Toward Improving the Accuracy of the Global Ocean Tide Model in Shallow and Coastal Waters

Motivated by the wide applications of empirical global ocean tide models in Earth science, particularly in shallow waters and coastal regions, we proposed an updated global ocean tide model representing all major diurnal and semidiurnal tidal constituents. We integrated the development technique of the Technical University of Denmark (DTU10) model and calculated the residual tides using the intermediary FES2012 model. We utilized all available Topex/Poseidon, Jason-1, Ocean Surface Topography Mission (OSTM)/Jason-2 primary and tandem missions to develop the new model. To reduce the discrepancies between the model and in situ measurements estimated S₂ tide constituent, the ERA-Interim model was selected for dry tropospheric correction of altimetry data. The newly developed model with an improved spatial resolution from 1/8°×1/8° to 1/16°×1/16° was assessed and compared against contemporary global ocean tide models using in situ measurements in coastal regions, continental shelf waters, marginal seas, and deep waters. The results demonstrate improvements in shallow waters and coastal regions, particularly in representative coastal regions such as the Northwest European Shelf and East Asian Marginal Seas. Moreover, the model performs well in simulating S₂ and K₂ tides with root mean square differences of 0.355 and 0.234 cm, respectively, against in situ measurements in deep waters worldwide. Compared with that of DTU10, the root sum square of the new model for the eight main tidal constituents decrease by 8.4% to 0.997 cm.