Satellite image application to assess sea level rise trends in northern Gulf of Tonkin’s waters

01/10/2025

Recent studies show that climate change is increasingly manifesting itself in clear ways. In particular, sea levels are trending upward at a much faster rate than in previous periods, which will have major impacts on natural resources and the environment in coastal areas. Therefore, research on the trends of sea level rise holds significant scientific and practical importance. However, tide gauge data from coastal and island hydrographic stations in our country currently face many limitations in terms of spatial coverage (sparse) and temporal measurement (only a few stations record hourly data).

Against this backdrop, the project “Research on the use of satellite image data to assess sea level rise due to climate change in the northern Gulf of Tonkin’s waters” (code: QTFR02.01/23-24) has been implemented under the scientific and technological cooperation programme between the Vietnam Academy of Science and Technology (VAST) and the French Institute of Research for Development (IRD), led on the Vietnamese side by Vu Duy Vinh, PhD, from the Institute of Marine Resources and Environment (now Institute of Science and Technology for Energy and Environment). This task was carried out to determine the trend of sea level rise due to climate change in the northern Gulf of Tonkin’s waters from satellite image data.

Vu Duy Vinh (sixth from left) with project members and partners surveying at the Van Uc estuary area

Within the framework of the project, the research team worked closely with scientists from IRD and the Laboratory for Space Geophysics and Oceanography Studies (LEGOS), the co-developer of the AVISO satellite image data system. Thanks to this collaboration, staff from the
Institute of Science and Technology for Energy and Environment had the opportunity to exchange, discuss, and work directly with leading experts in the field of ocean remote sensing, laying the foundation for tapping into and using the vast satellite data resource to study ocean physical processes at VAST.

Dr. Vu Duy Vinh discussing technical matters with the partner group at LEGOS

By analysing sea level rise trends at several gauge stations in the Gulf of Tonkin area such as Co To, Hon Dau, Bach Long Vi, and Hon Ngu, and comparing them with analysis results from satellite image data (AVISO and Copernicus) from 1993–2022, the study found that the anomalous sea level data at Hon Dau and Bach Long Vi stations showed a high degree of similarity with satellite image data, with R² correlation coefficients ranging from 0.743 to 0.837. This indicates the reliability of remote sensing data in assessing sea level fluctuations. At Co To and Hon Ngu stations, the correlation coefficients were lower (R² from 0.36 to 0.39), reflecting the influence of coastal topographic conditions and the quality of the measured data sources.

Comparison of monthly average anomalous sea levels (a) and annual average (b) from satellite image data and measured data in the Hon Dau area

In addition, the project contributed to enhancing the research capacity of domestic staff by enabling them to grasp modern methods for exploiting, using, and analysing satellite image data. This is an important foundation for expanding interdisciplinary research directions using satellite image data in the future. Initial results of the project have been published in an international journal indexed in the SCIE list and in a VAST2 group journal, and have supported the training of one PhD candidate.

Assessing the development potential of the research, Dr. Vinh noted that although certain discrepancies still exist between measured data and satellite image data, especially in coastal areas due to the influence of land-sea interaction processes, satellite image data, thanks to advanced image processing techniques and satellite technology developments—has become, and continues to be, an effective supplementary and replacement data source for hydrographic station measurements in Vietnam today.

With the existing cooperative foundation and the technical capacity strengthened through the project, the research team proposes expanding the scope of analysis to other sea areas with greater detail. This approach will integrate data from the national hydrographic station network and Copernicus satellite image data—the Earth Observation component of the European Union Space Programme—along with global satellite image data sources, to improve the accuracy of assessing and forecasting sea level rise trends. At the same time, the team also hopes to continue promoting international cooperation with IRD and LEGOS to update new technologies and expand interdisciplinary research directions to support disaster prevention, address coastal hazards, and adapt to climate change, serving the goal of sustainable marine economic development in the future.

Translated by Tuyet Nhung
Link to Vietnamese version

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