Calculation of the tide correction used in gravimetry

Abstract

In gravimetric surveys, the determination of the gravity at a specific point depends on field measurements and on the removal of the influence of the tide. With the current development of more sensitive gravimeters, a review of the tide correction calculation process applied in gravimetry is necessary because values that were once considered negligible may represent noise above the resolution of the new equipment. Much used until the present, the formulas shown in the study by Longman (1959) were elaborated with constants (distances, masses, ellipsoidal parameters, and orbital values) that can now be calculated more accurately, as well as conveniently rounded values for the time. The deformation of the crust caused by the terrestrial tide is another important factor that significantly affects the tide correction calculation results, and the Earth’s heterogeneity causes this deformation to differ between regions. Much effort has been made to map different regions with the objective of regionalizing the gravimetric factor; however, computer programs and even modern automated equipment still use fixed values. Therefore this paper aims to present a review that quantifies the impacts on the calculation of the tide correction considering parameters not yet used.