Imaging of ocean waves by synthetic aperture radar: a comparison of results from Seasat and SIR-B experiments in the North Atlantic

New analyses of wave spectra extracted from Seasat SAR images of the JASIN site in the northeast Atlantic are presented as tests of wave-imaging theory. Spectra extracted from orbit 757 during a high sea state are dominated by the effects of smearing, but the rms image smear is less than half that expected from in situ measurements of surface motions. In a low sea state on orbit 547 fair agreement can be achieved between SAR and buoy spectra, but this requires that the smearing length be greater than was observed on orbit 757. These findings are compared with results obtained from the Shuttle Imaging Radar SIR-B mission in order to assess the quantitative understanding of wave imaging by SAR.>