Video images of surface waves were recorded from a research vessel to characterize the internal wave-induced surface roughness modulations during the SAR Internal Wave Dynamics Experiment (SARSEX). These images have yielded two-dimensional slope spectra during the vessel's traversal of two internal wave packets. By sampling the spectra along the internal wave propagation direction, spectral modulation time series were generated for surface waves of 20- to 100-cm wavelength which clearly show roughness modulations correlated with the internal wave activity. Surface waves of 60-cm wavelength or longer were found to experience the largest modulations. The maximum roughness increases and decreases occur near regions where the internal wave surface current gradients are largest, with increased roughness occuring forward of the peak internal wave displacement. ¿ American Geophysical Union 1988