Developing a near-seamless tidal datum by integrating tidal and satellite altimetry data with a Digital Elevation Model for maritime boundary delimitation

Abstract

ABSTRACT The delimitation of maritime boundaries plays a significant role in preserving the country’s sovereignty and jurisdiction. The maritime baseline was established based on the combination of maritime basepoints, which represents the Lowest Astronomical Tide (LAT) along the coast. However, the current approach still relies on the limited and sparsely distributed tide gauge stations for the determination of LAT. Therefore, this study aims to develop the Peninsular Malaysia Near-Seamless Tidal Datum (PMNSTD) by integrating tide gauge, satellite altimetry, and Tide Model Driver (TMD) data. PMNSTD was further integrated with Digital Elevation Models (DEM) for the delimitation of maritime boundaries. This study methodology includes data acquisitions of 12 tide gauge stations along the coast of Peninsular Malaysia, satellite altimetry data for TOPEX, Jason-1, Jason-2, and GEOSAT Follow-On (GFO) from Radar Altimeter Database System (RADS), TMD, and TerraSAR-X add on for Digital Elevation Measurement 30 m (TanDEM-X) data. The tide gauge, satellite altimetry, and TMD data encompass 23 years of tidal observation data from 1993 to 2015. For the derivation of the tidal datum, the tide gauge and satellite altimetry data were analysed using harmonic analysis in UTide, whereas, for the TMD data, the tidal datum was determined based on tidal prediction. For compatibility in data integration, the derived Lowest and Highest Astronomical Tide (LAT and HAT) from tide gauge, satellite altimetry, and TMD data were referenced to the Mean Sea Level (MSL), denoted as and respectively. Next, the and was interpolated using Inverse Distance Weighting (IDW) to develop the PMNSTD (and ) using ArcGIS. The statistical assessment indicates that the PMNSTD ( and ) established from the integration of tide gauge, satellite altimetry, and TMD has a better agreement with the Department of Survey and Mapping Malaysia (DSMM) tide gauges with a Root Mean Square Error (RMSE) and Standard Deviation (STD) of 0.228 m and 0.175 m for , as well as 0.159 m and 0.079 m for . Next, the PMNSTD () was integrated with TanDEM-X using ArcGIS and SURFER for the delimitation of maritime boundaries. The reliability assessment illustrated a significant improvement in the continuation of 201 maritime basepoints in comparison to the 95 maritime basepoints by the DSMM. In conclusion, the proposed approach has shown a continuous, consistent, and wider establishment of the country’s maritime baseline for the Peninsular Malaysia region.