Source: Journal of Geophysical Research: Oceans
When ocean waves reach shallow water, their complex interactions can produce lower-frequency infragravity waves. These waves strongly affect—and are affected by—the shape of coastlines, meaning they are linked to the processes of erosion and sediment deposition and the degradation of coastal ice.
A new analysis from Henderson et al. used Bayesian probability methods to break down the contributions of different types of infragravity waves to wave run-up. For their work, the researchers collected data from a network of pressure and velocity sensors at Torrey Pines State Beach in California over a period of 60 days.
The Bayesian method the researchers used—known as the maximum a posteriori (MAP) technique—is effective for separating various components of a measured signal. In this case, it allowed the researchers to measure edge waves, which run parallel to the shoreline. They found edge waves are roughly 28% of the infragravity wave energy, a result that has important implications for nearshore wave processes.
When waves reach shallow water, they grow in amplitude, or grow higher, and eventually break. But when infragravity waves are added in, they can lead to wave interference and phenomena like the dangerous “sneaker waves” that can kill or injure beachgoers around the world.
This study demonstrates the ability to take oceanographic wave data and extract exactly how infragravity waves are involved in shore-wave interactions, which could prove helpful in researching phenomena such as sneaker waves and shoreline decay in the face of sea level rise. (Journal of Geophysical Research: Oceans, https://doi.org/10.1029/2026JC024479, 2026)
—Matthew R. Francis (@BowlerHatScience.org), Science Writer
