Bathymetry derived from images captured by satellites continues to advance and be refined. Scientists have mapped the bottom of a Mediterranean coastline using satellite images.
This study has verified the effectiveness of a methodology developed to obtain bathymetric data from satellite images in the western Mediterranean. This is the first time that this methodology has been tested in the presence of extensive areas covered by Posidonia oceanica. The results reaffirm the value of this tool for monitoring coastal areas with different levels of turbidity and diverse seabeds.
The study has been led by researchers from the Higher Council for Scientific Research (CSIC) at the Institute of Marine Sciences of Andalusia (ICMAN), in Spain.
The research has been carried out in Cala Millor (Mallorca, Balearic Islands), an ecosystem of great relevance for its marine biodiversity but also for its potential vulnerability to the effects of global climate change. Researchers have managed to accurately map its coastal bottom from images from the Sentinel-2 satellite.
The work has been carried out as a result of a collaboration between researchers from ICMAN, the Balearic Islands Coastal Observation and Prediction System (ICTS SOCIB) and NOAA (the US National Oceanic and Atmospheric Administration).
The island of Mallorca seen from space. (Photo: ISS Crew Earth Observations & Image Science & Analysis Laboratory, NASA Johnson Space Center)
“This type of tool is an invaluable support for the management of coastal zones, since they offer up-to-date and continuous information on the morphodynamic changes that occur in them. They are very useful to help managers in decision-making and to define effective adaptation measures against the effects of global climate change, achieving a more resilient coast”, explains Sandra Viaña-Borja, ICMAN researcher.
In this way, satellite-derived bathymetry (SDB, for its acronym in English) goes a step further to consolidate itself as an alternative to traditional bathymetric techniques that are carried out with aircraft or ships. The main advantages of satellites is that they allow the coastal bottom to be studied with greater spatial coverage and free of charge, without the need to be present in the area or carry out an expensive deployment. However, despite the great advances achieved in recent years, the main challenge researchers face is to demonstrate that these models can be replicated efficiently and accurately globally and operationally, regardless of the characteristics of the area.
This methodology had already been used with very favorable results in other regions of the planet, such as the east coast of the United States and the Caribbean. Now it has been evaluated in a different ecosystem, the Mediterranean, where the Mallorcan beach of Cala Millor is one of the most monitored by the ICTS SOCIB Beach Monitoring facility, which has been operating since 2011. Likewise, given its importance, the Commission The European Union has recently approved the grant for the LIFE AdaptCalaMillor project, in order to promote the adaptation of this beach to global climate change and increase the resilience of infrastructures, ecosystems and services.
Generating detailed maps of underwater topography is essential to support a wide range of near-shore activities such as dredging, environmental management, pipeline and communications cable routing, infrastructure maintenance, hydrographic applications, navigation , the transport of goods, aquaculture and fisheries, research, tourism or recreational sports. It should be noted that bathymetry is one of the decisive characteristics for the preparation of Marine Strategies, in accordance with the directives of the European Commission. This instrument constitutes the general regulatory framework to which the different sectoral policies and administrative actions with an impact on the marine environment must necessarily adhere.
“Currently, we are evaluating these tools in other regions, such as Galicia, South Korea and Alaska, where we have obtained promising results. It is important to highlight that, according to the International Hydrographic Organization, more than half of the shallow bottoms of our oceans remain unmapped or out of catalogue. Satellite-derived bathymetry is a free and easily accessible technology. Without a doubt, it is the future of coastal monitoring”, highlights Isabel Caballero de Frutos, ICMAN researcher.
The study is titled “Semi-automated bathymetry using Sentinel-2 for coastal monitoring in the Western Mediterranean”. And it has been published in the academic journal International Journal of Applied Earth Observation and Geoinformation. (Source: Erika López / CSIC)
