ON THE PHASE PROPAGATION OF EXTRATROPICAL OZONE QUASI-BIENNIAL OSCILLATION IN OBSERVATIONAL DATA

Global column ozone data from total ozone mapping spectrometer (TOMS), backscattered ultraviolet (BUV) and Dobson stations are analyzed to d etermine the pattern and phase property of the ozone quasi-biennial os cillation (QBO) signal. It is found that the ozone QBO signal is stron gest in middle and high latitudes and is present mainly in the winter- spring season in both hemispheres. The extratropical ozone QBO signal is out of phase with the equatorial ozone QBO, which is itself in phas e with the QBO in equatorial zonal wind. There are three;distinctive r egions, namely tropical, midlatitudinal, and polar regions, in each of which the ozone QBO signal has a fairly constant phase with respect t o latitude. There is a phase reversal (sign change) between the equato rial and the extratropical regions associated with the return branch o f the equatorial QBO secondary circulation, and this sign reversal occ urs at +/- 12 degrees of latitude symmetric about the equator. In the northern hemisphere between the midlatitudinal and polar regions, ther e is another possible phase reversal in some (but not all) years possi bly in connection with the presence or absence of midwinter sudden war ming, which creates a positive or negative anomaly relative to the reg ion outside the polar vortex. In the southern hemisphere polar latitud es, the ozone QBO signal is usually delayed until spring in connection with the final warming. These properties are found in all data sets a nalyzed by the same method. Evidence does not support a gradual phase propagation from the subtropical region to the high-latitude region. P revious reported evidence for phase propagation is reexamined and is f ound to be artifacts of data processing.