[S-GD01] Geodetic Advances in Crustal Dynamics and Environmental Change for Taiwan and Neighboring Regions

[SGD01-P06] Understanding uncertainties in satellite altimetry products in the coastal zone

*Meng-Hui Lin¹, Wen-Hau Lan¹, Chung-Yen Kuo², Chia-Sheng Hsieh¹, Tzu-Pang Tseng² (1.Department of Civil Engineering, National Kaohsiung University of Science and Technology, 2.Department of Geomatics, National Cheng Kung University)

Keywords:Satellite altimetry, Tide gauge, Sea level change, Sea level acceleration

Global warming has led to a continuous and accelerating rise in sea levels since 2000, exerting direct impacts on human society, infrastructure, ecosystems, and ocean dynamics. Since the early 1990s, satellite altimeters have provided long-term, high-precision, global-scale sea level observations with high spatiotemporal resolution. Various altimetry products, including gridded and along-track datasets, are available from international data centers. However, the accuracy of these products in coastal regions remains uncertain due to the influence of different processing algorithms. Therefore, a detailed assessment of the coastal accuracy of these altimeter products is an extremely important issue for physical oceanography. This study will calculate the root-mean-square error of the difference between the tide gauges and satellite altimeter data to evaluate the accuracy of international satellite altimeter products in the coastal zone. The vertical land motion trends at tide gauges derived from satellite altimetry and tide gauges are compared with the System d’Observation du Niveau des Eaux Littorales (SONEL) GNSS observations to evaluate the consistency of sea level trend between the altimeter product and local tide gauges. Finally, we also attempt to estimate the trend and acceleration of sea levels at global and basin scales over the last 30 years.