Radar and satellite shed new light on the UAE's fascinating past

Researchers in the UAE can unearth mysteries from the country's past without having to carry out a single excavation, with tombs, water channels and irrigation networks discovered at an archaeological site in Al Ain using radar technology. The teams from Khalifa University of Science and Technology and the Department of Culture and Tourism – Abu Dhabi were able to use ground-penetrating radar (GPR) to create an AI model replica – which showed that the area was busy with human activity from the Bronze Age through to the late Islamic period. Researchers created a detailed three-dimensional model of buried archaeological features at the eastern end of the Mutaredh Oasis. The GPR technology highlights features, otherwise known to researchers as anomalies, that have been covered up over time by sand to a depth of about 2.5 metres. The shallower anomalies tend to be linked to the Islamic era, which began early in the seventh century, while deeper anomalies are associated with the Bronze Age (3300 BC to 1200 BC) and the Iron Age (1200 BC to 550 BC). At the eastern part of the oasis researchers from Khalifa University of Science and Technology and the Department of Culture and Tourism have identified two Bronze Age circular tombs, as well as a system of water channels, known as falaj, and irrigation networks from the Iron Age. They also found the continuation of structures from the western part of the oasis, where a major archaeological site was discovered last year during a construction project. At the western site a range of important features were discovered, including a mosque and boundary walls built from compressed earth. Also identified were Iron Age irrigation systems and a Bronze Age circular stone tomb. Overall, the findings indicate that the site has seen much human activity from the Bronze Age through to the late Islamic period. Given the high concentration of anomalies in the results, it is thought likely that additional major features lie buried in the area. Earlier this year, the same team of researchers applied GPR technology to another important UAE archaeological site, Saruq Al Hadid in Dubai. This was carried out to validate previous work, described in a paper published last year, in which the scientists used satellite data to identify archaeological features there. The satellite data came from Synthetic Aperture Radar (SAR) band L, which refers to the frequency of the radio waves that the satellite bounces off the Earth’s surface to analyse it. "SAR can image broad areas with a high spatial resolution on the order of 10 metres or less without a requirement of ground-based instruments," a 2021 paper in Earth, Planets and Space stated. "The advantage of SAR as a powerful imaging tool is also because it works day and night regardless of clouds." One of the scientists leading the work, Dr Diana Francis, an assistant professor and head of the Environmental and Geophysical Sciences (Engeos) Laboratory at Khalifa University in Abu Dhabi, said that the researchers wanted a technology that could see underneath the sand. "Because of the desert nature of the country several sites get buried over time and are difficult to see from space with the usual observations, such as Google Earth," Dr Francis said. SAR band L was ideal, not least because it can penetrate up to two metres underground in arid regions. Saruq Al Hadid, meanwhile, was selected to test out the satellite method because it was known to have buried objects. "Once we identified the features of these buried objects in the SAR imagery, we trained a machine-learning algorithm with this information and applied it to a wider area with no known sites or buried objects," Dr Francis said. "The AI model indicated to us potential areas for excavation and further investigation. "We found a match between what the [satellite-based] model predicted and what we observed on site using ground penetrating radar, which mimics the satellite data but from the ground." Now that the model has been tested and shown to be effective, the researchers are turning their attention to other locations in Dubai and Al Ain, as well as in Umm Al Quwain.

Radar and satellite shed new light on the UAE's fascinating past

Features such as circular tombs from the Bronze Age have been identified using the cutting-edge technology