The Southern Oscillation, sea‐surface‐temperature, and interannual fluctuations in Australian tropical cyclone activity

Abstract The relationship between interannual variations of the number of tropical cyclones observed in the Australian region during a cyclone season and the Southern Oscillation (SO) has been explored. Strong, significant, stable correlations were found between the SO and cyclone numbers. Years with relatively many tropical cyclones were preceded by high North Australian SST, low east Pacific SST and low Darwin pressure. Such years also tended to be followed by the reverse pattern. The study confirms an earlier suggestion (Nicholls, 1979a) that Australian tropical cyclone activity is predictable some months prior to the start of the cyclone season. The observed correlations may result from feedback between the atmosphere and the ocean.