|
Accurate ocean tide load displacement (OTL) modeling plays a vital role in precision geodesy. This paper first compares the OTL displacement of the M2 constituent observed at seven GPS stations near French Polynesia with the modeled values. The analysis reveals that the root mean square error (RMS) of the residuals in the east component is 0.94mm, whereas the uncertainty of the GPS measurements is approximately 0.1mm. This indicates that the residuals are primarily influenced by the OTL modeling. Subsequently, by comparing the RMS between the OTL displacements modeled by different ocean tide models and the GPS observations, we found that the maximum difference in the east component was only 0.04mm. This suggests that the residuals may be influenced by the PREM model. Next, we consider the impact of anelastic dispersion in both the entire mantle and the asthenosphere on OTL modeling. The results show that considering the anelastic dispersion of the entire mantle can reduce the RMS of the east component residual to 0.75mm, indicating that its improvement effect in OTL modeling is more significant. Using the OTL displacement data of the M2 constituent observed by GPS, we verified the Q-value model in the French Polynesia region and found that the Q-value of the asthenosphere is more likely to be 71, while that of the lower mantle is more likely to be 104. After replacing the Q model of PREM and accounting for mantle anelastic dispersion, the RMS of the east component residual between the OTL model and the GPS observations dropped to 0.57mm, with the maximum residual reduced by 0.44mm. However, for the vertical residual, although it may be influenced by both the ocean tide model and anelastic dispersion, it is difficult to clearly distinguish between these factors. Therefore, further discussion and research are needed.
|
