RELATIONSHIP BETWEEN QBOS OF STRATOSPHERIC WINDS, ENSO VARIABILITY AND OTHER ATMOSPHERIC PARAMETERS

The 50-mbar tropical zonal wind has a predominent quasi-biennial oscillation (QBO) mode of an average period of ca. 28 months, with variation in the range 21-33 months and amplitudes varying within +/-20 per cent. For the Southern Oscillation, Tahiti minus Darwin (T-D), sea-surface temperature (SST) and equatorial rainfall indices, QBO is not the strongest mode. Periods of 3-6 and ca. 6 years are stronger. The QBO modes for these and other parameters (e.g. surface winds and winds in upper and lower troposphere and stratospheric winter temperature at the North Pole) are very irregular, with amplitudes, phases, and sometimes even period having large changes with time. It seems that these have little relationship with the 50-mbar zonal wind QBO and may have altogether different origins.