Parameterization Analysis of the Lagrange Basis Function Method for the Reconstruction of the Mean Dynamic Topography

  Objectives  The reconstruction of the mean dynamic topography (MDT) plays an important role in the fusion of the mean sea surface and geoid for high-precision MDT modelling.

  Methods  The parameterization algorithm based on the Lagrange basis functions (LBFs) is investigated, and the performance of the MDT solutions based on different choice of the LBFs is studied in detail, where the LBFs consist of 4/16/36 parameters (P) are introduced and analyzed.

  Results  The results show that the MDT solution based on 16 parameters is more consistent with the comparative data. The standard deviation (SD) of misfits between the solved MDT using 16P and the comparative data is 3.1 cm, which is 0.9 cm/1.1 cm smaller than that of the 4P/36P; and the misfits using 16P are improved by 5 cm than that using 4P/36P in regions with a strong variation of ocean current.

  Conclustions  The geostrophic velocities based on the 16P-solution are in good agreement with the comparative data, where the SD of misfits between the zonal geostrophic component by the 16P and the comparison data is reduced by 0.4 cm/s and 2.8 cm/s compared to the results of 4P/36P.