Runs

• NCEP: a three-year simulation (1991-1993) using NCAR/NCEP global reanalysis data for initial and boundary conditions. This run is used to verify the model performance against observational data. Any of the years or a climatology (average of the three years) can be selescted.
  
  
• AR4 Present-day: a five-year simulation (nominally 2000-2004) using NCAR CCSM3 IPCC A2 scenario (business-as-usual) for initial and boundary conditions. It is important to remember that, although this run is labeled with actual dates, it does not correspond to the actual weather of this period. It should, however, represent conditions that are similar, in a climatological sense, to those experienced at the beginning of the 21st century. Any of the years or a climatology (average of the five years) can be selescted.
  
  
• AR4 Mid-century: a five-year simulation (nominally 2050-2054) using NCAR CCSM3 IPCC A2 scenario (business-as-usual) for initial and boundary conditions. This run should represent conditions that are similar, in a climatological sense, to those expected in the middle of the 21st century, should the A2 scenario hold true. Any of the years or a climatology (average of the five years) can be selescted.
  
  
• AR4 2050s-2000s: the monthly-average differences between the two CCSM climatologies.