The Influence of the QBO on Western North Pacific Tropical Cyclone Tracks

The potential role that the stratospheric quasi-biennial oscillation (QBO) plays in western North Pacific tropical cyclone (TC) tracks is examined by using the TC best track data archived in the Tokyo Typhoon Center and the QBO index derived from the NCEP/NCAR reanalysis data. It is found that, while the number of TCs are essentially unchanged, their tracks are significantly affected by the QBO. In general, more TCs approach the East China Sea during the westerly phase of the QBO, while more TCs approach the eastern offshore of Japan during the opposite phase. This west-east shift in TC tracks is found to result from the background flow change associated with the QBO.