Estimating oceanic mixed-layer depth from internal wave evolution observedfrom Radarsat-1 SAR

One Radarsat-1 SAR image acquired on 31 July 1998 was used to study interna l wave characteristics off the northeastern coast of the United States. The image showed several trains of internal waves, with several wave packets i n each train. By assuming that the local semidiurnal tide period is the gen erating source fur these waves, and by measuring tl-le distance between the wave packets, we were able to derive the group velocity of the internal wa ves from synthetic aperture radar (SAR) images directly. If we also assume that the ocean is a two-layer finite depth model, we can then derive the mi xed-layer depth by matching the group velocity measured from the SAR image with that simulated by the model. Results show reasonably good agreement be tween in situ conductivity-temperature-depth data and expendable bathytherm ograyhic climatology measurements.