Subsurface layers refer to the areas beneath the surface of something, such as soil or water. It means the deeper parts or underground sections that are not visible from the outside. Full definition
Conversely, if the seafloor in front of a glacier is deep, the ice spills into the warm subsurface layer of saltwater and may melt relatively rapidly. (sciencedaily.com)
He said, «That no - till subsurface layer is often losing more soil organic carbon stock over time than is gained in the surface layer.» (en.wikipedia.org)
Furthermore, DIC allowed the Lawrence Livermore team to evaluate the coupled effects of laser power and speed, and to observe a potentially beneficial effect of subsurface layer heating on residual stress development. (sciencedaily.com)