Tropical cyclones and the Quasi-biennial Oscillation

In the 1980s, several studies found a significant correlation between the quasi-biennial oscillation (QBO) and tropical cyclone activity in the North Atlantic and the western North Pacific. The relationship was strong enough that it was used in the early seasonal TC forecasts for the North Atlantic by Gray and colleagues. In the last two decades, this relationship appears to have been much weaker. Considering the entire period from 1950 to present, we examine how the QBO relates to various tropical cyclone (TC) indices in all TC-prone regions, and give specific attention to how this relationship has changed in time. We attempt to discern whether the available evidence supports the hypothesis that the QBO has a real physical influence on TCs. Answering this question is important for understanding the potential stratospheric influence on TCs more broadly.