The first simulation of an ozone QBO in a general circulation model

Abstract

The quasi-biennial oscillation (QBO) of ozone has been simulated for the first ime in a general circulation model (GCM). The model employed is the first version GCM developed at the Center for Climate System Research/National Institute for Environmental Studies (CCSR/NIES). The model has a horizontal resolution of T21 and 60layers in the vertical. Modified Chapman reactions of ozone photochemistry are included in the model, allowing the ozone to be fully interactive with the radiative and dynamical fields. The simulaton is, for the most part, successfull except that a deficiency of about 40 DU exists in the total ozone in comparison with observations. The simulated zonal wind QBO has a rather short period (about 1.5 years) and somewhat weak easterlies. The lower stratospheric ozone QBO over the equator is qualitatively similar to that observed, although the simulated amplitude of about 0.3 ppmv is somewhat less than that observed. The phase relationship between the equatorial upper and lower stratospheric ozone QBOs is successfully reproduced, although the phase of the upper stratosphere. The mid-latitude ozone QBO is out of phase with the equatorial ozone QBO. The phase propagation of planetary-scale structure in ozone from the mid-latitudes to equatorial regions is more pronounced during the westerly than in the easterly phase of the stratosphere QBO, especially in the Northern Hemisphere winter.