Atmospheric refraction and scattering from the rough ocean surface together govern the propagation of EM signals over the ocean. Here we study experimentally the structure of the atmospheric refractive index and the ocean surface statistics, pertinent to EM signals scattering. The structure and the dynamics the marine atmospheric boundary layer is profoundly affected by the ocean surface waves, which deform the mean wind flow streamlines. In the presence of gradients of the atmospheric humidity and temperature, the deformation of the streamlines displaces the sheared profiles of these quantities and leads to wave-induced fluctuations of the atmospheric refractive index. As a result, EM signals propagating over the ocean encounter a semi-periodic refractive structure, which along with the turbulence can degrade signal's energy. The wave-induced fluctuations of the refractive index are unique to the oceanic environment. Their structure function does not follow the power 2/3 scaling law, valid for turbulent fluctuations, and thus their influence should be studied separately.

We analyze data of atmospheric turbulence, humidity, temperature, and sea surface temperature and waves from the Rough Evaporation Duct experiment, conducted in part from the instrument platform FLIP in the open ocean north of Oahu, Hawaii.