Abstract
AbstractThe recently upgraded barotropic tidal model TiME is employed to study the influence of fundamental tidal processes, the chosen model resolution, and the bathymetric map on the achievable model accuracy, exemplary for the M2 tide. Additionally, the newly introduced pole‐rotation scheme allows to estimate the model’s inherent precision (open ocean rms: 0.90 cm) and enables studies of the Arctic domain without numerical deviations originating from pole cap handling. We find that the smallest open ocean rms with respect to the FES14‐atlas (3.39 cm) is obtained when tidal dissipation is carried out to similar parts by quadratic bottom friction, wave drag, and parametrized eddy‐viscosity. This setting proves versatile to obtaining high accuracy values for a diverse ensemble of additional partial tides. Using the preferred model settings, we show that for certain minor tides it is possible to obtain solutions that are more accurate than results derived with admittance assumptions from data‐constrained tidal atlases. As linear admittance derived minor tides are routinely used for de‐aliasing of satellite gravimetric data, this opens the potential for improving gravity field products by employing the solutions from TiME.
Highlights
Signatures of ocean tidal dynamics are omnipresent in oceanographic and geodetic observations taken either on the ground or from space
We find that the smallest open ocean rms with respect to the FES14-atlas (3.39 cm) is obtained when tidal dissipation is carried out to similar parts by quadratic bottom friction, wave drag, and parametrized eddy-viscosity
This includes periodic variations in ocean currents registered by moored instruments or acoustic tomography (Dushaw et al, 1997; Luyten & Stommel, 1991; Ray, 2001) as well as by induced secondary magnetic fields (Maus & Kuvshinov, 2004; Saynisch et al, 2018), sea surface height changes measured from tide gauges and satellite altimetry (Doodson, 1928; Schrama & Ray, 1994), and global bottom pressure variations from pelagic pressure recorders and gravimetric satellite missions (Wiese et al, 2016)
Summary
Signatures of ocean tidal dynamics are omnipresent in oceanographic and geodetic observations taken either on the ground or from space. The existing weaknesses in present-day admittance methods, have been discussed extensively in the past (Ray, 2017), so that explicit tidal simulations with unconstrained numerical ocean tide models provide potentially valuable information on tidal lines less well constrained by satellite altimetry. Additional errors can be introduced, when estimating minor tidal excitations with admittance methods These deviations might be reduced by the explicit numerical modeling of minor tides. We start our work with the Tidal Model forced by Ephemerides (TiME) as described by Weis et al (2008), which simulates global barotropic tidal dynamics by solving the nonlinear shallow water equations (e.g., Pekeris, 1974).
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