Content - CCM Initiative

CCMI − Chemistry-Climate Model Initiative

Activity leaders

Michaela I. Hegglin
Department of Meteorology, University of Reading, UK

Bryan N. Duncan
NASA Goddard Space Flight Center Greenbelt, MD, USA

Activity description

Increasingly, the chemistry and dynamics of the stratosphere and troposphere are being studied and modeled as a single entity in global models. As evidence, in support of the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5), several groups had performed simulations in the Coupled Model Intercomparison Project Phase 5 (CMIP5) using global models with interactive chemistry spanning the surface through the stratosphere and above. In addition, tropospheric and stratospheric global chemistry-climate models are continuously being challenged by new observations and process analyses. Some recent intercomparison exercises have for example highlighted shortcomings in our understanding and/or modeling of long-term ozone trends and methane lifetime. Furthermore, there is growing interest in the impact of stratospheric ozone changes on tropospheric chemistry via both ozone fluxes (e.g. from the projected strengthening of the Brewer-Dobson circulation) and actinic fluxes. This highlights that there is a need to better coordinate activities focusing on the two domains and to assess scientific questions in the context of the more comprehensive stratosphere-troposphere resolving models with chemistry. To address the issues, the a joint IGAC/SPARC Chemistry-Climate Model Initiative (CCMI) was established to coordinate future (and to some extent existing) IGAC and SPARC chemistry-climate model evaluation and associated modeling activities.

Published results

Journal publications:

Duncan, B. N., A. Gettelman, P. Hess, G. Myhre, and P. Young (eds.), 2016: Chemistry–Climate Modelling Initiative (CCMI) (ACP/AMT/ESSD/GMD inter-journal SI). Special issue Atmos. Chem. Phys.

SPARC activity updates:

SPARC Newsletter No. 46, 2016, p. 37: Report on the IGAC/SPARC Chemistry-Climate Model Initiative (CCMI) 2015 Science Workshop, by Hegglin, M.I., J.-F. Lamarque, B. Duncan, V. Eyring, A. Gettelman, P. Hess, G. Myhre, T. Nagashima, D. Plummer, T. Ryerson, T. Shepherd, and D. Waugh.

SPARC Newsletter No. 43, 2014, p. 32: IGAC/SPARC Chemistry-Climate Model Initiative (CCMI) 2014 Science Workshop, by Hegglin, M. I., J.-F. Lamarque, V. Eyring, P. Hess, P. J. Young, A. M. Fiore, G. Myhre, T. Nagashima, T. Ryerson, T. G. Shepherd, and D. W. Waugh.

Find the full publication list at:

Website for further information