Preliminary results of the global ocean tide derived from HY-2A radar altimeter data

The HY-2A satellite, which is equipped with a radar altimeter and was launched on August 16, 2011, is the first Chinese marine dynamic environmental monitoring satellite. Extracting ocean tides is one of the important applications of the radar altimeter data. The radar altimeter data of the HY-2A satellite from November 1, 2011 to August 16, 2014 are used herein to extract global ocean tides. The constants representing the tidal constituents are extracted by HY-2A RA data with harmonic analysis based on the least squares method. Considering tide aliasing issues, the analysis of the alias periods and alias synodic periods of different tidal constituents shows that only the tidal constituents M-2, N-2, and K-2 are retrieved precisely by the HY-2A RA data. The derived tidal constants of the tidal constituents M-2, N-2 and K-2 are compared to those of tidal gauge data and the TPXO tide model results. The comparison between the derived results and the tidal gauge data shows that the RMSEs of the tidal amplitude and phase lag are 9.6 cm and 13.34 degrees, 2.4 cm and 10.47 degrees, and 8.1 cm and 14.19 degrees for tidal constituents M-2, N-2, and K-2, respectively. The comparisons of the semidiurnal tides with the TPXO model results show that tidal constituents have good consistency with the TPXO model results. These findings confirm the good performance of HY-2A RA for retrieving semidiurnal tides in the global ocean.