Modulation of Cyclone tracks in the Bay of Bengal by QBO

Abstract

The possible influence of stratospheric quasi-biennial oscillation on cyclone passages in the Bay of Bengal (BOB) is examined using Indian Ocean cyclone tracking data obtained from Joint Typhoon Warning Center (JTWC) during the period 1991-2008. During this period 52 cyclones traversed the BOB. The numbers of cyclones are more during east phase (29) of QBO as compared to west phase (23) of QBO. The QBO influence is observed to be significant during easterly phase than westerly phase. The numbers of cyclone are more during post-monsoon season as compared to pre-monsoon season. In post-monsoon season, during east phase, cyclones move westward/north westward while during westerly phase they move northward/north eastward. During pre-monsoon season, cyclones move northward/north eastward irrespective of phases of QBO. The possible interaction between the stratospheric QBO and cyclone during post-monsoon season is investigated from variation of winds, geopotential height, tropopause pressure, OLR and SST.