Sea level rise estimation and interpretation in Malaysian region using multi-sensor techniques

Abstract

Rise in sea level is one of the disastrous effects of climate change. A relatively small increase in sea level could affect the natural coastal system. This study presents an approach to estimate before interpreting the precise sea level trend based on a combination of multi-sensor techniques in the Malaysian region over a period of 19 years. In the study, six altimeter missions were used to derive the absolute sea levels which were processed in the Radar Altimeter Database System. Next, 21 tide gauge stations along the coastlines of Malaysia were utilised to derive the rate of relative sea levels that took into account sea level changes and vertical land motions. To obtain absolute sea level at tide gauge, vertical land motions at these stations were removed by employing three techniques, namely GPS, Persistent Scatterers Interferometric Synthetic Aperture Radar and altimeter minus tide gauge. Bernese software with double difference strategy was employed to process data from 87 local and 30 international GPS stations. Using Persistent Scatterers Interferometric Synthetic Aperture Radar, the Stanford Method for Persistent Scatterer software processed 111 images. Besides that, the satellite altimeter and tide gauges were used to retrieve the differential rates estimated by altimetry and tidal data to obtain the rate of vertical land motion. Following that, absolute sea level rates from the tide gauge stations and multi-satellite altimeter missions were combined. This combination produced the regional sea level trend of the Malaysian seas. The findings from the multi-sensor techniques showed that the regional sea level trend has been rising at a rate of 2.65 ± 0.86 mm/yr to 6.03 ± 0.79 mm/yr for the chosen sub-areas, with an overall mean of 4.47 ± 0.71 mm/yr. Upon completion of the study, a Sea Level Information System for the Malaysian seas was developed to facilitate users in analysing, manipulating and interpreting sea level and vertical land motion data. This system is expected to be valuable for a wide variety of climatic applications to study environmental issues related to flood and global warming in Malaysia.