scholarly journals GPS estimates of ocean tide loading in NW-France: determination of ocean tide loading constituents and comparison with a recent ocean tide model

2008 ◽  
Vol 173 (2) ◽  
pp. 444-458 ◽  
Author(s):  
M. Vergnolle ◽  
M.-N. Bouin ◽  
L. Morel ◽  
F. Masson ◽  
S. Durand ◽  
...  
2019 ◽  
Author(s):  
Junjie Wang ◽  
Nigel T. Penna ◽  
Peter J. Clarke ◽  
Machiel S. Bos

Abstract. Anelasticity may decrease the shear modulus of the asthenosphere by 8–10 % at semi-diurnal tidal periods compared with the reference 1 s period of seismological Earth models. We show that such anelastic effects are likely to be significant for ocean tide loading displacement at the M2 tidal period around the East China Sea. By comparison with tide gauge observations, we establish that NAO99Jb is the most accurate numerical ocean tide model in this region, and that related errors in the predicted M2 vertical ocean tide loading displacements will be 0.2–0.5 mm. In contrast, GPS observations on the Ryukyu Islands (Japan), with uncertainty 0.2–0.3 mm, show discrepancies of over 1.5 mm with respect to ocean tide loading displacements predicted using the purely elastic radial Preliminary Reference Earth Model. We show that the use of an anelastic PREM-based Earth model reduces these discrepancies to no more than 0.8 mm, which is of the same order as the sum of the remaining errors due to uncertainties in the ocean tide model and the GPS observations. Use of a regional Earth model based on the laterally-varying S362ANI, with or without further empirical tuning, results in minor additional improvements in fit.


Ocean Science ◽  
2011 ◽  
Vol 7 (3) ◽  
pp. 429-444 ◽  
Author(s):  
D. N. Arabelos ◽  
D. Z. Papazachariou ◽  
M. E. Contadakis ◽  
S. D. Spatalas

Abstract. The tides for the Mediterranean Sea are described through a high resolution model (MEDI10) developed by assimilation of tide-gauge data and T/P data into a barotropic ocean tide model. Tidal parameters from 56 coastal tide-gauge stations around the Mediterranean for eight principal constituents: M2, S2, N2, K2, K1, O1, P1 and Q1 and from 20 stations for M2, S2, K1, O1 are included in the model. TOPEX/Poseidon data with all corrections applied except for the ocean tides and bathymetry from TOPO 13.1 were used for development of the model. Numerical experiments were carried out for the estimation of the friction velocity and of the decorrelation length scale. The experiments related to the friction velocity showed that the use of spatially varying friction velocity, estimated as a function of position in the model domain, gives better results than a constant value. The experiments related to the estimation of the decorrelation length suggest that the results are not sensitive for lengths close to ten times the length of the grid cell. The assessment of the model is based on ten tide-gauge observations that are not used for the assimilation. Comparisons were carried out with contemporary published global or regional models. The final solution is computed using 76 selected coastal tide-gauge stations. The comparison between the observed and the model constituents results in a Root Sum of Squares (RSS) equal to 1.3 cm.


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