A Precise Gravity Tide Model for Port-au-Prince in Haiti

In this report, we present the results of earth tides analyses of long gravity time series at two different locations in the city of Port-au-Prince in Haiti. Measurements from two different generations of relative spring gravimeters are used: the 20-year-old Scintrex CG5-008 of the University of Luxembourg and the new Scintrex CG6-270 from the “Unité de Recherche en Géosciences” (URGEO) of the Faculty of Sciences of the State University of Haiti.

The earth tidal parameters are determined for both time series from the Scintrex CG5-008 and the Scintrex CG6-270. These parameters are extremely valuable either to assess the precision of the ocean tide models of the seas surrounding the Haitian Island or to make predictions of the gravity tides. Observed tidal parameters are indeed more precise than using a theoretical model of the Earth body tides combined with the attraction and loading gravity effects calculated with ocean tide models. These predictions provide the best tidal corrections for absolute gravity measurements as well as for relative gravity surveys on the Haitian Island. They will increase the accuracy of past and future geodetic observations.

After correcting the tidal parameters for the ocean loading and attraction effects calculated with a global ocean tides models, we found a close agreement with the state-of-the-art body earth model. On the other hand, the tidal parameters are sensitive to the structure and elastic properties of the upper crust (You and Yuan, 2021). The results presented in this report might be useful to investigate them.