Accuracy assessment of global barotropic ocean tide models

Abstract

The accuracy of state-of-the-art global barotropic tide models is assessed using bottom pressure data, coastal tide gauges, satellite altimetry, various geodetic data on Antarctic ice shelves, and independent tracked satellite orbit perturbations. Tide models under review include empirical, purely hydrodynamic ("forward"), and assimilative dynamical, i.e., constrained by observations. Ten dominant tidal constituents in the diurnal, semidiurnal, and quarter-diurnal bands are considered. Since the last major model comparison project in 1997, models have improved markedly, especially in shallow-water regions and also in the deep ocean. The root-sum-square differences between tide observations and the best models for eight major constituents are approximately 0.9, 5.0, and 6.5 cm for pelagic, shelf, and coastal conditions, respectively. Large intermodel discrepancies occur in high latitudes, but testing in those regions is impeded by the paucity of high-quality in situ tide records. Long-wavelength components of models tested by analyzing satellite laser ranging measurements suggest that several models are comparably accurate for use in precise orbit determination, but analyses of GRACE intersatellite ranging data show that all models are still imperfect on basin and subbasin scales, especially near Antarctica. For the M 2 constituent, errors in purely hydrodynamic models are now almost comparable to the 1980-era Schwiderski empirical solution, indicating marked advancement in dynamical modeling. Assessing model accuracy using tidal currents remains problematic owing to uncertainties in in situ current meter estimates and the inability to isolate the barotropic mode. Velocity tests against both acoustic tomography and current meters do confirm that assimilative models perform better than purely hydrodynamic models.

Tidal forcing, energetics, and mixing near the Yermak Plateau

“…It has been shown that the surface signature of internal tide, evaluated by sea surface satellite products, is reasonably well captured. The barotropictide-induced sea level variability is captured to 93 % and a recent barotropic tide model intercomparison shows that STORMTIDE ranks similar to other modern hydrodynamic tide models (Stammer et al, 2014).…”

Accuracy Assessment of Recent Global Ocean Tide Models Around Antarctica

“…The grid resolutions of these models vary from 1/30° to 1/2°. Different from Stammer et al (2014), OSU12 model is not adopted in our study, since it has not yet covered the polar oceans and defaults to GOT4.8 at high latitudes (Fok 2012). FES2004 is taken as the representative model of classical and conventional models, to validate the accuracy improvement of state-of-the-art models in Antarctica.…”

“…Where k is the index of grid point, P is the number of all grid wet points. The studying regions of this paper are oceans southward of 30°S, in order to show the real discrepancy between models, the down-weighted strategy of Stammer et al (2014) was not adopted, instead, we use evenly weighted strategy. The results are separately listed in the table 2 for the Ice Shelf regions (including regions of permanent sea ice), the shallow seas (depth < 1000 m) and the deep ocean (depth > 1000 m), respectively.…”

“…King et al (2005b) found that their selected models shown disagreement by up to several decimeters per constituent in the large ice shelf regions in Antarctica, TPXO6.2 is the relative high-accuracy model at that time. Shum et al (1997) and Stammer et al (2014) made comprehensive and systematic assessments of global ocean tide models, they not only gave detailed evaluation of each ocean tide models, but also described future prospects for improvement. Although progress in tide modelling has been achieved due to the remarkable success of altimetry missions, the quantitative analysis is still needed, especially in the Antarctica where lack of validation data (Dubock et al 2001, Zwally et al 2002, Labroue et al 2012).…”

Research Article. Towards a tidal loading model for the Argentine-German Geodetic Observatory (La Plata)

“…It participates in the ocean tides with substantial modulation of the tidal signal compared to the nearby Atlantic Ocean [5]. Satellite altimetry is the principal data source for recent global ocean tide models [6]; but its applicability over the narrow Río de la Plata is very limited because standard procedures do not provide reliable sea-surface heights in coastal waters [7]. [8] derived a regional tide model for the estuary from tide gauge records at 34 sites.…”