Quasibiennial Oscillation in Tropical Ozone as Revealed by Ozonesonde and Satellite Data

摘要

We present an analysis of the quasi-biennial oscillation (QBO) in tropical ozone using recent in situ measurements made by ozonesondes, supplemented by satellite profile and column data. The first in situ equatorial ozone profiles reveal the dramatic change in shape of the profile that accompanies the descent of the westerly shear zone. The partial pressure maximum in ozone increases by approx. 25% in 5-6 months as it descends from 17.5 to 24 hPa. The amplitude of the QBO anomaly that extends from 15 to 80 hPa is found to exceed plus or minus 20%, larger than indicated by earlier analyses of satellite data. The influence of the QBO on equatorial ozone is dominant between 10 and 45 hPa, but the seasonal cycle is more important below 50 hPa. The equatorial ozone anomalies are influenced by El Niiio-Southern Oscillation (ENSO) in the lowest part of the stratosphere. The ozone anomaly in the lower stratosphere at 20 degrees S lags that at the equator by only a few months during the easterlies from 1994 to 1998, contrary to the previous picture of the subtropical and equatorial anomalies being out of phase. There is often a three-cell structure in ozone anomalies at 20 degrees N and 20 degrees S, with the upper two related to the QBO and that below 50 hPa sometimes related to ENSO. We present an analysis of the contribution of the ozone anomalies as a function of altitude to the subtropical QBO in column ozone.