Vertical structure of MJO-related subtropical ozone variations from MLS, TES, and SHADOZ data
Tian et al. (2007) found that the MJO-related total column ozone (O_3) anomalies of 10 DU (peak-to-trough) are mainly evident over the subtropics and dynamically driven by the vertical movement of the subtropical tropopause layer. It was then hypothesized that the subtropical total column O_3 anomalies are primarily associated with the O_3 variability in the stratosphere rather the troposphere. In this paper, we investigate the vertical structure of MJO-related subtropical O_3 variations using the vertical O_3 profiles from the Aura Microwave Limb Sounder (MLS) and Tropospheric Emission Spectrometer (TES), as well as in-situ measurements by the Southern Hemisphere Additional Ozonesondes (SHADOZ) project. Our analysis indicates that the subtropical O_3 anomalies maximize approximately in the lower stratosphere (60–100 hPa). Furthermore, the spatial-temporal patterns of the subtropical O_3 anomalies in the lower stratosphere are very similar to that of the total column. In particular, they are both dynamically driven by the vertical movement of subtropical tropopause. The subtropical partial O_3 column anomalies between 30–200 hPa accounts for more than 50 % of the total O_3 column anomalies. TES measurements show that at most 27 % of the total O_3 column anomalies are contributed by the tropospheric components. This indicates that the subtropical total column O_3 anomalies are mostly from the O3 anomalies in the lower stratosphere, which supports the hypothesis of Tian et al. (2007). The strong connection between the intraseasonal subtropical stratospheric O_3 variations and the MJO implies that the stratospheric O_3 variations may be predictable with similar lead times over the subtropics. Future work could involve a similar study or an O_3 budget analysis using a sophisticated chemical transport model in the near-equatorial regions where the observed MJO signals of total column O_3 are weak.
Additional Information© Author(s) 2012. Published by Copernicus Publications on behalf of the European Geosciences Union. This work is distributed under the Creative Commons Attribution 3.0 License. Received: 5 August 2011; Published in Atmos. Chem. Phys. Discuss.: 31 August 2011 Revised: 21 December 2011; Accepted: 21 December 2011; Published: 6 January 2012. This research was supported in part by the National Science Foundation (NSF) grant ATM-0840787 to California Institute of Technology (Caltech) and ATM-0840755 to University of California, Los Angeles. Part of this research was carried out at Jet Propulsion Laboratory, Caltech, under a contract with National Aeronautics and Space Administration. ERA-Interim data were obtained from the ECMWF Data Server (http://data.ecmwf.int/data/). The RMM index was obtained from the Bureau of Meteorology website (http://www.bom.gov.au/climate/mjo/). The SHADOZ data were obtained from SHADOZ data server (http://croc.gsfc.nasa.gov/shadoz/). Edited by: G. Vaughan
Published - acp-12-425-2012.pdf