Stochastically forced variability in the Antarctic Circumpolar Current

Interannual fluctuations in the Antarctic Circumpolar Current (ACC) were co nsidered. In the present study we analyze a mode of variability in the Hamb urg Large-Scale Geostrophic ocean general circulation model which was drive n by stochastic atmospheric forcing. The short-term atmospheric weather flu ctuations were represented by a number of spatially coherent patterns of mo mentum, heat, and freshwater flux which were superimposed onto the climatol ogical fluxes, These patterns were derived from an experiment with an atmos pheric general circulation model forced with observed sea surface temperatu res, and they were chosen randomly at each month. We found anomalies which propagate along the ACC at an interannual timescale. They can be explained by the combined effects of anomaly advection with the mean ocean circulatio n and integration of the short-term atmospheric weather fluctuations, Some similarities were found between our results and the concept of the Antarcti c Circumpolar Wave, which was proposed recently to account for large-scale anomalies which propagate along the ACC in both the atmosphere and the ocea n.