This paper describes the multiscale structure in synthetic aperture radar (SAR) backscatter seen in an image of a cold-air outbreak as being due to the influence on the surface of the ocean of three scales of interacting atmospheric turbulence. A low-resolution (pixels have side lengths of 100 m) SAR image shows the first class of backscatter pattern to be broken lines of enhanced radar backscatter (&sgr;), of order 1 dB above the background, with an average cross-wind scale of 5 km and downwind lengths of many tens of kilometers. These are associated with quasi-two-dimensional roll vortices. The second class of radar backscatter pattern is two-dimensional backscatter regions whose linear aggregations constitute the lines of backscatter. They are, on average, 1 km wide in the cross-wind direction and are 2.5 km long in the downwind direction. A higher-resolution image (pixels have side lengths of 12.5 m) of the same area shows a third class of structure: smaller-scale regions of enhanced backscatter up to several hundred meters in length downwind and greater than 100 m across wind that are associated with 7-dB variations in &sgr; in the unaveraged image. The modulated, fine-scale backscatter structure compares favorably in both scale and effect to observations of the modulation of ''microfronts'' in the atmospheric surface layer by kilometer-scale ''inactive eddies,'' the latter being of uncertain origin. Therefore the hypothesis offered here is that the fine-scale SAR structure is caused by the influence of atmospheric microfronts on the ocean surface, while the two-dimensional, kilometer-scale backscatter features are the signature of inactive eddies linearly aggregated by or possibly intrinsic to the roll vortices. ¿ American Geophysical Union 1996