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Title: An Assessment of Global Ocean Barotropic Tide Models Using Geodetic Mission Altimetry and Surface Drifters
Abstract The accuracy of three data-constrained barotropic ocean tide models is assessed by comparison with data from geodetic mission altimetry and ocean surface drifters, data sources chosen for their independence from the observational data used to develop the tide models. Because these data sources do not provide conventional time series at single locations suitable for harmonic analysis, model performance is evaluated using variance reduction statistics. The results distinguish between shallow and deep-water evaluations of the GOT410, TPXO9A, and FES2014 models; however, a hallmark of the comparisons is strong geographic variability that is not well summarized by global performance statistics. The models exhibit significant regionally coherent differences in performance that should be considered when choosing a model for a particular application. Quantitatively, the differences in explained SSH variance between the models in shallow water are only 1%–2% of the root-mean-square (RMS) tidal signal of about 50 cm, but the differences are larger at high latitudes, more than 10% of 30-cm RMS. Differences with respect to tidal currents variance are strongly influenced by small scales in shallow water and are not well represented by global averages; therefore, maps of model differences are provided. In deep water, the performance of the models is practically indistinguishable from one another using the present data. The foregoing statements apply to the eight dominant astronomical tides M 2 , S 2 , N 2 , K 2 , K 1 , O 1 , P 1 , and Q 1 . Variance reduction statistics for smaller tides are generally not accurate enough to differentiate the models’ performance.  more » « less
Award ID(s):
2102740 1850961 1851166
PAR ID:
10224513
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Journal of Physical Oceanography
Volume:
51
Issue:
1
ISSN:
0022-3670
Page Range / eLocation ID:
63 to 82
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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