Determination of the Normal Earth Gravimetric Coefficients in Syria and Evaluation of Accuracy

Abstract

To model the local geoid in Syria, it is necessary to calculate the Earth's gravitational anomalies Δg, which represent the difference between actual gravity g on the Geoid and the theoretical gravity ɣ based on WGS 84. Historically, Cassini's original formula (1930) is used to compute the theoretical gravity from the global gravimetric coefficients β and β1. This formula assumes that the normal earth is homogeneous with equipotential density at all its points. This hypothesis is idealistic and does not accurately reflect reality. This study aims to determine the gravimetric coefficients β and β1 specific to Syria using terrestrial gravity measurements at 33 locations distributed across the country, by using three separate methods of measurement were taken advantage of, each according to the specific equipment utilized, to accurately determine the aforementioned gravimetric coefficients. These coefficients are calculated specifically to compute the theoretical gravity on WGS 84, to find a means for utilizing future GPS measurements to calculate the orthometric heights in Syria based on a future local geoid model. This research shows that the average values for Syria's normal earth gravimetric coefficients are β =0.0052497 and β₁=0.000058.