Detection of Massachusetts Bay internal waves by the synthetic aperture radar (SAR) on SEASAT

Abstract

We have examined all eight SEASAT passes over Massachusetts Bay that yielded synthetic aperture radar (SAR) imagery. Four of the passes showed banded surface features that suggested a group of internal waves propagating southwestward from Stellwagen Bank. Comparison of the positions of the SAR features with predictions of internal wave locations derived from earlier in situ work at Massachusetts Bay confirms that the SAR features are indeed rough and smooth bands of water caused by a propagating packet of internal waves. (The packet is caused by tidal currents interacting with the stratification over and the topography of Stellwagen Bank.) Even the four passes that do not show internal waves are consistent with the above conclusions since the predicted packet positions occur outside the region covered by those four passes. These comparisons are presented to show that the SEASAT SAR is indeed capable of detecting internal waves in Massachusetts Bay, even though these waves are considerably less intense than in some other reported areas of the world.