Effect of Stratospheric Ozone Depletion on the DMS and its Related Aerosols in the Southern Hemisphere

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Monday, 5 January 2015
Hiroaki Naoe, MRI, Tsukuba, Japan; and M. Deushi, T. Y. Tanaka, K. Yoshida, T. Maki, and N. Oshima

The effect of stratospheric ozone depletion on the tropospheric sulfur-related species and aerosols in the Southern Hemisphere (SH) is examined by contrasting a transient Meteorological Research Institute Earth System Model (MRI-ESM) integration, focusing on the SH summer. The MRI-ESM, which made important contributions to the fifth assessment report of the Intergovernmental Panel on Climate Change, constitutes a core component of the atmosphere-ocean coupled global climate model and components of sea-ice, aerosol, and ozone models; a flexible simple-coupler (Scup) is used to integrate each component model into the MRI-ESM. The rationale behind the future transient reference simulation (REF-C2), which is forced by trace gas projections and an interactively coupled ocean, is the projection of the future evolution of tropospheric and stratospheric ozone over the period from 1960 to 2100, under the IGAC/SPARC Chemistry-Climate Model Initiative (CCMI) activities. The southward shift of the SH summertime tropospheric mid-latitude jet due to Antarctic ozone depletion is confirmed in the transient simulation, by contrasting zonal wind field between the pre-ozonehole period (1960s) and the ozonehole period (1990s). Dimethylsulfide (DMS), whose emission is usually parameterized using the surface wind speed and the difference between the sea-surface and atmospheric concentrations of DMS, accounts for the largest source of natural sulfur to the global atmosphere, especially in the SH. The southward jet-shift in turn drives trends in surface winds and enhanced DMS emission around Antarctica in the largest ozone depletion period during the 1990s. Because the major gas-phase DMS oxidation includes products of sulfur dioxide, sulfuric acid, methanesulfonic acid, the southward jet-shift (due to Antarctic ozone depletion) may significantly affect the radiative budget of the background atmosphere in the SH.