Assessment of SARAL-ALTIKA Tidal Corrections in the Coastal Oceans Around India

ABSTRACT

The present tidal correction of sea level records of Satellite with ARgoes and ALtimeter (SARAL) is based on the finite element solution (FES) of global tide model FES2012 tidal solution. In this study, we examined the validity of the tidal corrections in the coastal oceans around India using tide gauge measurements and a regional tidal model. Our regional model is based on the barotropic version of the Princeton Ocean Model that is forced by the time-varying tidal levels at the open ocean end based on the global FES99 tidal solution. Tide charts prepared from the simulated tidal levels are very similar to the FES tidal solutions. Comparison with the tide gauge measurement shows close agreement with the regional tidal solutions. On the other hand, the agreement with the FES tide models differ significantly in the Gulf of Khambhat and the Gulf of Kutch on the northwest, and in the Hooghly estuary on the northeast continental shelf. However, the agreement is exceptional in other parts of the study domain. These tidal solutions are used in the SARAL-ALTIKA X-track data to assess the FES tidal correction and to draw some inferences associated with the coastal processes. It is revealed that these corrections are reasonably accurate for the coastal oceans around India except the aforementioned converging channels.

KEYWORDS:

• FES2012
• India coast
• SARAL-ALTIKA
• satellite altimeter
• tide gauge
• tides

Acknowledgements

This work is carried out under the SARAL-ALTIKA science program of the Space Application Centre (SAC), Ahmadabad. We thank the international team of SARAL and the Archiving, Validation and Interpretation of Satellite Oceanographic Data (AVISO) program at CNES, France for sharing FES tidal solutions and other auxiliary data products used in this study.