CMI Raster Layers for MGM21



The CMI provincial raster layers have been developed to simplify the acquisition of CMIs for use in MGM21.

Mean Climate Moisture Index from 1981-2010 is required to run MGM’s climate-sensitive survival functions (Cortini et al. 2017; Comeau 2021a) and maximum size-density relationship (Comeau 2021b). Climate Moisture Index (Hogg et al. 2013).

CMI must be:

  1. calculated using the MGM CMI Solver and ClimateNA (Wang et al. 2016) Version 6.11 data. The MGM CMI Solver workbook calculates mean CMI for the 30-year period between 1981-2010 using ClimateNA Version 6.11 data and a Microsoft Excel macro.


  1. obtained using the provided provincial CMI ArcMap raster layers. The CMI raster layers are based on a 1 km x 1 km grid where the CMI values have been  solved, for each pixel, using the Latitude and Longitude of the pixel centroid and the mean pixel Elevation.

Using the Raster Layers:

  • Add layer to ArcMap
  • To find a CMI using Latitude/Longitude
    1. Activate the Tools ribbon
    2. Select “Go to XY” Coordinate
    3. Select the Units – decimal degrees.
    4. Enter the Longitude and Latitude
      • You can:
        1. Zoom to location.
        2. Flash location
        3. Add Point (recommended)
          1. Select the “Identify” tool
          2. Click on point to view the CMI (Pixel Value)
        4. Add a Label
        5. Add a Caption


Other versions of ClimateNA may not be used to calculate CMI for MGM as all of the climate sensitive functions in MGM21 were calibrated using climate data from ClimateNA Version 6.11 or earlier.


ClimateNA’s historic monthly data underwent a major revision in Version 6.20.  This revised climate data produces substantially different CMI values than those used to calibrate MGM.  Although the newest versions of ClimateNA (Versions 6.30+) directly output CMI, these values, obtained directly as output from ClimateNA, should not be used with MGM21.