In December 1988, an experiment was conducted in Monterey Bay, California in order to verify earlier work [J. H. Miller, J. F. Lynch, and C. S. Chiu, J. Acoust. Soc. Am. 86, 326–345 (1989)] which proposed using acoustic tomography to observe the surface wave frequency-direction spectrum. In that paper, the relationships between both ray and model travel time spectra and the surface wave frequency-direction spectrum were derived for an otherwise range-independent waveguide. A mode description of the propagation on the continental shelf portion of the acoustic path in Monterey Bay is shown to be appropriate. The previous formulation to include a range-dependent bathymetry was modified. Tomographically derived wave spectra using the modal formalism agree well with spectra obtained from a wave buoy [Work supported by the Naval Postgraduate School and ONR.]