The 3-dimensional field of water motion in a natural estuary has been measured at a depth of 1 m below the surface. Resulting Fourier transforms of the 3-component records of water velocities at 1 m have been compared with Fourier transforms of the depth-attenuated surface-wave velocity record--obtained from a direct measurement of the surface-wave field.
Seitz, R. C.. 1971. "Measurement of a three-dimensional field of water velocities at a depth of one meter in an estuary." Journal of Marine Research 29, (2). https://elischolar.library.yale.edu/journal_of_marine_research/1208