Modelling the global ocean tides: modern insights from FES2004

Abstract

During the 1990s, a large number of new tidal atlases were developed, primarily to provide accurate tidal corrections for satellite altimetry applications. During this decade, the French tidal group (FTG), led by C. Le Provost, produced a series of finite element solutions (FES) tidal atlases, among which FES2004 is the latest release, computed from the tidal hydrodynamic equations and data assimilation. The aim of this paper is to review the state of the art of tidal modelling and the progress achieved during this past decade. The first sections summarise the general FTG approach to modelling the global tides. In the following sections, we introduce the FES2004 tidal atlas and validate the model against in situ and satellite data. We demonstrate the higher accuracy of the FES2004 release compared to earlier FES tidal atlases, and we recommend its use in tidal applications. The final section focuses on the new dissipation term added to the equations, which aims to account for the conversion of barotropic energy into internal tidal energy. There is a huge improvement in the hydrodynamic tidal solution and energy budget obtained when this term is taken into account.

2D PWV monitoring of a wide and orographically complex area with a low dense GNSS network

“…The GPT is based on 15° × 15° global grids of monthly mean P and T profiles from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data for 3 years (September 1999-August 2002); • the absolute antenna phase center was modeled using the IGS_08 model (Schmid et al 2007); • the ocean loading FES2004 (Lyard et al 2006) and atmospheric loading according to Tregoning and van Dam (2005) were considered; • the IGS final orbits were readjusted during the analysis and coherent Earth orientation parameters were used; • when available, a priori coordinates originated from ITRF2008 (Altamimi et al 2011) but were only loosely constrained. As already mentioned, a simultaneous daily positioning solution was estimated to guarantee the homogeneous adjustment of the parameters; • the cutoff elevation remained fixed to the conservative value of 10°.…”

Testing impact of the strategy of VLBI data analysis on the estimation of Earth Orientation Parameters and station coordinates

“…an earthquake. Moreover, we introduced station corrections due to the solid Earth tides, ocean tidal loading (FES2004, (Lyard et al, 2006)), atmosphere tidal and non-tidal loading after (Böhm et al, 2006), pole tide, ocean pole tide and thermal antenna deformation. The radio-source coordinates were fixed to their catalogue positions, and source structure corrections were not applied.…”

Impact of Ocean Tides Loading on Precise Point Positioning Based on FES2004 Model

“…The FES2004 ocean atlas was computed using the CEFMO hydrodynamic model (Code aux Eléments Finis pour la Marée Oceanique) with the CADOR (Code d'Assimilation de Données Orienté Représenteur) method for assimilating tide gauge and altimeter data (Lyard et al, 2006). Grid resolution is 0.125 degree (IERS Conventions, 2010).It uses finite element mesh named Global Finite Element Model-2 (GFEM-2), designed so that elements length is proportional to local ocean's depth and slope.…”

“…This enables to take into account coastlines, shelf breaks and volcanic ridges. The mesh results in 500000 elements and 1000000 computational nodes (Lyard et al, 2006).…”