The Canadian Centre for Climate Modelling and Analysis (CCCMA) has developed several climate simulation models for use in projecting natural climate change and assessing the impact of human activities on climate change. CCCMA's first-generation global coupled model (CGCM1) was run with three scenarios: one with constant atmospheric forcing (control run), one with carbon dioxide (CO2) increasing at a compounded one percent per year rate, and one with a combination of CO2 and sulfate aerosol concentrations.

The model was run at T32 resolution, resulting in a 97x48 gaussian latitude/longitude grid with approximately 3.75 degree by 3.75 degree resolution. Daily (once- or twice-daily depending on the parameter) and monthly output grids were produced. Upper level (850mb and 500mb) parameters include geopotential heights, temperature, winds, and humidity. At the surface, the model outputs include temperature, wind, humidity, pressure, sea-level pressure, precipitation, and radiation fluxes.

DSS has used the monthly-mean grids to compute decadal means for years zero through nine (e.g. 2000-2009) for each decade. DSS also computed smoothed decadal means which are 30-year running means of the raw decadal means. Because of the large variability in the decadal means of parameters such as precipitation, it is recommended that the smoothed decadal-mean grids be used and applyed to the middle decade of the period (e.g. apply the 2000-2029 mean to the year 2015).