WAVE-CURRENT INTERACTION STUDY IN THE GULF OF ALASKA FOR DETECTION OFEDDIES BY SYNTHETIC-APERTURE RADAR

High resolution ERS-1 Synthetic Aperture Radar (SAR) images are used t o detect a mesoscale eddy. Such features limit dispersal of pollock la rvae and therefore likely influence recruitment of fish in the Gulf of Alaska. During high sea states and high winds, the direct surface sig nature of the eddy was not clearly visible, but the wave refraction in the eddy area was observed. The rays of the wave field are traced-out directly from the SAR image. The ray pattern gives information on the refraction pattern and on the relative variation of the wave energy a long a ray through wave-current interaction. These observations are si mulated by a ray-tracing model which incorporates a surface current fi eld associated with the eddy. The numerical results of the model show that the waves are refracted and diverge in the eddy field with energy density decreasing. The model-data comparison for each ray shows the model predictions are in good agreement with the SAR data.