THE TROPICAL SEMIANNUAL OSCILLATIONS IN TEMPERATURE AND OZONE AS OBSERVED BY THE MLS

The first two years of MLS temperature and ozone data are used to exam ine the tropical upper-stratospheric SAO. Time series analysis reveale d that the strongest amplitudes of the SAO occurred near the equator a t 2 mb for temperature and 5 mb for ozone, consistent with previous ob servations. The first cycle of each calendar year was observed to have a much higher amplitude than the second cycle except for the warm pha se in late 1991. Interannual variability in the strength of the SAO, s uch as the much stronger warm phase of late 1991 as compared to late 1 992, was significant and could be partly attributed to the QBO in zona l wind.