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.