FES2014 global ocean tide atlas: design and performance

Abstract

Abstract. Since the mid-1990s, a series of FES (finite element solution) global ocean tidal atlases has been produced and released with the primary objective to provide altimetry missions with tidal de-aliasing correction at the best possible accuracy. We describe the underlying hydrodynamic and data assimilation design and accuracy assessments for the latest FES2014 release (finalized in early 2016), especially for the altimetry de-aliasing purposes. The FES2014 atlas shows extremely significant improvements compared to the standard FES2004 and (intermediary) FES2012 atlases, in all ocean compartments, especially in shelf and coastal seas, thanks to the unstructured grid flexible resolution, recent progress in the (prior to assimilation) hydrodynamic tidal solutions, and use of ensemble data assimilation technique. Compared to earlier releases, the available tidal constituent's spectrum has been significantly extended, the overall resolution has been augmented, and additional scientific byproducts such as loading and self-attraction, energy diagnostics, or lowest astronomical tides have been derived from the atlas and are available. Compared to the other available global ocean tidal atlases, FES2014 clearly shows improved de-aliasing performance in most of the global ocean areas and has consequently been integrated in satellite altimetry geophysical data records (GDRs) and gravimetric data processing and adopted in recently renewed ITRF standards (International Terrestrial Reference System, 2020). It also provides very accurate open-boundary tidal conditions for regional and coastal modelling.

Dissipation and Bathymetric Sensitivities in an Unstructured Mesh Global Tidal Model

“…There have been numerous studies on using frictional tuning parameters to improve tidal results. Approaches have varied from methodical searches of what parameters provide the best results (Lyard et al., 2006, 2021), using bedform information to select values for the open ocean (Pringle et al., 2018), adjoint‐type methodologies for selecting optimal coefficients (Graham et al., 2017; Qian et al., 2021; D. Wang, Zhang, & Wang, 2021) and, in the case of overland flooding, using land use information to select values (Bunya et al., 2010). Our investigation suggests that through careful consideration of which areas of the globe are most sensitive to frictional perturbations, and through the use of cost function minimization, it is possible to more efficiently find optimal friction coefficients for these sensitive areas, resulting in a high fidelity global tidal model.…”

Orbital Artifacts in Multi‐GNSS Precise Point Positioning Time Series

“…Signal variations in the Earth rotation (Desai & Sibois, 2016) and ocean tidal loading (Lyard et al, 2021), which are confirmed to be beneficial for the GNSS-based products.…”

“…However, we do not find any propagated residual signals above the noise level in the system‐specific series. The reader should be aware of the changes in the modeling of the tidal models in the IGS repro3 standards, that is, high‐frequency variations in the Earth rotation (Desai & Sibois, 2016) and ocean tidal loading (Lyard et al., 2021), which are confirmed to be beneficial for the GNSS‐based products.…”

“…Correction models Phase wind-up, relativistic delays, solid earth tides (Petit & Luzum, 2010), ocean tidal loading (FES2014b; Lyard et al, 2021), subdaily variations in Earth rotation (Desai & Sibois, 2016) Table 1 Description of the Processing Strategy Each of the proposed solutions was processed twice, aiming to achieve different time resolutions of estimated parameters. First, a standard 24 hr static solution was prepared reflecting the most commonly used daily sampled PPP products (daily solution).…”

ANU GRACE Data Analysis: Orbit Modeling, Regularization and Inter‐satellite Range Acceleration Observations

“…The purpose of calibrating the accelerometer observations is to turn the biased measurements into "absolute" measurements of the non-gravitational accelerations acting on each satellite. These calibrated measurements can Process Description static gravity field DIR-R4 (truncated to degree 200) (Bruinsma et al, 2013) dealiasing atmosphere and non-tidal ocean AOD1B-RL06 (Dobslaw et al, 2017) ocean tide model FES2014 (Carrere et al, 2015;Lyard et al, 2021) modified Antarctica from Padman et al (2002) atmospheric tides S 1 , S 2 and S 3 from the AOD1B product (Dobslaw et al, 2017) non-gravitational accelerations Level-1B data ACC1B/SCA1B…”