David Bekaert doesn’t much like the idea of a box.
“It’s funny, because people always get boxed: Either you’re an engineer or you’re a scientist,” he said. “I’ve always tried to place myself in between the two fields.”
It’s a space he occupies today: as project manager for NASA’s Observational Products for End-Users from Remote Sensing Analysis project, or OPERA, but also as a published scientist with a background in geophysics and geodesy.
OPERA, centered at NASA’s Jet Propulsion Laboratory (JPL) in Southern California is designed to improve monitoring Earth’s surface, with a focus on water, vegetation change, and ground surface displacement by using data from both radar and optical satellites. The project aims to provide more comprehensive and accurate maps of global land use, land cover, and changes to the environment, using a combination of advanced satellite technologies to U.S. Federal Stakeholders.
The Alaska Satellite Facility is NASA’s Distributed Active Archive Center for synthetic aperture radar (SAR) data and has already been distributing OPERA data from the Radiometric Terrain Corrected product and the Coregistered Single Look Complex product suite.
“The North America Displacement product suite is coming at the end of this calendar year,” Bekaert said. “We’re working with the ASF team to get ready for making that available to the community.”
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JPL is a long way from Bekaert’s hometown of Kapellen, Belgium, a small city of about 28,000 people but just 8 miles from the nation’s largest city, Antwerp, and its 540,000 residents.
But Kapellen made for easy access to top universities.
Bekaert holds a master’s in Earth and planetary observation from Delft University of Technology in the neighboring country of Netherlands. Delft is also where he completed his undergraduate work, earning a degree in aerospace engineering.
“Since I was young I’ve always been very passionate about space or astronauts or the moon or planets,” Bekaert said.
He later pursued a Ph.D. in geodesy and geophysics at the University of Leeds, in England just across the Strait of Dover from Belgium. At Leeds he developed expertise in radar remote sensing and geophysical applications.
“I’m very grateful for the mentorship and opportunities provided by my Ph.D. advisors Andy Hooper and Tim Wright providing me with a solid foundation in my research career.”
Bekaert’s own work in that field includes several published papers on which is lead author or a co-author. These include, among many, the use of interferometric synthetic aperture radar, or InSAR, for mapping and monitoring slow-moving landslides in Nepal; a SAR survey of subsidence in Hampton Roads, Virginia; and the use of unmanned aircraft to analyze Sacramento Delta subsidence, mapping of slow slip events, and tropospheric noise corrections.
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Sea level change is a major part of Bekaert’s packed professional life.
He is a science team member in NASA’s Sea Level Change program, which he first became involved with in 2017.
The program provides tools and resources to visualize and analyze sea level trends, helping researchers, policymakers, and coastal communities understand potential future scenarios and prepare for the impacts of rising seas.
Bekaert’s work on that team focuses on improved mapping of vertical land motion and its contribution to sea level rise using high resolution SAR observations from Sentinel-1 and the NASA-ISRO Synthetic Aperture Radar mission (NISAR).
“A lot of the population lives in the coastal zones, so being able to understand which communities are at risk in future projections and to better prepare some mitigation strategies, levies, and other defenses is important,” Bekaert said.
Products developed through OPERA, such as the North America Vertical Land Motion product suite, will be useful for that work.
His research into the use of SAR and InSAR to study sea level change and land subsidence is referenced extensively in California’s new sea level rise guidance document, adopted by the state’s Ocean Protection Council in June.
“That is getting us closer to integrating remote sensing into our daily life and helping inform policy decisions,” he said. “I’m very excited about that.”
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Bekaert’s ties to ASF also include continuing work through a NASA’s Advancing Collaborative Connections for Earth System Science, or ACCESS, award. The work for which Bekaert is the lead investigator, called “Enabling Cloud-Based InSAR Science for an Exploding NASA InSAR Data Archive,” was recently extended. ASF has been a collaborator on the project since 2018.
NASA writes that the ARIA-led open science initiative involves teams from ASF and scientists from across the U.S. to make SAR products “available rapidly and more easily used without the need for complex processing.”
“With the large volumes that we have, it becomes very difficult to move all that data to a local computer to do processing and analysis,” Bekaert said. “Cloud computing is definitely a way forward to help us analyze large amounts of data.”
The work has led to open-source tools and the creation of a large public archive of standardized Geo-coded Unwrapped InSAR products derived from Sentinel-1, referred to as ARIA-S1-GUNS, and which are publicly available through ASF.
Work underway now includes creation of an on-demand capability where users can go to the Vertex application to request custom products.
“They can use the pipeline we have developed, so we’re very excited about that,” Bekaert said.
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A lot has changed in the remote sensing world since Bekaert became involved.
Satellite image resolution was low, with imaged strips of about 100 kilometers in width and acquisitions sometimes monthly.
Things improved during his Ph.D. period, notably with the launch of Sentinel-1 and its increased 12-day cycle.
“It was global acquisitions of data, and a lot of development was happening around that time,” he said. “People were starting to scale up to large-scale processing.”
“And that is where we are today. You see these massive undertakings where people are doing countrywide, continental-scale analysis of radar and processing that data.”