Imaging of atmospheric boundary layer rolls by the synthetic aperture radar aboard the European ERS-1 satellite

A synthetic aperture radar (SAR) image acquired over the Jade-Weser estuary in the German Bight of the North Sea on 20 January 1992 by the European Remote Sensing Satellite ERS-1 is analyzed. The image shows sea surface manifestations of atmospheric boundary layer rolls generated by heating of a cold air mass moving over a warm sea surface. This is inferred from the orientation of the quasi-periodic sea surface pattern which is aligned approximately with the wind direction, from the ratio of the wavelength of the pattern to the height of the boundary layer, which is close to its theoretical value of 2.8, and from the conditions encountered in the atmospheric boundary layer as measured quasi-simultaneously by radiosondes. For the first time, quantitative estimates of variations of the wind velocity at the sea surface associated with the atmospheric rolls are extracted from a spaceborne radar SAR image.<>