May 30, 2025
Despite all the technological evolution in navigation, waters just off coastal shores around the globe have remained a black box. That is, until researchers from The University of Texas at Austin and Oregon State University developed a new technology that uses satellites in space to map out these tricky areas.
Together, they developed ATL24, the first global, space-based bathymetry product that will assist broadly with improving navigation safety and maritime security. This technology will shed new light on the nearshore, areas between the shoreline and deeper water where topographical knowledge of terrain below the water is largely unknown.
"These areas can be dangerous to navigate with uncharted hazards," said Lori Magruder, professor in the Cockrell School of Engineering's Department of Aerospace Engineering and Engineering Mechanics, director of the Center for Space Research at UT and co-leader of the ATL24 project. "By using bathymetry to probe the nearshore, we can make sure these crucial parts of our seas safer worldwide."
Bathymetric lidar uses spaceborne laser scanning to measure underwater terrain. The laser wavelength can penetrate the water column, providing both the water surface height and the sea floor depth.
“ATL” in ATL24 refers to the Advanced Topographic Laser Altimeter System (ATLAS), the lone instrument aboard the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) satellite. The satellite is part of NASA's Earth Observing System, for measuring ice sheet elevation and sea ice thickness, as well as land topography, vegetation characteristics, and clouds. Magruder has been instrumental in the success of ICESat-2, leading the science team that helps define and implement science goals for the program.
ATLAS’s green wavelength, photon-counting lidar signal can reach depths of up to 40 meters in regions with adequate water clarity to provide shallow, near-shore bathymetric data for a range of applications, including coastal and marine science management, nearshore habitat research, marine navigation, and engineering applications. Although ICESat-2 was designed primarily for cryospheric science, it didn’t take long for researchers to recognize its value as a spaceborne bathymetric lidar.
“After ICESat-2 launched, a lot of researchers developed their own algorithms, tools, and workflows for extracting bathymetry data, but unfortunately, a lot of the source code, the tools, and the final datasets were not made publicly available,” said Chris Parrish, professor and Plasker Faculty Scholar in Geomatics at Oregon State University and co-leader of the ATL24 team with Magruder. "To address that, our research team began work in 2022 as part of the ICESat-2 extended mission timeline on a new dedicated along track ICESat-2 bathymetric data product—ATL24.”
The chief advantage of obtaining bathymetry data from space is the spatial and temporal coverage: ICESat-2 provides coastal bathymetry coverage from 88° North to 88° South Latitude beginning in 2018, with places that are very difficult to access, such as islands in the South Pacific.
In addition, ICESat-2’s near-polar orbit and 91-day revisit time provides researchers with the opportunity to revisit areas where water clarity is seasonal, so if water is too opaque for its depth to be measured during one overpass, it might be more suitable on the next. Further, in places like the Florida Keys where the water is often clear, ICESat-2’s orbit allows researchers to create a time series of observations and explore bathymetric change across significant weather events or as a result of anthropogenic influences.
This research was made possible by NASA.
