Southern Oscillation influences on tropical cyclone activity in the Australian/south‐west Pacific region

Abstract Tropical cyclone activity within the Australian (105°–165°E) and south‐west Pacific (145°E–150°W approximately) regions is examined during seasons affected by contrasting extremes of the Southern Oscillation (SO). In the Australian region, the most pronounced and consistent contrast of tropical cyclone frequency variability was within the eastern Australian region (145°–165°E) where anti‐ENSO (ENSO) conditions were associated with a higher (lower) incidence of tropical cyclogenesis. This relationship appears to be a manifestation of tropical cyclone behaviour in the wider south‐west Pacific region, wherein tropical cyclone origin points exhibit distinct areal patterning associated with times of extreme SO states. Intra‐seasonal temporal distributions of the Australian region tropical cyclogenesis and the south‐west Pacific tropical cyclone incidence are also examined.