The Influence of the Madden–Julian Oscillation and the Quasi-Biennial Oscillation on Tropical Cyclone Formation

The role of the Madden-Julian Oscillation (MJO) and the Quasi Biennial Oscillation (QBO) on tropical cyclone (TC) formation and tracks is investigated in this study, motivated by recent research that suggested a correlation between MJO amplitude and QBO phase. TCs were subsetted by various strengths and phases of MJO and QBO. On the basis of stratospheric zonal wind data, it is found more TCs forming during strong easterly QBO phases. The subset of TCs forming in the strong easterly QBO phase was nearly 50% larger than that which formed in westerly phases of QBO. This result holds for all ocean basins, except for the Indian Ocean basin, which shows no tendency towards neither QBO phase. Though the easterly QBO phase typically lasts slightly longer than the westerly, the increase in cyclones from easterly to westerly is not proportionate to a 50% difference. Furthermore, formation of TCs is shown to oscillate with MJO phase, in agreement with prior research. When the subsetting is based on both QBO and MJO phases it shown that the largest amount of TCs form during joint QBO easterly and MJO westerly phases for all basins except the Indian Ocean.