On the selection of multi-satellite altimetry for empirical tide modelling over Indonesia

ABSTRACT

Multi-satellite altimetry has been employed in tidal modelling as its accuracy has been proven acceptable in constructing good-quality models. However, the modelling process often fails to consider the varying temporal resolution and observation periods among satellites, which can affect the accuracy of the model due to aliasing and Rayleigh effects. In Indonesia, we investigate and propose a satellite selection procedure for tidal modelling utilizing the response method, validated with along-track data obtained from both older and newer generations of ERM (Exact Repeat Mission)-type altimetry satellites, including the TOPEX/Jason series (TOPEX, Jason-1, Jason-2, Jason-3, and SENTINEL-6A), ENVISAT, ERS-2, GFO, SENTINEL-3B, and SENTINEL3A. The most optimal satellite combination identified is the TOPEX/Jason series, GFO, and ENVISAT, as they contribute significantly less error compared to ERS-2, SENTINEL-3A, and SENTINEL-3B, with errors exceeding 50%, primarily due to aliasing and Rayleigh effects. This combination of three satellites with tide gauge stations achieves higher precision (11.31 cm) than the current global tidal model. This study provides empirical evidence that the accuracy of tidal models is not solely dependent on the number of altimetry satellites utilized, but implementing effective satellite selection procedures is also crucial to enhance the precision of a model.

KEYWORDS:

• Satellite altimetry
• ocean tide model
• response method
• satellite selection

Acknowledgements

We would like to thank the Division for Horizontal Control Network and Geodynamics, the Indonesian Geospatial Information Agency (Badan Informasi Geospasial, BIG) for freely providing tidal stations data used in this present study. We would like to express our gratitude for the funding support provided by the ITB Flagship Research Grant 2022 and 2023 [Contract No. 223/IT1.B07.1/TA.00/2022 and Contract No. 308/IT1.B07.1/TA.00/2023]. We also extend our appreciation to the Radar Altimeter Database System (RADS) scharroo2013rads for granting access to altimetry data, including corrections, and its supporting software. Lastly, we acknowledge the Generic Mapping Tools (GMT) (Wessel et al. 2013) for its software modules, enabling the visualization of images and grid interpolation processes in this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The information substantiating the outcomes of this study can be obtained from RADS (Scharroo et al. 2013) and the Indonesian Geospatial Information Agency, upon a reasonable request. For tidal models, both in graphical and grid file formats, validation results, tide prediction services, and an explanation of the tidal modelling procedures applied are currently in the process of being published on the website https://srgi.big.go.id/page/model-pasut, as part of a collaboration with the Indonesian Geospatial Information Agency (Badan Informasi Geospasial, BIG). At present, the focus is on the SG-1 model and its concise explanation, along with tide prediction services. Further collaboration with BIG is anticipated to incorporate the remaining research findings from this paper, with implementation expected later this year, for potential applications in mapping, engineering, or research efforts, both domestically and internationally.

Additional information

Funding

This work was supported by the Lembaga Penelitian dan Pengabdian Masyarakat - Institut Teknologi Bandung (LPPM - ITB) under the ITB Flagship Research Grant 2022 and 2023 [Contract No. 223/IT1.B07.1/TA.00/2022 and Contract No. 308/IT1.B07.1/TA.00/2023].