Gravimetric Satellite Measurement Corrections with EOT20 Tidal Models

Abstract

The need to better quantify and monitor Climate Change (CC) is crucial for scientists and decision-makers alike to take timely actions to prevent irreversible damage. Space-based Earth Observation (EO) missions, such as the GRACE Follow-On (FO) Mission, play an irreplaceable role in understanding climate change. Observational data on environmental damages, such as the drastic changes in terrestrial water cycles, sea-level, and mass balance of ice sheets and glaciers, require higher temporal and spatial resolution in gravimetric measurements. To achieve this, the Relativistic Modelling Department at the DLR Institute of Satellite Geodesy and Inertial Sensing, aims to provide a Digital Twin for future EO Missions with higher resolution satellite simulations. Therefore, DLR and ZARM (University of Bremen) have developed the Hybrid Simulation Platform for Space Systems (HPS) to analyse emerging space technologies. This software includes disturbance forces on the satellite such as solar, albedo, and infrared radiation and aerodynamic drag. We aim to add some time-varying effects such as the oceanic tides, oceanic pole tides and the solid earth tides. This paper focuses on the current research status in the implementation of two empirical tidal models by DGFITUM - EOT11a (Empirical Ocean Tide 2011) and EOT20 (Empirical Ocean Tide 2020) to simulate the ocean tide effects on the satellite attitude and orbit. EOT20 provides 17 tidal coefficients in a spatial resolution of a 0.125degree grid using multi-satellite mission data from 1992 to 2018 and the FES2014 (Finite Element Solution 2014) as the reference oceanic tide model. In the future, the simulated satellite acceleration applying EOT20 is compared to those that are calculated incorporating EOT11a and the measurement data such as from GRACE-FO. Thus, Digital Twins of space-based technology provide data that helps to generate a more accurate model of the Earth and help tackle climate change.