Fire Research » Fire & Climate Change

Using Regional Climate Models for Future Fire Danger Scenarios

General Circulation Models (GCMs) have, by necessity, a coarse spatial resolution, as they must model the globe's entire surface. They also have the implicit problem, from the standpoint of calculating fire danger, that they represent climate variables averaged over a large grid cell and over a period of half a day.

Finer-scale regional climate models (RCMs) are currently being developed that will permit more detailed regional studies of the effects of climate change on the landscape. The Canadian Regional Climate Model (CRCM) runs are driven with outputs from the Canadian Climate Centre General Circulation Model (CGCM) every 6 hours. The horizontal resolution is 45 kilometres. The simulation domain comprises a 120 x 120 point grid; however, a nine-point buffer around the border is subtracted to limit edge effects. This leaves a 102 x 102 point grid domain for this analysis. The analysis also uses more detailed elevation over the CRCM domain. The vertical resolution of the CRCM is 18 levels. The time step within the simulation is 15 minutes; however, most simulation variables are archived at 6-hour intervals.

The RCM scenario used is a greenhouse gas and aerosol transient simulation. The three time slices output in this simulation are 1975–1985, 2040–2049, and 2080–2089, which correspond to equivalent carbon dioxide concentrations of 437, 827, and 1255 parts per million by volume, respectively.

The three CRCM scenarios:

• 1975–1985: 1 x CO₂
• 2040–2049: 2 x CO₂
• 2980–2089: 3 x CO₂

The end result is that more reliable fire weather and fire danger data sets can be created from the CRCM.