Version 4.3 of the Canadian Atmospheric Global Climate Model (CanAM4.3) is used to simulate aerosols and their impacts on climate in the Arctic. Aerosol microphysical processes in CanAM4.3 are simulated using the on-line 2-moment PLA Aerosol Model (PAM). Simulated radiative forcings account for direct radiative effects (absorption and scattering of radiation) and interactions with clouds (semi-direct and indirect effects). In addition, reductions in snow albedos from deposition of black carbon on snow are accounted for.
In NETCARE, a wide range of different observations is used to validate simulations of black carbon and other types of aerosols in CanAM4.3, including measurements of concentrations at surface sites and from aircraft campaigns. In addition, the model is used in NETCARE to assess impacts of black carbon on radiative forcings and Arctic temperatures, in support of Canada's membership in the Arctic Monitoring and Assessment Programme, Arctic Council.
Sea Ice - Ocean - Biogeochemical Models
A 1-D numerical sea ice - ocean - biogeochemical model that simulates the physical and biogeochemical processes involving the sulfur cycling within the sea ice and throughout the water column. The model is based on the General Ocean turbulence model GOTM and coupled to sea-ice and biogeochemical modules developed within NETCARE. The model is used to study the production, removal, and emission of dimethylsulfide (DMS), a climatically-important biogenic gas, within the Canadian Arctic. (Contact: H. Hayashida & N. Steiner)
A 3-D regional sea ice - ocean - biogeochemical model for the Arctic Ocean has been developed based on NEMO. The model is coupled to several ecosystem models for testing with a sulfur component currently being developed in 1-D. The model is forced with output from the Canadian Regional Climate Model (CanRCM4) for current and future time periods. (Contact: N. Steiner)
We apply the GEOS-Chem model (www.geos-chem.org) to interpret NETCARE observations to understand processes affecting Arctic aerosols with implications for radiative effects. Our foci include aerosol size distributions, black carbon, as well as aerosol precursors such as ammonia and DMS.
We are using the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM). This is a comprehensive GCM that is highly scalable in spatial resolution and physical complexity. We are using the model to quantify the impact on global and regional (primarily Arctic) climate projections arising from uncertainties in the representation of sulfate and black carbon aerosols.