Simulation of the Madden-Julian Oscillation in Wintertime Stratospheric Ozone over the Tibetan Plateau and East Asia: Results from the Specified Dynamics Version of the Whole Atmosphere Community Climate Model

The authors examined the Madden-Julian Oscillation (MJO) in stratospheric ozone during boreal winter using a simulation from the Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) in 2004 and 2010. Comparison with European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-Interim) data suggested that the model simulation represented well the three-dimensional structure of the MJO-related ozone anomalies in the upper troposphere and stratosphere (i.e., between 200 and 20 hPa). The negative ozone anomalies were over the Tibetan Plateau and East Asia in MJO phases 3-7, when the MJO convective anomalies travelled from the equatorial Indian Ocean towards the equatorial western Pacific Ocean. Due to the different vertical structures of the MJO-related circulation anomalies, the MJO-related stratospheric ozone anomalies showed different vertical structure over the Tibetan Plateau (25-40 degrees N, 75-105 degrees E) and East Asia (25-40 degrees N, 105-135 degrees E). As a result of the positive bias in the model-calculated ozone in the upper troposphere and lower stratosphere, the amplitude of MJO-related stratospheric ozone column anomalies (10-16 Dobson Units (DU)) in the SD-WACCM simulation was slightly larger than that (8-14 DU) in the ERA-Interim reanalysis.