Regional Mean Sea Surface and Mean Dynamic Topography Models Around Malaysian Seas Developed From 27 Years of Along-Track Multi-Mission Satellite Altimetry Data

Mohammad Hanif Hamden,Muhammad Faiz Pa’Suya,Ami Hassan Md Din,Dudy Darmawan Wijaya,Mohd Yunus Mohd Yusoff

doi:10.3389/feart.2021.665876

Abstract

Contemporary Universiti Teknologi Malaysia 2020 Mean Sea Surface (UTM20 MSS) and Mean Dynamic Topography (UTM20 MDT) models around Malaysian seas are introduced in this study. These regional models are computed via scrutinizing along-track sea surface height (SSH) points and specific interpolation methods. A 1.5-min resolution of UTM20 MSS is established by integrating 27 years of along-track multi-mission satellite altimetry covering 1993–2019 and considering the 19-year moving average technique. The Exact Repeat Mission (ERM) collinear analysis, reduction of sea level variability of geodetic mission (GM) data, crossover adjustment, and data gridding are presented as part of the MSS computation. The UTM20 MDT is derived using a pointwise approach from the differences between UTM20 MSS and the local gravimetric geoid. UTM20 MSS and MDT reliability are validated with the latest Technical University of Denmark (DTU) and Collecte Localisation Services (CLS) models along with coastal tide gauges. The findings presented that the UTM20, CLS15, and DTU18 MSS models exhibit good agreement. Besides, UTM20 MDT is also in good agreement with CLS18 and DTU15 MDT models with an accuracy of 5.1 and 5.5 cm, respectively. The results also indicate that UTM20 MDT statistically achieves better accuracy than global models compared to tide gauges. Meanwhile, the UTM20 MSS accuracy is within 7.5 cm. These outcomes prove that UTM20 MSS and MDT models yield significant improvement compared to the previous regional models developed by UTM, denoted as MSS1 and MSS2 in this study.

Highlights

Mean sea surface (MSS) is a term describing the average satellite-derived sea surface height (SSH) over a period of time (Andersen and Scharroo, 2011; Yuan et al, 2020)
The Universiti Teknologi Malaysia 2020 (UTM20) MSS entailed the altimetry-averaged height of the SSH, which derived from an integration of nine satellites encompassing the period from 1993 to 2019
UTM20(G) is established by applying a 19-year moving average technique, while UTM20(F) is established using a conventional average method. Both models are compared with CLS15 MSS and DTU18 MSS in the Malaysian seas

Summary

Introduction

Mean sea surface (MSS) is a term describing the average satellite-derived sea surface height (SSH) over a period of time (Andersen and Scharroo, 2011; Yuan et al, 2020). The MSS model plays a crucial role in computing marine gravity anomalies (Zhu et al, 2019) and bathymetry prediction (Andersen and Knudsen, 2009) in the context of geodetic applications. In line with this notion, researchers such as Nornajihah (2017) and Astina (2017) are among those who have utilized the regional MSS model to develop a marine geoid model and to estimate bathymetry over Malaysian seas, respectively. Ocean circulation yields an additional MDT component to the MSS, with the spatial variance within ±1 m at different locations across the global ocean

Methods

Results

Discussion

Conclusion