Summary
Preliminary findings from the Australian contribution to the Chemistry-Climate Model Initiative (CCMI) are presented. This initiative builds on the 2nd Chemistry Climate Modelling Validation (CCMVal-2), Atmospheric Chemistry & Climate (AC&C) and other global modelling. CCMI is designed to address new science questions in both the troposphere and the stratosphere using current state of art chemistry climate models, as well as support future ozone and climate assessments. Here, the Australian chemistry-climate model is used. This model is based on the UK Meteorological Office Unified Model (UM 7.3) and includes the United Kingdom Chemistry and Aerosols (UKCA) module from the NIWA-UKCA model for tropospheric and stratospheric chemistry. It has 3.75Ëš longitude by 2.5Ëš latitude horizontal resolution and 60 vertical levels extending to 84 km. The Australian contribution consists of Reference C1 (Ref-C1) hind cast model runs from 1960-2010, Reference-C2 (Ref-C2) model runs covering 1960-2100 and sensitivity simulations. Results from two model runs are presented. The core hind cast run follows the "REF-C1" definition, i.e., it uses observed sea surface temperatures and sea ice concentrations from the UK Met Office Hadley Centre data set HadISST1, greenhouse gases from Meinshausen et al. (2011) following the Representative Concentration Pathway (RCP) 8.5 and ozone depleting substances (ODSs) following WMO (2011). It covers the years 1950-2010. The second sensitivity simulation is similar to the core run except ODSs and GHGs are held constant at year-2000 levels. Internal variability of stratospheric polar ozone and temperatures are analysed within the model, the runs are compared with CCMVal-2 runs and ERA-interim data and preliminary results from the REF-C2 simulation are presented.
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