Broadband data were taken during the SWARM 95 experiment from airgun and linear frequency modulated sources while nonlinear internal waves were crossing two different propagation tracks. In a previous study, the geotime behavior of the depth-averaged received intensity was examined, and amplitude modulations were associated with the passage of internal waves. Additionally, a time-frequency analysis of the data exhibited periodic changes in the modal structure of the signals. Though some discrepancies occurred, both of these effects were observed in parabolic equation simulations of the SWARM environment. To address the discrepancies in received intensity levels, various physical mechanisms will be investigated, for example geoacoustic attenuation and ocean thermocline variability. Effects on the time-frequency representations of signals passing through internal wave packets will be documented and categorized. To understand features of frequency dependent transmission loss, relationships between the eigenvalues and the variable layer structure of the waveguide will be developed and applied to both measurements and simulations. Such relationships will aid in extracting the amplitude, width, and azimuthal propagation angle of nonlinear internal waves from broadband acoustic data. [Work supported by ONR.]