Assessment of sea level rise impact on peninsular malaysia geodetic vertical datum

Abstract. Sea level is the height of the ocean surface in relation to a benchmark or vertical control point. The rising of sea level has become a crucial topic, which frequently discussed among professionals, government, non-government, and researchers upon their devastating impacts on daily human life and human survival. Nevertheless, there is a great deal of ambiguity around the rates, ranges, and time frame of sea levels rise. It is importance to study the variation of present-day sea level rise to understand its impact, particularly on our National Geodetic Vertical Datum (NGVD). This study focuses on quantifying the rate and magnitude of sea level rise over Peninsular Malaysia using in-situ tide gauge and multi-mission satellite altimeter. The time period for tide gauge data used is 35 years (1984–2018) consisting 12 tide gauges in Peninsular Malaysia. Meanwhile, the period of satellite altimetry data is 26 years (1993–2018). This study uses robust fit regression (Iterative Re-weighted Least-Squares) for both tide gauge and satellite altimetry data to calculate the rate of sea level rise. The outcomes of this study show that the rate of sea level rise at Pelabuhan Kelang tide gauge station is the lowest among 12 other tide gauges with a rate of 2.36 ± 0.35 mm/year and slightly affected by sea level rise. Besides, the rate of sea level rise in Peninsular Malaysia is on an upward trend with an average of 3.20 ± 0.27 mm/year from tide gauge data and 4.14 ± 0.32 mm/year from satellite altimetry data. The sea level rise study provides insights to the rate and magnitude of sea level rise at tide gauge stations, particularly at Pelabuhan Kelang station for further study. Last but not least, this study would also benefit authorities in preparing mitigation plans to secure and improve our Peninsular Malaysia Geodetic Vertical Datum (PMGVD) for various applications.