Ocean tide model obtained from TOPEX/POSEIDON altimetry data

Abstract

Tidal corrections are very important for oceanographic study of altimetry because tidal signals contaminate the low‐frequency part of raw altimetric signals. Accurate tidal predictions are also necessary for geophysical research, such as with the superconducting gravimeter (SCG), which needs to distinguish very weak signals from the overwhelming tidal signals. The aim of this paper is to derive accurate global ocean tide models from the TOPEX/POSEIDON sea surface height data of 5 cm accuracy, more accurate than any other previous altimeter data. TOPEX geophysical data records of cycles 9–94 were processed and analyzed. We describe response analysis of tidal waves at crossover points and application of hydrodynamical interpolation. The tidal solutions with 0.5° grid system are obtained for eight major constituents (i.e., M2, S2, N2, K2, K1, O1, P1, and Q1) and compared with the Schwiderski (1980a, b, c) model, the Cartwright and Ray (1991) model, and the eight‐constituent version of the Egbert et al. (1994) model or TPXO.2. The accuracy of the models is checked using island and bottom tide gauge data in open ocean and using SCG data in Antarctica and Japan.

Ocean‐tide loading and Earth tides around New Zealand

“…Results of complex linear regression between M 2 loads calculated in this study and those of Ray (1998) and Matsumoto et al (1995) for 27 543 data points in the finite element grid. Amp and phase are the amplitude and phase of the complex number a in: h this study = a * h Ray or Matsumoto , an d r2 is the coefficient of determination.…”

“…Subsequently, Francis & Mazzega (1990) used this method and the tidal model of Schwiderski (1980a,b) to produce global charts of the ocean-tide loading. With the advent of TOPEX/Poseidon (henceforth referred to as T/P) global tidal models, these calculations were upgraded by various researchers (e.g., Matsumoto et al 1995) and loadings at 0.5 degree intervals around the whole globe are available in Anon. (1996).…”

“…Initially, the model was excited with boundary conditions which were the average of five global tidal models from Anon. (1996): TPXO.2 (Egbert et al 1994); AG95.2 (Andersen 1995); ORI (Matsumoto et al 1995);FES95.2 (Le Provost et al 1994);and SR95.1 (Schrama & Ray 1994). The boundary conditions for the model were then optimised for each tide to obtain the best fit with open-coast, sea level stations.…”

“…Thus, for example, the K1 Earth-tide amplitude is 67 mm and the O 1 Earth-tide amplitude is 55 mm and these are greater than the corresponding ocean-tide amplitudes (Walters et al 2001). Matsumoto et al (1995) produced a set of ocean-tide loadings using the Schwiderski (1980a,b,c) model tide data. Anon.…”

Altimeter sampling characteristics using a single satellite

“…When this is done, much of the mesoscale contribution disappears. In the case of deep water tidal solutions produced thus far, this has been done either explicitly [Matsumoto et al, 1995] or implicitly through largescale binning and smoothing [see, e.g., Desai and Wahr, 1995]. In the future, when altimetric data is used to investigate tides to finer scales in shallow water or over bathymetric features, care must be taken to avoid incorporation of mesoscale energy into tidal solutions.…”