Flammability

Flammability is defined as the likelihood of a pixel to burn across all 200 model replicates for each year. This is a value from 0.0 to 1.0, calculated by dividing the number of replicates with a fire at a given pixel by the number of total replicates (200). 1.0 means that all 200 replicates simulated a fire at that pixel. Years that were provided with historical fire polygons (1950-2021) always produce a fire scar for that polygon in the subsequent year, so the flammability for years 1951-2022 are either 0.0 (no fire) or 1.0 (a fire scar across all 200 replicates).

Modal vegetation

Each modal vegetation GeoTIFF pixel has nine possible values:

0: No Vegetation (Not Modeled)

1: Black Spruce

2: White Spruce

3: Deciduous

4: Shrub Tundra

5: Graminoid Tundra

6: Wetland Tundra

7: Barren/Lichen/Moss

8: Temperate Rainforest

These pixel values represent the modal (statistical mode) vegetation type across all 200 replicates for a given pixel. The 5 model average modal vegetation GeoTIFFs were calculated by combining all 200 replicates across all five models and taking the statistical mode across all 1,000 GeoTIFFs (200 replicates * 5 models).

Percent vegetation

Each percent vegetation GeoTIFF has nine bands, representing the following vegetation types:

Band 1: No Vegetation (Not Modeled)

Band 2: Black Spruce

Band 3: White Spruce

Band 4: Deciduous

Band 5: Shrub Tundra

Band 6: Graminoid Tundra

Band 7: Wetland Tundra

Band 8: Barren/Lichen/Moss

Band 9: Temperate Rainforest

The pixel values for each band represent the percentage of the 200 replicates that produced the corresponding vegetation type. For example, if 143 of the 200 replicates produced the “Deciduous” vegetation type for a given pixel, Band 4 will have a value of 71.5 for that pixel.

Included models:

GFDL-CM3

GISS-E2-R

IPSL-CM5A-LR

MRI-CGCM3

NCAR-CCSM4

5 model average

Included emission scenarios:

RCP 4.5

RCP 6.0

RCP 8.5

Included fire management options:

NoFMO: No fire suppression.

FMO: Fire suppression based on the 2022 fire management options geodatabase from AICC, added to the ALFRESCO runs starting in 1950.

AltFMO: The same fire suppression as FMO above, but with additional areas of fire suppression around Fort Wainwright, Fort Greely, and Eielson Air Force Base, added to the ALFRESCO runs starting in 2022.

For background on ALFRESCO, please refer to:

Daniel H. Mann, T. Scott Rupp, Mark A. Olson, and Paul A. Duffy. Is Alaska's Boreal Forest Now Crossing a Major Ecological Threshold?

Arctic, Antarctic, and Alpine Research 2012 44 (3), 319-331