Akademik Veri Yönetim Sistemi
Diğer Ülkelerdeki Kamu Kurumları Tarafından Desteklenmiş Proje, 2024 - 2024
This study investigates the effects of terrain roughness and density variations on geoid modeling in two regions: the Konya Closed Basin (KCB) in Turkiye and Auvergne in France. Using high-resolution Digital Elevation Models (DEMs) generated from SRTM mission (1 arc-second) and a 30 arc-second lateral density model (UNB_TopoDensT), the analysis explores how these factors influence geoid heights. Previous researchs have shown that variations in DEM resolution can lead to terrain correction changes of tens of mGal, particularly in mountainous regions. Finer resolution DEMs allow for higher accuracy in geoid models, which can be validated through GNSS/leveling data. Additionally, the study highlights the importance of accounting for density fluctuations between sedimentary layers and rock formations. Inaccuracies can arise when constant density values are used, especially near large water bodies. Topographical effects, such as the Bouguer shell effect, terrain corrections, isostatic effects, and residual terrain model (RTM) effects, must be considered when applying gravity data for geoid determination. The study emphasizes the importance of accurate topographic geometry and density distribution knowledge for determining geoid. High-resolution DEMs are essential for accurate direct and indirect topographic impacts on gravity measurements, which improves local gravity field interpretation. Validation of the gravimetric geoid models was conducted using GNSS/leveling data, revealing that terrain corrections significantly improved the accuracy of geoid model, particularly in high-
elevation regions. However, the contribution of the UNB_TopoDensT model showed inconsistency. In particular, employing density values below 2.4 g·cm3 in high-altitude areas resulted in inaccurate geoid determinations. The study concludes by emphasizing the need for incorporating accurate density models for regions with significant topographic and density variations. The geoid models in KCB and Auvergne demonstrate the potential of integrating lateral density models and detailed DEMs to enhance geoid accuracy, though careful consideration is necessary in high-altitude and density-fluctuating regions.