Analysis of high-resolution data from slow-ascent radiosondes released at Halley station, Antarctica (75°38′S, 26°40′W), shows that internal gravity wave phenomena are frequently present in the lower troposphere. There is a strong tendency for these waves to induce a vertical transport of the SE-NW component of momentum, this being the component perpendicular to the alignment of regular ridges in the ice shelf on which the base is built and is independent of the mean wind direction. A method for estimating the variation of the momentum fluxes with height is described. Results show that momentum flux divergences equivalent to accelerations of about 10 ms−1 per day are common at Halley.
